WorldWideScience

Sample records for aircraft structural components

  1. Structural Weight Optimization of Aircraft Wing Component Using FEM Approach.

    OpenAIRE

    Arockia Ruban M,; Kaveti Aruna

    2015-01-01

    One of the main challenges for the civil aviation industry is the reduction of its environmental impact by better fuel efficiency by virtue of Structural optimization. Over the past years, improvements in performance and fuel efficiency have been achieved by simplifying the design of the structural components and usage of composite materials to reduce the overall weight of the structure. This paper deals with the weight optimization of transport aircraft with low wing configuratio...

  2. Structural Weight Optimization of Aircraft Wing Component Using FEM Approach.

    Directory of Open Access Journals (Sweden)

    Arockia Ruban M,

    2015-06-01

    Full Text Available One of the main challenges for the civil aviation industry is the reduction of its environmental impact by better fuel efficiency by virtue of Structural optimization. Over the past years, improvements in performance and fuel efficiency have been achieved by simplifying the design of the structural components and usage of composite materials to reduce the overall weight of the structure. This paper deals with the weight optimization of transport aircraft with low wing configuration. The Linear static and Normal Mode analysis were carried out using MSc Nastran & Msc Patran under different pressure conditions and the results were verified with the help of classical approach. The Stress and displacement results were found and verified and hence arrived to the conclusion about the optimization of the wing structure.

  3. Methods of saving energy and materials in the manufacture of integrated aircraft structure components

    Energy Technology Data Exchange (ETDEWEB)

    Sturm, J.C.; Welschof, K.; Janssen, W.; Mahlke, M.; Sprangers, W.; Binding, J.

    1987-11-01

    In the framework of a special research unit, methods for saving energy and raw materials are investigated for selected production processes. Integral construction components of the aircraft industry which today are mostly produced by metal-cutting processes, are the basis of the joint research work of six of the total of nineteen participating projects. Research is carried out on the possibilities for reducing the expenditure of material and energy by the application of alternative production processes in the field of primary shaping, deforming and joining as well as by structural optimization. By means of a computer-aided evaluation of the possible production methods, the alternatives can be compared with regard to their energy and raw material requirements.

  4. Compton imaging tomography for nondestructive evaluation of large multilayer aircraft components and structures

    Science.gov (United States)

    Romanov, Volodymyr; Grubsky, Victor; Zahiri, Feraidoon

    2017-02-01

    We present a novel NDT/NDE tool for non-contact, single-sided 3D inspection of aerospace components, based on Compton Imaging Tomography (CIT) technique, which is applicable to large, non-uniform, and/or multilayer structures made of composites or lightweight metals. CIT is based on the registration of Compton-scattered X-rays, and permits the reconstruction of the full 3D (tomographic) image of the inspected objects. Unlike conventional computerized tomography (CT), CIT requires only single-sided access to objects, and therefore can be applied to large structures without their disassembly. The developed tool provides accurate detection, identification, and precise 3D localizations and measurements of any possible internal and surface defects (corrosions, cracks, voids, delaminations, porosity, and inclusions), and also disbonds, core and skin defects, and intrusion of foreign fluids (e.g., fresh and salt water, oil) inside of honeycomb sandwich structures. The NDE capabilities of the system were successfully demonstrated on various aerospace structure samples provided by several major aerospace companies. Such a CIT-based tool can detect and localize individual internal defects with dimensions about 1-2 mm3, and honeycomb disbond defects less than 6 mm by 6 mm area with the variations in the thickness of the adhesive by 100 m. Current maximum scanning speed of aircraft/spacecraft structures is about 5-8 min/ft2 (50-80 min/m2).

  5. Structural Diagnostics of CFRP Composite Aircraft Components by Ultrasonic Guided Waves and Built-In Piezoelectric Transducers

    Energy Technology Data Exchange (ETDEWEB)

    Matt, Howard M. [Univ. of California, San Diego, CA (United States)

    2006-01-01

    To monitor in-flight damage and reduce life-cycle costs associated with CFRP composite aircraft, an autonomous built-in structural health monitoring (SHM) system is preferred over conventional maintenance routines and schedules. This thesis investigates the use of ultrasonic guided waves and piezoelectric transducers for the identification and localization of damage/defects occurring within critical components of CFRP composite aircraft wings, mainly the wing skin-to-spar joints. The guided wave approach for structural diagnostics was demonstrated by the dual application of active and passive monitoring techniques. For active interrogation, the guided wave propagation problem was initially studied numerically by a semi-analytical finite element method, which accounts for viscoelastic damping, in order to identify ideal mode-frequency combinations sensitive to damage occurring within CFRP bonded joints. Active guided wave tests across three representative wing skin-to-spar joints at ambient temperature were then conducted using attached Macro Fiber Composite (MFC) transducers. Results from these experiments demonstrate the importance of intelligent feature extraction for improving the sensitivity to damage. To address the widely neglected effects of temperature on guided wave base damage identification, analytical and experimental analyses were performed to characterize the influence of temperature on guided wave signal features. In addition, statistically-robust detection of simulated damage in a CFRP bonded joint was successfully achieved under changing temperature conditions through a dimensionally-low, multivariate statistical outlier analysis. The response of piezoceramic patches and MFC transducers to ultrasonic Rayleigh and Lamb wave fields was analytically derived and experimentally validated. This theory is useful for designing sensors which possess optimal sensitivity toward a given mode-frequency combination or for predicting the frequency dependent

  6. 19 CFR 10.183 - Duty-free entry of civil aircraft, aircraft engines, ground flight simulators, parts, components...

    Science.gov (United States)

    2010-04-01

    ... Duty-free entry of civil aircraft, aircraft engines, ground flight simulators, parts, components, and... aircraft, aircraft engines, and ground flight simulators, including their parts, components, and... United States (HTSUS) by meeting the following requirements: (1) The aircraft, aircraft engines,...

  7. Structural Dynamics of Maneuvering Aircraft.

    Science.gov (United States)

    1987-09-01

    AD-RI92 376 STRUCTURAL DYNAMICS OF MANEUVERING RIRCRAFT(U) CONRAD I TECHNOLOGIES INC KING OF PRUSSIA PR M M REDDI SEP 97 CTI-8601 NRDC-88014-69...REPORT NO. NADC-8014-60 STRUCTURAL DYNAMICS OF MANEUVERING AIRCRAFT M. Mahadeva Reddi .4 Conrad Technologies, Inc. 650 S. Henderson Rd. D T IQ King of...NO A0 CCESSION NO. R02303001 107601 11. TITLE (Include Security Classfication) (u) STRUCTURAL DYNAMICS OF MANEUVERING AIRCRAFT 12. PERSONAL AUTHORS) M

  8. Aircraft propeller induced structure-borne noise

    Science.gov (United States)

    Unruh, James F.

    1989-01-01

    A laboratory-based test apparatus employing components typical of aircraft construction was developed that would allow the study of structure-borne noise transmission due to propeller induced wake/vortex excitation of in-wake structural appendages. The test apparatus was employed to evaluate several aircraft installation effects (power plant placement, engine/nacelle mass loading, and wing/fuselage attachment methods) and several structural response modifications for structure-borne noise control (the use of wing blocking mass/fuel, wing damping treaments, and tuned mechanical dampers). Most important was the development of in-flight structure-borne noise transmission detection techniques using a combination of ground-based frequency response function testing and in-flight structural response measurement. Propeller wake/vortex excitation simulation techniques for improved ground-based testing were also developed to support the in-flight structure-borne noise transmission detection development.

  9. Techno-economic requirements for composite aircraft components

    Science.gov (United States)

    Palmer, Ray

    1993-01-01

    The primary reason for use of composites is to save structural weight. A well designed composite aircraft structure will usually save 25-30 percent of a well designed metal structure. The weight savings then translates into improved performance of the aircraft in measures of greater payload, increased flying range or improved efficiency - less use of fuel. Composite materials offer technical advantages. Key technical advantages that composites offer are high stiffness, tailored strength capability, fatigue resistance, and corrosion resistance. Low thermal expansion properties produce dimensionally stable structures over a wide range of temperature. Specialty resin 'char' forming characteristics in a fire environment offer potential fire barrier application and safer aircraft. The materials and processes of composite fabrication offer the potential for lower cost structures in the near future. The application of composite materials to aircraft are discussed.

  10. Potential emissions savings of lightweight composite aircraft components evaluated through life cycle assessment

    Directory of Open Access Journals (Sweden)

    2011-03-01

    Full Text Available A cradle-to-grave life cycle assessment (LCA of structural aircraft materials has been utilised to assess and compare the total emissions produced during manufacturing, use and disposal of aerospace materials and their selected components. First, a comparison of aluminium, GLARE and carbon fibre reinforced polymer (CFRP plates was performed to investigate the potential of lightweight composites in reducing aviation emissions. Subsequently, a case study is presented on a tubular component for which more accurate manufacturing data were directly available. A structural steel tube was replaced with a composite tubular component. The analysis has shown that once the composite material is used as a component in the aircraft, there is a cumulative saving of aircraft fuel and emissions, in particular from CFRP structures. The environmental analysis included the long-term use predictions for CFRPs, involving detailed raw materials production, use and operation, and disposal scenarios.

  11. Global Local Structural Optimization of Transportation Aircraft Wings

    NARCIS (Netherlands)

    Ciampa, P.D.; Nagel, B.; Van Tooren, M.J.L.

    2010-01-01

    The study presents a multilevel optimization methodology for the preliminary structural design of transportation aircraft wings. A global level is defined by taking into account the primary wing structural components (i.e., ribs, spars and skin) which are explicitly modeled by shell layered finite e

  12. Validation Effectiveness of Develop Maintainability Allocation on Aircraft Mechanical Components

    Directory of Open Access Journals (Sweden)

    Wan Husain W.M.S.

    2016-01-01

    Full Text Available Maintainability Allocation is a process to identify the allowable maximum task time for each individual component. Consequently, this provides clear pictures to the designers to design and identify potential design improvement within allowable maintenance allocation time limits. During the design process elements such as missteps or misapplications most commonly occur. Here, the authors propose having the maximum target for each individual maintainability component. The main objective of this paper is to present the validation process of developed Maintainability Allocation to potentially eliminate previous problems. The process of validation begins with analysed all the data collected from Service Difficulty Reports (SDR for selected aircraft. This is to understand the problems from existing aircraft before a new design is proposed through the process of Maintainability Allocation prediction. The validation processes have discovered the importance of utilising historical information such as feedback information. The second area is looking at the element of quantifying the data collected from aircraft feedback information which contains various types of information that could be used for future improvement. Validation process shows that feedback information has helped to identify the critical and sensitive components that need more attention for further improvement. The study shows that the aircraft maintenance related feedback information systems analyses were very useful for deciding maintainability effectiveness; these include planning, organising maintenance and design improvement. There is no doubt that feedback information has the ability to contribute an important role in design activities. The results also show that maintainability is an important measure that can be used as a guideline for managing efforts made for the improvement of aircraft components.

  13. Investigation of aircraft vortex wake structure

    Science.gov (United States)

    Baranov, N. A.; Turchak, L. I.

    2014-11-01

    In this work we analyze the mechanisms of formation of the vortex wake structure of aircraft with different wing shape in the plan flying close to or away from the underlying surface cleaned or released mechanization wing.

  14. Titanium in fatigue critical military aircraft structure

    Energy Technology Data Exchange (ETDEWEB)

    Gillespie, F.

    1999-07-01

    This paper discusses the effect of fatigue requirements on titanium structure in military aircraft applications, specifically, fighter aircraft. The discussion covers how fatigue affects the design and analysis of detail parts, and how manufacturing processes affect the fatigue performance of titanium structure. Criteria for designing fighter aircraft have evolved from simple strength calculations to extremely complex computer generated analyses involving strength, durability, damage tolerance and fatigue. Fatigue life prediction is an important part of these analyses and dramatically affects the design and weight of fighter aircraft. Manufacturing processes affect fatigue performance both in a positive and negative manner. Designers must allow for the effect of these processes on titanium structure and consider the efficiency and economy of adding processes that increase fatigue life.

  15. Development of composite aircraft components in INCDT COMOTI, Bucharest

    Directory of Open Access Journals (Sweden)

    Raluca VOICU

    2012-12-01

    Full Text Available This paper presents the recent research activities within INCDT COMOTI, in the composite materials field. The author makes a short introduction of this field and presents an example of application developed within the composite materials laboratory from INCDT COMOTI, targeting the aeronautic field. The aircraft component is a stator blade made of CFRP composites, integrating new active noise reduction technologies and manufactured by means of the autoclave technology.

  16. Corrosion Preventative Compounds (CPCs) Effect on Aircraft Electrical Wiring Components

    Science.gov (United States)

    2011-08-01

    Electrical Wiring Components TR285HN301 Final Report Revision: - • Fretting research project was performed on nano -miniature connectors...CPCs, including gold plated edge card connectors, electrical connectors, tin plated pins, nano -miniature connectors. Current Air Force and NAVAIR...early 1980’s on many Navy aircraft. The Navy’s standard wire type. M5086/2-20 c Polyvinyl chloride, polyamide jacket, glass fiber braid ( PVC /glass

  17. Lectures on Composite Materials for Aircraft Structures,

    Science.gov (United States)

    1982-10-01

    lectures are related to structural applications of composites . In Lecture 7, the basic theory that is needed for composite structural analysis is...which composites have been taken up for aeronautical applications. Several specific applications of composites in aircraft structures am described in

  18. Improving transient analysis technology for aircraft structures

    Science.gov (United States)

    Melosh, R. J.; Chargin, Mladen

    1989-01-01

    Aircraft dynamic analyses are demanding of computer simulation capabilities. The modeling complexities of semi-monocoque construction, irregular geometry, high-performance materials, and high-accuracy analysis are present. At issue are the safety of the passengers and the integrity of the structure for a wide variety of flight-operating and emergency conditions. The technology which supports engineering of aircraft structures using computer simulation is examined. Available computer support is briefly described and improvement of accuracy and efficiency are recommended. Improved accuracy of simulation will lead to a more economical structure. Improved efficiency will result in lowering development time and expense.

  19. Effects of Structural Flexibility on Aircraft-Engine Mounts

    Science.gov (United States)

    Phillips, W. H.

    1986-01-01

    Analysis extends technique for design of widely used type of vibration-isolating mounts for aircraft engines, in which rubber mounting pads located in plane behind center of gravity of enginepropeller combination. New analysis treats problem in statics. Results of simple approach useful in providing equations for design of vibrationisolating mounts. Equations applicable in usual situation in which engine-mount structure itself relatively light and placed between large mass of engine and other heavy components of airplane.

  20. Evaluation of the doses to aircrew members by considering the aircraft structures

    Science.gov (United States)

    Battistoni, G.; Ferrari, A.; Pelliccioni, M.; Villari, R.

    A mathematical model of an aircraft has been developed with the aim to investigate the influence of the aircraft structures and contents on the exposure of aircrew and passengers to the galactic component of cosmic rays. The irradiation of the mathematical model in the cosmic ray environment has been simulated using the Monte Carlo transport code FLUKA. Effective dose and ambient dose equivalent rates have been determined inside the aircraft at several locations along the fuselage at typical civil aviation altitudes.

  1. Structural analysis at aircraft conceptual design stage

    Science.gov (United States)

    Mansouri, Reza

    In the past 50 years, computers have helped by augmenting human efforts with tremendous pace. The aircraft industry is not an exception. Aircraft industry is more than ever dependent on computing because of a high level of complexity and the increasing need for excellence to survive a highly competitive marketplace. Designers choose computers to perform almost every analysis task. But while doing so, existing effective, accurate and easy to use classical analytical methods are often forgotten, which can be very useful especially in the early phases of the aircraft design where concept generation and evaluation demands physical visibility of design parameters to make decisions [39, 2004]. Structural analysis methods have been used by human beings since the very early civilization. Centuries before computers were invented; the pyramids were designed and constructed by Egyptians around 2000 B.C, the Parthenon was built by the Greeks, around 240 B.C, Dujiangyan was built by the Chinese. Persepolis, Hagia Sophia, Taj Mahal, Eiffel tower are only few more examples of historical buildings, bridges and monuments that were constructed before we had any advancement made in computer aided engineering. Aircraft industry is no exception either. In the first half of the 20th century, engineers used classical method and designed civil transport aircraft such as Ford Tri Motor (1926), Lockheed Vega (1927), Lockheed 9 Orion (1931), Douglas DC-3 (1935), Douglas DC-4/C-54 Skymaster (1938), Boeing 307 (1938) and Boeing 314 Clipper (1939) and managed to become airborne without difficulty. Evidencing, while advanced numerical methods such as the finite element analysis is one of the most effective structural analysis methods; classical structural analysis methods can also be as useful especially during the early phase of a fixed wing aircraft design where major decisions are made and concept generation and evaluation demands physical visibility of design parameters to make decisions

  2. Aircraft detection based on probability model of structural elements

    Science.gov (United States)

    Chen, Long; Jiang, Zhiguo

    2014-11-01

    Detecting aircrafts is important in the field of remote sensing. In past decades, researchers used various approaches to detect aircrafts based on classifiers for overall aircrafts. However, with the development of high-resolution images, the internal structures of aircrafts should also be taken into consideration now. To address this issue, a novel aircrafts detection method for satellite images based on probabilistic topic model is presented. We model aircrafts as the connected structural elements rather than features. The proposed method contains two major steps: 1) Use Cascade-Adaboost classier to identify the structural elements of aircraft firstly. 2) Connect these structural elements to aircrafts, where the relationships between elements are estimated by hierarchical topic model. The model places strict spatial constraints on structural elements which can identify differences between similar features. The experimental results demonstrate the effectiveness of the approach.

  3. Structural analysis of Aircraft fuselage splice joint

    Science.gov (United States)

    Udaya Prakash, R.; Kumar, G. Raj; Vijayanandh, R.; Senthil Kumar, M.; Ramganesh, T.

    2016-09-01

    In Aviation sector, composite materials and its application to each component are one of the prime factors of consideration due to the high strength to weight ratio, design flexibility and non-corrosive so that the composite materials are widely used in the low weight constructions and also it can be treated as a suitable alternative to metals. The objective of this paper is to estimate and compare the suitability of a composite skin joint in an aircraft fuselage with different joints by simulating the displacement, normal stress, vonmises stress and shear stress with the help of numerical solution methods. The reference Z-stringer component of this paper is modeled by CATIA and numerical simulation is carried out by ANSYS has been used for splice joint presents in the aircraft fuselage with three combinations of joints such as riveted joint, bonded joint and hybrid joint. Nowadays the stringers are using to avoid buckling of fuselage skin, it has joined together by rivets and they are connected end to end by splice joint. Design and static analysis of three-dimensional models of joints such as bonded, riveted and hybrid are carried out and results are compared.

  4. Influence of environmental factors on corrosion damage of aircraft structure

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Corrosion is one of the important structural integrity concerns of aging aircraft, and it is estimated that a significant portion of airframe maintenance budgets is directed towards corrosion-related problems for both military and commercial aircraft. In order to better understand how environmental factors influence the corrosion damage initiation and propagation on aircraft structure and to predict pre-corrosion test pieces of fatigue life and structural integrity of an effective approach, this paper uses ...

  5. Aircraft Structural Analysis, Design Optimization, and Manufacturing Tool Integration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Innovative research is proposed in integrating fundamental aircraft design processes with an emphasis on composite structures. Efficient, lightweight composite...

  6. Fault mechanism analysis and simulation for continuity resistance test of electrical components in aircraft engine

    Science.gov (United States)

    Shi, Xudong; Yin, Yaping; Wang, Jialin; Sun, Zhaorong

    2017-01-01

    A large number of electrical components are used in civil aircraft engines, whose electrical circuits are usually intricate and complicated. Continuity resistance is an important parameter for the operating state of electrical components. Electrical continuity fault has serious impact on the reliability of the aircraft engine. In this paper, mathematical models of electrical components are established, and simulation is made by Simulink to analyze the electrical continuity fault.

  7. MULTI-CONTROLLER STRUCTURE OF SUPERMANEUVERABLE AIRCRAFT

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper proposes a method of using multi-controllers to control supermaneuverable aircraft. A nonlinear dynamic-inversion controller is used for supermaneuver. A gain-scheduled controller is used for routine maneuver. A switch algorithm is designed to switch the controllers. The flight envelopes of the controllers are different but have a common area in which the controllers are switched from one to the other. In the common area, some special boundaries are selected to decide switch conditions. The controllers all use vector-thrust for lower velocity maneuver control. Unlike the variation-structure theory to use a single boundary, this paper uses two boundaries for switching between the two controllers. One boundary is used for switching from dynamic-inversion to gain-scheduling, while the other is used for switching from gain-scheduling to dynamic-inversion. This can effectively avoid the system vibration caused by switching repeatedly at a single boundary. The method is very easy for engineering. It can reduce the risk of design of the supermaneuverable aircraft.

  8. Application of supersonic particle deposition to enhance the structural integrity of aircraft structures

    Science.gov (United States)

    Matthews, N.; Jones, R.; Sih, G. C.

    2014-01-01

    Aircraft metal components and structures are susceptible to environmental degradation throughout their original design life and in many cases their extended lives. This paper summarizes the results of an experimental program to evaluate the ability of Supersonic Particle Deposition (SPD), also known as cold spray, to extend the limit of validity (LOV) of aircraft structural components and to restore the structural integrity of corroded panels. In this study [LU1]the potential for the SPD to seal the mechanically fastened joints and for this seal to remain intact even in the presence of multi-site damage (MSD) has been evaluated. By sealing the joint the onset of corrosion damage in the joint can be significantly retarded, possibly even eliminated, thereby dramatically extending the LOV of mechanically fastened joints. The study also shows that SPD can dramatically increase the damage tolerance of badly corroded wing skins.

  9. An artificial intelligence-based structural health monitoring system for aging aircraft

    Science.gov (United States)

    Grady, Joseph E.; Tang, Stanley S.; Chen, K. L.

    1993-01-01

    To reduce operating expenses, airlines are now using the existing fleets of commercial aircraft well beyond their originally anticipated service lives. The repair and maintenance of these 'aging aircraft' has therefore become a critical safety issue, both to the airlines and the Federal Aviation Administration. This paper presents the results of an innovative research program to develop a structural monitoring system that will be used to evaluate the integrity of in-service aerospace structural components. Currently in the final phase of its development, this monitoring system will indicate when repair or maintenance of a damaged structural component is necessary.

  10. Reliability and optimization, application to safety of aircraft structures

    OpenAIRE

    Chu, Liu

    2016-01-01

    Tremendous struggles of researchers in the field of aerodynamic design and aircraft production were made to improve wing airfoil by optimization techniques. The development of computational fluid dynamic (CFD) in computer simulation cuts the expense of aerodynamic experiment while provides convincing results to simulate complicated situation of aircraft. In our work, we chose a special and important part of aircraft, namely, the structure of wing.Reliability based optimization is one of the m...

  11. Bonded structure application for aircraft. Kokuki ni okeru secchaku gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, O. (Japan Airlines Co. Ltd., Tokyo (Japan))

    1991-01-05

    Adhesives play an important role in a technology of the aircraft structure for which lightness and strength are required. The paper explains the present situation of bonding technology employed for aircraft, the honeycomb structure, production of composite materials and the related problems. Advantages and purposes of employing adhesives as substitutes for fasteners like screws, rivets, etc. are as follows: decreases in stress concentration, weight reduction, smoothing of surfaces, improvement of acoustic fatigue by adhesives flexibility, prevention of gas-liquid leakage. Epoxide adhesives are mainly used for aircraft. Together with tear straps, which are metal-metal bonded to the rear fuselage plate of aircraft, and waffle doublers, an aluminium honeycomb sandwich structure, whose weight is 1/7 of an aluminium plate same in rigidity, is used in such parts of aircraft as spoilers, outer plates of flaps, etc. The problem of the bonded structure is detachment. Therefore, how to prevent, discover and repair it is most important. 3 figs.

  12. Managing Life-Cycle Information of Aircraft Components

    Science.gov (United States)

    2012-04-01

    starting to implement Product Life Cycle Management ( PLM ), a closed-loop system that encompasses internationally standardized data-exchange technology...aircraft have much to gain from the use of tracking technologies in support of a PLM system. To investigate how efficiencies can be attained in the...missing the card. The problem stems from the lack of reliability of the card-based system. Moving to an automated PLM system would address these

  13. Aircraft vulnerability modeling and computation methods based on product structure and CATIA

    Institute of Scientific and Technical Information of China (English)

    Li Jun; Yang Wei; Zhang Yugang; Pei Yang; Ren Yunsong; Wang Wei

    2013-01-01

    Survivability strengthening/vulnerability reduction designs have become one of the most important design disciplines of military aircraft now.Due to progressiveness and complexity of modern combat aircraft,the existing vulnerability modeling and computation methods cannot meet the current engineering application requirements.Therefore,a vulnerability modeling and computation method based on product structure and CATIA is proposed in sufficient consideration of the design characteristics of modern combat aircraft.This method directly constructs the aircraft vulnerability model by CATIA or the digital model database,and manages all the product components of the vulnerability model via aircraft product structure.Using CAA second development,the detailed operations and computation methods of vulnerability analysis are integrated into CATIA software environment.Comprehensive assessment data and visual kill probability Iso-contours can also be presented,which meet the vulnerability analysis requirements of modern combat aircraft effectively.The intact vulnerability model of one hypothetical aircraft is constructed,and the effects of redundant technology to the aircraft vulnerability are assessed,which validate the engineering practicality of the method.

  14. Reengineering Aircraft Structural Life Prediction Using a Digital Twin

    Directory of Open Access Journals (Sweden)

    Eric J. Tuegel

    2011-01-01

    Full Text Available Reengineering of the aircraft structural life prediction process to fully exploit advances in very high performance digital computing is proposed. The proposed process utilizes an ultrahigh fidelity model of individual aircraft by tail number, a Digital Twin, to integrate computation of structural deflections and temperatures in response to flight conditions, with resulting local damage and material state evolution. A conceptual model of how the Digital Twin can be used for predicting the life of aircraft structure and assuring its structural integrity is presented. The technical challenges to developing and deploying a Digital Twin are discussed in detail.

  15. Backward Extrusion of Aluminum Alloy Sections Used in Aircraft Structural Components / Wyciskanie Przeciwbieżne Kształtowników Ze Stopów Aluminium Stosowanych Na Elementy Konstrukcji Lotniczych

    Directory of Open Access Journals (Sweden)

    Pawłowska B.

    2015-12-01

    Full Text Available The paper presents an analysis of selected aluminum alloys as structural materials used in production of aircraft parts as well as specification of technological parameters of Al alloys extrusion on a backward press with their effect on mechanical properties, microstructure and quality of the final product. Upsetting tests with backward extrusion complex cross-sectional profile tests were conducted on aluminum alloys 7075, 2024, 2099. Based on the results, specifications of forging in the form of unit stress - effective strain relations were determined using logarithmic deformation index, allowing proper choice of extrusion parameters. The range of temperatures for hot plastic treatment along with range of extrusion rate for the analyzed thin-walled aircraft profiles were determined. Tests were also conducted on the microstructure of Al alloys in the initial state as well as after the extrusion process had been completed. It has been proved that the proper choice of parameters in the case of a specific profile extruded from Aluminum alloys 2024, 7075, 2099, allows the manufacturing of products of complex crosssections and the quality required in aerospace industry. This has been demonstrated on the example of complex cross-sectional profiles using elements of varied wall thickness.

  16. An analysis of the aircraft engine Component Improvement Program (CIP) : a life cycle cost approach

    OpenAIRE

    Borer, Chris Joseph

    1990-01-01

    Approved for public release; distribution unlimited. Increasing budgetary constraints have prompted actions to reduce the maintenance cost of current naval aircraft. This thesis examines the Aircraft Engine Component Improvement Program (CIP), its impact on these cost at the organizational and intermediate levels of maintenance, and savings from these improvements. The objectives of the research were to identify current life cycle cost (LCC) models used by the Navy andor the other services...

  17. Application research of centrifugal investment cast TiAl component used for advanced aircraft engine

    Institute of Scientific and Technical Information of China (English)

    李俊涛; 李世琼; 张继; 马万青; 邹敦叙; 仲增墉

    2002-01-01

    A more complex structural component with small size and very thin walls and blades used for advanced aircraft engine was fabricated well by induction skull melting and centrifugal investment casting with a proper ceramic mold. The tensile elongation and ultimate strength of the hot isostatically pressed (HIPped) Ti-46.5Al-2.5V-1Cr (mole fraction, %) casting alloy sare up to 2.5% and 645 Mpa at room temperature, and 31% and 593 Mpa a t 800 ℃. The fracture roughness at room temperature is up to 28 Mpa*m1/2 . The endurance tensile strength at 800 ℃ for 150 h, is higher than 200 Mpa. The high cycle rotary bending fatigue strengths for 1×107 cycles at room temperature and 800 ℃ a re 412 Mpa and 270 Mpa, respectively.

  18. Reengineering Aircraft Structural Life Prediction Using a Digital Twin

    OpenAIRE

    Eric J. Tuegel; Anthony R. Ingraffea; Eason, Thomas G.; S. Michael Spottswood

    2011-01-01

    Reengineering of the aircraft structural life prediction process to fully exploit advances in very high performance digital computing is proposed. The proposed process utilizes an ultrahigh fidelity model of individual aircraft by tail number, a Digital Twin, to integrate computation of structural deflections and temperatures in response to flight conditions, with resulting local damage and material state evolution. A conceptual model of how the Digital Twin can be used for predicting the lif...

  19. Dichotomic Structure of DAEs Solutions for the Aircraft Control

    Directory of Open Access Journals (Sweden)

    Sorin Ştefan RADNEF

    2009-09-01

    Full Text Available The paper has its roots in earlier studies focused on DAEs solutions, for the aircraft flight control and intends to be a synthesis of them. The main goal is to structure the solution for the control laws so as to derive its components, which control any significant mechanical phenomenon for the controlled flight. The basic method used becomes from a unified manner of finding the solution of DAEs using a rigorous guideline stated as “necessary and sufficient condition” in an algebraic equation form that is used in an algorithmic procedure and for statement of the equations, which emphasises the dichotomic structure. The viewpoint considers an extended DAE system, including the differential equations of control variables, that allows to formulate this question as an inverse problem and to regard the algebraic equation, for constraints, as a singular implicit solution of the differential subsystem. Stating the necessary and sufficient condition for an implicit equation be a singular implicit solution of the extended differential system, we use it to approach the solution for flight control and for its dichotomic structure with additive components.

  20. Drag/thrust analysis of jet-propelled transonic transport aircraft; definition of physical drag components

    Energy Technology Data Exchange (ETDEWEB)

    Destarac, D. [Office National d' Etudes et de Recherches Aerospatiales (ONERA), 92 - Chatillon (France); Van der Vooren, J. [Senior research scientist, retired, Hoekse Waard (Netherlands)

    2004-09-01

    Drag/thrust analysis of jet-propelled transonic transport aircraft on the basis of calculated viscous flow is discussed. Unique definitions for viscous drag plus wave drag and for induced drag are established. The concept of additive through flow drag is introduced. Drag/thrust bookkeeping is given attention. All drag components can be calculated in the flow region adjacent to the aircraft, where numerical accuracy is expectingly highest. Uniform handling of complex aircraft configurations is brought within reach. Near-field/far-field drag balances are exact. Computational aspects are discussed, in particular the elimination of spurious drag sources. Numerical examples are given for a wing-body and for a wing-body-pylon-nacelle configuration. In either case, the spurious drag sources are eliminated. Acceptable agreement is obtained for the total drag in the first case, and for the installation drag in the second case. Extension of the analysis presented to propeller-driven transport aircraft is straightforward. (author)

  1. Probabilistic Remaining Useful Life Prediction of Composite Aircraft Components Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A Probabilistic Fatigue Damage Assessment Network (PFDAN) toolkit for Abaqus will be developed for probabilistic life management of a laminated composite structure...

  2. Integrated Control with Structural Feedback to Enable Lightweight Aircraft

    Science.gov (United States)

    Taylor, Brian R.

    2011-01-01

    This presentation for the Fundamental Aeronautics Program Technical Conference covers the benefits of active structural control, related research areas, and focuses on the use of optimal control allocation for the prevention of critical loads. Active control of lightweight structures has the potential to reduce aircraft weight and fuel burn. Sensor, control law, materials, control effector, and system level research will be necessary to enable active control of lightweight structures. Optimal control allocation with structural feedback has been shown in simulation to be feasible in preventing critical loads and is one example of a control law to enable future lightweight aircraft.

  3. A mathematical model of aircraft for evaluating the effects of shielding structure on aircrew exposure.

    Science.gov (United States)

    Ferrari, A; Pelliccioni, M; Villari, R

    2005-01-01

    To investigate the influence of the aircraft structures and contents on the exposure of aircrew to the galactic component of cosmic rays, a mathematical model of an aeroplane has been developed. The irradiation of the mathematical model in the cosmic ray environment has been simulated using the Monte Carlo transport code FLUKA. Effective dose andambient dose-equivalent rates have been determined inside the aircraft at several locations along the fuselage at a typicaI civil aviation altitude. A significant effect of the shielding of aircraft structures has been observed on the ambient dose-equivalent rates, while the impact on the effective dose rates seems to be minor. Care should be taken in positioning the detectors onboard when the measurements are aimed at validating the codes.

  4. Damage monitoring of aircraft structures made of composite materials using wavelet transforms

    Science.gov (United States)

    Molchanov, D.; Safin, A.; Luhyna, N.

    2016-10-01

    The present article is dedicated to the study of the acoustic properties of composite materials and the application of non-destructive testing methods to aircraft components. A mathematical model of a wavelet transformed signal is presented. The main acoustic (vibration) properties of different composite material structures were researched. Multiple vibration parameter dependencies on the noise reduction factor were derived. The main steps of a research procedure and new method algorithm are presented. The data obtained was compared with the data from a three dimensional laser-Doppler scanning vibrometer, to validate the results. The new technique was tested in the laboratory and on civil aircraft at a training airfield.

  5. Nuclear containment structure subjected to commercial and fighter aircraft crash

    Energy Technology Data Exchange (ETDEWEB)

    Sadique, M.R., E-mail: rehan.sadique@gmail.com; Iqbal, M.A., E-mail: iqbalfce@iitr.ernet.in; Bhargava, P., E-mail: bhpdpfce@iitr.ernet.in

    2013-07-15

    Highlights: • Nuclear containment response has been studied against aircraft crash. • Concrete damaged plasticity and Johnson–Cook elasto-viscoplastic models were employed. • Boeing 747-400 and Boeing 767-400 aircrafts caused global failure of containment. • Airbus A320 and Boeing 707-320 aircrafts caused local damage. • Tension damage of concrete was found more prominent compared to compression damage. -- Abstract: The response of a boiling water reactor (BWR) nuclear containment vessel has been studied against commercial and fighter aircraft crash using a nonlinear finite element code ABAQUS. The aircrafts employed were Boeing 747-400, Boeing 767-400, Airbus A-320, Boeing 707-320 and Phantom F4. The containment was modeled as a three-dimensional deformable reinforced concrete structure while the loading of aircraft was assigned using the respective reaction–time curve. The location of strike was considered near the junction of dome and cylinder, and the angle of incidence, normal to the containment surface. The material behavior of the concrete was incorporated using the damaged plasticity model while that of the reinforcement, the Johnson–Cook elasto-viscoplastic model. The containment could not sustain the impact of Boeing 747-400 and Boeing 767-400 aircrafts and suffered rupture of concrete around the impact region leading to global failure. On the other hand, the maximum local deformation at the point of impact was found to be 0.998 m, 0.099 m, 0.092 m, 0.089 m, and 0.074 m against Boeing 747-400, Phantom F4, Boeing 767, Boeing 707-320 and Airbus A-320 aircrafts respectively. The results of the present study were compared with those of the previous analytical and numerical investigations with respect to the maximum deformation and overall behavior of the containment.

  6. Structural Integrity Assessment of Reactor Containment Subjected to Aircraft Crash

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Junyong; Chang, Yoonsuk [Department of Nuclear Engineering/Kyung Hee Univ., Yongin (Korea, Republic of)

    2013-05-15

    When an accident occurs at the NPP, containment building which acts as the last barrier should be assessed and analyzed structural integrity by internal loading or external loading. On many occasions that can occur in the containment internal such as LOCA(Loss Of Coolant Accident) are already reflected to design. Likewise, there are several kinds of accidents that may occur from the outside of containment such as earthquakes, hurricanes and strong wind. However, aircraft crash that at outside of containment is not reflected yet in domestic because NPP sites have been selected based on the probabilistic method. After intentional aircraft crash such as World Trade Center and Pentagon accident in US, social awareness for safety of infrastructure like NPP was raised world widely and it is time for assessment of aircraft crash in domestic. The object of this paper is assessment of reactor containment subjected to aircraft crash by FEM(Finite Element Method). In this paper, assessment of structural integrity of containment building subjected to certain aircraft crash was carried out. Verification of structure integrity of containment by intentional severe accident. Maximum stress 61.21MPa of horizontal shell crash does not penetrate containment. Research for more realistic results needed by steel reinforced concrete model.

  7. Aircraft fiber optic structural health monitoring

    Science.gov (United States)

    Mrad, Nezih

    2012-06-01

    Structural Health Monitoring (SHM) is a sought after concept that is expected to advance military maintenance programs, increase platform operational safety and reduce its life cycle cost. Such concept is further considered to constitute a major building block of any Integrated Health Management (IHM) capability. Since 65% to 80% of military assets' Life Cycle Cost (LCC) is devoted to operations and support (O&S), the aerospace industry and military sectors continue to look for opportunities to exploit SHM systems, capability and tools. Over the past several years, countless SHM concepts and technologies have emerged. Among those, fiber optic based systems were identified of significant potential. This paper introduces the elements of an SHM system and investigates key issues impeding the commercial implementation of fiber optic based SHM capability. In particular, this paper presents an experimental study of short gauge, intrinsic, spectrometric-based in-fiber Bragg grating sensors, for potential use as a component of an SHM system. Fiber optic Bragg grating sensors are evaluated against resistance strain gauges for strain monitoring, sensitivity, accuracy, reliability, and fatigue durability. Strain field disturbance is also investigated by "embedding" the sensors under a photoelastic coating in order to illustrate sensor intrusiveness in an embedded configuration.

  8. A Study on External Fire Damage of Structures subjected to Aircraft Impact

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Sang Shup [Hanyang University, Seoul (Korea, Republic of); Hahm, Daegi; Kim, Min Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    A large commercial aircraft consists of various components as fuselage, wings, fuel tank, engine etc. During a collision of the aircraft, the fuel tank with a large amount of jet fuel have a significant effect on the total load of the aircraft as well as causing explosive fire and smoke which affect the safety of the structure and equipment. US Sandia National Laboratories and Finland VTT etc. performed the test and simulation studies to evaluate the dispersion range of the fluid after the crash of liquid filled cylinder missiles. The test condition and results have been referred in this paper. The fluid modeling approach using SPH is applied to evaluate the dispersing range of the fluid, and is compared with the Brown's results. The jet fuel is idealized as particles contained in an aluminum cylinder missile, where those particles can be dispersed to the surrounding area after the missile crashes into a rigid target. The fluid model using the SPH method is briefly verified through comparison with test results, and then the modelling method is applied to a jet fuel model in an aircraft model. The dispersion analysis of jet fuel caused by aircraft impact is performed using an aircraft model for the determination of fire duration and fire affected zone in a nuclear power plant. Finally, the structural integrity of the roof of the structure during a jet fuel fire is evaluated. In this study, the filled jet fuel was modeled by using smooth particle hydrodynamics technique; jet fuel spread area following an aircraft crash was analyzed.

  9. Creep-fatigue interaction in aircraft gas turbine components by simulation and testing at scaled temperatures

    Science.gov (United States)

    Sabour, Mohammad Hossein

    Advanced gas turbine engines, which use hot section airfoil cooling, present a wide range of design problems. The frequencies of applied loads and the natural frequencies of the blade also are important since they have significant effects on failure of the component due to fatigue phenomenon. Due to high temperature environment the thermal creep and fatigue are quite severe. One-dimensional creep model, using ANSYS has been formulated in order to predict the creep life of a gas turbine engine blade. Innovative mathematical models for the prediction of the operating life of aircraft components, specifically gas turbine blades, which are subjected to creep-fatigue at high temperatures, are proposed. The components are modeled by FEM, mathematically, and using similitude principles. Three models have been suggested and evaluated numerically and experimentally. Using FEM method for natural frequencies causes phenomena such as curve veering which is studied in more detail. The simulation studies on the life-limiting modes of failure, as well as estimating the expected lifetime of the blade, using the proposed models have been carried out. Although the scale model approach has been used for quite some time, the thermal scaling has been used in this study for the first time. The only thermal studies in literature using scaling for structures is by NASA in which materials of both the prototype and the model are the same, but in the present study materials also are different. The finite element method is employed to model the structure. Because of stress redistribution due to the creep process, it is necessary to include a full inelastic creep step in the finite element formulation. Otherwise over-conservative creep life predictions will be estimated if only the initial elastic stresses are considered. The experimental investigations are carried out in order to validate the models. The main contributions in the thesis are: (1) Using similitude theory for life prediction of

  10. Active Structural Control for Aircraft Efficiency with the X-56A Aircraft

    Science.gov (United States)

    Ouellette, Jeffrey

    2015-01-01

    The X-56A Multi-Utility Technology Testbed is an experimental aircraft designed to study active control of flexible structures. The vehicle is easily reconfigured to allow for testing of different configurations. The vehicle is being used to study new sensor, actuator, modeling and controls technologies. These new technologies will allow for lighter vehicles and new configurations that exceed the efficiency currently achievable. A description of the vehicle and the current research efforts that it enables are presented.

  11. Effect of Aging Aircraft Structure on Magnesium Parts

    Science.gov (United States)

    1945-04-01

    structural applications in aircraft, sheet compo - sitions corresponding to Dowmetal FS—1 and Dowmetal J—1 ordinarily are...in the hard—rolled condition. The Dow Chemical Company, Midland, Mich., October 30, 1944. NACA TN So. 979 . TA BIS I

  12. Aircraft

    Science.gov (United States)

    Hibbs, B.D.; Lissaman, P.B.S.; Morgan, W.R.; Radkey, R.L.

    1998-09-22

    This disclosure provides a solar rechargeable aircraft that is inexpensive to produce, is steerable, and can remain airborne almost indefinitely. The preferred aircraft is a span-loaded flying wing, having no fuselage or rudder. Travelling at relatively slow speeds, and having a two-hundred foot wingspan that mounts photovoltaic cells on most all of the wing`s top surface, the aircraft uses only differential thrust of its eight propellers to turn. Each of five sections of the wing has one or more engines and photovoltaic arrays, and produces its own lift independent of the other sections, to avoid loading them. Five two-sided photovoltaic arrays, in all, are mounted on the wing, and receive photovoltaic energy both incident on top of the wing, and which is incident also from below, through a bottom, transparent surface. The aircraft is capable of a top speed of about ninety miles per hour, which enables the aircraft to attain and can continuously maintain altitudes of up to sixty-five thousand feet. Regenerative fuel cells in the wing store excess electricity for use at night, such that the aircraft can sustain its elevation indefinitely. A main spar of the wing doubles as a pressure vessel that houses hydrogen and oxygen gases for use in the regenerative fuel cell. The aircraft has a wide variety of applications, which include weather monitoring and atmospheric testing, communications, surveillance, and other applications as well. 31 figs.

  13. Optical Fiber Sensors for Aircraft Structural Health Monitoring

    Directory of Open Access Journals (Sweden)

    Iker García

    2015-06-01

    Full Text Available Aircraft structures require periodic and scheduled inspection and maintenance operations due to their special operating conditions and the principles of design employed to develop them. Therefore, structural health monitoring has a great potential to reduce the costs related to these operations. Optical fiber sensors applied to the monitoring of aircraft structures provide some advantages over traditional sensors. Several practical applications for structures and engines we have been working on are reported in this article. Fiber Bragg gratings have been analyzed in detail, because they have proved to constitute the most promising technology in this field, and two different alternatives for strain measurements are also described. With regard to engine condition evaluation, we present some results obtained with a reflected intensity-modulated optical fiber sensor for tip clearance and tip timing measurements in a turbine assembled in a wind tunnel.

  14. Optical Fiber Sensors for Aircraft Structural Health Monitoring.

    Science.gov (United States)

    García, Iker; Zubia, Joseba; Durana, Gaizka; Aldabaldetreku, Gotzon; Illarramendi, María Asunción; Villatoro, Joel

    2015-06-30

    Aircraft structures require periodic and scheduled inspection and maintenance operations due to their special operating conditions and the principles of design employed to develop them. Therefore, structural health monitoring has a great potential to reduce the costs related to these operations. Optical fiber sensors applied to the monitoring of aircraft structures provide some advantages over traditional sensors. Several practical applications for structures and engines we have been working on are reported in this article. Fiber Bragg gratings have been analyzed in detail, because they have proved to constitute the most promising technology in this field, and two different alternatives for strain measurements are also described. With regard to engine condition evaluation, we present some results obtained with a reflected intensity-modulated optical fiber sensor for tip clearance and tip timing measurements in a turbine assembled in a wind tunnel.

  15. Active Structural Acoustic Control in an Original A400M Aircraft Structure

    Science.gov (United States)

    Koehne, C.; Sachau, D.; Renger, K.

    2016-09-01

    Low frequency noise has always been a challenge in propeller driven aircraft. At low frequencies passive noise treatments are not as efficient as active noise reduction systems. The Helmut-Schmidt-University has built up a full-scale test rig with an original A400M aircraft structure. This provides a good opportunity to develop and test active noise reduction systems in a realistic environment. The currently installed system consists of mechanical actuators and acoustical sensors. The actuators are called TVAs (Tuneable Vibration Absorber) and contain two spring-mass systems whose natural frequencies are adjusted to the BPFs (Blade Passage Frequency) of the propellers. The TVAs are mounted to the frames and the force direction is normal to the skin. The sensors are condenser microphones which are attached to the primary structure of the airframe. The TVAs are equipped with signal processing devices. These components carry out Fourier transforms and signal amplification for the sensor data and actuator signals. The communication between the TVAs and the central control unit is implemented by the CAN Bus protocol and mainly consists of complex coefficients for the sensor and actuator data. This paper describes the basic structure of the system, the hardware set-up and function tests of the controller.

  16. Federal Aviation Administration (FAA airworthiness certification for ceramic matrix composite components in civil aircraft systems

    Directory of Open Access Journals (Sweden)

    Gonczy Stephen T.

    2015-01-01

    Full Text Available Ceramic matrix composites (CMCs are being designed and developed for engine and exhaust components in commercial aviation, because they offer higher temperature capabilities, weight savings, and improved durability compared to metals. The United States Federal Aviation Administration (FAA issues and enforces regulations and minimum standards covering the safe manufacture, operation, and maintenance of civil aircraft. As new materials, these ceramic composite components will have to meet the certification regulations of the FAA for “airworthiness”. The FAA certification process is defined in the Federal Aviation Regulations (Title 14 of the Code of Federal Regulations, FAA policy statements, orders, advisory circulars, technical standard orders, and FAA airworthiness directives. These regulations and documents provide the fundamental requirements and guidelines for design, testing, manufacture, quality assurance, registration, operation, inspection, maintenance, and repair of aircraft systems and parts. For metallic parts in aircraft, the FAA certification and compliance process is well-established for type and airworthiness certification, using ASTM and SAE standards, the MMPDS data handbook, and FAA advisory circulars. In a similar manner for polymer matrix composites (PMC, the PMC industry and the FAA have jointly developed and are refining parallel guidelines for polymer matrix composites (PMCs, using guidance in FAA circulars and the CMH-17 PMC handbook. These documents discuss design methods and codes, material testing, property data development, life/durability assessment, production processes, QA procedures, inspection methods, operational limits, and repairs for PMCs. For ceramic composites, the FAA and the CMC and aerospace community are working together (primarily through the CMH-17 CMC handbook to define and codify key design, production, and regulatory issues that have to be addressed in the certification of CMC components in

  17. A new principle and device for large aircraft components gaining accurate support by ball joint

    Institute of Scientific and Technical Information of China (English)

    Bao-gui QIU; Jun-xia JIANG; Ying-lin KE

    2011-01-01

    How to obtain an accurate support for large components by ball joint is a key process in aircraft digital assembly. A novel principle and device is developed to solve the problem. Firstly, the working principle of the device is introduced. When three or four displacement sensors installed in the localizer are touched by the ball-head, the spatial relation is calculated between the large aircraft component's ball-head and the localizer's ball-socket. The localizer is driven to achieve a new position by compensation. Relatively, a support revising algorithm is proposed. The localizer's ball-socket approaches the ball-head based on the displacement sensors. According to the points selected from its spherical surface, the coordinates of ball-head spherical center are computed by geometry. Finally, as a typical application, the device is used to conduct a test-fuselage's ball-head into a localizer's ball-socket. Positional deviations of the spherical centers between the ball-head and the ball-socket in the x, y, and z directions are all controlled within ±0.05 mm under various working conditions. The results of the experiments show that the device has the characteristics of high precision, excellent stability, strong operability, and great potential to be applied widely in the modern aircraft industry.

  18. A finite element parametric modeling technique of aircraft wing structures

    Institute of Scientific and Technical Information of China (English)

    Tang Jiapeng; Xi Ping; Zhang Baoyuan; Hu Bifu

    2013-01-01

    A finite element parametric modeling method of aircraft wing structures is proposed in this paper because of time-consuming characteristics of finite element analysis pre-processing. The main research is positioned during the preliminary design phase of aircraft structures. A knowledge-driven system of fast finite element modeling is built. Based on this method, employing a template parametric technique, knowledge including design methods, rules, and expert experience in the process of modeling is encapsulated and a finite element model is established automatically, which greatly improves the speed, accuracy, and standardization degree of modeling. Skeleton model, geometric mesh model, and finite element model including finite element mesh and property data are established on parametric description and automatic update. The outcomes of research show that the method settles a series of problems of parameter association and model update in the pro-cess of finite element modeling which establishes a key technical basis for finite element parametric analysis and optimization design.

  19. Adhesive bonding of composite aircraft structures: Challenges and recent developments

    Science.gov (United States)

    Pantelakis, Sp.; Tserpes, K. I.

    2014-01-01

    In this review paper, the challenges and some recent developments of adhesive bonding technology in composite aircraft structures are discussed. The durability of bonded joints is defined and presented for parameters that may influence bonding quality. Presented is also, a numerical design approach for composite joining profiles used to realize adhesive bonding. It is shown that environmental ageing and pre-bond contamination of bonding surfaces may degrade significantly fracture toughness of bonded joints. Moreover, it is obvious that additional research is needed in order to design joining profiles that will enable load transfer through shearing of the bondline. These findings, together with the limited capabilities of existing non-destructive testing techniques, can partially explain the confined use of adhesive bonding in primary composite aircraft structural parts.

  20. Development of Textile Reinforced Composites for Aircraft Structures

    Science.gov (United States)

    Dexter, H. Benson

    1998-01-01

    NASA has been a leader in development of composite materials for aircraft applications during the past 25 years. In the early 1980's NASA and others conducted research to improve damage tolerance of composite structures through the use of toughened resins but these resins were not cost-effective. The aircraft industry wanted affordable, robust structures that could withstand the rigors of flight service with minimal damage. The cost and damage tolerance barriers of conventional laminated composites led NASA to focus on new concepts in composites which would incorporate the automated manufacturing methods of the textiles industry and which would incorporate through-the-thickness reinforcements. The NASA Advanced Composites Technology (ACT) Program provided the resources to extensively investigate the application of textile processes to next generation aircraft wing and fuselage structures. This paper discusses advanced textile material forms that have been developed, innovative machine concepts and key technology advancements required for future application of textile reinforced composites in commercial transport aircraft. Multiaxial warp knitting, triaxial braiding and through-the-thickness stitching are the three textile processes that have surfaced as the most promising for further development. Textile reinforced composite structural elements that have been developed in the NASA ACT Program are discussed. Included are braided fuselage frames and window-belt reinforcements, woven/stitched lower fuselage side panels, stitched multiaxial warp knit wing skins, and braided wing stiffeners. In addition, low-cost processing concepts such as resin transfer molding (RTM), resin film infusion (RFI), and vacuum-assisted resin transfer molding (VARTM) are discussed. Process modeling concepts to predict resin flow and cure in textile preforms are also discussed.

  1. On structural health monitoring of aircraft adhesively bonded repairs

    Science.gov (United States)

    Pavlopoulou, Sofia

    The recent interest in life extension of ageing aircraft and the need to address the repair challenges in the new age composite ones, led to the investigation of new repair methodologies such as adhesively bonded repair patches. The present thesis focuses on structural health monitoring aspects of the repairs, evaluating their performance with guided ultrasonic waves aiming to develop a monitoring strategy which would eliminate unscheduled maintenance and unnecessary inspection costs. To address the complex nature of the wave propagation phenomena, a finite element based model identified the existing challenges by exploring the interaction of the excitation waves with different levels of damage. The damage sensitivity of the first anti-symmetric mode was numerically investigated. An external bonded patch and a scarf repair, were further tested in static and dynamic loadings, and their performance was monitored with Lamb waves, excited by surface-bonded piezoelectric transducers.. The response was processed by means of advanced pattern recognition and data dimension reduction techniques such as novelty detection and principal component analysis. An optimisation of these tools enabled an accurate damage detection under complex conditions. The phenomena of mode isolation and precise arrival time determination under a noisy environment and the problem of inadequate training data were investigated and solved through appropriate transducer arrangements and advanced signal processing respectively. The applicability of the established techniques was demonstrated on an aluminium repaired helicopter tail stabilizer. Each case study utilised alternative non-destructive techniques for validation such as 3D digital image correlation, X-ray radiography and thermography. Finally a feature selection strategy was developed through the analysis of the instantaneous properties of guided waves for damage detection purposes..

  2. Optimization of structures and components

    CERN Document Server

    Muñoz-Rojas, Pablo Andrés

    2013-01-01

    Written by an international group of active researchers in the field, this volume presents innovative formulations and applied procedures for sensitivity analysis and structural design optimization. Eight chapters discuss subjects ranging from recent developments in the determination and application of topological gradients, to the use of evolutionary algorithms and meta-models to solve practical engineering problems. With such a comprehensive set of contributions, the book is a valuable source of information for graduate students and researchers entering or working in the matter.

  3. Generalized Structured Component Analysis with Latent Interactions

    Science.gov (United States)

    Hwang, Heungsun; Ho, Moon-Ho Ringo; Lee, Jonathan

    2010-01-01

    Generalized structured component analysis (GSCA) is a component-based approach to structural equation modeling. In practice, researchers may often be interested in examining the interaction effects of latent variables. However, GSCA has been geared only for the specification and testing of the main effects of variables. Thus, an extension of GSCA…

  4. Direct Adaptive Aircraft Control Using Dynamic Cell Structure Neural Networks

    Science.gov (United States)

    Jorgensen, Charles C.

    1997-01-01

    A Dynamic Cell Structure (DCS) Neural Network was developed which learns topology representing networks (TRNS) of F-15 aircraft aerodynamic stability and control derivatives. The network is integrated into a direct adaptive tracking controller. The combination produces a robust adaptive architecture capable of handling multiple accident and off- nominal flight scenarios. This paper describes the DCS network and modifications to the parameter estimation procedure. The work represents one step towards an integrated real-time reconfiguration control architecture for rapid prototyping of new aircraft designs. Performance was evaluated using three off-line benchmarks and on-line nonlinear Virtual Reality simulation. Flight control was evaluated under scenarios including differential stabilator lock, soft sensor failure, control and stability derivative variations, and air turbulence.

  5. Aircraft wing structural design optimization based on automated finite element modelling and ground structure approach

    Science.gov (United States)

    Yang, Weizhu; Yue, Zhufeng; Li, Lei; Wang, Peiyan

    2016-01-01

    An optimization procedure combining an automated finite element modelling (AFEM) technique with a ground structure approach (GSA) is proposed for structural layout and sizing design of aircraft wings. The AFEM technique, based on CATIA VBA scripting and PCL programming, is used to generate models automatically considering the arrangement of inner systems. GSA is used for local structural topology optimization. The design procedure is applied to a high-aspect-ratio wing. The arrangement of the integral fuel tank, landing gear and control surfaces is considered. For the landing gear region, a non-conventional initial structural layout is adopted. The positions of components, the number of ribs and local topology in the wing box and landing gear region are optimized to obtain a minimum structural weight. Constraints include tank volume, strength, buckling and aeroelastic parameters. The results show that the combined approach leads to a greater weight saving, i.e. 26.5%, compared with three additional optimizations based on individual design approaches.

  6. Aircraft structural health monitoring system development: overview of the Air Force/Navy smart metallic structures program

    Science.gov (United States)

    Van Way, Craig B.; Kudva, Jayanth N.; Schoess, Jeffrey N.; Zeigler, Michael L.; Alper, James M.

    1995-05-01

    Significant progress in fulfilling the current joint Air Force/Navy `Smart Metallic Structures (SMS)' program primary objective, to demonstrate a viable structural health monitoring system (SHMS) for a large structural aircraft component, is presented. Structural health monitoring and its relation to current Force Management (FM) and Aircraft Structural Integrity Program (ASIP) procedures are first reviewed together with a brief status overview of the relevant sensor technologies (e.g. AE, fiber-optic, corrosion, etc.). Key features of the SHMS architecture are described for the selected F/A-18 bulkhead and T-38 wing spar structural demonstration articles, highlighting sensors, processors, data busses, hardware, and software. Results from acoustic monitoring of the program sub-element structural tests are presented in some detail along with a status review of the SHMS multiplex bus component hardware and software. Finally, structural requirements for an SHMS meeting minimum ASIP guidelines for damage detection are discussed along with foals for future testing and development of the SHMS under the SMS program.

  7. Brazilian Air Force aircraft structural integrity program: An overview

    Directory of Open Access Journals (Sweden)

    Alberto W. S. Mello Junior

    2009-01-01

    Full Text Available This paper presents an overview of the activities developed by the Structural Integrity Group at the Institute of Aeronautics and Space - IAE, Brazil, as well as the status of ongoing work related to the life extension program for aircraft operated by the Brazilian Air Force BAF. The first BAF-operated airplane to undergo a DTA-based life extension was the F-5 fighter, in the mid 1990s. From 1998 to 2001, BAF worked on a life extension project for the BAF AT- 26 Xavante trainer. All analysis and tests were performed at IAE. The fatigue critical locations (FCLs were presumed based upon structural design and maintenance data and also from exchange of technical information with other users of the airplane around the world. Following that work, BAF started in 2002 the extension of the operational life of the BAF T-25 “Universal”. The T-25 is the basic training airplane used by AFA - The Brazilian Air Force Academy. This airplane was also designed under the “safe-life” concept. As the T-25 fleet approached its service life limit, the Brazilian Air Force was questioning whether it could be kept in flight safely. The answer came through an extensive Damage Tolerance Analysis (DTA program, briefly described in this paper. The current work on aircraft structural integrity is being performed for the BAF F-5 E/F that underwent an avionics and weapons system upgrade. Along with the increase in weight, new configurations and mission profiles were established. Again, a DTA program was proposed to be carried out in order to establish the reliability of the upgraded F-5 fleet. As a result of all the work described, the BAF has not reported any accident due to structural failure on aircraft submitted to Damage Tolerance Analysis.

  8. Smart aircraft composite structures with embedded small-diameter optical fiber sensors

    Science.gov (United States)

    Takeda, Nobuo; Minakuchi, Shu

    2012-02-01

    This talk describes the embedded optical fiber sensor systems for smart aircraft composite structures. First, a summary of the current Japanese national project on structural integrity diagnosis of aircraft composite structures is described with special emphasis on the use of embedded small-diameter optical fiber sensors including FBG sensors. Then, some examples of life-cycle monitoring of aircraft composite structures are presented using embedded small-diameter optical fiber sensors for low-cost and reliable manufacturing merits.

  9. Damage criticality and inspection concerns of composite-metallic aircraft structures under blunt impact

    Science.gov (United States)

    Zou, D.; Haack, C.; Bishop, P.; Bezabeh, A.

    2015-04-01

    Composite aircraft structures such as fuselage and wings are subject to impact from many sources. Ground service equipment (GSE) vehicles are regarded as realistic sources of blunt impact damage, where the protective soft rubber is used. With the use of composite materials, blunt impact damage is of special interest, since potential significant structural damage may be barely visible or invisible on the structure's outer surface. Such impact can result in local or non-local damage, in terms of internal delamination in skin, interfacial delamination between stiffeners and skin, and fracture of internal reinforced component such as stringers and frames. The consequences of these events result in aircraft damage, delays, and financial cost to the industry. Therefore, it is necessary to understand the criticality of damage under this impact and provide reliable recommendations for safety and inspection technologies. This investigation concerns a composite-metallic 4-hat-stiffened and 5-frame panel, designed to represent a fuselage structure panel generic to the new generation of composite aircraft. The test fixtures were developed based on the correlation between finite element analyses of the panel model and the barrel model. Three static tests at certain amount of impact energy were performed, in order to improve the understanding of the influence of the variation in shear ties, and the added rotational stiffness. The results of this research demonstrated low velocity high mass impacts on composite aircraft fuselages beyond 82.1 kN of impact load, which may cause extensive internal structural damage without clear visual detectability on the external skin surface.

  10. Resin transfer molding of textile preforms for aircraft structural applications

    Science.gov (United States)

    Hasko, Gregory H.; Dexter, H. Benson; Weideman, Mark H.

    1992-01-01

    The NASA LaRC is conducting and supporting research to develop cost-effective fabrication methods that are applicable to primary composite aircraft structures. One of the most promising fabrication methods that has evolved is resin transfer molding (RTM) of dry textile material forms. RTM has been used for many years for secondary structures, but has received increased emphasis because it is an excellent method for applying resin to damage-tolerant textile preforms at low cost. Textile preforms based on processes such as weaving, braiding, knitting, stitching, and combinations of these have been shown to offer significant improvements in damage tolerance compared to laminated tape composites. The use of low-cost resins combined with textile preforms could provide a major breakthrough in achieving cost-effective composite aircraft structures. RTM uses resin in its lowest cost form, and storage and spoilage costs are minimal. Near net shape textile preforms are expected to be cost-effective because automated machines can be used to produce the preforms, post-cure operations such as machining and fastening are minimized, and material scrap rate may be reduced in comparison with traditional prepreg molding. The purpose of this paper is to discuss experimental and analytical techniques that are under development at NASA Langley to aid the engineer in developing RTM processes for airframe structural elements. Included are experimental techniques to characterize preform and resin behavior and analytical methods that were developed to predict resin flow and cure kinetics.

  11. Elevated-temperature Al alloys for aircraft structure

    Energy Technology Data Exchange (ETDEWEB)

    Rainen, R.A.; Ekvall, J.C.

    1988-05-01

    Elevated-temperature powder metallurgy (P/M) aluminum alloys are being developed to replace titanium aircraft structure materials for operation in the 300-600 F temperature range. Typical mechanical properties of P/M Al-Fe-Ce and Al-Fe-V-Si alloys are superior to those of conventional materials, and cost savings of 50 to 70 percent have been projected for these alloys which can be fabricated and processed using methods similar to those used in the production of conventional aluminum. 5 references.

  12. Laser Welding of Large Scale Stainless Steel Aircraft Structures

    Science.gov (United States)

    Reitemeyer, D.; Schultz, V.; Syassen, F.; Seefeld, T.; Vollertsen, F.

    In this paper a welding process for large scale stainless steel structures is presented. The process was developed according to the requirements of an aircraft application. Therefore, stringers are welded on a skin sheet in a t-joint configuration. The 0.6 mm thickness parts are welded with a thin disc laser, seam length up to 1920 mm are demonstrated. The welding process causes angular distortions of the skin sheet which are compensated by a subsequent laser straightening process. Based on a model straightening process parameters matching the induced welding distortion are predicted. The process combination is successfully applied to stringer stiffened specimens.

  13. Experimental study on mechanical properties of aircraft honeycomb sandwich structures

    Directory of Open Access Journals (Sweden)

    Talebi Mazraehshahi H.

    2010-06-01

    Full Text Available Mechanical behaviour of sandwich panels under different conditions have been exprimentally studied in this research to increase the knowledge of aircraft sandwich panel structures and facilitate design criteria for aircraft structures. Tests were concentrated on the honeycomb sandwich structures under different loads including flexural, insert shear, flat wise tension and compression loads. Furthermore, effect of core density and face material on mechanical behavior of different samples were investigated and compared with analytical and FEM method. Effects of skin thickness on strength of honycomb sandwhich panels under shear pull out and moments have also been considerd in this study. According to this investigation, insert strength and flexural test under different load conditions is strongly affected by face thickness, but compression and tearoff (falt wise tensile properties of a sandwich panel depends on core material. The study concludes that the correlation between experimental results and the analytical predictions will enable the designer to predict the mechanical behaviour and strength of a sandwich beam; however, applied formula may lead engineers to unreliable results for shear modulus.

  14. Titanium honeycomb structure. [for supersonic aircraft wing structure

    Science.gov (United States)

    Davis, R. A.; Elrod, S. D.; Lovell, D. T.

    1972-01-01

    A brazed titanium honeycomb sandwich system for supersonic transport wing cover panels provides the most efficient structure spanwise, chordwise, and loadwise. Flutter testing shows that high wing stiffness is most efficient in a sandwich structure. This structure also provides good thermal insulation if liquid fuel is carried in direct contact with the wing structure in integral fuel tanks.

  15. Material Distribution Optimization for the Shell Aircraft Composite Structure

    Science.gov (United States)

    Shevtsov, S.; Zhilyaev, I.; Oganesyan, P.; Axenov, V.

    2016-09-01

    One of the main goal in aircraft structures designing isweight decreasing and stiffness increasing. Composite structures recently became popular in aircraft because of their mechanical properties and wide range of optimization possibilities.Weight distribution and lay-up are keys to creating lightweight stiff strictures. In this paperwe discuss optimization of specific structure that undergoes the non-uniform air pressure at the different flight conditions and reduce a level of noise caused by the airflowinduced vibrations at the constrained weight of the part. Initial model was created with CAD tool Siemens NX, finite element analysis and post processing were performed with COMSOL Multiphysicsr and MATLABr. Numerical solutions of the Reynolds averaged Navier-Stokes (RANS) equations supplemented by k-w turbulence model provide the spatial distributions of air pressure applied to the shell surface. At the formulation of optimization problem the global strain energy calculated within the optimized shell was assumed as the objective. Wall thickness has been changed using parametric approach by an initiation of auxiliary sphere with varied radius and coordinates of the center, which were the design variables. To avoid a local stress concentration, wall thickness increment was defined as smooth function on the shell surface dependent of auxiliary sphere position and size. Our study consists of multiple steps: CAD/CAE transformation of the model, determining wind pressure for different flow angles, optimizing wall thickness distribution for specific flow angles, designing a lay-up for optimal material distribution. The studied structure was improved in terms of maximum and average strain energy at the constrained expense ofweight growth. Developed methods and tools can be applied to wide range of shell-like structures made of multilayered quasi-isotropic laminates.

  16. Comparison of Response between RC and SC Containment Structures Subjected to Aircraft Impact

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Sang Shup; Choi, In Kil [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Tae Hyo [Hanyang University, Seoul (Korea, Republic of)

    2012-05-15

    Since the aircraft terror to the World Trade Center (WTC) on September 11, 2001, an aircraft impact problem has been increasingly interested. The possibilities of aircraft impacts against nuclear power plants are one of important category. To date, the impact load of the analysis on aircraft impacts has been applied to target structures in local areas by using the impact force-time history function of Riera. However, Riera forcing function is not recommended at the expectation of unreasonable damage or perforation to target structures. The numerical analysis of rc and sc containment structures subjected to aircraft impact is performed by using the AUTODYN-3D. It is carried out the four different types for RC and SC structures. Thus, in this study, the different behaviors of containment structures and the safety of SC structure are expected

  17. A Study of Vehicle Structural Layouts in Post-WWII Aircraft

    Science.gov (United States)

    Sensmeier, Mark D.; Samareh, Jamshid A.

    2004-01-01

    In this paper, results of a study of structural layouts of post-WWII aircraft are presented. This study was undertaken to provide the background information necessary to determine typical layouts, design practices, and industry trends in aircraft structural design. Design decisions are often predicated not on performance-related criteria, but rather on such factors as manufacturability, maintenance access, and of course cost. For this reason, a thorough understanding of current best practices in the industry is required as an input for the design optimization process. To determine these best practices and industry trends, a large number of aircraft structural cutaway illustrations were analyzed for five different aircraft categories (commercial transport jets, business jets, combat jet aircraft, single engine propeller aircraft, and twin-engine propeller aircraft). Several aspects of wing design and fuselage design characteristics are presented here for the commercial transport and combat aircraft categories. A great deal of commonality was observed for transport structure designs over a range of eras and manufacturers. A much higher degree of variability in structural designs was observed for the combat aircraft, though some discernable trends were observed as well.

  18. Fibre Optic Sensors for Structural Health Monitoring of Aircraft Composite Structures: Recent Advances and Applications.

    Science.gov (United States)

    Di Sante, Raffaella

    2015-07-30

    In-service structural health monitoring of composite aircraft structures plays a key role in the assessment of their performance and integrity. In recent years, Fibre Optic Sensors (FOS) have proved to be a potentially excellent technique for real-time in-situ monitoring of these structures due to their numerous advantages, such as immunity to electromagnetic interference, small size, light weight, durability, and high bandwidth, which allows a great number of sensors to operate in the same system, and the possibility to be integrated within the material. However, more effort is still needed to bring the technology to a fully mature readiness level. In this paper, recent research and applications in structural health monitoring of composite aircraft structures using FOS have been critically reviewed, considering both the multi-point and distributed sensing techniques.

  19. Fibre Optic Sensors for Structural Health Monitoring of Aircraft Composite Structures: Recent Advances and Applications

    Directory of Open Access Journals (Sweden)

    Raffaella Di Sante

    2015-07-01

    Full Text Available In-service structural health monitoring of composite aircraft structures plays a key role in the assessment of their performance and integrity. In recent years, Fibre Optic Sensors (FOS have proved to be a potentially excellent technique for real-time in-situ monitoring of these structures due to their numerous advantages, such as immunity to electromagnetic interference, small size, light weight, durability, and high bandwidth, which allows a great number of sensors to operate in the same system, and the possibility to be integrated within the material. However, more effort is still needed to bring the technology to a fully mature readiness level. In this paper, recent research and applications in structural health monitoring of composite aircraft structures using FOS have been critically reviewed, considering both the multi-point and distributed sensing techniques.

  20. Component Representation for Shock Qualified Foundation Structure

    Directory of Open Access Journals (Sweden)

    Timothy Coats

    2003-01-01

    Full Text Available Navy ship foundations are typically designed for shock using the Navy's Dynamic Design Analysis Method. The NAVSEA 0908-LP-000-3010, Rev. 1 manual states that a component modeled as a lumped mass with rigid links should not provide constraint to the support structure. This ensures foundations are designed to withstand all shock loads without accounting for additional stiffness provided by the component. Investigations are provided herein to illustrate the trade-offs and consequences of several approaches for component representations. The observations reinforce the notion that one must give careful consideration for the system being modeled, the expected modal characteristics, and compliance with NAVSEA 0908-LP-000-3010, Rev. 1.

  1. Special Issue: Adaptive/Smart Structures and Multifunctional Materials with Application to Morphing Aircraft

    Directory of Open Access Journals (Sweden)

    Rafic Ajaj

    2014-12-01

    Full Text Available Recent advances in smart structures and multifunctional materials have facilitated many novel aerospace technologies such as morphing aircraft. A morphing aircraft, bio-inspired by natural fliers, has gained a lot of interest as a potential technology to meet the ambitious goals of the Advisory Council for Aeronautics Research in Europe (ACARE Vision 2020 and the FlightPath 2050 documents. A morphing aircraft continuously adjusts its wing geometry to enhance flight performance, control authority, and multi-mission capability.[...

  2. Auto-normalization algorithm for robotic precision drilling system in aircraft component assembly

    Institute of Scientific and Technical Information of China (English)

    Tian Wei; Zhou Weixue; Zhou Wei; Liao Wenhe; Zeng Yuanfan

    2013-01-01

    A novel approach is proposed to detect the normal vector to product surface in real time for the robotic precision drilling system in aircraft component assembly,and the auto-normalization algorithm is presented based on the detection system.Firstly,the deviation between the normal vector and the spindle axis is measured by the four laser displacement sensors installed at the head of the multi-function end effector.Then,the robot target attitude is inversely solved according to the auto-normalization algorithm.Finally,adjust the robot to the target attitude via pitch and yaw rotations about the tool center point and the spindle axis is corrected in line with the normal vector simultaneously.To test and verify the auto-normalization algorithm,an experimental platform is established in which the laser tracker is introduced for accurate measurement.The results show that the deviations between the corrected spindle axis and the normal vector are all reduced to less than 0.5°,with the mean value 0.32°.It is demonstrated the detection method and the autonormalization algorithm are feasible and reliable.

  3. Aging Aircraft Fleets: Structural and Other Subsystem Aspects (le Vieillissement des flottes d’avions militaires : aspects structures et autres sous-systemes)

    Science.gov (United States)

    2007-11-02

    disbonding between the face sheets and honeycomb core. In addition, core buckling is seen. Figure 11. Typical Impact Damage in Sandwich Structure with...significant research and development efforts currently underway in the area of nondestructive evaluation of aging aircraft . NASA LaRC and several...composite, sandwich construction) 2. Type of structural component to be repaired (skin, spar, rib, longeron, etc.) 3. Type and extent of damage (e.g

  4. A Knowledge Based Approach for Automated Modelling of Extended Wing Structures in Preliminary Aircraft Design

    OpenAIRE

    Dorbath, Felix; Nagel, Björn; Gollnick, Volker

    2011-01-01

    This paper introduces the concept of the ELWIS model generator for Finite Element models of aircraft wing structures. The physical modelling of the structure is extended beyond the wing primary structures, to increase the level of accuracy for aircraft which diverge from existing configurations. Also the impact of novel high lift technologies on structural masses can be captured already in the early stages of design by using the ELWIS models. The ELWIS model generator is able to c...

  5. A study on the utilization of advanced composites in commercial aircraft wing structure: Executive summary

    Science.gov (United States)

    Watts, D. J.

    1978-01-01

    The overall wing study objectives are to study and plan the effort by commercial transport aircraft manufacturers to accomplish the transition from current conventional materials and practices to extensive use of advanced composites in wings of aircraft that will enter service in the 1985-1990 time period. Specific wing study objectives are to define the technology and data needed to support an aircraft manufacturer's commitment to utilize composites primary wing structure in future production aircraft and to develop plans for a composite wing technology program which will provide the needed technology and data.

  6. Structured automated code checking through structural components and systems engineering

    NARCIS (Netherlands)

    Coenders, J.L.; Rolvink, A.

    2014-01-01

    This paper presents a proposal to employ the design computing methodology proposed as StructuralComponents (Rolvink et al [6] and van de Weerd et al [7]) as a method to perform a digital verification process to fulfil the requirements related to structural design and engineering as part of a buildin

  7. High Energy Wide Area Blunt Impact on Composite Aircraft Structures

    Science.gov (United States)

    DeFrancisci, Gabriela K.

    The largest source of damage to commercial aircraft is caused by accidental contact with ground service equipment (GSE). The cylindrical bumper typically found on GSE distributes the impact load over a large contact area, possibly spanning multiple internal structural elements (frame bays) of a stiffened-skin fuselage. This type of impact can lead to damage that is widespread and difficult to detect visually. To address this problem, monolithic composite panels of various size and complexity have been modeled and tested quasi-statically and dynamically. The experimental observations have established that detectability is dependent on the impact location and immediately-adjacent internal structure of the panel, as well as the impactor geometry and total deformation of the panel. A methodology to model and predict damage caused by wide area blunt impact events was established, which was then applied to more general cases that were not tested in order to better understand the nature of this type of impact event and how it relates to the final damage state and visual detectability.

  8. Theory of Economic Life Prediction and Reliability Assessment of Aircraft Structures

    Institute of Scientific and Technical Information of China (English)

    YAN Chuliang; LIU Kege

    2011-01-01

    The theory of economic life prediction and reliability assessment of aircraft structures has a significant effect on safety of aircraft structures.It is based on the two-stage theory of fatigue process and can guarantee the safety and reliability of structures.According to the fatigue damage process, the fatigue scatter factors of crack initiation stage and crack propagation stage are given respectively.At the same time, mathematical models of fatigue life prediction are presented by utilizing the fatigue scatter factors and full scale test results of aircraft structures.Furthermore, the economic life model is put forward.The model is of significant scientific value for products to provide longer economic life, higher reliability and lower cost.The theory of economic life prediction and reliability assessment of aircraft structures has been successfully applied to determining and extending the structural life for thousands of airplanes.

  9. Structural Health Management of Damaged Aircraft Structures Using the Digital Twin Concept

    Science.gov (United States)

    Seshadri, Banavara R.; Krishnamurthy, Thiagarajan

    2017-01-01

    The development of multidisciplinary integrated Structural Health Management (SHM) tools will enable accurate detection, and prognosis of damaged aircraft under normal and adverse conditions during flight. As part of the digital twin concept, methodologies are developed by using integrated multiphysics models, sensor information and input data from an in-service vehicle to mirror and predict the life of its corresponding physical twin. SHM tools are necessary for both damage diagnostics and prognostics for continued safe operation of damaged aircraft structures. The adverse conditions include loss of control caused by environmental factors, actuator and sensor faults or failures, and structural damage conditions. A major concern in these structures is the growth of undetected damage/cracks due to fatigue and low velocity foreign object impact that can reach a critical size during flight, resulting in loss of control of the aircraft. To avoid unstable, catastrophic propagation of damage during a flight, load levels must be maintained that are below a reduced load-carrying capacity for continued safe operation of an aircraft. Hence, a capability is needed for accurate real-time predictions of damage size and safe load carrying capacity for structures with complex damage configurations. In the present work, a procedure is developed that uses guided wave responses to interrogate damage. As the guided wave interacts with damage, the signal attenuates in some directions and reflects in others. This results in a difference in signal magnitude as well as phase shifts between signal responses for damaged and undamaged structures. Accurate estimation of damage size, location, and orientation is made by evaluating the cumulative signal responses at various pre-selected sensor locations using a genetic algorithm (GA) based optimization procedure. The damage size, location, and orientation is obtained by minimizing the difference between the reference responses and the

  10. Resistance ability evaluation of safety-related structures for the simulated aircraft accident

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Jin; Kim, Sung Woon; Choi, Jang Kyu [Daewoo E and C Co., Ltd., Suwon (Korea, Republic of)] (and others)

    2003-03-15

    Aircraft accidents on nuclear safety-related structures can cause severe damage to the safety of NPP(Nuclear Power Plant)s. To assess the safety of nuclear safety-related structures, the local damage and the dynamic response of global structures should be investigated together. This study have compared several local damage assessment formulas suggested for aircraft as an impactor, and have set the assessment system of local damage for impact-proof design of NPP containment buildings. And the local damage of nuclear safety-related structures in operation in Korea for commercial aircraft as impactor have been estimated. Impact load-time functions of the aircraft crash have been decided to assessment the safety of nuclear safety-related structures against the intentional colliding of commercial aircraft. Boeing 747 and Boeing 767 is selected as target aircraft based on the operation frequencies and weights. Comparison of the fire analysis methods showed that the method considering heat convection and radiation is adequate for the temperature analysis of the aircraft fuel fire. Finally, the study covered the analysis of the major structural drawings and design drawings with which three-dimensional finite element model analysis is expected to be performed.

  11. Lightweight Thermoformed Structural Components and Optics

    Science.gov (United States)

    Zeiders, Glenn W.; Bradford, Larry J.

    2004-01-01

    A technique that involves the use of thermoformed plastics has been developed to enable the design and fabrication of ultra-lightweight structural components and mirrors for use in outer space. The technique could also be used to produce items for special terrestrial uses in which minimization of weight is a primary design consideration. Although the inherent strengths of thermoplastics are clearly inferior to those of metals and composite materials, thermoplastics offer a distinct advantage in that they can be shaped, at elevated temperatures, to replicate surfaces (e.g., prescribed mirror surfaces) precisely. Furthermore, multiple elements can be bonded into structures of homogeneous design that display minimal thermal deformation aside from simple expansion. The design aspect of the present technique is based on the principle that the deflection of a plate that has internal structure depends far more on the overall thickness than on the internal details; thus, a very stiff, light structure can be made from thin plastic that is heatformed to produce a sufficiently high moment of inertia. General examples of such structures include I beams and eggcrates.

  12. Graphene/Epoxy Coating as Multifunctional Material for Aircraft Structures

    Directory of Open Access Journals (Sweden)

    Tullio Monetta

    2015-06-01

    Full Text Available Recently, the use of graphene as a conductive nanofiller in the preparation of inorganic/polymer nanocomposites has attracted increasing interest in the aerospace field. The reason for this is the possibility of overcoming problems strictly connected to the aircraft structures, such as electrical conductivity and thus lightning strike protection. In addition, graphene is an ideal candidate to enhance the anti-corrosion properties of the resin, since it absorbs most of the light and provides hydrophobicity for repelling water. An important aspect of these multifunctional materials is that all these improvements can be realized even at very low filler loadings in the polymer matrix. In this work, graphene nanoflakes were incorporated into a water-based epoxy resin, and then the hybrid coating was applied to Al 2024-T3 samples. The addition of graphene considerably improved some physical properties of the hybrid coating as demonstrated by Electrochemical Impedance Spectroscopy (EIS analysis, ameliorating anti-corrosion performances of raw material. DSC measurements and Cross-cut Test showed that graphene did not affect the curing process or the adhesion properties. Moreover, an increment of water contact angle was displayed.

  13. Creating a Test Validated Structural Dynamic Finite Element Model of the X-56A Aircraft

    Science.gov (United States)

    Pak, Chan-Gi; Truong, Samson

    2014-01-01

    Small modeling errors in the finite element model will eventually induce errors in the structural flexibility and mass, thus propagating into unpredictable errors in the unsteady aerodynamics and the control law design. One of the primary objectives of the Multi Utility Technology Test-bed, X-56A aircraft, is the flight demonstration of active flutter suppression, and therefore in this study, the identification of the primary and secondary modes for the structural model tuning based on the flutter analysis of the X-56A aircraft. The ground vibration test-validated structural dynamic finite element model of the X-56A aircraft is created in this study. The structural dynamic finite element model of the X-56A aircraft is improved using a model tuning tool. In this study, two different weight configurations of the X-56A aircraft have been improved in a single optimization run. Frequency and the cross-orthogonality (mode shape) matrix were the primary focus for improvement, while other properties such as center of gravity location, total weight, and offdiagonal terms of the mass orthogonality matrix were used as constraints. The end result was a more improved and desirable structural dynamic finite element model configuration for the X-56A aircraft. Improved frequencies and mode shapes in this study increased average flutter speeds of the X-56A aircraft by 7.6% compared to the baseline model.

  14. Creating a Test-Validated Finite-Element Model of the X-56A Aircraft Structure

    Science.gov (United States)

    Pak, Chan-Gi; Truong, Samson

    2014-01-01

    Small modeling errors in a finite-element model will eventually induce errors in the structural flexibility and mass, thus propagating into unpredictable errors in the unsteady aerodynamics and the control law design. One of the primary objectives of the X-56A Multi-Utility Technology Testbed aircraft is the flight demonstration of active flutter suppression and, therefore, in this study, the identification of the primary and secondary modes for the structural model tuning based on the flutter analysis of the X-56A aircraft. The ground-vibration test-validated structural dynamic finite-element model of the X-56A aircraft is created in this study. The structural dynamic finite-element model of the X-56A aircraft is improved using a model-tuning tool. In this study, two different weight configurations of the X-56A aircraft have been improved in a single optimization run. Frequency and the cross-orthogonality (mode shape) matrix were the primary focus for improvement, whereas other properties such as c.g. location, total weight, and off-diagonal terms of the mass orthogonality matrix were used as constraints. The end result was an improved structural dynamic finite-element model configuration for the X-56A aircraft. Improved frequencies and mode shapes in this study increased average flutter speeds of the X-56A aircraft by 7.6% compared to the baseline model.

  15. Aircraft wing structural detail design (wing, aileron, flaps, and subsystems)

    Science.gov (United States)

    Downs, Robert; Zable, Mike; Hughes, James; Heiser, Terry; Adrian, Kenneth

    1993-01-01

    The goal of this project was to design, in detail, the wing, flaps, and ailerons for a primary flight trainer. Integrated in this design are provisions for the fuel system, the electrical system, and the fuselage/cabin carry-through interface structure. This conceptual design displays the general arrangement of all major components in the wing structure, taking into consideration the requirements set forth by the appropriate sections of Federal Aviation Regulation Part 23 (FAR23) as well as those established in the statement of work.

  16. A Study of the Utilization of Advanced Composites in Fuselage Structures of Commercial Aircraft

    Science.gov (United States)

    Watts, D. J.; Sumida, P. T.; Bunin, B. L.; Janicki, G. S.; Walker, J. V.; Fox, B. R.

    1985-01-01

    A study was conducted to define the technology and data needed to support the introduction of advanced composites in the future production of fuselage structure in large transport aircraft. Fuselage structures of six candidate airplanes were evaluated for the baseline component. The MD-100 was selected on the basis of its representation of 1990s fuselage structure, an available data base, its impact on the schedule and cost of the development program, and its availability and suitability for flight service evaluation. Acceptance criteria were defined, technology issues were identified, and a composite fuselage technology development plan, including full-scale tests, was identified. The plan was based on composite materials to be available in the mid to late 1980s. Program resources required to develop composite fuselage technology are estimated at a rough order of magnitude to be 877 man-years exclusive of the bird strike and impact dynamic test components. A conceptual composite fuselage was designed, retaining the basic MD-100 structural arrangement for doors, windows, wing, wheel wells, cockpit enclosure, major bulkheads, etc., resulting in a 32 percent weight savings.

  17. StructuralComponents: a software system for conceptual structural design

    NARCIS (Netherlands)

    Van de Weerd, B.; Rolvink, A.; Coenders, J.L.

    2012-01-01

    Conceptual design is the starting point of the design process. The conceptual design stage comprises the formation of several ideas or design concepts to meet the imposed constraints. StructuralComponents is a software application that attempts to provide the designing engineer with a suitable set o

  18. Proceedings of the Symposium on Welding, Bonding, and Fastening. [production engineering for aircraft and spacecraft structures

    Science.gov (United States)

    Stein, B. A. (Compiler); Buckley, J. D. (Compiler)

    1972-01-01

    Various technological processes to achieve lightweight reliable joining systems for structural elements of aircraft and spacecraft are considered. Joining methods, combinations of them, and nondestructive evaluation and quality assurance are emphasized.

  19. Aeroelasticity of Axially Loaded Aerodynamic Structures for Truss-Braced Wing Aircraft

    Science.gov (United States)

    Nguyen, Nhan; Ting, Eric; Lebofsky, Sonia

    2015-01-01

    This paper presents an aeroelastic finite-element formulation for axially loaded aerodynamic structures. The presence of axial loading causes the bending and torsional sitffnesses to change. For aircraft with axially loaded structures such as the truss-braced wing aircraft, the aeroelastic behaviors of such structures are nonlinear and depend on the aerodynamic loading exerted on these structures. Under axial strain, a tensile force is created which can influence the stiffness of the overall aircraft structure. This tension stiffening is a geometric nonlinear effect that needs to be captured in aeroelastic analyses to better understand the behaviors of these types of aircraft structures. A frequency analysis of a rotating blade structure is performed to demonstrate the analytical method. A flutter analysis of a truss-braced wing aircraft is performed to analyze the effect of geometric nonlinear effect of tension stiffening on the flutter speed. The results show that the geometric nonlinear tension stiffening effect can have a significant impact on the flutter speed prediction. In general, increased wing loading results in an increase in the flutter speed. The study illustrates the importance of accounting for the geometric nonlinear tension stiffening effect in analyzing the truss-braced wing aircraft.

  20. A KBE-enabled design framework for cost/weight optimization study of aircraft composite structures

    Science.gov (United States)

    Wang, H.; La Rocca, G.; van Tooren, M. J. L.

    2014-10-01

    Traditionally, minimum weight is the objective when optimizing airframe structures. This optimization, however, does not consider the manufacturing cost which actually determines the profit of the airframe manufacturer. To this purpose, a design framework has been developed able to perform cost/weight multi-objective optimization of an aircraft component, including large topology variations of the structural configuration. The key element of the proposed framework is a dedicated knowledge based engineering (KBE) application, called multi-model generator, which enables modelling very different product configurations and variants and extract all data required to feed the weight and cost estimation modules, in a fully automated fashion. The weight estimation method developed in this research work uses Finite Element Analysis to calculate the internal stresses of the structural elements and an analytical composite plate sizing method to determine their minimum required thicknesses. The manufacturing cost estimation module was developed on the basis of a cost model available in literature. The capability of the framework was successfully demonstrated by designing and optimizing the composite structure of a business jet rudder. The study case indicates the design framework is able to find the Pareto optimal set for minimum structural weight and manufacturing costin a very quick way. Based on the Pareto set, the rudder manufacturer is in conditions to conduct both internal trade-off studies between minimum weight and minimum cost solutions, as well as to offer the OEM a full set of optimized options to choose, rather than one feasible design.

  1. Current and Future Research in Active Control of Lightweight, Flexible Structures Using the X-56 Aircraft

    Science.gov (United States)

    Ryan, John J.; Bosworth, John T.; Burken, John J.; Suh, Peter M.

    2014-01-01

    The X-56 Multi-Utility Technology Testbed aircraft system is a versatile experimental research flight platform. The system was primarily designed to investigate active control of lightweight flexible structures, but is reconfigurable and capable of hosting a wide breadth of research. Current research includes flight experimentation of a Lockheed Martin designed active control flutter suppression system. Future research plans continue experimentation with alternative control systems, explore the use of novel sensor systems, and experiments with the use of novel control effectors. This paper describes the aircraft system, current research efforts designed around the system, and future planned research efforts that will be hosted on the aircraft system.

  2. Optimization of a Human-Powered Aircraft Using Fluid–Structure Interaction Simulations

    Directory of Open Access Journals (Sweden)

    Bob Vanderhoydonck

    2016-08-01

    Full Text Available The special type of aircrafts in which the human power of the pilot is sufficient to take off and sustain flight are known as Human-Powered Aircrafts (HPAs. To explore the peculiarities of these aircrafts, the aerodynamic performance of an existing design is evaluated first, using both the vortex lattice method and computational fluid dynamics. In a second step, it is attempted to design and optimize a new HPA capable of winning the Kremer International Marathon Competition. The design will be special in that it allows one to include a second pilot on board the aircraft. As the structural deflection of the wing is found to be a key aspect during design, fluid–structure interaction simulations are performed and included in the optimization procedure. To assess the feasibility of winning the competition, the physical performance of candidate pilots is measured and compared with the predicted required power.

  3. Role of structural noise in aircraft pressure cockpit from vibration action of new-generation engines

    Science.gov (United States)

    Baklanov, V. S.

    2016-07-01

    The evolution of new-generation aircraft engines is transitioning from a bypass ratio of 4-6 to an increased ratio of 8-12. This is leading to substantial broadening of the vibration spectrum of engines with a shift to the low-frequency range due to decreased rotation speed of the fan rotor, in turn requiring new solutions to decrease structural noise from engine vibrations to ensure comfort in the cockpits and cabins of aircraft.

  4. Measurements of the high energy neutron component of cosmic radiation fields in aircraft using etched track dosemeters

    CERN Document Server

    Bartlett, D T; Tanner, R J; Steele, J D

    2001-01-01

    Measurements of the complex cosmic radiation field in aircraft at altitude are made with a passive survey meter comprising routine-use thermoluminescent detectors and etched track detectors. The energy dependence of response of the etched track detectors used to determine the neutron component has been characterized, partly, up to a neutron energy of 180 MeV. The neutron detectors are routinely calibrated in the CERN EC Ref.Field. The 15% determination level for total dose equivalent is 100 mu Sv. The evidence is that the passive survey meter provides a reliable determination of route dose. (41 refs).

  5. Application of variable structure system theory to aircraft flight control. [AV-8A and the Augmentor Wing Jet STOL Research Aircraft

    Science.gov (United States)

    Calise, A. J.; Kadushin, I.; Kramer, F.

    1981-01-01

    The current status of research on the application of variable structure system (VSS) theory to design aircraft flight control systems is summarized. Two aircraft types are currently being investigated: the Augmentor Wing Jet STOL Research Aircraft (AWJSRA), and AV-8A Harrier. The AWJSRA design considers automatic control of longitudinal dynamics during the landing phase. The main task for the AWJSRA is to design an automatic landing system that captures and tracks a localizer beam. The control task for the AV-8A is to track velocity commands in a hovering flight configuration. Much effort was devoted to developing computer programs that are needed to carry out VSS design in a multivariable frame work, and in becoming familiar with the dynamics and control problems associated with the aircraft types under investigation. Numerous VSS design schemes were explored, particularly for the AWJSRA. The approaches that appear best suited for these aircraft types are presented. Examples are given of the numerical results currently being generated.

  6. Investigation on strain sensing properties of carbon-based nanocomposites for structural aircraft applications

    Science.gov (United States)

    Lamberti, Patrizia; Spinelli, Giovanni; Tucci, Vincenzo; Guadagno, Liberata; Vertuccio, Luigi; Russo, Salvatore

    2016-05-01

    The mechanical and electrical properties of a thermosetting epoxy resin particularly indicated for the realization of structural aeronautic components and reinforced with multiwalled carbon nanotubes (MWCNTs, at 0.3 wt%) are investigated for specimens subjected to cycles and different levels of applied strain (i.e. ɛ) loaded both in axial tension and flexural mode. It is found that the piezoresistive behavior of the resulting nanocomposite evaluated in terms of variation of the electrical resistance is strongly affected by the applied mechanical stress mainly due to the high sensibility and consequent rearrangement of the electrical percolating network formed by MWCNTs in the composite at rest or even under a small strain. In fact, the variations in electrical resistance that occur during the mechanical stress are correlated to the deformation exhibited by the nanocomposites. In particular, the overall response of electrical resistance of the composite is characterized by a linear increase with the strain at least in the region of elastic deformation of the material in which the gauge factor (i.e. G.F.) of the sensor is usually evaluated. Therefore, the present study aims at investigating the possible use of the nanotechnology for application of embedded sensor systems in composite structures thus having capability of self-sensing and of responding to the surrounding environmental changes, which are some fundamental requirements especially for structural aircraft monitoring applications.

  7. Development of pressure containment and damage tolerance technology for composite fuselage structures in large transport aircraft

    Science.gov (United States)

    Smith, P. J.; Thomson, L. W.; Wilson, R. D.

    1986-01-01

    NASA sponsored composites research and development programs were set in place to develop the critical engineering technologies in large transport aircraft structures. This NASA-Boeing program focused on the critical issues of damage tolerance and pressure containment generic to the fuselage structure of large pressurized aircraft. Skin-stringer and honeycomb sandwich composite fuselage shell designs were evaluated to resolve these issues. Analyses were developed to model the structural response of the fuselage shell designs, and a development test program evaluated the selected design configurations to appropriate load conditions.

  8. Monitoring of hidden fatigue crack growth in multi-layer aircraft structures using high frequency guided waves

    Science.gov (United States)

    Chan, H.; Masserey, B.; Fromme, P.

    2015-03-01

    Varying loading conditions of aircraft structures result in stress concentration at fastener holes, where multi-layered components are connected, potentially leading to the development of hidden fatigue cracks in inaccessible layers. High frequency guided waves propagating along the structure allow for the structural health monitoring (SHM) of such components, e.g., aircraft wings. Experimentally the required guided wave modes can be easily excited using standard ultrasonic wedge transducers. However, the sensitivity for the detection of small, potentially hidden, fatigue cracks has to be ascertained. The type of multi-layered model structure investigated consists of two adhesively bonded aluminum plate-strips with a sealant layer. Fatigue experiments were carried out and the growth of fatigue cracks at the fastener hole in one of the metallic layers was monitored optically during cyclic loading. The influence of the fatigue cracks of increasing size on the scattered guided wave field was evaluated. The sensitivity and repeatability of the high frequency guided wave modes to detect and monitor the fatigue crack growth was investigated, using both standard pulse-echo equipment and a laser interferometer. The potential for hidden fatigue crack growth monitoring at critical and difficult to access fastener locations from a stand-off distance was ascertained. The robustness of the methodology for practical in situ ultrasonic monitoring of fatigue crack growth is discussed.

  9. An estimation method for direct maintenance cost of aircraft components based on particle swarm optimization with immunity algorithm

    Institute of Scientific and Technical Information of China (English)

    WU Jing-min; ZUO Hong-fu; CHEN Yong

    2005-01-01

    A particle swarm optimization (PSO) algorithm improved by immunity algorithm (IA) was presented.Memory and self-regulation mechanisms of IA were used to avoid PSO plunging into local optima. Vaccination and immune selection mechanisms were used to prevent the undulate phenomenon during the evolutionary process. The algorithm was introduced through an application in the direct maintenance cost (DMC) estimation of aircraft components. Experiments results show that the algorithm can compute simply and run quickly. It resolves the combinatorial optimization problem of component DMC estimation with simple and available parameters. And it has higher accuracy than individual methods, such as PLS, BP and v-SVM, and also has better performance than other combined methods, such as basic PSO and BP neural network.

  10. 飞机结构性腐蚀和维护%Aircraft Structure Corrosion and Maintenance

    Institute of Scientific and Technical Information of China (English)

    姜福成

    2016-01-01

    在飞机的日常检修和维护过程中,其飞机结构性的腐蚀所造成的问题困扰着日常的航空飞机检修工作。本文通过简述飞机所面对的结构腐蚀问题产生的原因和特点,指出其结构腐蚀对于飞机的发动机、性能等的伤害,并总结日常生活中对飞机结构腐蚀的维护和预防方法。通过探讨这些问题,希望能对航空的机务维修工作带来一些可操作性的建议。%In the daily maintenance and maintenance of the airplane in the process, because of the aircraft structural corrosion caused by problems with daily aviation aircraft maintenance work. Based on aircraft structure corrosion problems facing, through briefly describes the reasons and characteristics, and points out its structure corrosion for aircraft engine, performance such as damage, through these phenomena summarized in daily life for the maintenance of aircraft structure corrosion and prevention method, based on the discussion to these questions, hope to have the aviation maintenance repair work to bring some feasibility Suggestions.

  11. Robust identification method for nonlinear model structures and its application to high-performance aircraft

    Science.gov (United States)

    Shi, Zhong-Ke; Wu, Fang-Xiang

    2013-06-01

    A common assumption is that the model structure is known for modelling high performance aircraft. In practice, this is not the case. Actually, structure identification plays the most important role in the processing of nonlinear system modelling. The integration of mode structure identification and parameter estimation is an efficient method to construct the model for high performance aircraft, which is nonlinear and also contains uncertainties. This article presents an efficient method for identifying nonlinear model structure and estimating parameters for high-performance aircraft model, which contains uncertainties. The parameters associated with nonlinear terms are considered one after the other if they should be included in the nonlinear model until a stopping criterion is met, which is based on Akaike's information criterion. A numerically efficient U-D factorisation is presented to avoid complex computation of high-order matrices. The proposed method is applied to flight test data of a high-performance aircraft. The results demonstrate that the proposed method could obtain the good aircraft model with a reasonably good fidelity based on the comparison with flight test data.

  12. Investigation of vulnerability of aircraft structure and materials towards cabin explosions

    NARCIS (Netherlands)

    Wentzel, C.M.; Kasteele, R.M. van de; Soetens, F.

    2007-01-01

    Damage Tolerance of aircraft fuselage structures has a strong link to explosion resistance. Though accidental explosions can and do occur, intentional explosions are more common as the terrorist threat increases. Structural toughness is as welcome in these scenarios as it is under penetration of non

  13. Aircraft noise reduction technology. [to show impact on individuals and communities, component noise sources, and operational procedures to reduce impact

    Science.gov (United States)

    1973-01-01

    Aircraft and airport noise reduction technology programs conducted by NASA are presented. The subjects discussed are: (1) effects of aircraft noise on individuals and communities, (2) status of aircraft source noise technology, (3) operational procedures to reduce the impact of aircraft noise, and (4) NASA relations with military services in aircraft noise problems. References to more detailed technical literature on the subjects discussed are included.

  14. Evaluation of Braided Stiffener Concepts for Transport Aircraft Wing Structure Applications

    Science.gov (United States)

    Deaton, Jerry W.; Dexter, H. Benson (Editor); Markus, Alan; Rohwer, Kim

    1995-01-01

    Braided composite materials have potential for application in aircraft structures. Stiffeners, wing spars, floor beams, and fuselage frames are examples where braided composites could find application if cost effective processing and damage requirements are met. Braiding is an automated process for obtaining near-net shape preforms for fabrication of components for structural applications. Previous test results on braided composite materials obtained at NASA Langley indicate that damage tolerance requirements can be met for some applications. In addition, the braiding industry is taking steps to increase the material through-put to be more competitive with other preform fabrication processes. Data are presented on the compressive behavior of three braided stiffener preform fabric constructions as determined from individual stiffener crippling test and three stiffener wide panel tests. Stiffener and panel fabrication are described and compression data presented for specimens tested with and without impact damage. In addition, data are also presented on the compressive behavior of the stitched stiffener preform construction currently being used by McDonnell Douglas Aerospace in the NASA ACT wing development program.

  15. Probabilistic analysis of aircraft crashes with explicit analysis of the building structure perforation; Probabilistische Analyse von Flugzeugabstuerzen mit expliziter Analyse der Perforation von Gebaeudestrukturen

    Energy Technology Data Exchange (ETDEWEB)

    Reichert, Mathias; Pacharzina, Benedykt; Oberste-Schemmann, Andre; Sassen, Felix [Westinghouse Electric Germany GmbH, Mannheim (Germany)

    2012-11-01

    For probabilistic safety analyses (PSA) the estimation of aircraft crash induced core damage frequencies is required. Westinghouse developed a methodology for a realistic evaluation of accident sequences caused by aircraft crashes. The analysis includes two steps: the analysis of sequence of accident events and the analysis of damage mechanisms. For the aircraft crash induced accident sequences new detailed event trees were prepared for application in the PSA. The damage mechanisms include kerosene combustion, by building structures transferred vibrations with direct or mediated effects on safety systems, and direct impacts due to the penetration of building structures. The presented methodology evaluates solely the direct impact by penetration of building structures by simulation of the aircraft crash. It was assumed that the other damage mechanisms do not yield significant contributions to the non-availability of safety system components. It was shown that the calculated core damage frequencies for hypothetical aircraft crashes using the new methodology are about one magnitude lower than the results of conservative methods.

  16. Frequency-domain identification of aircraft structural modes from short-duration flight tests

    Science.gov (United States)

    Vayssettes, J.; Mercère, G.; Vacher, P.; De Callafon, R. A.

    2014-07-01

    This article presents identification algorithms dedicated to the modal analysis of civil aircraft structures during in-flight flutter tests. This particular operational framework implies several specifications for the identification procedure. To comply with these requirements, the identification problem is formulated in the frequency domain as an output-error problem. Iterative identification methods based on structured matrix fraction descriptions are used to solve this problem and to identify a continuous-time model. These iterative methods are specifically designed to deal with experiments where short-duration tests with multiple-input excitations are used. These algorithms are first discussed and then evaluated through a simulation example illustrative of the in-flight modal analysis of a civil aircraft. Based on these evaluation results, an efficient iterative algorithm is suggested and applied to real flight-test data measured on board a military aircraft.

  17. Structural Load Alleviation Applied to Next Generation Aircraft and Wind Turbines

    Science.gov (United States)

    Frost, Susan

    2011-01-01

    Reducing the environmental impact of aviation is a goal of the Subsonic Fixed Wing Project under the Fundamental Aeronautics Program of NASAs Aeronautics Research Mission Directorate. Environmental impact of aviation is being addressed by novel aircraft configurations and materials that reduce aircraft weight and increase aerodynamic efficiency. NASA is developing tools to address the challenges of increased airframe flexibility created by wings constructed with reduced structural material and novel light-weight materials. This talk will present a framework and demonstration of a flight control system using optimal control allocation with structural load feedback and constraints to achieve safe aircraft operation. As wind turbines age, they become susceptible to many forms of blade degradation. Results will be presented on work in progress that uses adaptive contingency control for load mitigation in a wind turbine simulation with blade damage progression modeled.

  18. Examination of pulsed eddy current for inspection of second layer aircraft wing lap-joint structures using outlier detection methods

    Energy Technology Data Exchange (ETDEWEB)

    Butt, D.M., E-mail: Dennis.Butt@forces.gc.ca [Royal Military College of Canada, Dept. of Chemistry and Chemical Engineering, Kingston, Ontario (Canada); Underhill, P.R.; Krause, T.W., E-mail: Thomas.Krause@rmc.ca [Royal Military College of Canada, Dept. of Physics, Kingston, Ontario (Canada)

    2016-09-15

    Ageing aircraft are susceptible to fatigue cracks at bolt hole locations in multi-layer aluminum wing lap-joints due to cyclic loading conditions experienced during typical aircraft operation, Current inspection techniques require removal of fasteners to permit inspection of the second layer from within the bolt hole. Inspection from the top layer without fastener removal is desirable in order to minimize aircraft downtime while reducing the risk of collateral damage. The ability to detect second layer cracks without fastener removal has been demonstrated using a pulsed eddy current (PEC) technique. The technique utilizes a breakdown of the measured signal response into its principal components, each of which is multiplied by a representative factor known as a score. The reduced data set of scores, which represent the measured signal, are examined for outliers using cluster analysis methods in order to detect the presence of defects. However, the cluster analysis methodology is limited by the fact that a number of representative signals, obtained from fasteners where defects are not present, are required in order to perform classification of the data. Alternatively, blind outlier detection can be achieved without having to obtain representative defect-free signals, by using a modified smallest half-volume (MSHV) approach. Results obtained using this approach suggest that self-calibrating blind detection of cyclic fatigue cracks in second layer wing structures in the presence of ferrous fasteners is possible without prior knowledge of the sample under test and without the use of costly calibration standards. (author)

  19. Full-Scale Structural and NDI Validation Tests of Bonded Composite Doublers for Commercial Aircraft Applications

    Energy Technology Data Exchange (ETDEWEB)

    Roach, D.; Walkington, P.

    1999-02-01

    Composite doublers, or repair patches, provide an innovative repair technique which can enhance the way aircraft are maintained. Instead of riveting multiple steel or aluminum plates to facilitate an aircraft repair, it is possible to bond a single Boron-Epoxy composite doubler to the damaged structure. Most of the concerns surrounding composite doubler technology pertain to long-term survivability, especially in the presence of non-optimum installations, and the validation of appropriate inspection procedures. This report focuses on a series of full-scale structural and nondestructive inspection (NDI) tests that were conducted to investigate the performance of Boron-Epoxy composite doublers. Full-scale tests were conducted on fuselage panels cut from retired aircraft. These full-scale tests studied stress reductions, crack mitigation, and load transfer capabilities of composite doublers using simulated flight conditions of cabin pressure and axial stress. Also, structures which modeled key aspects of aircraft structure repairs were subjected to extreme tension, shear and bending loads to examine the composite laminate's resistance to disbond and delamination flaws. Several of the structures were loaded to failure in order to determine doubler design margins. Nondestructive inspections were conducted throughout the test series in order to validate appropriate techniques on actual aircraft structure. The test results showed that a properly designed and installed composite doubler is able to enhance fatigue life, transfer load away from damaged structure, and avoid the introduction of new stress risers (i.e. eliminate global reduction in the fatigue life of the structure). Comparisons with test data obtained prior to the doubler installation revealed that stresses in the parent material can be reduced 30%--60% through the use of the composite doubler. Tests to failure demonstrated that the bondline is able to transfer plastic strains into the doubler and that

  20. Numerical simulation of aircraft crash on nuclear containment structure

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, M.A., E-mail: iqbalfce@iitr.ernet.in [Department of Civil Engineering, Indian Institute of Technology Roorkee, Roorkee 247667 (India); Rai, S.; Sadique, M.R.; Bhargava, P. [Department of Civil Engineering, Indian Institute of Technology Roorkee, Roorkee 247667 (India)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer The deformation was more localised at the center of cylindrical portion. Black-Right-Pointing-Pointer The peak deflection at the junction of dome and cylinder was found to be 67 mm. Black-Right-Pointing-Pointer The peak deflection at midpoint of the cylindrical portion was found to be 88.9 mm. Black-Right-Pointing-Pointer The strain rate was found to be an important parameter to effect the deformation. Black-Right-Pointing-Pointer The model without strain rate and 290 s{sup -1} strain rate predicted very high deformations. - Abstract: Numerical simulations were carried with ABAQUS/Explicit finite element code in order to predict the response of BWR Mark III type nuclear containment against Boeing 707-320 aircraft crash. The load of the aircraft was applied using and force history curve. The damaged plasticity model was used to predict the behavior of concrete while the Johnson-Cook elasto-viscoplastic material model was used to incorporate the behavior of steel reinforcement. The crash was considered to occur at two different locations i.e., the midpoint of the cylindrical portion and the junction of dome and cylinder. The midpoint of the cylindrical portion experienced more deformation. The strain rate in the material model was varied and found to have a significant effect on the response of containment. The results of the present investigation were compared with those of the studies available in literature and a close agreement with the previous results was found in terms of maximum target deformation.

  1. Aircraft health and usage monitoring system for in-flight strain measurement of a wing structure

    Science.gov (United States)

    Kim, Jin-Hyuk; Park, Yurim; Kim, Yoon-Young; Shrestha, Pratik; Kim, Chun-Gon

    2015-10-01

    This paper presents an aircraft health and usage monitoring system (HUMS) using fiber Bragg grating (FBG) sensors. This study aims to implement and evaluate the HUMS for in-flight strain monitoring of aircraft structures. An optical-fiber-based HUMS was developed and applied to an ultralight aircraft that has a rectangular wing shape with a strut-braced configuration. FBG sensor arrays were embedded into the wing structure during the manufacturing process for effective sensor implementation. Ground and flight tests were conducted to verify the integrity and availability of the installed FBG sensors and HUMS devices. A total of 74 flight tests were conducted using the HUMS implemented testbed aircraft, considering various maneuvers and abnormal conditions. The flight test results revealed that the FBG-based HUMS was successfully implemented on the testbed aircraft and operated normally under the actual flight test environments as well as providing reliable in-flight strain data from the FBG sensors over a long period of time.

  2. Temperature-compensated strain measurement of full-scale small aircraft wing structure using low-cost FBG interrogator

    Science.gov (United States)

    Kim, J. H.; Lee, Y. G.; Park, Y.; Kim, C. G.

    2013-04-01

    Recently, health and usage monitoring systems (HUMS) are being studied to monitor the real-time condition of aircrafts during flight. HUMSs can prevent aircraft accidents and reduce inspection time and cost. Fiber Bragg grating (FBG) sensors are widely used for aircraft HUMSs with many advantages such as light weight, small size, easy-multiplexing, and EMI immunity. However, commercial FBG interrogators are too expensive to apply for small aircrafts. Generally the cost of conventional FBG interrogators is over 20,000. Therefore, cost-effective FBG interrogation systems need to be developed for small aircraft HUMSs. In this study, cost-effective low speed FBG interrogator was applied to full-scale small aircraft wing structure to examine the operational applicability of the low speed FBG interrogator to the monitoring of small aircrafts. The cost of the developed low speed FBG interrogator was about 10,000, which is an affordable price for a small aircraft. 10 FBG strain sensors and 1 FBG temperature sensor were installed on the surface of the full-scale wing structure. Load was applied to the tip of the wing structure, and the low speed interrogator detected the change in the center wavelength of the FBG sensors at the sampling rate of 10Hz. To assess the applicability of the low-cost FBG interrogator to full-scale small aircraft wing structure, a temperature-compensated strain measurement algorithm was verified experimentally under various loading conditions of the wing structure with temperature variations.

  3. Factor structure underlying components of allostatic load.

    Directory of Open Access Journals (Sweden)

    Jeanne M McCaffery

    Full Text Available Allostatic load is a commonly used metric of health risk based on the hypothesis that recurrent exposure to environmental demands (e.g., stress engenders a progressive dysregulation of multiple physiological systems. Prominent indicators of response to environmental challenges, such as stress-related hormones, sympatho-vagal balance, or inflammatory cytokines, comprise primary allostatic mediators. Secondary mediators reflect ensuing biological alterations that accumulate over time and confer risk for clinical disease but overlap substantially with a second metric of health risk, the metabolic syndrome. Whether allostatic load mediators covary and thus warrant treatment as a unitary construct remains to be established and, in particular, the relation of allostatic load parameters to the metabolic syndrome requires elucidation. Here, we employ confirmatory factor analysis to test: 1 whether a single common factor underlies variation in physiological systems associated with allostatic load; and 2 whether allostatic load parameters continue to load on a single common factor if a second factor representing the metabolic syndrome is also modeled. Participants were 645 adults from Allegheny County, PA (30-54 years old, 82% non-Hispanic white, 52% female who were free of confounding medications. Model fitting supported a single, second-order factor underlying variance in the allostatic load components available in this study (metabolic, inflammatory and vagal measures. Further, this common factor reflecting covariation among allostatic load components persisted when a latent factor representing metabolic syndrome facets was conjointly modeled. Overall, this study provides novel evidence that the modeled allostatic load components do share common variance as hypothesized. Moreover, the common variance suggests the existence of statistical coherence above and beyond that attributable to the metabolic syndrome.

  4. Structural Analysis Approach to Fault Diagnosis with Application to Fixed-wing Aircraft Motion

    DEFF Research Database (Denmark)

    Izadi-Zamanabadi, Roozbeh

    2001-01-01

    The paper presents a structural analysis based method for fault diagnosis purposes. The method uses the structural model of the system and utilizes the matching idea to extract system's inherent redundant information. The structural model is represented by a bipartite directed graph. FDI Possibil...... Possibilities are examined by further analysis of the obtained information. The method is illustrated by applying on the LTI model of motion of a fixed-wing aircraft....

  5. Structural Analysis Approach to Fault Diagnosis with Application to Fixed-wing Aircraft Motion

    DEFF Research Database (Denmark)

    Izadi-Zamanabadi, Roozbeh

    2002-01-01

    The paper presents a structural analysis based method for fault diagnosis purposes. The method uses the structural model of the system and utilizes the matching idea to extract system's inherent redundant information. The structural model is represented by a bipartite directed graph. FDI Possibil...... Possibilities are examined by further analysis of the obtained information. The method is illustrated by applying on the LTI model of motion of a fixed-wing aircraft....

  6. Polymer matrix nanocomposites for automotive structural components

    Science.gov (United States)

    Naskar, Amit K.; Keum, Jong K.; Boeman, Raymond G.

    2016-12-01

    Over the past several decades, the automotive industry has expended significant effort to develop lightweight parts from new easy-to-process polymeric nanocomposites. These materials have been particularly attractive because they can increase fuel efficiency and reduce greenhouse gas emissions. However, attempts to reinforce soft matrices by nanoscale reinforcing agents at commercially deployable scales have been only sporadically successful to date. This situation is due primarily to the lack of fundamental understanding of how multiscale interfacial interactions and the resultant structures affect the properties of polymer nanocomposites. In this Perspective, we critically evaluate the state of the art in the field and propose a possible path that may help to overcome these barriers. Only once we achieve a deeper understanding of the structure-properties relationship of polymer matrix nanocomposites will we be able to develop novel structural nanocomposites with enhanced mechanical properties for automotive applications.

  7. Optimisation of component performance via structuring

    Directory of Open Access Journals (Sweden)

    Psyk Verena

    2015-01-01

    Full Text Available Ecological and economic reasons are forcing industry to improve efficiency and to save energy and resources by reducing product weight. In current product designs often insufficient geometric stiffness of the part prohibits exploiting the full potential of weight reduction offered by modern materials. Ideally adapting the geometry to the load profile by implementing appropriate structures often allows a wall thickness and weight reduction and improves the acoustic properties. To enable a target-oriented design, structures manufactured by working media and working energy based forming technologies were analysed.

  8. A single frequency component-based re-estimated MUSIC algorithm for impact localization on complex composite structures

    Science.gov (United States)

    Yuan, Shenfang; Bao, Qiao; Qiu, Lei; Zhong, Yongteng

    2015-10-01

    The growing use of composite materials on aircraft structures has attracted much attention for impact monitoring as a kind of structural health monitoring (SHM) method. Multiple signal classification (MUSIC)-based monitoring technology is a promising method because of its directional scanning ability and easy arrangement of the sensor array. However, for applications on real complex structures, some challenges still exist. The impact-induced elastic waves usually exhibit a wide-band performance, giving rise to the difficulty in obtaining the phase velocity directly. In addition, composite structures usually have obvious anisotropy, and the complex structural style of real aircrafts further enhances this performance, which greatly reduces the localization precision of the MUSIC-based method. To improve the MUSIC-based impact monitoring method, this paper first analyzes and demonstrates the influence of measurement precision of the phase velocity on the localization results of the MUSIC impact localization method. In order to improve the accuracy of the phase velocity measurement, a single frequency component extraction method is presented. Additionally, a single frequency component-based re-estimated MUSIC (SFCBR-MUSIC) algorithm is proposed to reduce the localization error caused by the anisotropy of the complex composite structure. The proposed method is verified on a real composite aircraft wing box, which has T-stiffeners and screw holes. Three typical categories of 41 impacts are monitored. Experimental results show that the SFCBR-MUSIC algorithm can localize impact on complex composite structures with an obviously improved accuracy.

  9. 76 FR 35912 - Business Jet Aircraft Industry: Structure and Factors Affecting Competitiveness; Institution of...

    Science.gov (United States)

    2011-06-20

    ... the extent that information is publicly available, the report will include-- 1. An overview of the structure of the global industry, including supply chain relationships and foreign direct investment; 2. An overview of the global market for business jet aircraft and recent developments, such as the...

  10. Structured Observation Component. Secondary Teacher Education Program.

    Science.gov (United States)

    Berger, Michael L.; Keen, Phyllis A.

    A format is presented for use of student teachers in structuring their classroom observation techniques. Fifteen classroom and school activities are listed with a comprehensive questionnaire accompanying each. These questionnaires guide the student on what behaviors to observe and suggest objective and subjective responses to these behaviors to be…

  11. Failure Analysis of Crack on Aircraft's Strengthened Wing Rib Component%某型飞机加强翼肋组件裂纹失效分析

    Institute of Scientific and Technical Information of China (English)

    吴江; 周毅; 杨兆军

    2013-01-01

    通过化学成分分析、金相组织检测、硬度检测、断口形貌分析以及工况分析,对某型飞机加强翼肋组件裂纹的失效原因进行分析.结果表明,加强翼肋组件制造质量正常无缺陷,由于其结构设计不当,导致在冲击载荷作用下工作应力过大而发生低周疲劳断裂.%The failure analysis of crack on a certain type of aircraft's strengthened wing rib components were accomplished based on chemical composition analysis, metallographic examination, hardness testing, fracture morphology analysis and performance analysis. The results show that the manufacturing quality of the strengthened wing rib component is normal without defect. Low cycle fatigue fracture on the strengthened wing rib components appears because the structural design is undeserved and it causes too big impact load stress.

  12. A novel actuator phasing method for ultrasonic de-icing of aircraft structures

    Science.gov (United States)

    Borigo, Cody J.

    Aircraft icing is a critical concern for commercial and military rotorcraft and fixed-wing aircraft. In-flight icing can lead to dramatic decreases in lift and increases in drag that have caused more than a thousand deaths and hundreds of accidents over the past three decades alone. Current ice protection technologies have substantial drawbacks due to weight, power consumption, environmental concerns, or incompatibility with certain structures. In this research, an actuator phasing method for ultrasonic de-icing of aircraft structures was developed and tested using a series of finite element models, 3D scanning laser Doppler vibrometer measurements, and experimental de-icing tests on metallic and composite structures including plates and airfoils. An independent actuator analysis method was developed to allow for practical evaluation of many actuator phasing scenarios using a limited number of finite element models by properly calculating the phased stress fields and electromechanical impedance curves using a complex coupled impedance model. A genetic algorithm was utilized in conjunction with a series of finite element models to demonstrate that phase inversion, in which only in-phase and anti-phase signal components are applied to actuators, can be utilized with a small number of phasing combinations to achieve substantial improvements in de-icing system coverage. Finite element models of a 48"-long airfoil predicted that phase inversion with frequency sweeping can provide an improvement in the shear stress coverage levels of up to 90% compared to frequency sweeping alone. Experimental evaluation of the phasing approach on an icing grid showed a 189% improvement in de-icing coverage compared to frequency sweeping alone at comparable power levels. 3D scanning laser Doppler vibrometer measurements confirmed the increased variation in the surface vibration field induced by actuator phasing compared to unphased frequency sweeping. Additional contributions were made

  13. PREDICTIVE ASSESSMENT OF AN AIRCRAFT STRUCTURE BEHAVIOUR FOR PASSENGER AND CREW SECURITY

    Directory of Open Access Journals (Sweden)

    Daniela BARAN

    2009-12-01

    Full Text Available In the aerospace industry one of the most important requirements in the aircraft design andoperation is the high level of fiability under various atmosphere and environmental conditions. Thedesign and validation of such a system is a great challenge. It must meet several requirements suchas: high resistence, low weight and a small occupied volume. The stresses that occur during theaircraft operation are extremely complex, being the result of the interaction of differentsystems.Consequently, in order to obtain an optimal design of the whole system, the design, testingand operating processes require a combination of laborious analysis and experimental data. As upto 90% of the structure failures are du to the fatigue, high performance methods of fatigue analysisare needed to estimate the aircraft ressources. These methods must enable a precise determinationof the static and dynamic strains inder to correctly estimate the aircraft ressource. The projectproposes an approach of some aspects of the aircraft/ aircraft subassemblies simulation and testingand develop o calculation methodology of experimental data and high performance numericmethods integration in order to establish the ressource.

  14. Study on utilization of advanced composites in commercial aircraft wing structures. Volume 1: Executive summary

    Science.gov (United States)

    Sakata, I. F.; Ostrom, R. B.; Cardinale, S. V.

    1978-01-01

    The effort required by commercial transport manufacturers to accomplish the transition from current construction materials and practices to extensive use of composites in aircraft wings was investigated. The engineering and manufacturing disciplines which normally participate in the design, development, and production of an aircraft were employed to ensure that all of the factors that would enter a decision to commit to production of a composite wing structure were addressed. A conceptual design of an advanced technology reduced energy aircraft provided the framework for identifying and investigating unique design aspects. A plan development effort defined the essential technology needs and formulated approaches for effecting the required wing development. The wing development program plans, resource needs, and recommendations are summarized.

  15. Evaluation of the doses to aircrew members taking into consideration the aircraft structures

    Science.gov (United States)

    Battistoni, G.; Ferrari, A.; Pelliccioni, M.; Villari, R.

    The radiation field originated by the interactions of primary galactic cosmic rays in the atmosphere has been investigated using the FLUKA code. From the calculated differential fluence distributions in particle energy and direction, the values of effective and ambient dose equivalent rates have been derived as a function of vertical cut-off, altitude and deceleration potential. A mathematical model of an aircraft has been developed using the combinatorial geometry package of FLUKA. The irradiation of the mathematical model in the cosmic ray environment has been simulated at 10.7 km of altitude using the calculated fluence distributions at the polar region for a deceleration potential of 465 MV. Effective dose rate and ambient dose equivalent rate have been determined inside the aircraft at several locations along the fuselage. A significant shielding effect from the aircraft structures has been observed in the middle section of the passenger cabin.

  16. Structural integrity and life extension of high-temperature components

    Institute of Scientific and Technical Information of China (English)

    WANG Chun; SHEN Shi-ming

    2005-01-01

    Four different topics for high-temperature components, namely the development of the assessment codes for the structural integrity of high-temperature components, the application of continuous damage mechanics and probabilistic damage mode on the life assessment of high-temperature components, the life extension for high-tem perature components and a proposed strategy for remanufacturing of high-temperature components were discussed in this paper. These topics should provide some important insights for the design and re-design of high- temperature components.

  17. Molecular Component Structures Mediated Formation of Self-assemblies

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Molecular recognition directed self-assemblies from complementary molecular components, melamine and barbituric acid derivatives were studied by means of NMR, fluorescence, and TEM. It was found that both the process of the self-assembly and the morphologies of the result ed self-assemblies could be mediated by modifying the structures of the molecular components used. The effect of the structures of the molecular components on the formation of the self-as semblies was discussed in terms of intermolecular interactions.

  18. Modal content based damage indicators and phased array transducers for structural health monitoring of aircraft structures using ultrasonic guided waves

    Science.gov (United States)

    Ren, Baiyang

    Composite materials, especially carbon fiber reinforced polymers (CFRP), have been widely used in the aircraft industry because of their high specific strength and stiffness, resistance to corrosion and good fatigue life. Due to their highly anisotropic material properties and laminated structures, joining methods like bolting and riveting are no longer appropriate for joining CFRP since they initiate defects during the assembly and severely compromise the integrity of the structure; thus new techniques for joining CFRP are highly demanded. Adhesive bonding is a promising method because it relieves stress concentration, reduces weight and provides smooth surfaces. Additionally, it is a low-cost alternative to the co-cured method which is currently used to manufacture components of aircraft fuselage. Adhesive defects, disbonds at the interface between adherend and adhesive layer, are focused on in this thesis because they can be initialized by either poor surface preparation during the manufacturing or fatigue loads during service. Aircraft need structural health monitoring (SHM) systems to increase safety and reduce loss, and adhesive bonds usually represent the hotspots of the assembled structure. There are many nondestructive evaluation (NDE) methods for bond inspection. However, these methods cannot be readily integrated into an SHM system because of the bulk size and weight of the equipment and requirement of accessibility to one side of the bonded joint. The first objective of this work is to develop instruments, actuators, sensors and a data acquisition system for SHM of bond lines using ultrasonic guided waves which are well known to be able to cover large volume of the structure and inaccessible regions. Different from widely used guided wave sensors like PZT disks, the new actuators, piezoelectric fiber composite (PFC) phased array transducers0 (PAT), can control the modal content of the excited waves and the new sensors, polyvinylidene fluoride (PVDF

  19. Synthesis and processing of intelligent cost-effective structures phase II (SPICES II): smart materials aircraft applications evaluation

    Science.gov (United States)

    Dunne, James P.; Jacobs, Steven W.; Baumann, Erwin W.

    1998-06-01

    The second phase of the synthesis and processing of intelligent cost effective structures (SPICES II) program sought to identify high payoff areas for both naval and aerospace military systems and to evaluate military systems and to evaluate the benefits of smart materials incorporation based on their ability to redefine the mission scenario of the candidate platforms in their respective theaters of operation. The SPICES II consortium, consisting of The Boeing Company, Electric Boat Corporation, United Technologies Research Center, and Pennsylvania State University, surveyed the state-of-the-art in smart structures and evaluated potential applications to military aircraft, marine and propulsion systems components and missions. Eleven baseline platforms comprising a wide variety of missions were chosen for evaluation. Each platform was examined in its field of operation for areas which can be improved using smart materials insertion. Over 250 smart materials applications were proposed to enhance the platforms. The applications were examined and, when possible, quantitatively analyzed for their effect on mission performance. The applications were then ranked for payoff, risk, and time frame for development and demonstration. Details of the efforts made in the SPICES II program pertaining to smart structure applications on military and transport aircraft will be presented. A brief discussion of the core technologies will be followed by presentation of the criteria used in ranking each application. Thereafter, a selection of the higher ranking proposed concepts are presented in detail.

  20. Research of hail impact on aircraft wheel door with lattice hybrid structure

    Science.gov (United States)

    Li, Shengze; Jin, Feng; Zhang, Weihua; Meng, Xuanzhu

    2016-09-01

    Aimed at a long lasting issue of hail impact on aircraft structures and aviation safety due to its high speed, the resistance performance of hail impact on the wheel door of aircraft with lattice hybrid structure is investigated. The proper anti-hail structure can be designed both efficiency and precision based on this work. The dynamic responses of 8 different sandwich plates in diverse impact speed are measured. Smoothed Particle Hydrodynamic (SPH) method is introduced to mimic the speciality of solid-liquid mixture trait of hailstone during the impact process. The deformation and damage degree of upper and lower panel of sandwich plate are analysed. The application range and failure mode for the relevant structure, as well as the energy absorbing ratio between lattice structure and aluminium foam are summarized. Results show that the tetrahedral sandwich plate with aluminium foam core is confirmed the best for absorbing energy. Furthermore, the high absorption characteristics of foam material enhance the capability of the impact resistance for the composition with lattice structure without increasing the structure surface density. The results of study are of worth to provide a reliable basis for reduced weight aircraft wheel door.

  1. Fabrication and evaluation of advanced titanium structural panels for supersonic cruise aircraft

    Science.gov (United States)

    Payne, L.

    1977-01-01

    Flightworthy primary structural panels were designed, fabricated, and tested to investigate two advanced fabrication methods for titanium alloys. Skin-stringer panels fabricated using the weldbraze process, and honeycomb-core sandwich panels fabricated using a diffusion bonding process, were designed to replace an existing integrally stiffened shear panel on the upper wing surface of the NASA YF-12 research aircraft. The investigation included ground testing and Mach 3 flight testing of full-scale panels, and laboratory testing of representative structural element specimens. Test results obtained on full-scale panels and structural element specimens indicate that both of the fabrication methods investigated are suitable for primary structural applications on future civil and military supersonic cruise aircraft.

  2. Study on utilization of advanced composites in commercial aircraft wing structures, volume 2

    Science.gov (United States)

    Sakata, I. F.; Ostrom, R. B.

    1978-01-01

    A plan is defined for a composite wing development effort which will assist commercial transport manufacturers in reaching a level of technology readiness where the utilization of composite wing structure is a cost competitive option for a new aircraft production plan. The recommended development effort consists of two programs: a joint government/industry material development program and a wing structure development program. Both programs are described in detail.

  3. Identifying the Component Structure of Satisfaction Scales by Nonlinear Principal Components Analysis

    NARCIS (Netherlands)

    Manisera, M.; Kooij, A.J. van der; Dusseldorp, E.

    2010-01-01

    The component structure of 14 Likert-type items measuring different aspects of job satisfaction was investigated using nonlinear Principal Components Analysis (NLPCA). NLPCA allows for analyzing these items at an ordinal or interval level. The participants were 2066 workers from five types of social

  4. On the use of a compact optical fiber sensor system in aircraft structural health monitoring

    Science.gov (United States)

    Mrad, Nezih; Guo, Honglei; Xiao, Gaozhi; Rocha, Bruno; Sun, Zhigang

    2012-06-01

    Structural Health Monitoring (SHM) has been identified as an area of significant potential for advanced aircraft maintenance programs that ensure continued airworthiness, enhanced operational safety and reduced life cycle cost. Several sensors and sensory systems have been developed for the implementation of such health monitoring capability. Among a wide range of developed technologies, fiber optic sensor technology, in particular fiber Bragg grating based emerged as one of the most promising for aircraft structural applications. This paper is set to explore the suitability of using a new Fiber Bragg Grating sensor (FBG) system developed for operation in two modes, low and high speed sensing modes, respectively. The suitability of the system for potential use in aircraft load monitoring and damage detection applications has been demonstrated. Results from FBG sensor system were in good agreement with results from conventional resistive strain gauges, validating this capability for load monitoring. For damage detection, the FBG sensor system was able to detect acoustic waves generated 52 inches (1.32 m) away. The initial results, obtained in a full stale experimentation, demonstrate the potential of using FBG sensors for both load monitoring and damage detection in aircraft environment.

  5. Mechanical Behaviour of Inconel 718 Thin-Walled Laser Welded Components for Aircraft Engines

    Directory of Open Access Journals (Sweden)

    Enrico Lertora

    2014-01-01

    Full Text Available Nickel alloys are very important in many aerospace applications, especially to manufacture gas turbines and aero engine components, where high strength and temperature resistance are necessary. These kinds of alloys have to be welded with high energy density processes, in order to preserve their high mechanical properties. In this work, CO2 laser overlap joints between Inconel 718 sheets of limited thickness in the absence of postweld heat treatment were made. The main application of this kind of joint is the manufacturing of a helicopter engine component. In particular the aim was to obtain a specific cross section geometry, necessary to overcome the mechanical stresses found in these working conditions without failure. Static and dynamic tests were performed to assess the welds and the parent material fatigue life behaviour. Furthermore, the life trend was identified. This research pointed out that a full joint shape control is possible by choosing proper welding parameters and that the laser beam process allows the maintenance of high tensile strength and ductility of Inconel 718 but caused many liquation microcracks in the heat affected zone (HAZ. In spite of these microcracks, the fatigue behaviour of the overlap welds complies with the technical specifications required by the application.

  6. Cradle-to-Grave Monitoring of Composite Aircraft Structures Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NextGen is proposing a simple yet powerful damage identification technique for advanced composite structures. We propose to develop a damage index based on vibration...

  7. A numerical model for bird strike on sidewall structure of an aircraft nose

    Institute of Scientific and Technical Information of China (English)

    Liu Jun; Li Yulong; Gao Xiaosheng; Yu Xiancheng

    2014-01-01

    In order to examine the potential of using the coupled smooth particles hydrodynamic (SPH) and finite element (FE) method to predict the dynamic responses of aircraft structures in bird strike events, bird-strike tests on the sidewall structure of an aircraft nose are carried out and numerically simulated. The bird is modeled with SPH and described by the Murnaghan equation of state, while the structure is modeled with finite elements. A coupled SPH-FE method is developed to simulate the bird-strike tests and a numerical model is established using a commercial software PAM-CRASH. The bird model shows no signs of instability and correctly modeled the break-up of the bird into particles. Finally the dynamic response such as strains in the skin is simulated and compared with test results, and the simulated deformation and fracture process of the sidewall structure is compared with images recorded by a high speed camera. Good agreement between the simulation results and test data indicates that the coupled SPH-FE method can provide a very powerful tool in predicting the dynamic responses of aircraft structures in events of bird strike.

  8. A numerical model for bird strike on sidewall structure of an aircraft nose

    Directory of Open Access Journals (Sweden)

    Liu Jun

    2014-06-01

    Full Text Available In order to examine the potential of using the coupled smooth particles hydrodynamic (SPH and finite element (FE method to predict the dynamic responses of aircraft structures in bird strike events, bird-strike tests on the sidewall structure of an aircraft nose are carried out and numerically simulated. The bird is modeled with SPH and described by the Murnaghan equation of state, while the structure is modeled with finite elements. A coupled SPH–FE method is developed to simulate the bird-strike tests and a numerical model is established using a commercial software PAM-CRASH. The bird model shows no signs of instability and correctly modeled the break-up of the bird into particles. Finally the dynamic response such as strains in the skin is simulated and compared with test results, and the simulated deformation and fracture process of the sidewall structure is compared with images recorded by a high speed camera. Good agreement between the simulation results and test data indicates that the coupled SPH–FE method can provide a very powerful tool in predicting the dynamic responses of aircraft structures in events of bird strike.

  9. Compliant load-bearing skins and structures for morphing aircraft applications

    Science.gov (United States)

    Olympio, Kingnide Raymond

    Aircraft morphing has the potential to significantly improve the performance of an aircraft over its flight envelope and expand its ight capability to allow it to perform dramatically different missions. The multiple projects carried on in the past three decades have considerably helped improve the designing of actuation systems and the utilization of smart materials for morphing aircraft structures. However, morphing aircraft and especially aircraft undergoing large shape change still face some significant technical issues. Among them, the skin covering the morphing structure must meet challenging requirements that no current conventional material fully satisfy. The design of such skin, which should be able to undergo large deformations and to carry air-loads, has received some attention in the last several years but no satisfactory solution has been found yet. In the current study, the design of compliant cellular structures and flexible skins for morphing aircraft structures is investigated for two different morphing deformations. The first morphing deformation considered corresponds to one-dimensional morphing which is representative of a wing or blade changing its chord or span. The second morphing deformation considered is shear-compression morphing which can be found in some morphing wing undergoing change in area, sweep and chord such as NextGen Aeronautics' morphing wing. Topologies of compliant cellular structures which can be used for these two types of structures are first calculated using a multi-objective approach. These topologies are calculated based on linear kinematics but the effect of geometric nonlinearities is also investigated. Then, ways to provide a smooth surface were investigated by considering a general honeycomb substructure with infill, bonded face-sheet or scales. This allowed justifying an overall skin concept made of a cellular substructure with a bonded face-sheet. Lastly, the design of an improved skin for NextGen Aeronautics

  10. The Influence of Large Scale Computing on Aircraft Structural Design

    Science.gov (United States)

    1984-08-01

    following sets of technical needs can be identified- ci^ nieve 2-2 1) Expanding the scope of engineering problems considered. This includes examin...Storaasli, 0.0. and Murphy, R. C, "Finite Element Analysis in a Minicomputer/ M^c^J^o’^ oJo ’^T™^"^’" ’^^ Research in Computerized Structural Analysis

  11. Block-Krylov component synthesis method for structural model reduction

    Science.gov (United States)

    Craig, Roy R., Jr.; Hale, Arthur L.

    1988-01-01

    A new analytical method is presented for generating component shape vectors, or Ritz vectors, for use in component synthesis. Based on the concept of a block-Krylov subspace, easily derived recurrence relations generate blocks of Ritz vectors for each component. The subspace spanned by the Ritz vectors is called a block-Krylov subspace. The synthesis uses the new Ritz vectors rather than component normal modes to reduce the order of large, finite-element component models. An advantage of the Ritz vectors is that they involve significantly less computation than component normal modes. Both 'free-interface' and 'fixed-interface' component models are derived. They yield block-Krylov formulations paralleling the concepts of free-interface and fixed-interface component modal synthesis. Additionally, block-Krylov reduced-order component models are shown to have special disturbability/observability properties. Consequently, the method is attractive in active structural control applications, such as large space structures. The new fixed-interface methodology is demonstrated by a numerical example. The accuracy is found to be comparable to that of fixed-interface component modal synthesis.

  12. Detection and sizing of short fatigue cracks in a simulated aircraft structure of aluminum thin plate

    Energy Technology Data Exchange (ETDEWEB)

    KIm, Jung Chan; Kwon, Oh Yang [Inha University, Incheon (Korea, Republic of)

    2004-05-15

    Since the fatigue damage usually occurs around the rivet holes in aircraft structures, the detection and sizing of short fatigue cracks emanating from rivet holes is extremely important. The initiation of fatigue cracks in a simulated aircraft structures with a series of rivet holes was detected by acoustic emission(AE), and the crack length was determined by the surface acoustic wave(SAW) technique. AE events increased intermittently with the initiation and growth of short cracks to form a stepwise incremental curve of cumulative AE events. with the SAW technique employed, the crack sizing in the range of 1-8 mm long was possible but it was impossible in the range shorter than 1 mm.

  13. An automatic 3D CAD model errors detection method of aircraft structural part for NC machining

    Directory of Open Access Journals (Sweden)

    Bo Huang

    2015-10-01

    Full Text Available Feature-based NC machining, which requires high quality of 3D CAD model, is widely used in machining aircraft structural part. However, there has been little research on how to automatically detect the CAD model errors. As a result, the user has to manually check the errors with great effort before NC programming. This paper proposes an automatic CAD model errors detection approach for aircraft structural part. First, the base faces are identified based on the reference directions corresponding to machining coordinate systems. Then, the CAD models are partitioned into multiple local regions based on the base faces. Finally, the CAD model error types are evaluated based on the heuristic rules. A prototype system based on CATIA has been developed to verify the effectiveness of the proposed approach.

  14. Practical Application of Finite Element Analysis to Aircraft Structural Design

    Science.gov (United States)

    1986-08-01

    analysis and mechanical properties, including the equivalent inclusion method, elastic constants and internal friction in composites, finite element...intensity factors are not available. The inclusion of fracture constraints in the automated design process is a logical extension of present structural...September 30-Dctober 3, 1975, Proceedings. Volume 1. (A78-19026 06-01) Turin, Libreria Editrice Universitaria Levrotto e Bella, 1975, p. 291-300. In

  15. Bayesian Computational Sensor Networks for Aircraft Structural Health Monitoring

    Science.gov (United States)

    2016-02-02

    emissions as well as delamination-dominated and fiber-dominated damage. The three frequency regions identified were 10 - 100 kHz, 100 - 250 kHz, and 250...the RD patterns can be used for Bayesian model accuracy assessment of the difference between a uniform grid layout of the nodes versus an irregular... grid due to error in node placement. SLAMBOT: Structural Health Monitoring Robot using Lamb Waves We developed the combination of a mobile robot and

  16. ENERGY SCAVENGING BASED ON TRANSIENT THERMAL GRADIENTS: APPLICATION TO STRUCTURAL HEALTH MONITORING OF AIRCRAFTS

    OpenAIRE

    2008-01-01

    International audience; Results about energy capture from the environment associated with the self-powering of a wireless sensor network (WSN) for structural health monitoring of aircrafts (SHM) are presented. Thermal gradients taking place during specific flight phases are converted into electrical energy by using a small water tank coupled to a thermoelectric generator which output is connected to a storage circuit. The proposed system is experimentally assessed in an environmental chamber....

  17. Aircraft-crash-protected steel reactor building roof structure for the European market

    Energy Technology Data Exchange (ETDEWEB)

    Posta, B.A.; Kadar, I. [Bechtel Corp., San Francisco, CA (United States); Rao, A.S. [General Electric Nuclear Engineering, San Jose, CA (United States)

    1996-07-01

    This paper recommends the use of all steel roof structures for the reactor building of European Boiling Water Reactor (BWR) plants. This change would make the advanced US BWR designs more compatible with European requirements. Replacement of the existing concrete roof slab with a sufficiently thick steel plate would eliminate the concrete spelling resulting from a postulated aircraft crash, potentially damaging the drywell head or the spent fuel pool.

  18. Engine structures analysis software: Component Specific Modeling (COSMO)

    Science.gov (United States)

    McKnight, R. L.; Maffeo, R. J.; Schwartz, S.

    1994-08-01

    A component specific modeling software program has been developed for propulsion systems. This expert program is capable of formulating the component geometry as finite element meshes for structural analysis which, in the future, can be spun off as NURB geometry for manufacturing. COSMO currently has geometry recipes for combustors, turbine blades, vanes, and disks. Component geometry recipes for nozzles, inlets, frames, shafts, and ducts are being added. COSMO uses component recipes that work through neutral files with the Technology Benefit Estimator (T/BEST) program which provides the necessary base parameters and loadings. This report contains the users manual for combustors, turbine blades, vanes, and disks.

  19. Computation of aircraft component flow fields at transonic Mach numbers using a three-dimensional Navier-Stokes algorithm

    Science.gov (United States)

    Shrewsbury, George D.; Vadyak, Joseph; Schuster, David M.; Smith, Marilyn J.

    1989-01-01

    A computer analysis was developed for calculating steady (or unsteady) three-dimensional aircraft component flow fields. This algorithm, called ENS3D, can compute the flow field for the following configurations: diffuser duct/thrust nozzle, isolated wing, isolated fuselage, wing/fuselage with or without integrated inlet and exhaust, nacelle/inlet, nacelle (fuselage) afterbody/exhaust jet, complete transport engine installation, and multicomponent configurations using zonal grid generation technique. Solutions can be obtained for subsonic, transonic, or hypersonic freestream speeds. The algorithm can solve either the Euler equations for inviscid flow, the thin shear layer Navier-Stokes equations for viscous flow, or the full Navier-Stokes equations for viscous flow. The flow field solution is determined on a body-fitted computational grid. A fully-implicit alternating direction implicit method is employed for the solution of the finite difference equations. For viscous computations, either a two layer eddy-viscosity turbulence model or the k-epsilon two equation transport model can be used to achieve mathematical closure.

  20. Contribution to the modelling and simulation of aircraft structures impacting on water

    OpenAIRE

    Toso, Nathalie Renée Solange

    2009-01-01

    The impact on water of aeronautical structures is of concern as soon as an aircraft is designed to operate over sea. For the need of the ditching certification, it can be summarised that the structure should be able to land on water and float long enough to enable the passengers and crew members to evacuate. Until the middle of the 90's, compliance to the regulations was mainly shown by tests performed in a basin using a mock-up structure completed by relative simple theoretical evaluations o...

  1. Computer-aided methods for analysis and synthesis of supersonic cruise aircraft structures

    Science.gov (United States)

    Giles, G. L.

    1976-01-01

    Computer-aided methods are reviewed which are being developed by Langley Research Center in-house work and by related grants and contracts. Synthesis methods to size structural members to meet strength and stiffness (flutter) requirements are emphasized and described. Because of the strong interaction among the aerodynamic loads, structural stiffness, and member sizes of supersonic cruise aircraft structures, these methods are combined into systems of computer programs to perform design studies. The approaches used in organizing these systems to provide efficiency, flexibility of use in an iterative process, and ease of system modification are discussed.

  2. Conceptual Design and Structural Optimization of NASA Environmentally Responsible Aviation (ERA) Hybrid Wing Body Aircraft

    Science.gov (United States)

    Quinlan, Jesse R.; Gern, Frank H.

    2016-01-01

    Simultaneously achieving the fuel consumption and noise reduction goals set forth by NASA's Environmentally Responsible Aviation (ERA) project requires innovative and unconventional aircraft concepts. In response, advanced hybrid wing body (HWB) aircraft concepts have been proposed and analyzed as a means of meeting these objectives. For the current study, several HWB concepts were analyzed using the Hybrid wing body Conceptual Design and structural optimization (HCDstruct) analysis code. HCDstruct is a medium-fidelity finite element based conceptual design and structural optimization tool developed to fill the critical analysis gap existing between lower order structural sizing approaches and detailed, often finite element based sizing methods for HWB aircraft concepts. Whereas prior versions of the tool used a half-model approach in building the representative finite element model, a full wing-tip-to-wing-tip modeling capability was recently added to HCDstruct, which alleviated the symmetry constraints at the model centerline in place of a free-flying model and allowed for more realistic center body, aft body, and wing loading and trim response. The latest version of HCDstruct was applied to two ERA reference cases, including the Boeing Open Rotor Engine Integration On an HWB (OREIO) concept and the Boeing ERA-0009H1 concept, and results agreed favorably with detailed Boeing design data and related Flight Optimization System (FLOPS) analyses. Following these benchmark cases, HCDstruct was used to size NASA's ERA HWB concepts and to perform a related scaling study.

  3. NASA-UVa Light Aerospace Alloy and Structures Technology Program: Aluminum-Based Materials for High Speed Aircraft

    Science.gov (United States)

    Starke, E. A., Jr. (Editor)

    1996-01-01

    This report is concerned with 'Aluminum-Based Materials for High Speed Aircraft' which was initiated to identify the technology needs associated with advanced, low-cost aluminum base materials for use as primary structural materials. Using a reference baseline aircraft, these materials concept will be further developed and evaluated both technically and economically to determine the most attractive combinations of designs, materials, and manufacturing techniques for major structural sections of an HSCT. Once this has been accomplished, the baseline aircraft will be resized, if applicable, and performance objectives and economic evaluations made to determine aircraft operating costs. The two primary objectives of this study are: (1) to identify the most promising aluminum-based materials with respect to major structural use on the HSCT and to further develop those materials, and (2) to assess these materials through detailed trade and evaluation studies with respect to their structural efficiency on the HSCT.

  4. Resonant loading of aircraft secondary structure panels for use with thermoelastic stress analysis and digital image correlation

    Science.gov (United States)

    Waugh, Rachael C.; Dulieu-Barton, Janice M.; Quinn, S.

    2015-03-01

    Thermoelastic stress analysis (TSA) is an established active thermographic approach which uses the thermoelastic effect to correlate the temperature change that occurs as a material is subjected to elastic cyclic loading to the sum of the principal stresses on the surface of the component. Digital image correlation (DIC) tracks features on the surface of a material to establish a displacement field of a component subjected to load, which can then be used to calculate the strain field. The application of both DIC and TSA on a composite plate representative of aircraft secondary structure subject to resonant frequency loading using a portable loading device, i.e. `remote loading' is described. Laboratory based loading for TSA and DIC is typically imparted using a test machine, however in the current work a vibration loading system is used which is able to excite the component of interest at resonant frequency which enables TSA and DIC to be carried out. The accuracy of the measurements made under remote loading of both of the optical techniques applied is discussed. The data are compared to extract complimentary information from the two techniques. This work forms a step towards a combined strain based non-destructive evaluation procedure able to identify and quantify the effect of defects more fully, particularly when examining component performance in service applications.

  5. Certification of Discontinuous Composite Material Forms for Aircraft Structures

    Science.gov (United States)

    Arce, Michael Roger

    New, high performance chopped, discontinuous, or short fiber composites (DFCs), DFCs, such as HexMC and Lytex, made by compression molding of randomly oriented pre-impregnated unidirectional tape, can be formed into complex geometry while retaining mechanical properties suitable for structural use. These DFCs provide the performance benefits of Continuous Fiber Composites (CFCs) in form factors that were previously unavailable. These materials demonstrate some notably different properties from continuous fiber composites, especially with respect to damage tolerance and failure behavior. These behaviors are not very well understood, and fundamental research efforts are ongoing to better characterize the material and to ease certification for future uses. Despite this, these new DFCs show such promise that they are already in service in the aerospace industry, for instance in the Boeing 787. Unfortunately, the relative novelty of these parts means that they needed to be certified by “point design”, an excess of physical testing, rather than by a mix of physical testing and finite element analysis, which would be the case for CFCs or metals. In this study, one particular approach to characterizing both linear-elastic and failure behaviors are considered. The Stochastic Laminate Analogy, which represents a novel approach to modeling DFCs, and its combination with a Ply Discount scheme. Owing to limited available computational resources, only preliminary results are available, but those results are quite promising and warrant further investigation.

  6. Protein structure similarity from principle component correlation analysis

    Directory of Open Access Journals (Sweden)

    Chou James

    2006-01-01

    Full Text Available Abstract Background Owing to rapid expansion of protein structure databases in recent years, methods of structure comparison are becoming increasingly effective and important in revealing novel information on functional properties of proteins and their roles in the grand scheme of evolutionary biology. Currently, the structural similarity between two proteins is measured by the root-mean-square-deviation (RMSD in their best-superimposed atomic coordinates. RMSD is the golden rule of measuring structural similarity when the structures are nearly identical; it, however, fails to detect the higher order topological similarities in proteins evolved into different shapes. We propose new algorithms for extracting geometrical invariants of proteins that can be effectively used to identify homologous protein structures or topologies in order to quantify both close and remote structural similarities. Results We measure structural similarity between proteins by correlating the principle components of their secondary structure interaction matrix. In our approach, the Principle Component Correlation (PCC analysis, a symmetric interaction matrix for a protein structure is constructed with relationship parameters between secondary elements that can take the form of distance, orientation, or other relevant structural invariants. When using a distance-based construction in the presence or absence of encoded N to C terminal sense, there are strong correlations between the principle components of interaction matrices of structurally or topologically similar proteins. Conclusion The PCC method is extensively tested for protein structures that belong to the same topological class but are significantly different by RMSD measure. The PCC analysis can also differentiate proteins having similar shapes but different topological arrangements. Additionally, we demonstrate that when using two independently defined interaction matrices, comparison of their maximum

  7. Integration of structural health monitoring solutions onto commercial aircraft via the Federal Aviation Administration structural health monitoring research program

    Science.gov (United States)

    Swindell, Paul; Doyle, Jon; Roach, Dennis

    2017-02-01

    The Federal Aviation Administration (FAA) started a research program in structural health monitoring (SHM) in 2011. The program's goal was to understand the technical gaps of implementing SHM on commercial aircraft and the potential effects on FAA regulations and guidance. The program evolved into a demonstration program consisting of a team from Sandia National Labs Airworthiness Assurance NDI Center (AANC), the Boeing Corporation, Delta Air Lines, Structural Monitoring Systems (SMS), Anodyne Electronics Manufacturing Corp (AEM) and the FAA. This paper will discuss the program from the selection of the inspection problem, the SHM system (Comparative Vacuum Monitoring-CVM) that was selected as the inspection solution and the testing completed to provide sufficient data to gain the first approved use of an SHM system for routine maintenance on commercial US aircraft.

  8. Novel matrix resins for composites for aircraft primary structures, phase 1

    Science.gov (United States)

    Woo, Edmund P.; Puckett, P. M.; Maynard, S.; Bishop, M. T.; Bruza, K. J.; Godschalx, J. P.; Mullins, M. J.

    1992-01-01

    The objective of the contract is the development of matrix resins with improved processability and properties for composites for primarily aircraft structures. To this end, several resins/systems were identified for subsonic and supersonic applications. For subsonic aircraft, a series of epoxy resins suitable for RTM and powder prepreg was shown to give composites with about 40 ksi compressive strength after impact (CAI) and 200 F/wet mechanical performance. For supersonic applications, a thermoplastic toughened cyanate prepreg system has demonstrated excellent resistance to heat aging at 360 F for 4000 hours, 40 ksi CAI and useful mechanical properties at greater than or equal to 310 F. An AB-BCB-maleimide resin was identified as a leading candidate for the HSCT. Composite panels fabricated by RTM show CAI of approximately 50 ksi, 350 F/wet performance and excellent retention of mechanical properties after aging at 400 F for 4000 hours.

  9. Adaptive support for aircraft panel testing: New method and its experimental verification on a beam structure

    Science.gov (United States)

    Sachau, Delf; Baschke, Manuel

    2017-04-01

    Acoustic transmissibility of aircraft panels is measured in full-scale test rigs. The panels are supported at their frames. These boundary conditions do not take into account the dynamic influence of the fuselage, which is significant in the frequency range below 300 Hz. This paper introduces a new adaptive boundary system (ABS). It combines accelerometers and electrodynamic shakers with real-time signal processing. The ABS considers the dynamic effect of the fuselage on the panel. The frames are dominating the dynamic behaviour of a fuselage in the low-frequency range. Therefore, the new method is applied to a beam representing a frame of the aircraft structure. The experimental results are evaluated and the precision of the ABS is discussed. The theoretical apparent mass representing the cut-off part of a frame is calculated and compared with the apparent mass, as provided by the ABS. It is explained how the experimental set-up limits the precision of the ABS.

  10. Comparison of structural response and fatigue endurance of aircraft flap-like box structures subjected to acoustic loading.

    Science.gov (United States)

    Xiao, Y; White, R G; Aglietti, G S

    2005-05-01

    The results of an extensive test program to characterize the behavior of typical aircraft structures under acoustic loading and to establish their fatigue endurance are presented. The structures tested were the three flap-like box-type of structures. Each structure consisted of one flat (bottom) and one curved (top) stiffener stiffened skin panel, front, and rear spars, and ribs that divided the structures into three bays. The three structures, constructed from three different materials (aircraft standard aluminum alloy, Carbon Fibre Reinforced Plastic, and a Glass Fibre Metal Laminate, i.e., GLARE) had the same size and configuration, with only minor differences due to the use of different materials. A first set of acoustic tests with excitations of intensity ranging from 140 to 160 dB were carried out to obtain detailed data on the dynamic response of the three structures. The FE analysis of the structures is also briefly described and the results compared with the experimental data. The fatigue endurance of the structures was then determined using random acoustic excitation with an overall sound pressure level of 161 dB, and details of crack propagation are reported.

  11. 飞行器结构设计特点及演变%Aircraft Structural Design Features and Evolution

    Institute of Scientific and Technical Information of China (English)

    赵智姝; 李伟; 李映红

    2014-01-01

    飞行器结构设计是飞行器设计中重要的组成部分,本文从飞行器结构设计的要求出发、详细介绍了机身、机翼、尾翼的设计特点,总结了飞行器结构设计的演变趋势,对飞行器设计人员和维修人员具有一定的参考价值。%Structural design is a very important part of aircraft design . Starting from aircraft structural design requirement , this paper introduces in detail the design features of fuselage, wing, and empennage, and summarizes evolution trends of aircraft structural design , which has a certain reference value for aircraft design and maintenance personnel .

  12. A Finite Element Method for Cracked Components of Structures

    Institute of Scientific and Technical Information of China (English)

    刘立名; 段梦兰; 秦太验; 刘玉标; 柳春图; 余建星

    2003-01-01

    In this paper, a method is developed for determining the effective stiffness of the cracked component. The stiffness matrix of the cracked component is integrated into the global stiffness matrix of the finite element model of the global platform for the FE calculation of the structure in any environmental conditions. The stiffness matrix equation of the cracked component is derived by use of the finite variation principle and fracture mechanics. The equivalent parameters defining the element that simulates the cracked component are mathematically presented, and can be easily used for the FE calculation of large scale cracked structures together with any finite element program. The theories developed are validated by both lab tests and numerical calculations, and applied to the evaluation of crack effect on the strength of a fixed platform and a self-elevating drilling rig.

  13. Structural influence of cabin floor on sound transmission into propeller aircraft - Analytical investigations

    Science.gov (United States)

    Fuller, C. R.

    1986-01-01

    The structural influence of the cabin floor on the transmission of low frequency propeller noise into aircraft interiors has been examined using a simplified analytical model. The response amplitudes and distributions of shell displacement and internal acoustic pressure are examined for various frequencies and floor configurations. In general, at lower frequencies the floor exerts little structural influence on the transmission of acoustic energy to the interior. However, as the frequency nears half the cylinder ring frequency the floor can be seen to significantly alter the internal pressure distributions and response.

  14. No Longer the Outlier: Updating the Air Component Structure

    Science.gov (United States)

    2016-06-23

    4 | Air & Space Power Journal No Longer the Outlier Updating the Air Component Structure Lt Gen CQ Brown Jr., USAF Lt Col Rick Fournier, USAF...This article may be reproduced in whole or in part without permission. If it is reproduced, the Air and Space Power Journal requests a courtesy...COCOM) with a highly competent air component that is capable of con- ducting and supporting air , space , and cyberspace operations within its assigned

  15. Local Impact Simulation of SC Wall Structures using Aircraft Engine Projectile

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Chulhun; Lee, Jungwhee; Lee, Hanjoo [Dankook Univ., Yongin (Korea, Republic of); Jung, Raeyoung; Hyun, Changhun [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2013-05-15

    SC wall structure developed for nuclear power plant buildings consists of plain concrete and two steel plates on both surface of the concrete, while RC structure consists of re bar and concrete. SC structure has higher scabbing resistance than RC structure due to the action of steel plate on the rear side of impact. Therefore SC structure is known as more effective structure from the viewpoint of aircraft crash than RC structure. However, most of the recent researches and experiments about local impact damage deal with RC structures, and the effect of re bar and steel plate is not considered reasonably. Although Walter et al. and Make-work et al. suggested a formula for evaluating perforation depth of steel plate covered RC walls, most of the previous researches about SC structure are focused on perforation and scabbing due to the impact of hard projectile, rather than soft projectile such as an aircraft. In this research a soft projectile, i. e. aircraft engine, is utilized for impact simulation of RC and SC walls. To evaluate local damage of SC wall structures, parametric study with the variables of wall thickness and steel ratio of the cover plate is performed, and the results are compared with those of RC structures. Since scabbing was prevented by the steel plates, penetration mode of damage was observed in SC walls while scabbing damage was occurred in RC walls. It is confirmed that the rear steel plate not only contains concrete debris, but also reduces the internal damage of the concrete walls. Penetration depth of SC walls did not largely vary due to the increasing steel ratio, and similar results to RC walls were observed when the wall thickness is larger than a certain value since the impact resistance of SC wall is mainly governed by the thickness of concrete part. Therefore, it is expected that similar level of impact resistance to RC structure can be produced with the minimum thickness of steel plates of SC structure. According to these results, SC

  16. Dynamic response analysis of an aircraft structure under thermal-acoustic loads

    Science.gov (United States)

    Cheng, H.; Li, H. B.; Zhang, W.; Wu, Z. Q.; Liu, B. R.

    2016-09-01

    Future hypersonic aircraft will be exposed to extreme combined environments includes large magnitude thermal and acoustic loads. It presents a significant challenge for the integrity of these vehicles. Thermal-acoustic test is used to test structures for dynamic response and sonic fatigue due to combined loads. In this research, the numerical simulation process for the thermal acoustic test is presented, and the effects of thermal loads on vibro-acoustic response are investigated. To simulate the radiation heating system, Monte Carlo theory and thermal network theory was used to calculate the temperature distribution. Considering the thermal stress, the high temperature modal parameters are obtained with structural finite element methods. Based on acoustic finite element, modal-based vibro-acoustic analysis is carried out to compute structural responses. These researches are very vital to optimum thermal-acoustic test and structure designs for future hypersonic vehicles structure

  17. Smart Intelligent Aircraft Structures (SARISTU) : Proceedings of the Final Project Conference

    CERN Document Server

    Papadopoulos, Michael

    2016-01-01

    The book includes the research papers presented in the final conference of the EU funded SARISTU (Smart Intelligent Aircraft Structures) project, held at Moscow, Russia between 19-21 of May 2015. The SARISTU project, which was launched in September 2011, developed and tested a variety of individual applications as well as their combinations. With a strong focus on actual physical integration and subsequent material and structural testing, SARISTU has been responsible for important progress on the route to industrialization of structure integrated functionalities such as Conformal Morphing, Structural Health Monitoring and Nanocomposites. The gap- and edge-free deformation of aerodynamic surfaces known as conformal morphing has gained previously unrealized capabilities such as inherent de-icing, erosion protection and lightning strike protection, while at the same time the technological risk has been greatly reduced. Individual structural health monitoring techniques can now be applied at the part-manufacturin...

  18. A Framework for Preliminary Design of Aircraft Structures Based on Process Information. Part 1

    Science.gov (United States)

    Rais-Rohani, Masoud

    1998-01-01

    This report discusses the general framework and development of a computational tool for preliminary design of aircraft structures based on process information. The described methodology is suitable for multidisciplinary design optimization (MDO) activities associated with integrated product and process development (IPPD). The framework consists of three parts: (1) product and process definitions; (2) engineering synthesis, and (3) optimization. The product and process definitions are part of input information provided by the design team. The backbone of the system is its ability to analyze a given structural design for performance as well as manufacturability and cost assessment. The system uses a database on material systems and manufacturing processes. Based on the identified set of design variables and an objective function, the system is capable of performing optimization subject to manufacturability, cost, and performance constraints. The accuracy of the manufacturability measures and cost models discussed here depend largely on the available data on specific methods of manufacture and assembly and associated labor requirements. As such, our focus in this research has been on the methodology itself and not so much on its accurate implementation in an industrial setting. A three-tier approach is presented for an IPPD-MDO based design of aircraft structures. The variable-complexity cost estimation methodology and an approach for integrating manufacturing cost assessment into design process are also discussed. This report is presented in two parts. In the first part, the design methodology is presented, and the computational design tool is described. In the second part, a prototype model of the preliminary design Tool for Aircraft Structures based on Process Information (TASPI) is described. Part two also contains an example problem that applies the methodology described here for evaluation of six different design concepts for a wing spar.

  19. Optimum element density studies for finite-element thermal analysis of hypersonic aircraft structures

    Science.gov (United States)

    Ko, William L.; Olona, Timothy; Muramoto, Kyle M.

    1990-01-01

    Different finite element models previously set up for thermal analysis of the space shuttle orbiter structure are discussed and their shortcomings identified. Element density criteria are established for the finite element thermal modelings of space shuttle orbiter-type large, hypersonic aircraft structures. These criteria are based on rigorous studies on solution accuracies using different finite element models having different element densities set up for one cell of the orbiter wing. Also, a method for optimization of the transient thermal analysis computer central processing unit (CPU) time is discussed. Based on the newly established element density criteria, the orbiter wing midspan segment was modeled for the examination of thermal analysis solution accuracies and the extent of computation CPU time requirements. The results showed that the distributions of the structural temperatures and the thermal stresses obtained from this wing segment model were satisfactory and the computation CPU time was at the acceptable level. The studies offered the hope that modeling the large, hypersonic aircraft structures using high-density elements for transient thermal analysis is possible if a CPU optimization technique was used.

  20. Aircraft Wood Structures, Covering and Finishing Methods (Course Outline), Aviation Mechanics 2 (Air Frame): 9065.01.

    Science.gov (United States)

    Dade County Public Schools, Miami, FL.

    This document presents an outline for a 135-hour course designed to familiarize the student with aircraft wood structures and related Federal Aviation Agency requirements. Topics outlined are identification of defects on wood samples, defining terms used on wood structures, inspecting wood structure together with servicing and repair of wood…

  1. Nominal and Structural Subtyping in Component-Based Programming

    DEFF Research Database (Denmark)

    Ostermann, Klaus

    2007-01-01

    type. We analyze structural and different flavors of nominal subtyping from the perspective of component-based programming, where issues such as blame assignment and modular extensibility are important. Our analysis puts various existing subtyping mechanisms into a common frame of reference...

  2. Structural ECM components in the premetastatic and metastatic niche

    DEFF Research Database (Denmark)

    Høye, Anette M; Erler, Janine T

    2016-01-01

    The aim of this review is to give an overview of the extracellular matrix (ECM) components that are important for creating structural changes in the premetastatic and metastatic niche. The successful arrival and survival of cancer cells that have left the primary tumor and colonized distant sites...

  3. Biomimetic FAA-certifiable, artificial muscle structures for commercial aircraft wings

    Science.gov (United States)

    Barrett, Ronald M.; Barrett, Cassandra M.

    2014-07-01

    This paper is centered on a new form of adaptive material which functions much in the same way as skeletal muscle tissue, is structurally modeled on plant actuator cells and capable of rapidly expanding or shrinking by as much as an order of magnitude in prescribed directions. Rapid changes of plant cell shape and sizes are often initiated via ion-transport driven fluid migration and resulting turgor pressure variation. Certain plant cellular structures like those in Mimosa pudica (sensitive plant), Albizia julibrissin (Mimosa tree), or Dionaea muscipula (Venus Flytrap) all exhibit actuation physiology which employs such turgor pressure manipulation. The paper begins with dynamic micrographs of a sectioned basal articulation joint from A. julibrissin. These figures show large cellular dimensional changes as the structure undergoes foliage articulation. By mimicking such structures in aircraft flight control mechanisms, extremely lightweight pneumatic control surface actuators can be designed. This paper shows several fundamental layouts of such surfaces with actuator elements made exclusively from FAA-certifiable materials, summarizes their structural mechanics and shows actuator power and energy densities that are higher than nearly all classes of conventional adaptive materials available today. A sample flap structure is shown to possess the ability to change its shape and structural stiffness as its cell pressures are manipulated, which in turn changes the surface lift-curve slope when exposed to airflows. Because the structural stiffness can be altered, it is also shown that the commanded section lift-curve slope can be similarly controlled between 1.2 and 6.2 rad-1. Several aircraft weight reduction principles are also shown to come into play as the need to concentrate loads to pass through point actuators is eliminated. The paper concludes with a summary of interrelated performance and airframe-level improvements including enhanced gust rejection, load

  4. Effect of noise reducing components on nose landing gear stability for a mid-size aircraft coupled with vortex shedding and freeplay

    Science.gov (United States)

    Eret, Petr; Kennedy, John; Bennett, Gareth J.

    2015-10-01

    In the pursuit of quieter aircraft, significant effort has been dedicated to airframe noise identification and reduction. The landing gear is one of the main sources of airframe noise on approach. The addition of noise abatement technologies such as fairings or wheel hub caps is usually considered to be the simplest solution to reduce this noise. After touchdown, noise abatement components can potentially affect the inherently nonlinear and dynamically complex behaviour (shimmy) of landing gear. Moreover, fairings can influence the aerodynamic load on the system and interact with the mechanical freeplay in the torque link. This paper presents a numerical study of nose landing gear stability for a mid-size aircraft with low noise solutions, which are modelled by an increase of the relevant model structural parameters to address a hypothetical effect of additional fairings and wheel hub caps. The study shows that the wheel hub caps are not a threat to stability. A fairing has a destabilising effect due to the increased moment of inertia of the strut and a stabilising effect due to the increased torsional stiffness of the strut. As the torsional stiffness is dependent on the method of attachment, in situations where the fairing increases the torsional inertia with little increase to the torsional stiffness, a net destabilising effect can result. Alternatively, it is possible that for the case that if the fairing were to increase equally both the torsional stiffness and the moment of inertia of the strut, then their effects could be mutually negated. However, it has been found here that for small and simple fairings, typical of current landing gear noise abatement design, their implementation will not affect the dynamics and stability of the system in an operational range (Fz ≤ 50 000 N, V ≤ 100 m/s). This generalisation is strictly dependent on size and installation methods. The aerodynamic load, which would be influenced by the presence of fairings, was modelled

  5. Hail damage to typical aircraft surfaces.

    Science.gov (United States)

    Hayduk, R. J.

    1972-01-01

    Severe structural damage can occur when aircraft collide with hailstones. Consequently, methods of predicting hail damage to airplane surfaces are needed by the aircraft designer. This paper describes an analytical method of predicting the dent depth and final deformed shape for simple structural components impacted by hailstones. The solution was accomplished by adapting the DEPROSS computer program to the problem of normal impact of hail on flat metallic sheets and spherical metallic caps. Experimental data and analytical predictions are presented for hail damage to typical aircraft surfaces along with a description of the hail gun and hail simulation technique used in the experimental study.

  6. Experimental and Numerical Investigation of Wide Area Blunt Impact Damage to Composite Aircraft Structures

    Science.gov (United States)

    Chen, Zhi Ming

    Due to their high performance and weight efficiency, carbon fiber composites are increasingly being used in aircraft primary structure applications. Exposed composite structures (e.g., fuselage lower body) are susceptible accidental impacts by ground service equipment (GSE). The very high mass (over 10,000 kg) of GSE impact can involve high energy (over 1000 J) and thus can induce significant internal damage. Furthermore, the large contact area potentially involved with GSE impact can create significant internal delamination and fiber failure without leaving exterior-visible signs that any damage has occurred. The objectives of the research described herein are to: (1) conduct experimental investigation into the composite aircraft damage caused by GSE impact, (2) examine the small-scale failure modes in focused, element-level studies, (3) establish a finite element modeling methodology involving detailed simulation capability that is validated via small-scale tests, and (4) apply these modeling capabilities to accurately predict full-scale structural behavior without adjustment (e.g., tuning) of modeling input parameters.

  7. Planform, aero-structural, and flight control optimization for tailless morphing aircraft

    Science.gov (United States)

    Molinari, Giulio; Arrieta, Andres F.; Ermanni, Paolo

    2015-04-01

    Tailless airplanes with swept wings rely on variations of the spanwise lift distribution to provide controllability in roll, pitch and yaw. Conventionally, this is achieved utilizing multiple control surfaces, such as elevons, on the wing trailing edge. As every flight condition requires different control moments (e.g. to provide pitching moment equilibrium), these surfaces are practically permanently displaced. Due to their nature, causing discontinuities, corners and gaps, they bear aerodynamic penalties, mostly in terms of shape drag. Shape adaptation, by means of chordwise morphing, has the potential of varying the lift of a wing section by deforming its profile in a way that minimizes the resulting drag. Furthermore, as the shape can be varied differently along the wingspan, the lift distribution can be tailored to each specific flight condition. For this reason, tailless aircraft appear as a prime choice to apply morphing techniques, as the attainable benefits are potentially significant. In this work, we present a methodology to determine the optimal planform, profile shape, and morphing structure for a tailless aircraft. The employed morphing concept is based on a distributed compliance structure, actuated by Macro Fiber Composite (MFC) piezoelectric elements. The multidisciplinary optimization is performed considering the static and dynamic aeroelastic behavior of the resulting structure. The goal is the maximization of the aerodynamic efficiency while guaranteeing the controllability of the plane, by means of morphing, in a set of flight conditions.

  8. `Research and Development of Technology for Controlling the Structure of Multiple-Function Component,` local research and development of important technology for fiscal 1997. 2. Technological development of advanced surface treatment for methane-powered aircraft engine components (Laser-aided advanced treatment system (technology)); 1997 nendo juyo chiiki gijutsu kenkyu kaihatsu `fukugo kino buzai kozo seigyo gijutsu no kenkyu kaihatsu`. 2. Methane nenryo kokukiyo engine buzai no kodo hyomen kako gijutsu kaihatsu (laser oyo senshin kako system gijutsu)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    Surface reforming technologies, such as laser-aided Ti alloying, are studied for developing erosion-resistant materials for the fore section of a methane-fueled aircraft engine. In the formation of intermetallic compound film, the laser plasma hybrid spraying is applied for the formation of a film which is 100-400 times higher than Ti6Al4V in terms of resistance to erosion. For the quantitative evaluation of bond strength, a boundary shear testing jig is built. When the laser irradiating conditions are optimized, the boundary shear strength is elevated to 150-230MPa. NiAl film is studied for realizing resistance to high-temperature oxidation, and then a perfect NiAl film is obtained, which is done by use of a mechanical alloying powder mixed on the atomic level. In the manufacture of ceramic cermet film, a powder is studied, in which powder SiC and Al2O3, excellent in high-temperature oxidation characteristics and fracture toughness, are the parent materials which are coated by NiCr. It is found that an excellent oxidation-resistant film will be manufactured by use of this powder. 40 refs., 132 figs., 12 tabs.

  9. Crystal structure of the RNA component of bacterial ribonuclease P

    Energy Technology Data Exchange (ETDEWEB)

    Torres-Larios, Alfredo; Swinger, Kerren K.; Krasilnikov, Andrey S.; Pan, Tao; Mondragon, Alfonso (NWU); (UC)

    2010-03-08

    Transfer RNA (tRNA) is produced as a precursor molecule that needs to be processed at its 3' and 5' ends. Ribonuclease P is the sole endonuclease responsible for processing the 5' end of tRNA by cleaving the precursor and leading to tRNA maturation. It was one of the first catalytic RNA molecules identified and consists of a single RNA component in all organisms and only one protein component in bacteria. It is a true multi-turnover ribozyme and one of only two ribozymes (the other being the ribosome) that are conserved in all kingdoms of life. Here we show the crystal structure at 3.85 {angstrom} resolution of the RNA component of Thermotoga maritima ribonuclease P. The entire RNA catalytic component is revealed, as well as the arrangement of the two structural domains. The structure shows the general architecture of the RNA molecule, the inter- and intra-domain interactions, the location of the universally conserved regions, the regions involved in pre-tRNA recognition and the location of the active site. A model with bound tRNA is in agreement with all existing data and suggests the general basis for RNA-RNA recognition by this ribozyme.

  10. Crystal structure of the RNA component of bacterial ribonuclease P.

    Science.gov (United States)

    Torres-Larios, Alfredo; Swinger, Kerren K; Krasilnikov, Andrey S; Pan, Tao; Mondragón, Alfonso

    2005-09-22

    Transfer RNA (tRNA) is produced as a precursor molecule that needs to be processed at its 3' and 5' ends. Ribonuclease P is the sole endonuclease responsible for processing the 5' end of tRNA by cleaving the precursor and leading to tRNA maturation. It was one of the first catalytic RNA molecules identified and consists of a single RNA component in all organisms and only one protein component in bacteria. It is a true multi-turnover ribozyme and one of only two ribozymes (the other being the ribosome) that are conserved in all kingdoms of life. Here we show the crystal structure at 3.85 A resolution of the RNA component of Thermotoga maritima ribonuclease P. The entire RNA catalytic component is revealed, as well as the arrangement of the two structural domains. The structure shows the general architecture of the RNA molecule, the inter- and intra-domain interactions, the location of the universally conserved regions, the regions involved in pre-tRNA recognition and the location of the active site. A model with bound tRNA is in agreement with all existing data and suggests the general basis for RNA-RNA recognition by this ribozyme.

  11. Effects of reinforcement ratio and arrangement on the structural behavior of a nuclear building under aircraft impact

    Energy Technology Data Exchange (ETDEWEB)

    Thai, Duc-Kien; Kim, Seung-Eock, E-mail: sekim@sejong.ac.kr; Lee, Hyuk-Kee

    2014-09-15

    Highlights: • Numerical analysis of RC nuclear building model under aircraft impact was conducted. • The analysis result shows similar behavior as compared to the Riera function. • The effects of reinforcement ratio and arrangement were enumerated. • The appropriate number of layer of longitudinal rebar was recommended. - Abstract: This study presents the effectiveness of the rebar ratio and the arrangement of reinforced concrete (RC) structures on the structural behavior of nuclear buildings under aircraft impact using a finite element (FE) approach. A simplified model of a fictitious nuclear building using RC structures was fully modeled. The aircraft model of a Boeing 767-400 was used for impact simulation and was developed and verified with a conventional impact force–time history curve. The IRIS Punching test was used to validate the damage prediction capabilities of the RC wall under impact loading. With regard to the different rebar ratios and rebar arrangements of a nuclear RC building, the structural behavior of a building under aircraft impact was investigated. The structural behavior investigated included plastic deformation, displacement, energy dissipation, perforation/penetration depth and scabbing area. The results showed that the rebar ratio has a significant effect on withstanding aircraft impact and reducing local damage. With four layers of rebar, the RC wall absorbed and dissipated the impact energy more than once with only two layers of rebar for the same rebar ratio.

  12. Real-time aircraft structural damage identification with flight condition variations

    Science.gov (United States)

    Lew, Jiann-Shiun; Loh, Chin-Hsiung

    2012-04-01

    This paper presents a real-time structural damage identification method for aircraft with flight condition variations. The proposed approach begins by identifying the dynamic models under various test conditions from time-domain input/output data. A singular value decomposition technique is then used to characterize and quantify the parameter uncertainties from the identified models. The uncertainty coordinates, corresponding to the identified principal directions, of the identified models are computed, and the residual errors between the identified uncertainty coordinates and the estimated uncertainty coordinates of the health structure are used to identify damage status. A correlation approach is applied to identify damage type and intensity, based on the difference between the identified parameters and the estimated parameters of the healthy structure. The proposed approach is demonstrated by application to the Benchmark Active Controls Technology (BACT) wind-tunnel model.

  13. Structure-borne transmissibility evaluation through modeling and analysis of aircraft vibration dampers

    Directory of Open Access Journals (Sweden)

    Isabel Lima Hidalgo

    2011-05-01

    Full Text Available In the aircraft industry a great practical relevance is given to the extensive use of vibration dampers between fuselage and interior panels. The proper representation of these isolators in computer models is of vital importance for the accurate evaluation of the vibration transmission paths for interior noise prediction. In general, simplified models are not able to predict the component performance at mid and high frequencies, since they do not take into account the natural frequencies of the damper. Experimental tests are carried out to evaluate the dynamic stiffness and the identification of the material properties for a damper available in the market. Different approaches for its modeling are analyzed via FEA, resulting in distinct dynamic responses as function of frequency. The dynamic behavior, when the damper natural mode are considered jointly with the high modal density of the plate that represents the fuselage, required the averaging of results in the high frequency range. At this aim, the statistical energy analysis is then used to turn the comparison between models easier by considering the averaged energy parameters. From simulations, it is possible to conclude how the damper natural modes influence the dynamic response of aircraft interior panels for high frequencies.

  14. 民机结构设计中的系统工程问题%Systems Engineering for Commercial Aircraft Structural Design

    Institute of Scientific and Technical Information of China (English)

    张绪

    2015-01-01

    Systems engineering has been widely applied into highly-integrated complex commercial aircraft development.As an important component,the aircraft structural design will receive innovation with systems engineering introduced.Systems engineering processes in commercial aircraft structural design include function analysis,requirements analysis,structural synthesis, structure production,structural integration,structural tests and so on.Structural requirements are built based on structural design levels and shall be validated and verified.Other systems engineering process include interface management,configuration management and technical risk management.%系统工程在高度集成的复杂民机产品的研制中已得到广泛应用。作为民机设计的重要组成部分,民机结构设计中如能引入系统工程过程和方法,必能有效促进民机结构设计工作的革新。民机结构设计的系统工程过程包括功能分析、需求分析、结构设计、零部件生产、部段和全机结构集成及试验试飞等过程。民机结构需求体系须按照结构设计层级进行制定,并依次进行需求确认和需求验证。民机结构设计相关的系统工程问题还包括接口管理、构型管理、技术风险管理等。

  15. Development of structural health monitoring systems for composite bonded repairs on aircraft structures

    Science.gov (United States)

    Galea, Stephen C.; Powlesland, Ian G.; Moss, Scott D.; Konak, Michael J.; van der Velden, Stephen P.; Stade, Bryan; Baker, Alan A.

    2001-08-01

    The application of bonded composite patches to repair or reinforce defective metallic structures is becoming recognized as a very effective versatile repair procedure for many types of problems. Immediate applications of bonded patches are in the fields of repair of cracking, localized reinforcement after removal of corrosion damage and for reduction of fatigue strain. However, bonded repairs to critical components are generally limited due to certification concerns. For certification and management of repairs to critical structure, the Smart Patch approach may be an acceptable solution from the airworthiness prospective and be cost effective for the operator and may even allow some relaxation of the certification requirements. In the most basic form of the Smart Patch in-situ sensors can be used as the nerve system to monitor in service the structural condition (health or well-being) of the patch system and the status of the remaining damage in the parent structure. This application would also allow the operator to move away from current costly time-based maintenance procedures toward real-time health condition monitoring of the bonded repair and the repaired structure. TO this end a stand-alone data logger device, for the real-time health monitoring of bonded repaired systems, which is in close proximity to sensors on a repair is being developed. The instrumentation will measure, process and store sensor measurements during flight and then allow this data to be up-loaded, after the flight, onto a PC, via remote (wireless) data access. This paper describes two in-situ health monitoring systems which will be used on a composite bonded patch applied to an F/A-18. The two systems being developed consists of a piezoelectric (PVDF) film-based and a conventional electrical-resistance foil strain gauge-based sensing system. The latter system uses a primary cell (Lithium- based battery) as the power source, which should enable an operating life of 1-2 years. The patch

  16. Testing and Analysis of a Composite Non-Cylindrical Aircraft Fuselage Structure . Part II; Severe Damage

    Science.gov (United States)

    Przekop, Adam; Jegley, Dawn C.; Lovejoy, Andrew E.; Rouse, Marshall; Wu, Hsi-Yung T.

    2016-01-01

    The Environmentally Responsible Aviation Project aimed to develop aircraft technologies enabling significant fuel burn and community noise reductions. Small incremental changes to the conventional metallic alloy-based 'tube and wing' configuration were not sufficient to achieve the desired metrics. One airframe concept identified by the project as having the potential to dramatically improve aircraft performance was a composite-based hybrid wing body configuration. Such a concept, however, presented inherent challenges stemming from, among other factors, the necessity to transfer wing loads through the entire center fuselage section which accommodates a pressurized cabin confined by flat or nearly flat panels. This paper discusses a finite element analysis and the testing of a large-scale hybrid wing body center section structure developed and constructed to demonstrate that the Pultruded Rod Stitched Efficient Unitized Structure concept can meet these challenging demands of the next generation airframes. Part II of the paper considers the final test to failure of the test article in the presence of an intentionally inflicted severe discrete source damage under the wing up-bending loading condition. Finite element analysis results are compared with measurements acquired during the test and demonstrate that the hybrid wing body test article was able to redistribute and support the required design loads in a severely damaged condition.

  17. Accelerated corrosion test and corrosion failure distribution model of aircraft structural aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    LIU Wen-lin; MU Zhi-tao; JIN Ping

    2006-01-01

    Based on corrosion damage data of 10 years for a type of aircraft aluminum alloy, the statistical analysis was conducted by Gumbel, Normal and two parameters Weibull distribution function. The results show that aluminum alloy structural member has the corrosion history of pitting corrosion-intergranular corrosion-exfoliation corrosion, and the maximum corrosion depth is in conformity to normal distribution. The accelerated corrosion test was carried out with the complied equivalent airport accelerated environment spectrum. The corrosion damage failure modes of aluminum alloy structural member indicate that the period of validity of the former protective coating is about 2.5 to 3 years, and that of the novel protective coating is about 4.0 to 4.5 years. The corrosion kinetics law of aluminum spar flange was established by fitting corrosion damage test data. The law indicates two apparent corrosion stages of high strength aluminum alloy section material: pitting corrosion and intergranular corrosion/exfoliation corrosion.The test results agree with the statistical fit result of corrosion data collected from corrosion member in service. The fractional error is 5.8% at the same calendar year. The accelerated corrosion test validates the corrosion kinetics law of aircraft aluminum alloy in service.

  18. Structural and wetting properties of fuel cell components

    Science.gov (United States)

    Volfkovich, Yu. M.; Sosenkin, V. E.; Bagotsky, V. S.

    The operation of proton exchange membrane (PEMFC) and direct methanol fuel cells (DMFC) is connected with the flow of different gaseous and liquid components in the cell's membrane-electrode assembly (MEA). The structural and wetting properties of different components of the MEA influence the rate and direction of these flows and hence the fuel cell's efficiency. For a better understanding of the mechanism of all processes influencing the fuel cell efficiency, for a mathematical modelling of these processes, and for a possibility of their optimization, a detailed knowledge of the geometrical structure and wetting properties of all MEA components is necessary. This review describes the results of such investigations performed mainly by using the method of standard contact porosimetry (MSCP). This method gives the possibility to receive information on multicomponent porous and powdered materials hitherto not accessible, viz. their wetting and swelling properties, pore corrugation, and also isotherms of capillary pressure and bond energy. Measurements of MEA components by this method can be performed under exactly the same conditions (temperature, compression degree, contact with water, etc.) as those existing in real fuel cells.

  19. A new method to determine dynamically equivalent finite element models of aircraft structures from modal test data

    Science.gov (United States)

    Karaağaçlı, Taylan; Yıldız, Erdinç N.; Nevzat Özgüven, H.

    2012-08-01

    Flutter analysis is a major requirement to predict safe flight envelops and to decide on flutter testing conditions of newly designed or modified aircraft structures. In order to achieve reliable flutter analysis of an aircraft structure, it is necessary to obtain a good correlation between its finite element (FE) model and experimental modal data. Currently available model updating methods require construction of a detailed initial FE model in order to achieve convergence of the modes obtained from updated FE model to their experimental counterparts. If the updating procedure is not carried out by the original design team of the aircraft structure but a subsidiary company that makes certain modification on it, construction of an appropriate initial FE model from scratch becomes a tedious task requiring considerable amount of engineering work. To overcome the foregoing problem, this paper presents a new method that aims to derive dynamically equivalent FE model of an aircraft structure directly from its experimental modal data. The application of the method is illustrated with two case studies. In the first case study, the performance of the method is tested with the modal test data of a benchmark structure built to simulate dynamic behavior of an airplane, namely GARTEUR SM-AG 19 test bed, and very satisfactory results are obtained: the first 10 elastic FE modes of the test bed closely correlate with experimental data. In the second case study, the method is applied to the modal test data obtained from ground vibration test (GVT) of a real aircraft. In this application, it is observed that only the first 4 modes of the resultant FE model correlate well with experimental data. It is concluded that the method suggested works perfectly well for simple structures like GARTEUR test bed, and it gives quite promising results when applied to real aircraft structures.

  20. Nonlinear Finite Element Analysis of a Composite Non-Cylindrical Pressurized Aircraft Fuselage Structure

    Science.gov (United States)

    Przekop, Adam; Wu, Hsi-Yung T.; Shaw, Peter

    2014-01-01

    The Environmentally Responsible Aviation Project aims to develop aircraft technologies enabling significant fuel burn and community noise reductions. Small incremental changes to the conventional metallic alloy-based 'tube and wing' configuration are not sufficient to achieve the desired metrics. One of the airframe concepts that might dramatically improve aircraft performance is a composite-based hybrid wing body configuration. Such a concept, however, presents inherent challenges stemming from, among other factors, the necessity to transfer wing loads through the entire center fuselage section which accommodates a pressurized cabin confined by flat or nearly flat panels. This paper discusses a nonlinear finite element analysis of a large-scale test article being developed to demonstrate that the Pultruded Rod Stitched Efficient Unitized Structure concept can meet these challenging demands of the next generation airframes. There are specific reasons why geometrically nonlinear analysis may be warranted for the hybrid wing body flat panel structure. In general, for sufficiently high internal pressure and/or mechanical loading, energy related to the in-plane strain may become significant relative to the bending strain energy, particularly in thin-walled areas such as the minimum gage skin extensively used in the structure under analysis. To account for this effect, a geometrically nonlinear strain-displacement relationship is needed to properly couple large out-of-plane and in-plane deformations. Depending on the loading, this nonlinear coupling mechanism manifests itself in a distinct manner in compression- and tension-dominated sections of the structure. Under significant compression, nonlinear analysis is needed to accurately predict loss of stability and postbuckled deformation. Under significant tension, the nonlinear effects account for suppression of the out-of-plane deformation due to in-plane stretching. By comparing the present results with the previously

  1. Mechanical and materials engineering of modern structure and component design

    CERN Document Server

    Altenbach, Holm

    2015-01-01

    This book presents the latest findings on mechanical and materials engineering as applied to the design of modern engineering materials and components. The contributions cover the classical fields of mechanical, civil and materials engineering, as well as bioengineering and advanced materials processing and optimization. The materials and structures discussed can be categorized into modern steels, aluminium and titanium alloys, polymers/composite materials, biological and natural materials, material hybrids and modern nano-based materials. Analytical modelling, numerical simulation, state-of-the-art design tools and advanced experimental techniques are applied to characterize the materials’ performance and to design and optimize structures in different fields of engineering applications.

  2. Topological structures of vortex flow on a flying wing aircraft, controlled by a nanosecond pulse discharge plasma actuator

    Science.gov (United States)

    Du, Hai; Shi, Zhiwei; Cheng, Keming; Wei, Dechen; Li, Zheng; Zhou, Danjie; He, Haibo; Yao, Junkai; He, Chengjun

    2016-06-01

    Vortex control is a thriving research area, particularly in relation to flying wing or delta wing aircraft. This paper presents the topological structures of vortex flow on a flying wing aircraft controlled by a nanosecond plasma dielectric barrier discharge actuator. Experiments, including oil flow visualization and two-dimensional particle image velocimetry (PIV), were conducted in a wind tunnel with a Reynolds number of 0.5 × 106. Both oil and PIV results show that the vortex can be controlled. Oil topological structures on the aircraft surface coincide with spatial PIV flow structures. Both indicate vortex convergence and enhancement when the plasma discharge is switched on, leading to a reduced region of separated flow.

  3. The Vibration Impact Determination of the Helicopter Structural Components

    Directory of Open Access Journals (Sweden)

    Khaksar Zeinab

    2017-01-01

    Full Text Available This paper presents the determination of the vibration impact of the helicopter structural components and skin repairs in terms of frequency characteristics. To address this issue, a 3D Finite Element Method (FEM model of 349 Gazelle helicopter has been developed in ABAQUS and the frequency analysis is conducted. The results on the natural frequencies of the full structure reasonably match with the literature giving confidence in the baseline model. The main advantage of this FEM model is that, it can be used to predict the natural frequencies of the full structure, precisely. In addition, the material properties and conditions of the components can be updated based on the applied conditions during the repair and maintenance period. Thus, the model gives a comprehensive design tool for analysing the frequencies of the helicopter with differing components. The effective variations in the frequency changes due to repair are predicted numerically. The discussion of these results helps in developing leads to improved selection of replacement materials and their properties.

  4. Evaluation of a large capacity heat pump concept for active cooling of hypersonic aircraft structure

    Science.gov (United States)

    Pagel, L. L.; Herring, R. L.

    1978-01-01

    Results of engineering analyses assessing the conceptual feasibility of a large capacity heat pump for enhancing active cooling of hypersonic aircraft structure are presented. A unique heat pump arrangement which permits cooling the structure of a Mach 6 transport to aluminum temperatures without the aid of thermal shielding is described. The selected concept is compatible with the use of conventional refrigerants, with Freon R-11 selected as the preferred refrigerant. Condenser temperatures were limited to levels compatible with the use of conventional refrigerants by incorporating a unique multipass condenser design, which extracts mechanical energy from the hydrogen fuel, prior to each subsequent pass through the condenser. Results show that it is technically feasible to use a large capacity heat pump in lieu of external shielding. Additional analyses are required to optimally apply this concept.

  5. A water tunnel flow visualization study of the vortex flow structures on the F/A-18 aircraft

    Science.gov (United States)

    Sandlin, Doral R.; Ramirez, Edgar J.

    1991-01-01

    The vortex flow structures occurring on the F/A-18 aircraft at high angles of attack were studied. A water tunnel was used to gather flow visualization data on the forebody vortex and the wing leading edge extension vortex. The longitudinal location of breakdown of the leading edge vortex was found to be consistently dependent on the angle of attack. Other parameters such as Reynolds number, model scale, and model fidelity had little influence on the overall behavior of the flow structures studied. The lateral location of the forebody vortex system was greatly influenced by changes in the angle of sideslip. Strong interactions can occur between the leading edge extension vortex and the forebody vortex. Close attention was paid to vortex induced flows on various airframe components of the F/A-18. Reynolds number and angle of attack greatly affected the swirling intensity, and therefore the strength of the studied vortices. Water tunnel results on the F/A-18 correlated well with those obtained in similar studies at both full and sub scale levels. The water tunnel can provide, under certain conditions, good simulations of realistic flows in full scale configurations.

  6. Structural design optimization of vehicle components using Cuckoo Search Algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Yildiz, Ali Riza [Bursa Technical Univ., Bursa (Turkey). Dept. of Mechanical Engineering; Durgun, Ismail

    2012-07-01

    In order to meet today's vehicle design requirements and to improve the cost and fuel efficiency, there is an increasing interest to design light-weight and cost-effective vehicle components. In this research, a new optimization algorithm, called the Cuckoo Search Algorithm (CS) algorithm, is introduced for solving structural design optimization problems. This research is the first application of the CS to the shape design optimization problems in the literature. The CS algorithm is applied to the structural design optimization of a vehicle component to illustrate how the present approach can be applied for solving structural design problems. Results show the ability of the CS to find better optimal structural design. [German] Um heutige Anforderungen an das Fahrzeugdesign zu beruecksichtigen und um die Kosten- und Kraftstoffeffektivitaet zu erhoehen, nimmt das Interesse am Design leichter und kosteneffektiver Fahrzeugkomponenten weiterhin zu. In der diesem Beitrag zugrunde liegenden Studie wurde ein neuer Optimierungsalgorithmus angewendet, der so genannte Cuckoo Suchalgorithmus (CS). Es handelt sich um die erste CS-Applikation fuer das Formdesign in der Literatur. Der CS-Algorithmus wird hierbei zur Strukturdesignoptimierung einer Fahrzeugkomponente angewendet, um zu zeigen, wie er bei der Loesung von Strukturdesignaufgaben angewendet werden kann. Die Ergebnisse zeigen, wie damit ein verbessertes Design erreicht werden kann.

  7. Fielding a structural health monitoring system on legacy military aircraft: A business perspective

    Energy Technology Data Exchange (ETDEWEB)

    Bos, Marcel J. [Dept. of Gas Turbines and Structural Integrity, National Aerospace Laboratory NLR, Amsterdam (Netherlands)

    2015-12-15

    An important trend in the sustainment of military aircraft is the transition from preventative maintenance to condition based maintenance (CBM). For CBM, it is essential that the actual system condition can be measured and the measured condition can be reliably extrapolated to a convenient moment in the future in order to facilitate the planning process while maintaining flight safety. Much research effort is currently being made for the development of technologies that enable CBM, including structural health monitoring (SHM) systems. Great progress has already been made in sensors, sensor networks, data acquisition, models and algorithms, data fusion/mining techniques, etc. However, the transition of these technologies into service is very slow. This is because business cases are difficult to define and the certification of the SHM systems is very challenging. This paper describes a possibility for fielding a SHM system on legacy military aircraft with a minimum amount of certification issues and with a good prospect of a positive return on investment. For appropriate areas in the airframe the application of SHM will reconcile the fail-safety and slow crack growth damage tolerance approaches that can be used for safeguarding the continuing airworthiness of these areas, combining the benefits of both approaches and eliminating the drawbacks.

  8. STRUCTURAL AND TECHNOLOGICAL ANALYSIS OF THE AIRCRAFT LIQUID-GAS SYSTEMS

    Directory of Open Access Journals (Sweden)

    Mr. Dmitrii G. Kolykhalov

    2016-09-01

    Full Text Available Тhis article is devoted to the gas-liquid systems of the aircraft and their structural and technological analysis. The paper shows the characteristics of pipelines, considers the types of working fluids and gases and covers the range of perceived internal pressures. The paper presents the classification of pipelines of flying vehicles from the point of view of their working conditions, taking into account the perceived internal pressure. The article also shows the classification scheme of major groups and types of pipe connections and fittings. The article focuses on the scheme of permanent joints made with soldering and welding, as well as the split of mobile and fixed joints of different types. The authors study the combined connections. The authors have also developed classification schemes of aircraft piping systems that depend on the system pressure. A classification scheme of piping connections, depending on the method of connection, mobility, presence of seals is singled out. The research is ilustrated with examples of compounds of different types.

  9. Elastomeric Structural Attachment Concepts for Aircraft Flap Noise Reduction - Challenges and Approaches to Hyperelastic Structural Modeling and Analysis

    Science.gov (United States)

    Sreekantamurthy, Thammaiah; Turner, Travis L.; Moore, James B.; Su, Ji

    2014-01-01

    Airframe noise is a significant part of the overall noise of transport aircraft during the approach and landing phases of flight. Airframe noise reduction is currently emphasized under the Environmentally Responsible Aviation (ERA) and Fixed Wing (FW) Project goals of NASA. A promising concept for trailing-edge-flap noise reduction is a flexible structural element or link that connects the side edges of the deployable flap to the adjacent main-wing structure. The proposed solution is distinguished by minimization of the span-wise extent of the structural link, thereby minimizing the aerodynamic load on the link structure at the expense of increased deformation requirement. Development of such a flexible structural link necessitated application of hyperelastic materials, atypical structural configurations and novel interface hardware. The resulting highly-deformable structural concept was termed the FLEXible Side Edge Link (FLEXSEL) concept. Prediction of atypical elastomeric deformation responses from detailed structural analysis was essential for evaluating feasible concepts that met the design constraints. The focus of this paper is to describe the many challenges encountered with hyperelastic finite element modeling and the nonlinear structural analysis of evolving FLEXSEL concepts. Detailed herein is the nonlinear analysis of FLEXSEL concepts that emerged during the project which include solid-section, foamcore, hollow, extended-span and pre-stressed concepts. Coupon-level analysis performed on elastomeric interface joints, which form a part of the FLEXSEL topology development, are also presented.

  10. Kinetic Metallization. Repair of IVD Al Coatings and Mg Alloys Aircraft Components Using Portable Kinetic Metallization Systems

    Science.gov (United States)

    2008-02-27

    person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number...aircraft carriers & depots Environmentally sustainable Meets Navy JTP-2003 Portable system & Handheld spray gun Robotic deployment for OEM Applications...Problem - Field & Depot Repair of Damaged IVD-Al & Mg Alloys NADEP Facilities PEO(T) F/A-18, EA-18G PMA -271 E-6B

  11. Vibro-acoustic modelling of aircraft double-walls with structural links using Statistical Energy Analysis

    Science.gov (United States)

    Campolina, Bruno L.

    The prediction of aircraft interior noise involves the vibroacoustic modelling of the fuselage with noise control treatments. This structure is composed of a stiffened metallic or composite panel, lined with a thermal and acoustic insulation layer (glass wool), and structurally connected via vibration isolators to a commercial lining panel (trim). The goal of this work aims at tailoring the noise control treatments taking design constraints such as weight and space optimization into account. For this purpose, a representative aircraft double-wall is modelled using the Statistical Energy Analysis (SEA) method. Laboratory excitations such as diffuse acoustic field and point force are addressed and trends are derived for applications under in-flight conditions, considering turbulent boundary layer excitation. The effect of the porous layer compression is firstly addressed. In aeronautical applications, compression can result from the installation of equipment and cables. It is studied analytically and experimentally, using a single panel and a fibrous uniformly compressed over 100% of its surface. When compression increases, a degradation of the transmission loss up to 5 dB for a 50% compression of the porous thickness is observed mainly in the mid-frequency range (around 800 Hz). However, for realistic cases, the effect should be reduced since the compression rate is lower and compression occurs locally. Then the transmission through structural connections between panels is addressed using a four-pole approach that links the force-velocity pair at each side of the connection. The modelling integrates experimental dynamic stiffness of isolators, derived using an adapted test rig. The structural transmission is then experimentally validated and included in the double-wall SEA model as an equivalent coupling loss factor (CLF) between panels. The tested structures being flat, only axial transmission is addressed. Finally, the dominant sound transmission paths are

  12. Analysis methods for structure reliability of piping components

    Energy Technology Data Exchange (ETDEWEB)

    Schimpfke, T.; Grebner, H.; Sievers, J. [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH, Koeln (Germany)

    2004-07-01

    In the frame of the German reactor safety research program of the Federal Ministry of Economics and Labour (BMWA) GRS has started to develop an analysis code named PROST (PRObabilistic STructure analysis) for estimating the leak and break probabilities of piping systems in nuclear power plants. The long-term objective of this development is to provide failure probabilities of passive components for probabilistic safety analysis of nuclear power plants. Up to now the code can be used for calculating fatigue problems. The paper mentions the main capabilities and theoretical background of the present PROST development and presents some of the results of a benchmark analysis in the frame of the European project NURBIM (Nuclear Risk Based Inspection Methodologies for Passive Components). (orig.)

  13. Lightning protection guidelines and test data for adhesively bonded aircraft structures

    Science.gov (United States)

    Pryzby, J. E.; Plumer, J. A.

    1984-01-01

    The highly competitive marketplace and increasing cost of energy has motivated manufacturers of general aviation aircraft to utilize composite materials and metal-to-metal bonding in place of conventional fasteners and rivets to reduce weight, obtain smoother outside surfaces and reduce drag. The purpose of this program is protection of these new structures from hazardous lightning effects. The program began with a survey of advance-technology materials and fabrication methods under consideration for future designs. Sub-element specimens were subjected to simulated lightning voltages and currents. Measurements of bond line voltages, electrical sparking, and mechanical strength degradation were made to comprise a data base of electrical properties for new technology materials and basic structural configurations. The second hase of the program involved tests on full scale wing structures which contained integral fuel tanks and which were representative of examples of new technology structures and fuel systems. The purpose of these tests was to provide a comparison between full scale structural measurements and those obtained from the sub-element specimens.

  14. Bonded repair of composite aircraft structures: A review of scientific challenges and opportunities

    Science.gov (United States)

    Katnam, K. B.; Da Silva, L. F. M.; Young, T. M.

    2013-08-01

    Advanced composite materials have gained popularity in high-performance structural designs such as aerospace applications that require lightweight components with superior mechanical properties in order to perform in demanding service conditions as well as provide energy efficiency. However, one of the major challenges that the aerospace industry faces with advanced composites - because of their inherent complex damage behaviour - is structural repair. Composite materials are primarily damaged by mechanical loads and/or environmental conditions. If material damage is not extensive, structural repair is the only feasible solution as replacing the entire component is not cost-effective in many cases. Bonded composite repairs (e.g. scarf patches) are generally preferred as they provide enhanced stress transfer mechanisms, joint efficiencies and aerodynamic performance. With an increased usage of advanced composites in primary and secondary aerospace structural components, it is thus essential to have robust, reliable and repeatable structural bonded repair procedures to restore damaged composite components. But structural bonded repairs, especially with primary structures, pose several scientific challenges with the current existing repair technologies. In this regard, the area of structural bonded repair of composites is broadly reviewed - starting from damage assessment to automation - to identify current scientific challenges and future opportunities.

  15. Study on the Similarity Criteria of Aircraft Structure Temperature/Stress/Dynamic Response

    Science.gov (United States)

    Liu, Lei; Gui, Ye-Wei; Du, Yan-Xia; Geng, Xiang-Ren; Wang, An-Ling

    The performance parameters of thermal protection system are essential for the design and optimization of high-speed aircraft. The flight-ground conversion is a valid method to provide the effective support to the design of the thermal protection structure (TPS), because the performance data of TPS were generally obtained from wind tunnel test and should be conversed to the corresponding environment. In this paper, the similarity parameters of heat conduction and thermoelasticity equations are studied, the similarity criteria proposed, and the effectiveness of some of the similar parameters are calculated and analyzed. The research results indicated that wind tunnel test can be better designed using the proposed similarity criteria, and the data obtained from wind tunnel test can be modified more rational to accommodate the reality flight condition so as to improve the precision and the efficiency of wind tunnel experiment.

  16. Wavlet Decomposition based Diagnostic for Structural Health Monitoring on Metallic Aircrafts: Case of Crack Triangulation and Corrosion Detection

    OpenAIRE

    jean yves fourniols; christophe escriba; sabeha zedek; hamza boukabache

    2013-01-01

    This work focus on the structural health monitoring of aircrafts parts specimen structures made of 2024 Aluminum alloys using a reliable Joint Time Frequency Analysis calculation (Joint Temporal Frequency Analysis). In this paper we demonstrate the feasibility of a new non destructive control method capable to probe very large structures within a short time. The method we developed is based through a wide piezoelectric sensors network on a smart comparison between two acoustic signatures: the...

  17. Eddy current measurement system evaluation for corrosion depth determination on cast aluminum aircraft structure

    Science.gov (United States)

    Singh, Surendra; Greving, Dan; Kinney, Andy; Vensel, Fred; Ohm, Jim; Peeler, Mike

    2013-01-01

    An eddy current (EC) technique was developed to determine the corrosion depth on a bare flange face of a cast aluminum A356-T6 aircraft engine structure. The EC response and the corrosion depths determined through metallurgical cross sections were used to develop an empirical relation between EC response and depth. The EC technique and depth determination are used to inspect the engine structures during overhaul to determine if they are fit for continued service. An accurate and reliable Non-Destructive Inspection is required to ensure that structures returned to service are safe for continued operation. NDE system reliability demonstrations of the eddy current technique are traditionally reported in terms of Probability of Detection (POD) data using MIL-HDBK-1823A. However, the calculation of POD data is based on a simple linear predictive model that is valid only if certain criteria are met. These are: 1) NDE system response is measurable (i.e. continuous data), 2) Flaw size is known and measurable (i.e. continuous data), 3) relationship between the NDE system response and flaw size is linear (or linear on a log scale), 4) variation in measured responseresponse around a predicted response for a given flaw size is normally distributed, 5) the variation around the predicted response is constant (i.e. variation does not change with flaw size), and 6) inherent variability in the NDE system is known and fully understood. In this work, a Measurement System Evaluation (MSE) of the Eddy Current System was used to address some of these concerns. This work was completed on two aircraft structures having varying corrosion depths. The data were acquired in a random manner at fifty regions of interests (ROIs). Three operators participated in this study, and each operator measured Eddy Current response three times in each ROI. In total, there were four hundred and fifty data points collected. Following this, the two structures were sectioned for measuring corrosion depth. The

  18. Structures and components in galaxy clusters: observations and models

    CERN Document Server

    Bykov, A M; Ferrari, C; Forman, W R; Kaastra, J S; Klein, U; Markevitch, M; de Plaa, J

    2015-01-01

    Clusters of galaxies are the largest gravitationally bounded structures in the Universe dominated by dark matter. We review the observational appearance and physical models of plasma structures in clusters of galaxies. Bubbles of relativistic plasma which are inflated by supermassive black holes of AGNs, cooling and heating of the gas, large scale plasma shocks, cold fronts, non-thermal halos and relics are observed in clusters. These constituents are reflecting both the formation history and the dynamical properties of clusters of galaxies. We discuss X-ray spectroscopy as a tool to study the metal enrichment in clusters and fine spectroscopy of Fe X-ray lines as a powerful diagnostics of both the turbulent plasma motions and the energetics of the non-thermal electron populations. The knowledge of the complex dynamical and feedback processes is necessary to understand the energy and matter balance as well as to constrain the role of the non-thermal components of clusters.

  19. Multigroup Moderation Test in Generalized Structured Component Analysis

    Directory of Open Access Journals (Sweden)

    Angga Dwi Mulyanto

    2016-05-01

    Full Text Available Generalized Structured Component Analysis (GSCA is an alternative method in structural modeling using alternating least squares. GSCA can be used for the complex analysis including multigroup. GSCA can be run with a free software called GeSCA, but in GeSCA there is no multigroup moderation test to compare the effect between groups. In this research we propose to use the T test in PLS for testing moderation Multigroup on GSCA. T test only requires sample size, estimate path coefficient, and standard error of each group that are already available on the output of GeSCA and the formula is simple so the user does not need a long time for analysis.

  20. Detection of Component Failures for Smart Structure Control Systems

    Science.gov (United States)

    Okubo, Hiroshi

    Uncertainties in the dynamics model of a smart structure are often of significance due to model errors caused by parameter identification errors and reduced-order modeling of the system. Design of a model-based Failure Detection and Isolation (FDI) system for smart structures, therefore, needs careful consideration regarding robustness with respect to such model uncertainties. In this paper, we proposes a new method of robust fault detection that is insensitive to the disturbances caused by unknown modeling errors while it is highly sensitive to the component failures. The capability of the robust detection algorithm is examined for the sensor failure of a flexible smart beam control system. It is shown by numerical simulations that the proposed method suppresses the disturbances due to model errors and markedly improves the detection performance.

  1. Structural ECM components in the premetastatic and metastatic niche.

    Science.gov (United States)

    Høye, Anette M; Erler, Janine T

    2016-06-01

    The aim of this review is to give an overview of the extracellular matrix (ECM) components that are important for creating structural changes in the premetastatic and metastatic niche. The successful arrival and survival of cancer cells that have left the primary tumor and colonized distant sites depends on the new microenvironment they encounter. The primary tumor itself releases factors into the circulation that travel to distant organs and then initiate structural changes, both non-enzymatic and enzymatic, to create a favorable niche for the disseminating tumor cells. Therapeutic strategies aimed at targeting cell-ECM interactions may well be one of the best viable approaches to combat metastasis and thus improve patient care.

  2. Magnons in one-dimensional k-component Fibonacci structures

    Science.gov (United States)

    Costa, C. H.; Vasconcelos, M. S.

    2014-05-01

    We have studied the magnon transmission through of one-dimensional magnonic k-component Fibonacci structures, where k different materials are arranged in accordance with the following substitution rule: Sn(k)=Sn-1(k)Sn-k(k) (n ≥k=0,1,2,…), where Sn(k) is the nth stage of the sequence. The calculations were carried out in exchange dominated regime within the framework of the Heisenberg model and taking into account the RPA approximation. We have considered multilayers composed of simple cubic spin-S Heisenberg ferromagnets, and, by using the powerful transfer-matrix method, the spin wave transmission is obtained. It is demonstrated that the transmission coefficient has a rich and interesting magnonic pass- and stop-bands structures, which depends on the frequency of magnons and the k values.

  3. Magnons in one-dimensional k-component Fibonacci structures

    Energy Technology Data Exchange (ETDEWEB)

    Costa, C. H., E-mail: carloshocosta@hotmail.com [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59072-970 Natal-RN (Brazil); Escola de Ciências e Tecnologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal-RN (Brazil); Vasconcelos, M. S. [Escola de Ciências e Tecnologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal-RN (Brazil)

    2014-05-07

    We have studied the magnon transmission through of one-dimensional magnonic k-component Fibonacci structures, where k different materials are arranged in accordance with the following substitution rule: S{sub n}{sup (k)}=S{sub n−1}{sup (k)}S{sub n−k}{sup (k)} (n≥k=0,1,2,…), where S{sub n}{sup (k)} is the nth stage of the sequence. The calculations were carried out in exchange dominated regime within the framework of the Heisenberg model and taking into account the RPA approximation. We have considered multilayers composed of simple cubic spin-S Heisenberg ferromagnets, and, by using the powerful transfer-matrix method, the spin wave transmission is obtained. It is demonstrated that the transmission coefficient has a rich and interesting magnonic pass- and stop-bands structures, which depends on the frequency of magnons and the k values.

  4. Study of flutter related computational procedures for minimum weight structural sizing of advanced aircraft

    Science.gov (United States)

    Oconnell, R. F.; Hassig, H. J.; Radovcich, N. A.

    1976-01-01

    Results of a study of the development of flutter modules applicable to automated structural design of advanced aircraft configurations, such as a supersonic transport, are presented. Automated structural design is restricted to automated sizing of the elements of a given structural model. It includes a flutter optimization procedure; i.e., a procedure for arriving at a structure with minimum mass for satisfying flutter constraints. Methods of solving the flutter equation and computing the generalized aerodynamic force coefficients in the repetitive analysis environment of a flutter optimization procedure are studied, and recommended approaches are presented. Five approaches to flutter optimization are explained in detail and compared. An approach to flutter optimization incorporating some of the methods discussed is presented. Problems related to flutter optimization in a realistic design environment are discussed and an integrated approach to the entire flutter task is presented. Recommendations for further investigations are made. Results of numerical evaluations, applying the five methods of flutter optimization to the same design task, are presented.

  5. Application of the active camber morphing concept based on compliant structures to a regional aircraft

    Science.gov (United States)

    De Gaspari, Alessandro; Ricci, Sergio

    2014-04-01

    The present work addresses the optimal design of a morphing mechanism based on compliant structures used to implement the active camber morphing concept. The subject of the work is part of the FP7-NOVEMOR project (Novel Air Vehicle Configurations: From Fluttering Wings to Morphing Flight) which is one of the many projects from the seventh European Framework Programme. The implementation of active camber concept is based on the use of conformable morphing control surfaces. Aiming at the optimal design of such as morphing devices, two dedicated tools called PHORMA and SPHERA, respectively, are introduced. The definition of the optimal shape taking into account both aerodynamic and structural constraints is done by PHORMA. Then SPHERA, based on the load path approach codified by coupling a non linear beam solver to a genetic multi- objective optimizer, is adopted to generate the optimal internal structure able to produce, when loaded, the target optimal shape. The paper is mainly focused on the optimal design of the compliant structures starting from the optimal shape already available for a Reference Aircraft (RA) developed inside NOVEMOR project and representative of a typical regional jet capable to carry 113 PAX in a single economic class.

  6. Energy Finite Element Analysis Developments for Vibration Analysis of Composite Aircraft Structures

    Science.gov (United States)

    Vlahopoulos, Nickolas; Schiller, Noah H.

    2011-01-01

    The Energy Finite Element Analysis (EFEA) has been utilized successfully for modeling complex structural-acoustic systems with isotropic structural material properties. In this paper, a formulation for modeling structures made out of composite materials is presented. An approach based on spectral finite element analysis is utilized first for developing the equivalent material properties for the composite material. These equivalent properties are employed in the EFEA governing differential equations for representing the composite materials and deriving the element level matrices. The power transmission characteristics at connections between members made out of non-isotropic composite material are considered for deriving suitable power transmission coefficients at junctions of interconnected members. These coefficients are utilized for computing the joint matrix that is needed to assemble the global system of EFEA equations. The global system of EFEA equations is solved numerically and the vibration levels within the entire system can be computed. The new EFEA formulation for modeling composite laminate structures is validated through comparison to test data collected from a representative composite aircraft fuselage that is made out of a composite outer shell and composite frames and stiffeners. NASA Langley constructed the composite cylinder and conducted the test measurements utilized in this work.

  7. Transport jet aircraft noise abatement in foreign countries: Growth, structure, impact. Volume 1: Europe, July 1980. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, F.A.

    1980-07-01

    The development and implementation of aircraft noise control regulations in various European states are described. The countries include the United Kingdom, France, Switzerland, Federal Republic of Germany, Sweden, Denmark, and the Netherlands. Topics discussed include noise monitoring, airport curfews, land use planning, and the government structure for noise regulation.

  8. Residual strength evaluation of concrete structural components under fatigue loading

    Indian Academy of Sciences (India)

    A Rama Chandra Murthy; G S Palani; Nagesh R Iyer; Smitha Gopinath; B K Raghu Prasad

    2012-02-01

    This paper presents methodologies for residual strength evaluation of concrete structural components using linear elastic and nonlinear fracture mechanics principles. The effect of cohesive forces due to aggregate bridging has been represented mathematically by employing tension softening models. Various tension softening models such as linear, bilinear, trilinear, exponential and power curve have been described with appropriate expressions. These models have been validated by predicting the remaining life of concrete structural components and comparing with the corresponding experimental values available in the literature. It is observed that the predicted remaining life by using power model and modified bi-linear model is in good agreement with the corresponding experimental values. Residual strength has also been predicted using these tension softening models and observed that the predicted residual strength is in good agreement with the corresponding analytical values in the literature. In general, it is observed that the variation of predicted residual moment with the chosen tension softening model follows the similar trend as in the case of remaining life. Linear model predicts large residual moments followed by trilinear, bilinear and power models.

  9. Numerical and Experimental Investigation of the Structural Behavior during Aircraft Emergency Landing on Water

    OpenAIRE

    Siemann, Martin

    2016-01-01

    Although occurring infrequent, the emergency landing of aircraft on water constitutes a crucial facet within aviation safety and, hence, it engages aircraft manufacturers within design and certification processes. Currently employed methods to analyze ditching comprise experimental testing, comparison with already ditching-certified aircraft designs, and semi-analytical as well as uncoupled numerical simulations. Since these means comprise several drawbacks and limitations, there is the motiv...

  10. NASA-UVa light aerospace alloy and structures technology program supplement: Aluminum-based materials for high speed aircraft

    Science.gov (United States)

    Starke, E. A., Jr. (Editor)

    1995-01-01

    This report on the NASA-UVa light aerospace alloy and structure technology program supplement: Aluminum-Based Materials for High Speed Aircraft covers the period from July 1, 1992. The objective of the research is to develop aluminum alloys and aluminum matrix composites for the airframe which can efficiently perform in the HSCT environment for periods as long as 60,000 hours (certification for 120,000 hours) and, at the same time, meet the cost and weight requirements for an economically viable aircraft. Current industry baselines focus on flight at Mach 2.4. The research covers four major materials systems: (1) Ingot metallurgy 2XXX, 6XXX, and 8XXX alloys, (2) Powder metallurgy 2XXX alloys, (3) Rapidly solidified, dispersion strengthened Al-Fe-X alloys, and (4) Discontinuously reinforced metal matrix composites. There are ten major tasks in the program which also include evaluation and trade-off studies by Boeing and Douglas aircraft companies.

  11. Structural Analysis and Optimization of a Composite Fan Blade for Future Aircraft Engine

    Science.gov (United States)

    Coroneos, Rula M.; Gorla, Rama Subba Reddy

    2012-09-01

    This paper addresses the structural analysis and optimization of a composite sandwich ply lay-up of a NASA baseline solid metallic fan blade comparable to a future Boeing 737 MAX aircraft engine. Sandwich construction with a polymer matrix composite face sheet and honeycomb aluminum core replaces the original baseline solid metallic fan model made of Titanium. The focus of this work is to design the sandwich composite blade with the optimum number of plies for the face sheet that will withstand the combined pressure and centrifugal loads while the constraints are satisfied and the baseline aerodynamic and geometric parameters are maintained. To satisfy the requirements a sandwich construction for the blade is proposed with composite face sheets and a weak core made of honeycomb aluminum material. For aerodynamic considerations, the thickness of the core is optimized where as the overall blade thickness is held fixed in order not to alter the original airfoil geometry. Weight reduction is taken as the objective function by varying the core thickness of the blade within specified upper and lower bounds. Constraints are imposed on radial displacement limitations and ply failure strength. From the optimum design, the minimum number of plies, which will not fail, is back-calculated. The ply lay-up of the blade is adjusted from the calculated number of plies and final structural analysis is performed. Analyses were carried out by utilizing the OpenMDAO Framework, developed at NASA Glenn Research Center combining optimization with structural assessment.

  12. Probabilistic model, analysis and computer code for take-off and landing related aircraft crashes into a structure

    Energy Technology Data Exchange (ETDEWEB)

    Glaser, R.

    1996-02-06

    A methodology is presented that allows the calculation of the probability that any of a particular collection of structures will be hit by an aircraft in a take-off or landing related accident during a specified window of time with a velocity exceeding a given critical value. A probabilistic model is developed that incorporates the location of each structure relative to airport runways in the vicinity; the size of the structure; the sizes, types, and frequency of use of commercial, military, and general aviation aircraft which take-off and land at these runways; the relative frequency of take-off and landing related accidents by aircraft type; the stochastic properties of off-runway crashes, namely impact location, impact angle, impact velocity, and the heading, deceleration, and skid distance after impact; and the stochastic properties of runway overruns and runoffs, namely the position at which the aircraft exits the runway, its exit velocity, and the heading and deceleration after exiting. Relevant probability distributions are fitted from extensive commercial, military, and general aviation accident report data bases. The computer source code for implementation of the calculation is provided.

  13. X-Aerogels for Structural Components and High Temperature Applications

    Science.gov (United States)

    2005-01-01

    Future NASA missions and space explorations rely on the use of materials that are strong ultra lightweight and able to withstand extreme temperatures. Aerogels are low density (0.01-0.5 g/cu cm) high porosity materials that contain a glass like structure formed through standard sol-gel chemistry. As a result of these structural properties, aerogels are excellent thermal insulators and are able to withstand temperatures in excess of l,000 C. The open structure of aerogels, however, renders these materials extremely fragile (fracturing at stress forces less than 0.5 N/sq cm). The goal of NASA Glenn Research Center is to increase the strength of these materials by templating polymers and metals onto the surface of an aerogel network facilitating the use of this material for practical applications such as structural components of space vehicles used in exploration. The work this past year focused on two areas; (1) the research and development of new templated aerogels materials and (2) process development for future manufacturing of structural components. Research and development occurred on the production and characterization of new templating materials onto the standard silica aerogel. Materials examined included polymers such as polyimides, fluorinated isocyanates and epoxies, and, metals such as silver, gold and platinum. The final properties indicated that the density of the material formed using an isocyanate is around 0.50 g/cc with a strength greater than that of steel and has low thermal conductivity. The process used to construct these materials is extremely time consuming and labor intensive. One aspect of the project involved investigating the feasibility of shortening the process time by preparing the aerogels in the templating solvent. Traditionally the polymerization used THF as the solvent and after several washes to remove any residual monomers and water, the solvent around the aerogels was changed to acetonitrile for the templating step. This process

  14. Local atomic structures of single-component metallic glasses

    Science.gov (United States)

    Trady, Salma; Hasnaoui, Abdellatif; Mazroui, M.'hammed; Saadouni, Khalid

    2016-10-01

    In this study we examine the structural properties of single-component metallic glasses of aluminum. We use a molecular dynamics simulation based on semi-empirical many-body potential, derived from the embedded atom method (EAM). The radial distribution function (RDF), common neighbors analysis method (CNA), coordination number analysis (CN) and Voronoi tessellation are used to characterize the metal's local structure during the heating and cooling (quenching). The simulation results reveal that the melting temperature depends on the heating rate. In addition, atomic visualization shows that the structure of aluminum after fast quenching is in a glassy state, confirmed quantitatively by the splitting of the second peak of the radial distribution function, and by the appearance of icosahedral clusters observed via CNA technique. On the other hand, the Wendt-Abraham parameters are calculated to determine the glass transition temperature (Tg), which depends strongly on the cooling rate; it increases while the cooling rate increases. On the basis of CN analysis and Voronoi tessellation, we demonstrate that the transition from the Al liquid to glassy state is mainly due to the formation of distorted and perfect icosahedral clusters.

  15. On the Deflexion of Anisotropic Structural Composite Aerodynamic Components

    Directory of Open Access Journals (Sweden)

    J. Whitty

    2014-01-01

    Full Text Available This paper presents closed form solutions to the classical beam elasticity differential equation in order to effectively model the displacement of standard aerodynamic geometries used throughout a number of industries. The models assume that the components are constructed from in-plane generally anisotropic (though shown to be quasi-isotropic composite materials. Exact solutions for the displacement and strains for elliptical and FX66-S-196 and NACA 63-621 aerofoil approximations thin wall composite material shell structures, with and without a stiffening rib (shear-web, are presented for the first time. Each of the models developed is rigorously validated via numerical (Runge-Kutta solutions of an identical differential equation used to derive the analytical models presented. The resulting calculated displacement and material strain fields are shown to be in excellent agreement with simulations using the ANSYS and CATIA commercial finite element (FE codes as well as experimental data evident in the literature. One major implication of the theoretical treatment is that these solutions can now be used in design codes to limit the required displacement and strains in similar components used in the aerospace and most notably renewable energy sectors.

  16. System-on-Chip Integration of a New Electromechanical Impedance Calculation Method for Aircraft Structure Health Monitoring

    OpenAIRE

    Daniel Medale; Sebastien Rolet; Jean Yves Fourniols; Sabeha Zedek; Christophe Escriba; Hamza Boukabache

    2012-01-01

    The work reported on this paper describes a new methodology implementation for active structural health monitoring of recent aircraft parts made from carbon-fiber-reinforced polymer. This diagnosis is based on a new embedded method that is capable of measuring the local high frequency impedance spectrum of the structure through the calculation of the electro-mechanical impedance of a piezoelectric patch pasted non-permanently onto its surface. This paper involves both the laboratory based E/M...

  17. Component

    Directory of Open Access Journals (Sweden)

    Tibor Tot

    2011-01-01

    Full Text Available A unique case of metaplastic breast carcinoma with an epithelial component showing tumoral necrosis and neuroectodermal stromal component is described. The tumor grew rapidly and measured 9 cm at the time of diagnosis. No lymph node metastases were present. The disease progressed rapidly and the patient died two years after the diagnosis from a hemorrhage caused by brain metastases. The morphology and phenotype of the tumor are described in detail and the differential diagnostic options are discussed.

  18. Conceptual Design of Structural Components of a Dual Cooled Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyung-Kyu; Lee, Young-Ho; Lee, Kang-Hee; Kim, Jae-Yong; Yoon, Kyung-Ho

    2008-01-15

    A dual cooled fuel, featured by an internal as well as an external coolant flow passage of a fuel rod, was suggested to enable a large-scaled power-uprate of PWR plant and launched as one of the National Nuclear R and D Projects in 2007. It is necessary to make the dual cooled fuel be compatible with an OPR-1000 system to maximize the economy. Also, the structural components of the dual cooled fuel should be designed to realize their features. To this end, a conceptual design of a spacer grid, outer and center guide tubes, and top and bottom end pieces has been carried out in the project 'Development of Design Technology for Dual Cooled Fuel Structure'. For the spacer grids, it is suggested that springs and dimples are located at or near the cross points of the straps due to a considerably narrowed rod-to-rod gap. Candidate shapes of the grids were also developed and applied for domestic patents. For the outer and center guide tubes, a dual tube like a fuel rod was suggested to make the subchannel areas around the guide tubes be similar to those around the fuel rods of enlarged diameter. It was applied for the domestic patent as well. For the top and bottom end pieces, the shape and pattern have been changed from the conventional ones reflecting the fuel rods' changes. Technical issues and method of resolution for each components were listed up for a basic design works in the following years.

  19. 14 CFR 43.7 - Persons authorized to approve aircraft, airframes, aircraft engines, propellers, appliances, or...

    Science.gov (United States)

    2010-01-01

    ..., airframes, aircraft engines, propellers, appliances, or component parts for return to service after... Administrator, may approve an aircraft, airframe, aircraft engine, propeller, appliance, or component part for..., airframe, aircraft engine, propeller, appliance, or component part for return to service as provided...

  20. Resin Film Infusion (RFI) Process Modeling for Large Transport Aircraft Wing Structures

    Science.gov (United States)

    Knott, Tamara W.; Loos, Alfred C.

    2000-01-01

    Resin film infusion (RFI) is a cost-effective method for fabricating stiffened aircraft wing structures. The RFI process lends itself to the use of near net shape textile preforms manufactured through a variety of automated textile processes such as knitting and braiding. Often, these advanced fiber architecture preforms have through-the-thickness stitching for improved damage tolerance and delamination resistance. The challenge presently facing RFI is to refine the process to ensure complete infiltration and cure of a geometrically complex shape preform with the high fiber volume fraction needed for structural applications. An accurate measurement of preform permeability is critical for successful modeling of the RFI resin infiltration process. Small changes in the permeability can result in very different infiltration behavior and times. Therefore, it is important to accurately measure the permeabilities of the textile preforms used in the RFI process. The objective of this investigation was to develop test methods that can be used to measure the compaction behavior and permeabilities of high fiber volume fraction, advanced fiber architecture textile preforms. These preforms are often highly compacted due to through-the-thickness stitching used to improve damage tolerance. Test fixtures were designed and fabricated and used to measure both transverse and in-plane permeabilities. The fixtures were used to measure the permeabilities of multiaxial warp knit and triaxial braided preforms at fiber volume fractions from 55% to 65%. In addition, the effects of stitching characteristics, thickness, and batch variability on permeability and compaction behavior were investigated.

  1. Process-scheme-driven automatic construction of NC machining cell for aircraft structural parts

    Institute of Scientific and Technical Information of China (English)

    Chen Shulin; Zheng Guolei; Zhou Min; Du Baorui; Chu Hongzhen

    2013-01-01

    In order to enhance the NC programming efficiency and quality of aircraft structural parts (ASPs), an intelligent NC programming pattern driven by process schemes is presented. In this pattern, the NC machining cell is the minimal organizational structure in the technological process, consisting of an operation machining volume cell, and the type and parameters of the machining operation. After the machining cell construction, the final NC program can be easily obtained in a CAD/CAM system by instantiating the machining operation for each machining cell. Accord-ingly, how to automatically establish the machining cells is a key issue in intelligent NC program-ming. On the basis of the NC machining craft of ASP, the paper aims to make an in-depth research on this issue. Firstly, some new terms about the residual volume and the machinable volume are defined, and then, the technological process is modeled with a process scheme. Secondly, the approach to building the machining cells is introduced, in which real-time complement machining is mainly considered to avoid interference and overcutting. Thirdly, the implementing algorithm is designed and applied to the Intelligent NC Programming System of ASP. Finally, the developed algorithm is validated through two case studies.

  2. The Analysis of Fatigue Behavior of Joint-strengthened Component in Aircraft%飞机连接加强件疲劳特性分析

    Institute of Scientific and Technical Information of China (English)

    何宇廷; 富贵华

    2001-01-01

    To analyze the fatigue behavior of joint-strengthened component in aircraft, a series of special finite element method (FEM) programs, in which 4-node isoparametric plane elements and two-dimensional rivet elements are used, are presented to analyze the detail stresses of the riveted component. After calculating the detail stresses of joint-strengthened component and determining its fatigue dangerous position, the stress severity factor method is used to calculate the fatigue life of the component and its fatigue safety life is gained.%针对飞机上一重要承力连接加强件,采用平 面四节点等参元与二维受剪钉元组合而成的有限元程序进行了细节应力分析,确定了疲劳危 险部位。接着,在给定的等效载荷谱作用下,采用应力严重系数法计算了其疲劳寿命,得到 了有益的结果。

  3. Recognizing genes and other components of genomic structure

    Energy Technology Data Exchange (ETDEWEB)

    Burks, C. (Los Alamos National Lab., NM (USA)); Myers, E. (Arizona Univ., Tucson, AZ (USA). Dept. of Computer Science); Stormo, G.D. (Colorado Univ., Boulder, CO (USA). Dept. of Molecular, Cellular and Developmental Biology)

    1991-01-01

    The Aspen Center for Physics (ACP) sponsored a three-week workshop, with 26 scientists participating, from 28 May to 15 June, 1990. The workshop, entitled Recognizing Genes and Other Components of Genomic Structure, focussed on discussion of current needs and future strategies for developing the ability to identify and predict the presence of complex functional units on sequenced, but otherwise uncharacterized, genomic DNA. We addressed the need for computationally-based, automatic tools for synthesizing available data about individual consensus sequences and local compositional patterns into the composite objects (e.g., genes) that are -- as composite entities -- the true object of interest when scanning DNA sequences. The workshop was structured to promote sustained informal contact and exchange of expertise between molecular biologists, computer scientists, and mathematicians. No participant stayed for less than one week, and most attended for two or three weeks. Computers, software, and databases were available for use as electronic blackboards'' and as the basis for collaborative exploration of ideas being discussed and developed at the workshop. 23 refs., 2 tabs.

  4. Lifetime and structures of TLEs captured by high-speed camera on board aircraft

    Science.gov (United States)

    Takahashi, Y.; Sanmiya, Y.; Sato, M.; Kudo, T.; Inoue, T.

    2012-12-01

    Temporal development of sprite streamer is the manifestation of the local electric field and conductivity. Therefore, in order to understand the mechanisms of sprite, which show a large variety in temporal and spatial structures, the detailed analysis of both fine and macro-structures with high time resolution are to be the key approach. However, due to the long distance from the optical equipments to the phenomena and to the contamination by aerosols, it's not easy to get clear images of TLEs on the ground. In the period of June 27 - July 10, 2011, a combined aircraft and ground-based campaign, in support of NHK Cosmic Shore project, was carried with two jet airplanes under collaboration between NHK, Japan Broadcasting Corporation, and universities. On 8 nights out of 16 standing-by, the jets took off from the airport near Denver, Colorado, and an airborne high speed camera captured over 60 TLE events at a frame rate of 8000-10,000 /sec. Some of them show several tens of streamers in one sprite event, which repeat splitting at the down-going end of streamers or beads. The velocities of the bottom ends and the variations of their brightness are traced carefully. It is found that the top velocity is maintained only for the brightest beads and others become slow just after the splitting. Also the whole luminosity of one sprite event has short time duration with rapid downward motion if the charge moment change of the parent lightning is large. The relationship between diffuse glows such as elves and sprite halos, and subsequent discrete structure of sprite streamers is also examined. In most cases the halo and elves seem to show inhomogenous structures before being accompanied by streamers, which develop to bright spots or streamers with acceleration of the velocity. Those characteristics of velocity and lifetime of TLEs provide key information of their generation mechanism.

  5. Static Aeroelasticity in Combat Aircraft.

    Science.gov (United States)

    1986-01-01

    Simulation Maneuverability Performance System Integration Design Load Spectren FIG. 1 HIGH PERFORMANCE AIRCRAFT DESIGN Simulation has a great potential...Aeroelasticity has also a great effect on the flight control system design. If the basic control powers are reduced by increasing dynamic pressure...Components Flight Envelope Structure Concept a Total Aircraf Analysis FIG, 2 BASIC DATAS FOR AEROELASTIC DESIGN STUDIES Aeroelastic activities are now devided

  6. YF-12 Lockalloy ventral fin program, volume 1. [design analysis, fabrication, and manufacturing of aircraft structures using aluminum and beryllium alloys for the lockheed YF-12 aircraft

    Science.gov (United States)

    Duba, R. J.; Haramis, A. C.; Marks, R. F.; Payne, L.; Sessing, R. C.

    1976-01-01

    Results are presented of the YF-12 Lockalloy Ventral Fin Program which was carried out by Lockheed Aircraft Corporation - Advanced Development Projects for the joint NASA/USAF YF-12 Project. The primary purpose of the program was to redesign and fabricate the ventral fin of the YF-12 research airplane (to reduce flutter) using Lockalloy, and alloy of beryllium and aluminum, as a major structural material. A secondary purpose, was to make a material characterization study (thermodynamic properties, corrosion; fatigue tests, mechanical properties) of Lockalloy to validate the design of the ventral fin and expand the existing data base on this material. All significant information pertinent to the design and fabrication of the ventral fin is covered. Emphasis throughout is given to Lockalloy fabrication and machining techniques and attendant personnel safety precautions. Costs are also examined. Photographs of tested alloy specimens are shown along with the test equipment used.

  7. Spiral Passive Electromagnetic Sensor (SPES) for composite structural changes in aircraft structures

    Science.gov (United States)

    Iervolino, Onorio; Meo, Michele

    2016-04-01

    A major goal of structural health monitoring (SHM) is to provide accurate and responsive detection and monitoring of flaws. This research work reports an investigation of SPES sensors for damage detection, investigating different sensor sizes and how they affect the sensor's signal. A sensor able to monitor structural change that can be remotely interrogated and does not need a power supply is presented in this work. The SPES-sensor presents the great advantage of monitoring conductive and non-conductive structures such as fiberglass-reinforced composites (FRC) and carbon fiber-reinforced polymers (CFRP). Any phenomena that affect the magnetic field of the SPES can be detected and monitored. A study was conducted to investigate the capability of sensor to give information on structural changes, simulated by the presence of an external mass placed in the proximity of sensor. Effect of different positions of the SPES within the sample, and how to extend the area of inspection using multiple sensors was investigated. The sensor was tested embedded in the samples, simulating the structural change on both sides of the sample. In both configurations the sensor described herein demonstrated a great potential to monitor structural changes.

  8. Characterization of Unsteady Flow Structures Around Tandem Cylinders for Component Interaction Studies in Airframe Noise

    Science.gov (United States)

    Jenkins, Luther N.; Khorrami, Mehdi R.; Choudhari, Meelan M.; McGinley, Catherine B.

    2005-01-01

    A joint computational and experimental study has been performed at NASA Langley Research Center to investigate the unsteady flow generated by the components of an aircraft landing gear system. Because the flow field surrounding a full landing gear is so complex, the study was conducted on a simplified geometry consisting of two cylinders in tandem arrangement to isolate and characterize the pertinent flow phenomena. This paper focuses on the experimental effort where surface pressures, 2-D Particle Image Velocimetry, and hot-wire anemometry were used to document the flow interaction around the two cylinders at a Reynolds Number of 1.66 x 10(exp 5), based on cylinder diameter, and cylinder spacing-todiameter ratios, L/D, of 1.435 and 3.70. Transition strips were applied to the forward cylinder to produce a turbulent boundary layer upstream of the flow separation. For these flow conditions and L/D ratios, surface pressures on both the forward and rear cylinders show the effects of L/D on flow symmetry, base pressure, and the location of flow separation and attachment. Mean velocities and instantaneous vorticity obtained from the PIV data are used to examine the flow structure between and aft of the cylinders. Shedding frequencies and spectra obtained using hot-wire anemometry are presented. These results are compared with unsteady, Reynolds-Averaged Navier-Stokes (URANS) computations for the same configuration in a companion paper by Khorrami, Choudhari, Jenkins, and McGinley (2005). The experimental dataset produced in this study provides information to better understand the mechanisms associated with component interaction noise, develop and validate time-accurate computer methods used to calculate the unsteady flow field, and assist in modeling of the radiated noise from landing gears.

  9. Aircraft Measurements of Convective System Vertical Structure and Coldpools during the DYNAMO Project

    Science.gov (United States)

    Guy, N.; Jorgensen, D. P.; Chen, S. S.; Wang, Q.

    2012-12-01

    The DYNAMO (Dynamics of the Madden-Julian Oscillation) field experiment employed a large number of measurement platforms with which to study environmental and convective cloud system characteristics of the MJO initiation region in the Indian Ocean. One such platform, the NOAA P-3 instrumented aircraft, provided mobility to sample convective cloud systems along with the surrounding environment. The tail-mounted, X-band Doppler radar allowed a pseudo-dual-Doppler analysis technique to study system kinematics and derive vertical wind motion. GPS dropwindsondes provided a robust means for thermodynamic characterization both in and around the sampled convective cloud systems. This presentation will focus on the relationships between coldpool strength and depth (along with other environmental characteristics) and the vertical structure of convective systems. In addition, a comparison of the DYNAMO observations to previous results in the region (e.g. TOGA COARE) will be presented. Differences in organizational aspects of convective clouds into mesoscale convective systems between the studies will provide a context of regional differences, which may serve as a basis for future model simulations.

  10. Flammability of self-extinguishing kenaf/ABS nanoclays composite for aircraft secondary structure

    Science.gov (United States)

    Karunakaran, S.; Majid, D. L.; Mohd Tawil, M. L.

    2016-10-01

    This study investigates the flammability properties of kenaf fiber reinforced acrylonitrile butadiene styrene (ABS) with nanoclays composites. Natural fiber is one of the potential materials to be used with thermoplastic as a composite due to its attractive properties such as lightweight and strong. In this paper, flammability properties of this material are evaluated through Underwriters Laboratory 94 Horizontal Burning (UL94 HB), which has been conducted for both controlled and uncontrolled conditions, smoke density and limiting oxygen index tests (LOI). These flammability tests are in compliance with the Federal Aviation Regulation (FAR) requirement. The results from UL94 HB and smoke density tests show that the presence of nanoclays with effective composition of kenaf fiber reinforced ABS has enhanced the burning characteristics of the material by hindering propagation of flame spread over the surface of the material through char formation. Consequently, this decreases the burning rate and produces low amount of smoke during burning. On contrary, through LOI test, this material requires less oxygen to burn when exposed to fire, which hinders the enhancement of burning characteristics. This is due to burning mechanism exhibited by nanoclays that catalyzes barrier formation and flame propagation rate over the surface of the biocomposite material. Overall, these experimental results suggest that this biocomposite material is capable of self-extinguishing and possesses effective fire extinction. The observed novel synergism from the result obtained is promising to be implemented in secondary structures of aircraft with significant benefits such as cost-effective, lightweight and biodegradable self-extinguishing biocomposite.

  11. The effect of material heterogeneity in curved composite beams for use in aircraft structures

    Science.gov (United States)

    Otoole, Brendan J.; Santare, Michael H.

    1992-01-01

    A design tool is presented for predicting the effect of material heterogeneity on the performance of curved composite beams for use in aircraft fuselage structures. Material heterogeneity can be induced during processes such as sheet forming and stretch forming of thermoplastic composites. This heterogeneity can be introduced in the form of fiber realignment and spreading during the manufacturing process causing a gradient in material properties in both the radial and tangential directions. The analysis procedure uses a separate two-dimensional elasticity solution for the stresses in the flanges and web sections of the beam. The separate solutions are coupled by requiring the forces and displacements match at the section boundaries. Analysis is performed for curved beams loaded in pure bending and uniform pressure. The beams can be of any general cross-section such as a hat, T-, I-, or J-beam. Preliminary results show that geometry of the beam dictates the effect of heterogeneity on performance. Heterogeneity plays a much larger role in beams with a small average radius to depth ratio, R/t, where R is the average radius of the beam and t is the difference between the inside and outside radius. Results of the analysis are in the form of stresses and displacements, and they are compared to both mechanics of materials and numerical solutions obtained using finite element analysis.

  12. Structures, Components and Functions of Secretory Tissues in Houttuynia cordata

    Institute of Scientific and Technical Information of China (English)

    Xi-Lu Ni; Li Peng; Wen-Zhe Liu

    2007-01-01

    Houttuynia cordata Thunb., traditionally used as a therapeutic plant in folk medicine, has shown antioxidant and anticancer activities.The species, as a core component of paleoherbs, is normally characterized based on the presence of different types of secretory tissue: oil cells, three types of secretory cells and glandular hairs.The aim of this work was to study the structural, componential, and the functional characteristics of the secretory tissues in both the floral and vegetative parts.The results indicate that oll cells and secretory cells are distributed in all organs of the plant, while glandular hairs are situated on the aerial stems and leaves.Both oil cells and glandular hairs initiate from the protoderm, but their developmental processes are different.Although three types of secretory cells initiate from different primary meristems, the developmental pattems of different secretory cells are the same.Also, although the origins of secretory cells are different from oil cells, their early developmental processes are the same.Histochemical results show that oil cells, secretory cells and glandular hairs produce flavonoids, phenolic compounds, tannins, lipids, aldehyde and ketone-compounds.In addition, there are terpenoids and pectic-like substances in oil cells, alkaloids in secretory cells of aerial stems, and terpenoids and alkaloids in glandular hairs.These compounds play very important roles in protecting plants from being eaten by herbivores (herbivory) and infected by microbial pathogens.The oil cell and secretory cell, as unicellular secretory tissues, are intermediates between the primitive surface glandular and secretory cavity and canal during the evolution of secretory structures.

  13. Volume-imaging lidar observations of the convective structure surrounding the flight path of a flux-measuring aircraft

    Energy Technology Data Exchange (ETDEWEB)

    Eloranta, E.W.; Forrest, D.K. (Univ. of Wisconsin, Madison (United States))

    1992-11-30

    This work is part of the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE), an international land-surface-atmosphere experiment aimed at improving the way climate models represent energy, water, heat, and carbon exchanges, and improving the utilization of satellite based remote sensing to monitor such parameters. Here the authors report on convective structure measurements in the atmospheric boundary layer (ABL) made from instrumented aircraft flights. To compensate for the limited spatial resolution of the aircraft flight path the data is correlated with simultaneous LIDAR measurements which provide a much larger scale picture of the atmosphere. Together these two diagnostics provide a much more informative picture of the ABL, especially in the vicinity of particular convective eddy structures. It becomes clear from this work that stable results require longer flight paths than the 15km legs in this sample area. Horizontal wind speeds from the two instruments agree very well.

  14. Vortex Structures in a Rotating BEC Dark Matter Component

    Directory of Open Access Journals (Sweden)

    N. T. Zinner

    2011-01-01

    Full Text Available We study the effects of a dark matter component that consists of bosonic particles with ultralight masses in the condensed state. We compare previous studies for both noninteracting condensates and with repulsive two-body terms and show consistency between the proposals. Furthermore, we explore the effects of rotation on a superfluid dark matter condensate, assuming that a vortex lattice is formed as seen in ultracold atomic gas experiments. The influence of such a lattice in virialization of gravitationally bound structures and on galactic rotation velocity curves is explored. With fine-tuning of the bosonic particle mass and the two-body repulsive interaction strength, we find that one can have substructure on rotation curves that resembles some observations in spiral galaxies. This occurs when the dark matter halo has an array of hollow cylinders. This can cause oscillatory behavior in the galactic rotation curves in similar fashion to the well-known effect of the spiral arms. We also consider how future experiments and numerical simulations with ultracold atomic gases could tell us more about such exotic dark matter proposals.

  15. 76 FR 74831 - Aging Management of Stainless Steel Structures and Components in Treated Borated Water

    Science.gov (United States)

    2011-12-01

    ... COMMISSION Aging Management of Stainless Steel Structures and Components in Treated Borated Water AGENCY...- ISG-2011-01, ``Aging Management of Stainless Steel Structures and Components in Treated Borated Water... management of stainless steel structures and components exposed to treated borated water. In response to...

  16. Cooperative Autonomous Observation of Coherent Atmospheric Structures using Small Unmanned Aircraft Systems

    Science.gov (United States)

    Ravela, S.

    2014-12-01

    Mapping the structure of localized atmospheric phenomena, from sea breeze and shallow cumuli to thunderstorms and hurricanes, is of scientific interest. Low-cost small unmanned aircraft systems (sUAS) open the possibility for autonomous "instruments" to map important small-scale phenomena (kilometers, hours) and serve as a testbed for for much larger scales. Localized phenomena viewed as coherent structures interacting with their large-scale environment are difficult to map. As simple simulations show, naive Eulerian or Lagrangian strategies can fail in mapping localized phenomena. Model-based techniques are needed. Meteorological targeting, where supplementary UAS measurements additionally constrain numerical models is promising, but may require many primary measurements to be successful. We propose a new, data-driven, field-operable, cooperative autonomous observing system (CAOS) framework. A remote observer (on a UAS) tracks tracers to identify an apparent motion model over short timescales. Motion-based predictions seed MCMC flight plans for other UAS to gather in-situ data, which is fused with the remote measurements to produce maps. The tracking and mapping cycles repeat, and maps can be assimilated into numerical models for longer term forecasting. CAOS has been applied to study small scale emissions. At Popocatepetl, in collaboration with CENAPRED and IPN, it is being applied map the plume using remote IR/UV UAS and in-situ SO2 sensing, with additional plans for water vapor, the electric field and ash. The combination of sUAS with autonomy appears to be highly promising methodology for environmental mapping. For more information, please visit http://caos.mit.edu

  17. Enhanced radiographic imaging of defects in aircraft structure materials with the dehazing method

    Science.gov (United States)

    Yahaghi, Effat; Movafeghi, Amir; Mohmmadzadeh, Nooreddin

    2015-04-01

    The aircraft structures are made of aluminium alloys because of its various advantages, including ease of manufacture, high tolerance and ease of maintenance. Corrosions and cracks are often found in high-strength aluminium alloys. The industrial radiographic testing method and digital radiography are two most important tools for detecting different kinds of defects in aluminium structures. However, because of greater sensitivity and dynamic range of phosphor plates in computed radiography than in film, digital radiography can produce clear and high-contrast images, but digital radiography images appear foggy. In this study, a dehazing algorithm is implemented for the digital radiography images of airplane parts to remove fog. The used dehazing algorithm is based on the dark channel prior and it is based on the statistics of outdoor haze-free images. In most of the local regions of the radiography images, some pixels very often have very low intensity in at least one colour (RGB: red, green, blue) channel which are called dark pixels. In hazy radiography images, the intensity of these dark pixels in that channel is mainly contributed by scattering. Therefore, these dark pixels can directly provide an accurate estimation of the haze transmission and combining a haze imaging model and a soft matting interpolation method can be recovered a high-quality haze free in the radiography image and produce a good depth map and the defects. The results show that the fog-removed images have better contrast and the shapes of defects are very clear. In addition, some invisible cracks in the digital images can be seen in the defogged image.

  18. Structural materials for ITER in-vessel component design

    Science.gov (United States)

    Kalinin, G.; Gauster, W.; Matera, R.; Tavassoli, A.-A. F.; Rowcliffe, A.; Fabritsiev, S.; Kawamura, H.

    1996-10-01

    The materials proposed for ITER in-vessel components have to exhibit adequate performance for the operating lifetime of the reactor or for specified replacement intervals. Estimates show that maximum irradiation dose to be up to 5-7 dpa (for 1 MWa/m 2 in the basic performance phase (BPP)) within a temperature range from 20 to 300°C. Austenitic SS 316LN-ITER Grade was defined as a reference option for the vacuum vessel, blanket, primary wall, pipe lines and divertor body. Conventional technologies and mill products are proposed for blanket, back plate and manifold manufacturing. HIPing is proposed as a reference manufacturing method for the primary wall and blanket and as an option for the divertor body. The existing data show that mechanical properties of HIPed SS are no worse than those of forged 316LN SS. Irradiation will result in property changes. Minimum ductility has been observed after irradiation in an approximate temperature range between 250 and 350°C, for doses of 5-10 dpa. In spite of radiation-induced changes in tensile deformation behavior, the fracture remains ductile. Irradiation assisted corrosion cracking is a concern for high doses of irradiation and at high temperatures. Re-welding is one of the critical issues because of the need to replace failed components. It is also being considered for the replacement of shielding blanket modules by breeding modules after the BPP. Estimates of radiation damage at the locations for re-welding show that the dose will not exceed 0.05 dpa (with He generation of 1 appm) for the manifold and 0.01 dpa (with He generation 0.1 appm) for the back plate for the BPP of ITER operation. Existing experimental data show that these levels will not result in property changes for SS; however, neutron irradiation and He generation promote crack formation in the heat affected zone during welding. Cu based alloys, DS-Cu (Glidcop A125) and PHCu CuCrZr bronze) are proposed as a structural materials for high heat flux

  19. Component-specific modeling. [jet engine hot section components

    Science.gov (United States)

    Mcknight, R. L.; Maffeo, R. J.; Tipton, M. T.; Weber, G.

    1992-01-01

    Accomplishments are described for a 3 year program to develop methodology for component-specific modeling of aircraft hot section components (turbine blades, turbine vanes, and burner liners). These accomplishments include: (1) engine thermodynamic and mission models, (2) geometry model generators, (3) remeshing, (4) specialty three-dimensional inelastic structural analysis, (5) computationally efficient solvers, (6) adaptive solution strategies, (7) engine performance parameters/component response variables decomposition and synthesis, (8) integrated software architecture and development, and (9) validation cases for software developed.

  20. Definition of 1992 Technology Aircraft Noise Levels and the Methodology for Assessing Airplane Noise Impact of Component Noise Reduction Concepts

    Science.gov (United States)

    Kumasaka, Henry A.; Martinez, Michael M.; Weir, Donald S.

    1996-01-01

    This report describes the methodology for assessing the impact of component noise reduction on total airplane system noise. The methodology is intended to be applied to the results of individual study elements of the NASA-Advanced Subsonic Technology (AST) Noise Reduction Program, which will address the development of noise reduction concepts for specific components. Program progress will be assessed in terms of noise reduction achieved, relative to baseline levels representative of 1992 technology airplane/engine design and performance. In this report, the 1992 technology reference levels are defined for assessment models based on four airplane sizes - an average business jet and three commercial transports: a small twin, a medium sized twin, and a large quad. Study results indicate that component changes defined as program final goals for nacelle treatment and engine/airframe source noise reduction would achieve from 6-7 EPNdB reduction of total airplane noise at FAR 36 Stage 3 noise certification conditions for all of the airplane noise assessment models.

  1. Strength of Composite Joints in Structural Components and Articles

    Directory of Open Access Journals (Sweden)

    A. A. Bakulin

    2016-01-01

    Full Text Available Currently, the composite materials (CM are widely used in the aerospace technology and mechanical engineering where the key parameters characterizing structural components and articles are related to their weight characteristics as well as their performance under high temperatures.For the experimental investigation of composite-based threaded items, the rod-based 3Dreinforced carbon-carbon composite material (CCCM was chosen.The subject of the research was the metric thread. The test samples were cut of the aforesaid material along one of the reinforcement direction. The following thread sizes were analyzed: М24×1.5; М24×2; М24×3.Dependence of the thread strength on the number of thread turns was determined within the range of 1 to 10 thread turns for М24×2 thread size. The remaining test samples were used to obtain the relationship between the thread load bearing capacity and the thread pitch.The obtained dependence of the thread load bearing capacity on the number of thread turns showed the following:a An increment in the thread load bearing capacity decreases with increasing number of thread turns. However, this effect is less pronounced than that observed for the metal ‘screw/nut’ pair.b With the CCCM material under study, it proved to be impossible to test configurations having only 1 or 2 thread turns.c The wide confidence range (CR of the failure load can be explained by the fact that the material under study features an apparent structural heterogeneity, with a different probability of hitting a unit cell of the matrix and filler of the material. Nevertheless, the confidence range is stable, thus indicating indirectly the possibility of using this test method for further study of composite-based threaded items.There is an explicit correlation between the thread load bearing capacity and the thread pitch. Increase in the thread strength with increasing thread pitch depends on the relationship between the pitch size and the

  2. An Advanced Open-Source Aircraft Design Platform for Personal Air Vehicle Geometry, Aerodynamics, and Structures Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Innovators working to revolutionize air travel through personal aviation pioneers need innovative aircraft design tools. Vehicle Sketch Pad (VSP) is an aircraft...

  3. NASA-UVA Light Aerospace Alloy and Structure Technology Program Supplement: Aluminum-Based Materials for High Speed Aircraft

    Science.gov (United States)

    Starke, E. A., Jr.

    1997-01-01

    This is the final report of the study "Aluminum-Based Materials for High Speed Aircraft" which had the objectives (1) to identify the most promising aluminum-based materials with respect to major structural use on the HSCT and to further develop those materials and (2) to assess the materials through detailed trade and evaluation studies with respect to their structural efficiency on the HSCT. The research team consisted of ALCOA, Allied-Signal, Boeing, McDonnell Douglas, Reynolds Metals and the University of Virginia. Four classes of aluminum alloys were investigated: (1) I/M 2XXX containing Li and I/M 2XXX without Li, (2) I/M 6XXX, (3) two P/M 2XXX alloys, and (4) two different aluminum-based metal matrix composites (MMC). The I/M alloys were targeted for a Mach 2.0 aircraft and the P/M and MMC alloys were targeted for a Mach 2.4 aircraft. Design studies were conducted using several different concepts including skin/stiffener (baseline), honeycomb sandwich, integrally stiffened and hybrid adaptations (conventionally stiffened thin-sandwich skins). Alloy development included fundamental studies of coarsening behavior, the effect of stress on nucleation and growth of precipitates, and fracture toughness as a function of temperature were an integral part of this program. The details of all phases of the research are described in this final report.

  4. Bird impact at aircraft structure - Damage analysis using Coupled Euler Lagrangian Approach

    Science.gov (United States)

    Smojver, I.; Ivancevic, D.

    2010-06-01

    Numerical bird strike damage prediction procedure has been applied on the very detailed large airplane secondary structure consisting of sandwich, composite and metallic structural items. The impacted inboard flap finite element model is modelled using 3D, shell and continuum shell elements, coupled with appropriate kinematic constraints. The bird has been modelled using Coupled Euler Lagrangian approach, in order to avoid the numerical difficulties connected with mesh distortion. Various failure modes, such as Carbon Fibre Reinforced Plastics (CFRP) face layer rupture, failure of composite matrix, damage initiation / evolution in the sandwich structure Nomex core and elastoplastic failure of a metallic structure have been investigated. Besides, general contact has been applied as to efficiently capture the contact between Eulerian bird material and the structure, as well as large deformations of the different structural components. Compared to the classic Lagrangian modelling of the bird, the analysis has proven to be more stable, and the results, such as damage areas, physically more realistic. The impact has been applied in the area that is the most probably subjected to the impact damage during exploitation.

  5. Economic security and its components in agro business structures

    OpenAIRE

    MUZYKA T.P.

    2011-01-01

    The place and role of economic security of new organization agro business in the national security system, proposed to form the system of economic security agro businesses, which would include public and private components.

  6. All-Fiber Components for Micro-Structured Fibers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose new concepts for developing components for high performance space based Lidar systems. While it is generally recognized that photonic crystal fiber...

  7. An analysis of the costs and benefit in improving the T56-A-427 interconnector harness end and mating thermocouple end connector under the aircraft engine Component Improvement Program (CIP)

    OpenAIRE

    Murphy, Thomas Joseph

    1994-01-01

    Approved for public release; distribution is unlimited. This thesis is a study validating the cost effectiveness of the Component Improvement Program for aircraft engines. It determines the costs and benefits derived from the Navy incorporating Power Plant Change 111 which improved the interconnector harness end and mating thermocouple end connector of the T56-A-427 engine. Useful maintenance data pertaining to this component was extracted from the Naval Logistics Data Analysis (NALDA) sys...

  8. Space life sciences: structure and dynamics of the global space radiation field at aircraft altitudes.

    Science.gov (United States)

    2003-01-01

    This issue is devoted to research papers on the radiation environment encountered by aircraft crew members and the flying public, both of which are exposed to a higher than average radiation dose. Two types of space radiation are considered: galactic cosmic radiation and solar activity. The papers include reviews on atmospheric ionization radiation, the factors controlling this radiation, the modeling of this radiation, and measurements made on board specific aircraft flights during solar minimum and solar maximum conditions, and during the major solar proton events that occurred in 1989 and 2001.

  9. Survival analysis of aging aircraft

    Science.gov (United States)

    Benavides, Samuel

    work demonstrates the development of a probabilistic corrosion failure model using survival analysis methods and techniques. Using a parsimonious approach, the coefficients of a Cox proportional hazards model were derived from a set of environmental, geographical and operational predictor variables. To determine if the variables satisfied the proportional hazard assumption, numerous statistical tests were performed---such as the equivalence tests of the log rank, Wilcoxon, Peto-Peto and Fleming-Harrington---and graphical plots generated such as observed-versus-expected plots and log(-log) survival curves. Finally, in a paradigm enhancement to current design methodologies, this dissertation place sets survival analysis modeling in the context of an emerging holistic structural integrity philosophy. While traditional aircraft design and life prediction methodologies consider only the cyclic fatigue domain without consideration to the environmental or unique operating spectrum that aircraft may fly in, a holistic approach considers the cradle-to-grave driving forces in the life of a component, such as corrosion assisted crack nucleation in a material. This dissertation, which uses real-world failure data obtained from structural aircraft components, is poised to narrow the cradle-to-grave loop and provide holistic feedback in the understanding of aircraft structural system failures.

  10. Aircraft-skin Infrared Radiation Characteristics Modeling and Analysis

    Institute of Scientific and Technical Information of China (English)

    Lu Jianwei; Wang Qiang

    2009-01-01

    One of the most important problems of stealth technology is to evaluate the infrared radiation (IR) level received by IR sensors from fighters to be detected. This article presents a synthetic method for calculating the IR emitted from aircraft-skin. By reckoning the aerodynamic heating and hot engine casing to be the main heat sources of the exposed aircraft-skin, a numerical model of skin temperature distribution is established through computational fluid dynamics (CFD) technique. Based on it, an infrared signature model for solving the complex geometry and structure of a fighter is proposed with the reverse Monte Carlo (RMC) method. Finally, by way of determining the IR intensity from aircraft-skin, the aircraft components that emit the most IR can be identified; and the cooling effects of the main aircraft components on IR intensity are investigated. It is found that reduction by 10 K in the skin temperature of head, vertical stabilizers and wings could lead to decline of more than 8% of the IR intensity on the aircraft-skin in front view while at the broadside of the aircraft, the drops in IR intensity could attain under 8%. The results provide useful reference in designing stealthy aircraft.

  11. A Component-Based Debugging Approach for Detecting Structural Inconsistencies in Declarative Equation Based Models

    Institute of Scientific and Technical Information of China (English)

    Jian-Wan Ding; Li-Ping Chen; Fan-Li Zhou

    2006-01-01

    Object-oriented modeling with declarative equation based languages often unconsciously leads to structural inconsistencies. Component-based debugging is a new structural analysis approach that addresses this problem by analyzing the structure of each component in a model to separately locate faulty components. The analysis procedure is performed recursively based on the depth-first rule. It first generates fictitious equations for a component to establish a debugging environment, and then detects structural defects by using graph theoretical approaches to analyzing the structure of the system of equations resulting from the component. The proposed method can automatically locate components that cause the structural inconsistencies, and show the user detailed error messages. This information can be a great help in finding and localizing structural inconsistencies, and in some cases pinpoints them immediately.

  12. Effective L/D: A Theoretical Approach to the Measurement of Aero-Structural Efficiency in Aircraft Design

    Science.gov (United States)

    Guynn, Mark D.

    2015-01-01

    There are many trade-offs in aircraft design that ultimately impact the overall performance and characteristics of the final design. One well recognized and well understood trade-off is that of wing weight and aerodynamic efficiency. Higher aerodynamic efficiency can be obtained by increasing wing span, usually at the expense of higher wing weight. The proper balance of these two competing factors depends on the objectives of the design. For example, aerodynamic efficiency is preeminent for sailplanes and long slender wings result. Although the wing weight-drag trade is universally recognized, aerodynamic efficiency and structural efficiency are not usually considered in combination. This paper discusses the concept of "aero-structural efficiency," which combines weight and drag characteristics. A metric to quantify aero-structural efficiency, termed effective L/D, is then derived and tested with various scenarios. Effective L/D is found to be a practical and robust means to simultaneously characterize aerodynamic and structural efficiency in the context of aircraft design. The primary value of the effective L/D metric is as a means to better communicate the combined system level impacts of drag and structural weight.

  13. High-frequency guided ultrasonic waves for hidden defect detection in multi-layer aircraft structures

    Science.gov (United States)

    Masserey, B.; Raemy, C.; Fromme, P.

    2012-05-01

    Aerospace structures contain multi-layer components subjected to cyclic loading conditions; fatigue cracks and disbonds can develop, often at fastener holes. High-frequency guided waves have the potential for non-destructive damage detection at critical and difficult to access locations from a stand-off distance. Using commercially available ultrasonic transducers, high frequency guided waves were generated that penetrate through the complete thickness of a model structure, consisting of two adhesively bonded aluminum plates. The wave propagation along the specimen was measured and quantified using a laser interferometer. The wave propagation and scattering at internal defects was simulated using Finite Element (FE) models and good agreement with the measurement results found. The detection sensitivity using standard pulse-echo measurements was verified and the influence of the stand-off distance predicted from the FE simulation results.

  14. Testing a theory of aircraft noise annoyance: A structural equation analysis

    NARCIS (Netherlands)

    Kroesen, M.; Molin, E.J.E.; Van Wee, B.

    2008-01-01

    Previous research has stressed the relevance of nonacoustical factors in the perception of aircraft noise. However, it is largely empirically driven and lacks a sound theoretical basis. In this paper, a theoretical model which explains noise annoyance based on the psychological stress theory is empi

  15. 飞机结构的腐蚀与防护%Corrosion and Protection of Aircraft Structure

    Institute of Scientific and Technical Information of China (English)

    李东帆

    2016-01-01

    Objective To study the structure corrosion of military aircraft, to accomplish corrosion repair and protection,in order to ensure the flight safety and economic operation. Methods The typical structure corrosion in the repair works was analyzed, the main causes for the corrosion were found out, and targeted repair and protection measures were taken. Results The structure corrosion of aircraft was effectively controlled,the maintenance cost was greatly reduced, the aircraft′s flight safety and service life were guaranteed. Conclusion The structure corrosion of military aircraft is more and more serious, we must put prevention at the first position, and wipe out the corrosion at the starting stage by combining prevention and repair.%目的 研究军用飞机结构腐蚀情况,做好腐蚀的修理与防护,确保飞行安全和经济运行.方法 对修理中遇到的典型飞机结构腐蚀进行分析,找出腐蚀的主要原因,并作出针对性修理与防护措施.结果 飞机结构腐蚀得到了有效的控制,维修费用大大降低,飞机的飞行安全和使用寿命得到保障.结论 军用飞机结构腐蚀越来越严重,日常维修中必须做到预防为主,防治结合,把腐蚀消灭在萌芽状态.

  16. Structure of multi-component/multi-Yukawa mixtures

    Science.gov (United States)

    Blum, L.; Arias, M.

    2006-09-01

    Recent small angle scattering experiments reveal new peaks in the structure function S(k) of colloidal systems (Liu et al 2005 J. Chem. Phys. 122 044507), in a region that was inaccessible with older instruments. It has been increasingly evident that a single (or double) Yukawa MSA-closure cannot account for these observations, and three or more terms are needed. On the other hand the MSA is not sufficiently accurate (Broccio et al 2005 Preprint); more accurate theories such as the HNC have been tried. But while the MSA is asymptotically exact at high densities (Rosenfield and Blum 1986 J. Chem. Phys. 85 1556), it does not satisfy the low density asymptotics. This has been corrected in the soft MSA (Blum et al 1972 J. Chem. Phys. 56 5197, Narten et al 1974 J. Chem. Phys. 60 3378) by adding exponential type terms. The results compared to experiment and simulation for liquid sodium by Rahman and Paskin (as shown in Blum et al 1972 J. Chem. Phys. 56 5197) are remarkably good. We use here a general closure of the Ornstein-Zernike equation, which is not necessarily the MSA closure (Blum and Hernando 2001 Condensed Matter Theories vol 16 ed Hernandez and Clark (New York: Nova) p 411). \\begin{equation} \\fl c_{ij}(r)=\\sum_{n=1}^{M}{\\cal{K}}_{ij}^{(n)}\\rme^{-z_{n}r}/r\\tqs {\\cal{K}}_{ij}^{(n)}=K^{(n)}\\delta_{i}^{(n)}\\delta_{j}^{(n)}\\tqs r\\geq \\sigma_{ij} \\label{eq1} \\end{equation} with the boundary condition for gij(r) = 0 for r<=σij. This general closure of the Ornstein-Zernike equation will go well beyond the MSA since it has been tested by Monte Carlo simulation for tetrahedral water (Blum et al 1999 Physica A 265 396), toroidal ion channels (Enriquez and Blum 2005 Mol. Phys. 103 3201) and polyelectrolytes (Blum and Bernard 2004 Proc. Int. School of Physics Enrico Fermi, Course CLV vol 155, ed Mallamace and Stanley (Amsterdam: IOS Press) p 335). For this closure we get for the Laplace transform of the pair correlation function an explicitly symmetric result

  17. HOTCFGM-2D: A Coupled Higher-Order Theory for Cylindrical Structural Components with Bi-Directionally Components with Bi-Directionally Graded Microstructures

    Science.gov (United States)

    Pindera, Marek-Jerzy; Aboudi, Jacob

    2000-01-01

    The objective of this two-year project was to develop and deliver to the NASA-Glenn Research Center a two-dimensional higher-order theory, and related computer codes, for the analysis and design of cylindrical functionally graded materials/structural components for use in advanced aircraft engines (e.g., combustor linings, rotor disks, heat shields, brisk blades). To satisfy this objective, two-dimensional version of the higher-order theory, HOTCFGM-2D, and four computer codes based on this theory, for the analysis and design of structural components functionally graded in the radial and circumferential directions were developed in the cylindrical coordinate system r-Theta-z. This version of the higher-order theory is a significant generalization of the one-dimensional theory, HOTCFGM-1D, developed during the FY97 for the analysis and design of cylindrical structural components with radially graded microstructures. The generalized theory is applicable to thin multi-phased composite shells/cylinders subjected to steady-state thermomechanical, transient thermal and inertial loading applied uniformly along the axial direction such that the overall deformation is characterized by a constant average axial strain. The reinforcement phases are uniformly distributed in the axial direction, and arbitrarily distributed in the radial and circumferential direction, thereby allowing functional grading of the internal reinforcement in the r-Theta plane. The four computer codes fgmc3dq.cylindrical.f, fgmp3dq.cylindrical.f, fgmgvips3dq.cylindrical.f, and fgmc3dq.cylindrical.transient.f are research-oriented codes for investigating the effect of functionally graded architectures, as well as the properties of the multi-phase reinforcement, in thin shells subjected to thermomechanical and inertial loading, on the internal temperature, stress and (inelastic) strain fields. The reinforcement distribution in the radial and circumferential directions is specified by the user. The thermal

  18. 78 FR 13911 - Proposed Revision to Design of Structures, Components, Equipment and Systems

    Science.gov (United States)

    2013-03-01

    ..., ``Concrete And Steel Internal Structures of Steel Or Concrete Containments, ``Section 3.8.4, ``Other Seismic... COMMISSION Proposed Revision to Design of Structures, Components, Equipment and Systems AGENCY: Nuclear..., ``Design of Structures, Components, Equipment, and Systems'' and is soliciting public comment on...

  19. Structure and function of ferricyanide in the formation of chromate conversion coatings on aluminum aircraft alloy

    Energy Technology Data Exchange (ETDEWEB)

    Xia, L.; McCreery, R.L.

    1999-10-01

    Raman and infrared spectroscopy were used to determine the structure of Fe(CN){sup {minus}3}{sub 6} and its reaction products in chromate conversion coatings (CCCs) on AA 2024-T3 aluminum aircraft alloy. In addition, Raman spectroscopy was used to monitor CCC growth rates and their dependence on coating bath composition. The IR and Raman spectra of the air-dried CCC corresponded to those of Berlin green, a Fe{sup +3}-CN-FE{sup +3} polymer, and Fe(CN){sub 6}{sup {minus}3} physisorbed on Cr(OH){sub 3}. No other cyano-containing products were observed. When Fe(CN){sub 6}{sup {minus}3} was excluded from the coating bath, CCC formation rate greatly decreased. In addition, it was observed that Fe(CN){sub 6}{sup {minus}3} could rapidly oxidize AA 2024-T3, and Fe(CN){sub 6}{sup {minus}4} rapidly reduced Cr(VI) in bath conditions. These results indicate a redox mediation action for Fe(CN){sub 6}{sup {minus}3/{minus}4}, which greatly increases the reduction of Cr(VI) to Cr(III) by the alloy. This process is normally quite slow, and redox mediation by Fe(CN){sub 6}{sup {minus}3} is critical to CCC formation. IrCl{sub 6}{sup {minus}3}/{sup {minus}2} could substitute for Fe(CN){sub 6}{sup {minus}3/{minus}4} to produce a chromate film with properties very similar to a conventional CCC. The results establish redox mediation as the mechanism of acceleration of CCC formation, but provide no evidence for any additional role of Fe(CN){sub 6}{sup {minus}3/{minus}4} to produce a chromate film with properties very similar to a conventional CCC. The results establish redox mediation as the mechanism of acceleration of CCC formation, but provide no evidence for any additional role of Fe(CN){sub 6}{sup {minus}3/{minus}4} in corrosion protection.

  20. Peak earthquake response of structures under multi-component excitations

    Institute of Scientific and Technical Information of China (English)

    Jianwei Song; Zach Liang; Yi-Lun Chu; George C.Lee

    2007-01-01

    Accurate estimation of the peak seismic responses of structures is important in earthquake resistant design.The internal force distributions and the seismic responses of structures are quite complex,since ground motions are multidirectional.One key issue is the uncertainty of the incident angle between the directions of ground motion and the reference axes of the structure.Different assumed seismic incidences can result in difierent peak values within the scope of design spectrum analysis for a given structure and earthquake ground motion record combination.Using time history analysis to determine the maximum structural responses excited by a given earthquake record requires repetitive calculations to determine the critical incident angle.This paper presents a transformation approach for relatively accurate and rapid determination of the maximum peak responses of a linear structure subjected to three-dimensional excitations within all possible seismic incident angles.The responses can be deformations,internal forces,strains and so on.An irregular building structure model is established using SAP2000 program.Several typical earthquake records and an artificial white noise are applied to the structure model to illustrate the variation of the maximum structural responses for different incident angles.Numerical results show that for many structural parameters,the variation can be greater than 100%.This method can be directly applied to time history analysis of structures using existing computer software to determine the peak responses without carrying out the analyses for all possible incident angles.It can also be used to verify and/or modify aseismic designs by using response spectrum analysis.

  1. HOTCFGM-1D: A Coupled Higher-Order Theory for Cylindrical Structural Components with Through-Thickness Functionally Graded Microstructures

    Science.gov (United States)

    Pindera, Marek-Jerzy; Aboudi, Jacob

    1998-01-01

    The objective of this three-year project was to develop and deliver to NASA Lewis one-dimensional and two-dimensional higher-order theories, and related computer codes, for the analysis, optimization and design of cylindrical functionally graded materials/structural components for use in advanced aircraft engines (e.g., combustor linings, rotor disks, heat shields, blisk blades). To satisfy this objective, a quasi one-dimensional version of the higher-order theory, HOTCFGM-1D, and four computer codes based on this theory, for the analysis, design and optimization of cylindrical structural components functionally graded in the radial direction were developed. The theory is applicable to thin multi-phased composite shell/cylinders subjected to macroscopically axisymmetric thermomechanical and inertial loading applied uniformly along the axial direction such that the overall deformation is characterized by a constant average axial strain. The reinforcement phases are uniformly distributed in the axial and circumferential directions, and arbitrarily distributed in the radial direction, thereby allowing functional grading of the internal reinforcement in this direction.

  2. Creating a Test Validated Structural Dynamic Finite Element Model of the Multi-Utility Technology Test Bed Aircraft

    Science.gov (United States)

    Pak, Chan-Gi; Truong, Samson S.

    2014-01-01

    Small modeling errors in the finite element model will eventually induce errors in the structural flexibility and mass, thus propagating into unpredictable errors in the unsteady aerodynamics and the control law design. One of the primary objectives of Multi Utility Technology Test Bed, X-56A, aircraft is the flight demonstration of active flutter suppression, and therefore in this study, the identification of the primary and secondary modes for the structural model tuning based on the flutter analysis of X-56A. The ground vibration test validated structural dynamic finite element model of the X-56A is created in this study. The structural dynamic finite element model of the X-56A is improved using a model tuning tool. In this study, two different weight configurations of the X-56A have been improved in a single optimization run.

  3. Parametric Analysis of the Reciprocating Sealing Structure for Aircraft Actuator%航空作动器往复密封结构参数化分析

    Institute of Scientific and Technical Information of China (English)

    杨杰; 索双富; 吴长贵

    2016-01-01

    The primary seal of aircraft actuators belongs to typical reciprocating seals, which is adopt as a component of the wings, doors, and many other parts of an aircraft, Its failure will directly affect flight safety, and even cause major accidents, therefore it is a great signifi-cance to analyze its sealing structure parameters. In this paper, Reciprocating seals were taken as the research object,it establish a reciprocat-ing seal mixed lubrication model, and used the friction ,reverse pump rate and maximum pressure in contact area as evaluation of sealing per-formance, made parametric analysis of seal structure by changing oil roll Angle, air roll Angle ,and the surface roughness of the sealing lip.%航空作动器主密封是典型的往复密封,广泛应用在飞机机翼、舱门等众多部位。它的失效会直接影响飞行安全,甚至会造成重大的人身事故,因此对其密封结构参数进行分析具有重要意义。本文以往复密封作为研究对象,建立往复密封混合润滑模型,以摩擦力、反向泵回率及接触区接触压力最大值作为评价密封性能好坏的指标,分别改变油侧倾角、空气侧倾角,改变密封唇表面粗糙度,对密封结构进行参数化分析。

  4. Transport jet aircraft noise abatement in foreign countries: Growth, structure, impact. Volume 2: Pacific Basin, August 1980. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, F.A.

    1980-08-01

    Noise control measures at the international airports of Hawaii, New Zealand, Australia, Hong Kong, Japan, and Singapore were studied. Factors in noise control, such as government structure are examined. The increasing power of environmental agencies vis-a-vis aviation departments is noted. The following methods of dealing with aircraft noise are examined by type of control: noise at the source control noise emmission controls, zoning, building codes, subsidies for relocation, insulation, loss in property values, and for TV, radio and telephone interference and noise-related landing charges.

  5. Development and applications of two computational procedures for determining the vibration modes of structural systems. [aircraft structures - aerospaceplanes

    Science.gov (United States)

    Kvaternik, R. G.

    1975-01-01

    Two computational procedures for analyzing complex structural systems for their natural modes and frequencies of vibration are presented. Both procedures are based on a substructures methodology and both employ the finite-element stiffness method to model the constituent substructures. The first procedure is a direct method based on solving the eigenvalue problem associated with a finite-element representation of the complete structure. The second procedure is a component-mode synthesis scheme in which the vibration modes of the complete structure are synthesized from modes of substructures into which the structure is divided. The analytical basis of the methods contains a combination of features which enhance the generality of the procedures. The computational procedures exhibit a unique utilitarian character with respect to the versatility, computational convenience, and ease of computer implementation. The computational procedures were implemented in two special-purpose computer programs. The results of the application of these programs to several structural configurations are shown and comparisons are made with experiment.

  6. Aircraft observations of the vertical structure of stratiform precipitation relevant to microwave radiative transfer

    Energy Technology Data Exchange (ETDEWEB)

    Chang, A.T.C. (NASA Goddard Space Flight Center, Greenbelt, MD (United States)); Barnes, A.; Glass, M. (Phillips Lab., Hanscom AFB, MA (United States)); Kakar, R. (NASA Headquarters, Washington, DC (United States)); Wilheit, T.T. (Texas A M Univ., College Station (United States))

    1993-06-01

    The retrieval of rainfall intensity over the oceans from passive microwave observations is based on a radiative transfer model. direct rainfall observations of oceanic rainfall are virtually nonexistent making validation of the retrievals extremely difficult. Observations of the model assumptions provide an alternative approach for improving and developing confidence in the rainfall retrievals. In the winter of 1983, the NASA CV-990 aircraft was equipped with a payload suitable for examining several of the model assumptions. The payload included microwave and infrared radiometers, mirror hygrometers, temperature probes, and PMS probes. On two occasions the aircraft ascended on a spiral track through stratiform precipitation providing an opportunity to study the atmospheric parameters. The assumptions concerning liquid hydrometeors, water vapor, lapse rate, and nonprecipitating clouds were studied. Model assumptions seem to be supported by these observations. 23 refs., 7 figs.

  7. Development and Validation of Fluid-Structure Interaction in Aircraft Crashworthiness Studies

    OpenAIRE

    Satterwhite, Matthew Ryan

    2013-01-01

    Current Federal Aviation Regulations require costly and time consuming crashworthiness testing to certify aircraft. These tests are only capable of a limited assessment of progressive damage and all crash configurations and scenarios cannot be physically evaluated. Advancements in technology have led to accurate and effective developments in numerical modeling that have the possibility of replacing these rigorous physical experiments. Through finite element analysis, an in-depth investigation...

  8. Aircraft Structural Fatigue. Proceedings of a Symposium held in Melbourne on 19-20 October, 1976.

    Science.gov (United States)

    1977-04-01

    Between Ferstat, Q. Perth and Darwin . CSiR Div. of Aero. Rep. SM!35, 1949 12. Hooke, F. H. Load Frequency Measurements on a Linc-n Aircraft. CSIR Div. of...Aeronautical Research Laboratories, Aus- tralia, 1967 28. Cartwright , D. I., and Methods of Determining Stress Intensity Factors. Rooke, D. P. RAE TR 73031...Stress Intensity Factors. Cartwright , D. J. Her Majesty’s Stationery Office, London, 1976. 33. Chan, S. K., On the Finite Element Method in Linear

  9. Structure analysis of active components of traditional Chinese medicines

    DEFF Research Database (Denmark)

    Zhang, Wei; Sun, Qinglei; Liu, Jianhua

    2013-01-01

    Traditional Chinese Medicines (TCMs) have been widely used for healing of different health problems for thousands of years. They have been used as therapeutic, complementary and alternative medicines. TCMs usually consist of dozens to hundreds of various compounds, which are extracted from raw...... herbal sources by aqueous or alcoholic solvents. Therefore, it is difficult to correlate the pharmaceutical effect to a specific lead compound in the TCMs. A detailed analysis of various components in TCMs has been a great challenge for modern analytical techniques in recent decades. In this chapter...

  10. Two-dimensional structure of mountain wave observed by aircraft during the PYREX experiment

    Directory of Open Access Journals (Sweden)

    J. L. Attié

    Full Text Available This study presents an experimental analysis from aircraft measurements above the Pyrenees chain during the PYREX experiment. The Pyrenees chain, roughly WE oriented, is a major barrier for northerly and southerly airflows. We present a case of southerly flow (15 October 1990 and three successive cases of northerly flows above the Pyrenees (14, 15 and 16 November 1990 documented by two aircraft. The aircraft have described a vertical cross section perpendicular to the Pyrenean ridge. This area is described via the thermodynamical and dynamical fields which have a horizontal resolution of 10 km. Three methods for computing the vertical velocity of the air are presented. The horizontal advection terms which play a role in the budget equations are also evaluated. The altitude turbulence zone of 15 October are shown via turbulent fluxes, turbulent kinetic energy (TKE, dissipation rate of TKE and inertial length-scale. A comparison of results obtained by eddy-correlation and inertial-dissipation method is presented. The experimental results show a warm and dry downdraft for the southerly flow with large values for advection terms. All the mountain wave cases are also shown to present an important dynamical perturbation just above the Pyrenees at upper altitudes.

  11. Release strategies for making transferable semiconductor structures, devices and device components

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, John A.; Nuzzo, Ralph G.; Meitl, Matthew; Ko, Heung Cho; Yoon, Jongseung; Menard, Etienne; Baca, Alfred J.

    2016-05-24

    Provided are methods for making a device or device component by providing a multi layer structure having a plurality of functional layers and a plurality of release layers and releasing the functional layers from the multilayer structure by separating one or more of the release layers to generate a plurality of transferable structures. The transferable structures are printed onto a device substrate or device component supported by a device substrate. The methods and systems provide means for making high-quality and low-cost photovoltaic devices, transferable semiconductor structures, (opto-)electronic devices and device components.

  12. The Structural Geographic Components of a Territorial Survey

    Directory of Open Access Journals (Sweden)

    POMPEI COCEAN

    2006-01-01

    Full Text Available When using regional geographic approaches, i.e. when applying its concepts to the problems of anthropic communities from a certain territory, is compulsory. In this study we have taken into account the complex and the etymologically adequate meaning of the notion and not the meaning most commonly used at present (i.e. the functional zoning and regionalisation of the territory. Relying on the estimations of territorial surveys, one may give the solutions for the extant malfunctions and for optimising future developments. The geographic components of this parameter (the territorial survey are: the natural support basis, the population and its settlements, the social and economic development level, the technical equipment of the territory, and the extant risks and malfunctions. Indices from 1 to 10 will be summed in order to give us the big picture, namely the present-day situation and the favourability level of that territory for various anthropic interventions.

  13. An ongoing role for structural sarcomeric components in maintaining Drosophila melanogaster muscle function and structure.

    Directory of Open Access Journals (Sweden)

    Alexander D Perkins

    Full Text Available Animal muscles must maintain their function while bearing substantial mechanical loads. How muscles withstand persistent mechanical strain is presently not well understood. The basic unit of muscle is the sarcomere, which is primarily composed of cytoskeletal proteins. We hypothesized that cytoskeletal protein turnover is required to maintain muscle function. Using the flight muscles of Drosophila melanogaster, we confirmed that the sarcomeric cytoskeleton undergoes turnover throughout adult life. To uncover which cytoskeletal components are required to maintain adult muscle function, we performed an RNAi-mediated knockdown screen targeting the entire fly cytoskeleton and associated proteins. Gene knockdown was restricted to adult flies and muscle function was analyzed with behavioural assays. Here we analyze the results of that screen and characterize the specific muscle maintenance role for several hits. The screen identified 46 genes required for muscle maintenance: 40 of which had no previously known role in this process. Bioinformatic analysis highlighted the structural sarcomeric proteins as a candidate group for further analysis. Detailed confocal and electron microscopic analysis showed that while muscle architecture was maintained after candidate gene knockdown, sarcomere length was disrupted. Specifically, we found that ongoing synthesis and turnover of the key sarcomere structural components Projectin, Myosin and Actin are required to maintain correct sarcomere length and thin filament length. Our results provide in vivo evidence of adult muscle protein turnover and uncover specific functional defects associated with reduced expression of a subset of cytoskeletal proteins in the adult animal.

  14. Testing and Analysis of a Composite Non-Cylindrical Aircraft Fuselage Structure. Part 1; Ultimate Design Loads

    Science.gov (United States)

    Przekop, Adam; Jegley, Dawn C.; Lovejoy, Andrew E.; Rouse, Marshall; Wu, Hsi-Yung T.

    2016-01-01

    The Environmentally Responsible Aviation Project aimed to develop aircraft technologies enabling significant fuel burn and community noise reductions. Small incremental changes to the conventional metallic alloy-based 'tube and wing' configuration were not sufficient to achieve the desired metrics. One airframe concept identified by the project as having the potential to dramatically improve aircraft performance was a composite-based hybrid wing body configuration. Such a concept, however, presented inherent challenges stemming from, among other factors, the necessity to transfer wing loads through the entire center fuselage section which accommodates a pressurized cabin confined by flat or nearly flat panels. This paper discusses finite element analysis and testing of a large-scale hybrid wing body center section structure developed and constructed to demonstrate that the Pultruded Rod Stitched Efficient Unitized Structure concept can meet these challenging demands of the next generation airframes. Part I of the paper considers the five most critical load conditions, which are internal pressure only and positive and negative g-loads with and without internal pressure. Analysis results are compared with measurements acquired during testing. Performance of the test article is found to be closely aligned with predictions and, consequently, able to support the hybrid wing body design loads in pristine and barely visible impact damage conditions.

  15. System-on-chip integration of a new electromechanical impedance calculation method for aircraft structure health monitoring.

    Science.gov (United States)

    Boukabache, Hamza; Escriba, Christophe; Zedek, Sabeha; Medale, Daniel; Rolet, Sebastien; Fourniols, Jean Yves

    2012-10-11

    The work reported on this paper describes a new methodology implementation for active structural health monitoring of recent aircraft parts made from carbon-fiber-reinforced polymer. This diagnosis is based on a new embedded method that is capable of measuring the local high frequency impedance spectrum of the structure through the calculation of the electro-mechanical impedance of a piezoelectric patch pasted non-permanently onto its surface. This paper involves both the laboratory based E/M impedance method development, its implementation into a CPU with limited resources as well as a comparison with experimental testing data needed to demonstrate the feasibility of flaw detection on composite materials and answer the question of the method reliability. The different development steps are presented and the integration issues are discussed. Furthermore, we present the unique advantages that the reconfigurable electronics through System-on-Chip (SoC) technology brings to the system scaling and flexibility. At the end of this article, we demonstrate the capability of a basic network of sensors mounted onto a real composite aircraft part specimen to capture its local impedance spectrum signature and to diagnosis different delamination sizes using a comparison with a baseline.

  16. System-on-Chip Integration of a New Electromechanical Impedance Calculation Method for Aircraft Structure Health Monitoring

    Science.gov (United States)

    Boukabache, Hamza; Escriba, Christophe; Zedek, Sabeha; Medale, Daniel; Rolet, Sebastien; Fourniols, Jean Yves

    2012-01-01

    The work reported on this paper describes a new methodology implementation for active structural health monitoring of recent aircraft parts made from carbon-fiber-reinforced polymer. This diagnosis is based on a new embedded method that is capable of measuring the local high frequency impedance spectrum of the structure through the calculation of the electro-mechanical impedance of a piezoelectric patch pasted non-permanently onto its surface. This paper involves both the laboratory based E/M impedance method development, its implementation into a CPU with limited resources as well as a comparison with experimental testing data needed to demonstrate the feasibility of flaw detection on composite materials and answer the question of the method reliability. The different development steps are presented and the integration issues are discussed. Furthermore, we present the unique advantages that the reconfigurable electronics through System-on-Chip (SoC) technology brings to the system scaling and flexibility. At the end of this article, we demonstrate the capability of a basic network of sensors mounted onto a real composite aircraft part specimen to capture its local impedance spectrum signature and to diagnosis different delamination sizes using a comparison with a baseline. PMID:23202013

  17. System-on-Chip Integration of a New Electromechanical Impedance Calculation Method for Aircraft Structure Health Monitoring

    Directory of Open Access Journals (Sweden)

    Daniel Medale

    2012-10-01

    Full Text Available The work reported on this paper describes a new methodology implementation for active structural health monitoring of recent aircraft parts made from carbon-fiber-reinforced polymer. This diagnosis is based on a new embedded method that is capable of measuring the local high frequency impedance spectrum of the structure through the calculation of the electro-mechanical impedance of a piezoelectric patch pasted non-permanently onto its surface. This paper involves both the laboratory based E/M impedance method development, its implementation into a CPU with limited resources as well as a comparison with experimental testing data needed to demonstrate the feasibility of flaw detection on composite materials and answer the question of the method reliability. The different development steps are presented and the integration issues are discussed. Furthermore, we present the unique advantages that the reconfigurable electronics through System-on-Chip (SoC technology brings to the system scaling and flexibility. At the end of this article, we demonstrate the capability of a basic network of sensors mounted onto a real composite aircraft part specimen to capture its local impedance spectrum signature and to diagnosis different delamination sizes using a comparison with a baseline.

  18. Design-Load Basis for LANL Structures, Systems, and Components

    Energy Technology Data Exchange (ETDEWEB)

    I. Cuesta

    2004-09-01

    This document supports the recommendations in the Los Alamos National Laboratory (LANL) Engineering Standard Manual (ESM), Chapter 5--Structural providing the basis for the loads, analysis procedures, and codes to be used in the ESM. It also provides the justification for eliminating the loads to be considered in design, and evidence that the design basis loads are appropriate and consistent with the graded approach required by the Department of Energy (DOE) Code of Federal Regulation Nuclear Safety Management, 10, Part 830. This document focuses on (1) the primary and secondary natural phenomena hazards listed in DOE-G-420.1-2, Appendix C, (2) additional loads not related to natural phenomena hazards, and (3) the design loads on structures during construction.

  19. Vertical Distribution of Structural Components in Corn Stover

    OpenAIRE

    Jane M. F. Johnson; Karlen,Douglas L.; Garold L. Gresham; Cantrell, Keri B.; David W. Archer; Brian J. Wienhold; Gary E. Varvel; David A. Laird; John Baker; Tyson E. Ochsner; Jeff M. Novak; Ardell D. Halvorson; Francisco Arriaga; David T. Lightle; Amber Hoover

    2014-01-01

    In the United States, corn ( Zea mays L.) stover has been targeted for second generation fuel production and other bio-products. Our objective was to characterize sugar and structural composition as a function of vertical distribution of corn stover (leaves and stalk) that was sampled at physiological maturity and about three weeks later from multiple USA locations. A small subset of samples was assessed for thermochemical composition. Concentrations of lignin, glucan, and xylan were about 10...

  20. 76 FR 69292 - Aging Management of Stainless Steel Structures and Components in Treated Borated Water

    Science.gov (United States)

    2011-11-08

    ... COMMISSION Aging Management of Stainless Steel Structures and Components in Treated Borated Water AGENCY... Staff Guidance (LR-ISG), LR- ISG-2011-01, ``Aging Management of Stainless Steel Structures and Components in Treated Borated Water.'' This LR-ISG revises the guidance in the Standard Review Plan...

  1. 77 FR 27815 - Aging Management of Stainless Steel Structures and Components in Treated Borated Water

    Science.gov (United States)

    2012-05-11

    ... COMMISSION Aging Management of Stainless Steel Structures and Components in Treated Borated Water AGENCY..., ``Aging Management of Stainless Steel Structures and Components in Treated Borated Water.'' This LR-ISG... Power Plants (SRP-LR) and Generic Aging Lessons Learned (GALL) Report for the aging management...

  2. Structural Integrity of Water Reactor Pressure Boundary Components.

    Science.gov (United States)

    1981-02-20

    RES-79-103 UNCLASSIFIED NRL--- 400 NURE-CR-17B3 NL mnmmnuunin -’El-.--. IIIIIIINI ., *q. - - ,aM T? * NUREG /CI 73 NIL Iteof AW, SOIituA 1 nert of Water...Progress Report for July-September 1979," NUREG /CR-1197, Oak Ridge National Labora- tory, Oak Ridge, Tn., Oct. 1978. 2. F. J. Loss, Ed., "Structural...Progress Report for April-June 1976," ORNL/ NUREG /TM-49, Oak Ridge National Labora- tory, Oak Ridge, Tn., Oct. 1976, pp. 27-38. 5. R. G. Berggren

  3. X-ray inspection of composite materials for aircraft structures using detectors of Medipix type

    Science.gov (United States)

    Jandejsek, I.; Jakubek, J.; Jakubek, M.; Prucha, P.; Krejci, F.; Soukup, P.; Turecek, D.; Vavrik, D.; Zemlicka, J.

    2014-05-01

    This work presents an overview of promising X-ray imaging techniques employed for non-destructive defectoscopy inspections of composite materials intended for the Aircraft industry. The major emphasis is placed on non-tomographic imaging techniques which do not require demanding spatial and time measurement conditions. Imaging methods for defects visualisation, delamination detection and porosity measurement of various composite materials such as carbon fibre reinforced polymers and honeycomb sendwiches are proposed. We make use of the new large area WidePix X-ray imaging camera assembled from up to 100 edgeless Medipix type detectors which is highly suitable for this type of measurements.

  4. Structural Aspects of Flexible Aircraft Control (les Aspects structuraux du controle actif et flexible des aeronefs)

    Science.gov (United States)

    2000-05-01

    bodies of longitudinal accelerations must be included in the water and many other problems. In our application, if flexibility equations. the radial...energy due to gravity will come from our MW [0+1 - f q 1+V -wp PQ -(P’ + R) gravitational model. In the case of a "flat earth ": [V -S 0 R VP -UQ] 1 QR...electronic flight control system apparition [GAF (M, m/V)] ,z [gaf (M, p)] p = j.m The first historical model of the flexible aircraft consists Where in

  5. Optimal Topology of Aircraft Rib and Spar Structures under Aeroelastic Loads

    Science.gov (United States)

    Stanford, Bret K.; Dunning, Peter D.

    2014-01-01

    Several topology optimization problems are conducted within the ribs and spars of a wing box. It is desired to locate the best position of lightening holes, truss/cross-bracing, etc. A variety of aeroelastic metrics are isolated for each of these problems: elastic wing compliance under trim loads and taxi loads, stress distribution, and crushing loads. Aileron effectiveness under a constant roll rate is considered, as are dynamic metrics: natural vibration frequency and flutter. This approach helps uncover the relationship between topology and aeroelasticity in subsonic transport wings, and can therefore aid in understanding the complex aircraft design process which must eventually consider all these metrics and load cases simultaneously.

  6. Comparative study on structure, corrosion and hardness of Zn-Ni alloy deposition on AISI 347 steel aircraft material

    Energy Technology Data Exchange (ETDEWEB)

    Gnanamuthu, RM. [Department of Chemical Engineering, College of Engineering, Kyung Hee University, 1732 Deogyeong-daero, Gihung, Yongin, Gyeonggi 446-701 (Korea, Republic of); Mohan, S., E-mail: sanjnamohan@yahoo.com [Central Electrochemical Research Institute, (CSIR), Karaikudi 630 006, Tamilnadu (India); Saravanan, G. [Central Electrochemical Research Institute, (CSIR), Karaikudi 630 006, Tamilnadu (India); Lee, Chang Woo, E-mail: cwlee@khu.ac.kr [Department of Chemical Engineering, College of Engineering, Kyung Hee University, 1732 Deogyeong-daero, Gihung, Yongin, Gyeonggi 446-701 (Korea, Republic of)

    2012-02-05

    Highlights: Black-Right-Pointing-Pointer Electrodeposition of Zn-Ni alloy on AISI 347 steel as an aircraft material has been carried out from various baths. Black-Right-Pointing-Pointer The effect of pulse duty cycle on thickness, current efficiency and hardness reached maximum values at 40% duty cycle and for 50 Hz frequencies average current density of 4 A dm{sup -2}. Black-Right-Pointing-Pointer The XRF characterizations of 88:12% Zn-Ni alloy provided excellent corrosion resistance. Black-Right-Pointing-Pointer It is found that Zn-Ni alloy on AISI 347 aircraft material has better structure and corrosion resistance by pulse electrodeposits from electrolyte-4. - Abstract: Zn-Ni alloys were electrodeposited on AISI 347 steel aircraft materials from various electrolytes under direct current (DCD) and pulsed electrodepositing (PED) techniques. The effects of pulse duty cycle on thickness, current efficiency and hardness of electrodeposits were studied. Alloy phases of the Zn-Ni were indexed by X-ray diffraction (XRD) techniques. Microstructural morphology, topography and elemental compositions were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray fluorescence spectroscopy (XRF). The corrosion resistance properties of electrodeposited Zn-Ni alloy in 3.5% NaCl aqueous solution obtained by DCD and PED were compared using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) technique. Elemental analysis showed that 88% of Zn and 12% of Ni obtained from electrolyte-4 by PED technique at 40% duty cycle for 50 Hz frequencies having better corrosion resistance than that of deposits obtained from other electrolytes.

  7. Statistical time series methods for damage diagnosis in a scale aircraft skeleton structure: loosened bolts damage scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Kopsaftopoulos, Fotis P; Fassois, Spilios D, E-mail: fkopsaf@mech.upatras.gr, E-mail: fassois@mech.upatras.gr [Stochastic Mechanical Systems and Automation (SMSA) Laboratory Department of Mechanical and Aeronautical Engineering University of Patras, GR 265 00 Patras (Greece)

    2011-07-19

    A comparative assessment of several vibration based statistical time series methods for Structural Health Monitoring (SHM) is presented via their application to a scale aircraft skeleton laboratory structure. A brief overview of the methods, which are either scalar or vector type, non-parametric or parametric, and pertain to either the response-only or excitation-response cases, is provided. Damage diagnosis, including both the detection and identification subproblems, is tackled via scalar or vector vibration signals. The methods' effectiveness is assessed via repeated experiments under various damage scenarios, with each scenario corresponding to the loosening of one or more selected bolts. The results of the study confirm the 'global' damage detection capability and effectiveness of statistical time series methods for SHM.

  8. Influence of the aircraft crash induced local nonlinearities on the overall dynamic response of a RC structure through a parametric study

    Energy Technology Data Exchange (ETDEWEB)

    Rouzaud, C., E-mail: crouzaud@adm.estp.fr [LMT (ENS Cachan, CNRS, Université Paris Saclay) 61 avenue du Président Wilson, 94235 Cachan (France); Université Paris-Est, Institut de Recherche en Constructibilité, ESTP 28 avenue du Président Wilson, 94230 Cachan (France); AREVA, 10 rue Juliette Récamier, 69006 Lyon (France); Gatuingt, F. [LMT (ENS Cachan, CNRS, Université Paris Saclay) 61 avenue du Président Wilson, 94235 Cachan (France); Hervé, G. [Université Paris-Est, Institut de Recherche en Constructibilité, ESTP 28 avenue du Président Wilson, 94230 Cachan (France); Moussallam, N. [AREVA, 10 rue Juliette Récamier, 69006 Lyon (France); Dorival, O. [Icam, Site de Toulouse, 75 avenue de Grande-Bretagne, 31076 Toulouse Cedex 3 (France); Université de Toulouse, Institut Clément Ader (ICA), INSA, UPS, Mines Albi, ISAE 135 avenue de Rangueil, 31077 Toulouse Cedex (France)

    2016-03-15

    Highlights: • Structures could resist to the induced accelerations which they might undergo. • The characterization of non-linearities in the signal of an aircraft impact. • The non linear impact area are studied through a sensitivity analysis. • This analysis should allow to achieve a link between aircraft impact parameters. - Abstract: In the process of nuclear power plant design, the safety of structures is an important aspect. Civil engineering structures have to resist the accelerations induced by, for example, seismic loads or shaking loads resulting from the aircraft impact. This is even more important for the in-structures equipments that have also to be qualified against the vibrations generated by this kind of hazards. In the case of aircraft crash, as a large variety of scenarios has to be envisaged, it is necessary to use methods that are less CPU-time consuming and that consider appropriately the nonlinearities. The analysis presented in this paper deals with the problem of the characterization of nonlinearities (damaged area, transmitted force) in the response of a structure subjected to an aircraft impact. The purpose of our study is part of the development of a new decoupled nonlinear and elastic way for calculating the shaking of structures following an aircraft impact which could be very numerically costly if studied with classical finite element methods. The aim is to identify which parameters control the dimensions of the nonlinear zone and so will have a direct impact on the induced vibrations. In a design context, several load cases (and simulations) are analyzed in order to consider a wide range of impact (different loading surfaces, momentum) and data sets of the target (thickness, reinforcements). In this work, the nonlinear area generated by the impact is localized and studied through a parametric analysis associated with a sensitivity analysis to identify the boundaries between the elastic domain and this nonlinear area.

  9. 飞机结构单机寿命监控的几个关键问题的研究%Research on Several Key Problems of Individual Aircraft Fatigue Life Monitoring for Aircraft Structure

    Institute of Scientific and Technical Information of China (English)

    张泰峰; 孙文胜; 杨晓华; 赵维义

    2011-01-01

    飞机结构的使用寿命取决于使用方法,实施单机寿命监控能够有效地体现出这种差异性.基于飞行参数监控的思想,综合考虑了计算精度和计算效率,对不同采样率和不同滤波门槛值的影响进行了分析,确定了适用的采样率和门槛值;综合分析了不同情况下外挂质量对损伤计算结果的影响,为飞机结构实施单机寿命监控提供了技术保障.%The life of aircraft structure depends on its manipulating methods, and individual aircraft fatigue life monitoring is an effective way to reflect the difference. Based on the theory of flight data monitoring, the influences of different sample rate and different threshold were analyzed in detail by considering its efficiency and precision, and the sample rate and threshold for certain aircraft were proposed. The influence of different suspension weights on calculation result of damage was discussed. The purpose was to provide theoretical basis for individual aircraft fatigue life monitoring.

  10. Vertical Distribution of Structural Components in Corn Stover

    Directory of Open Access Journals (Sweden)

    Jane M. F. Johnson

    2014-11-01

    Full Text Available In the United States, corn (Zea mays L. stover has been targeted for second generation fuel production and other bio-products. Our objective was to characterize sugar and structural composition as a function of vertical distribution of corn stover (leaves and stalk that was sampled at physiological maturity and about three weeks later from multiple USA locations. A small subset of samples was assessed for thermochemical composition. Concentrations of lignin, glucan, and xylan were about 10% greater at grain harvest than at physiological maturity, but harvestable biomass was about 25% less due to stalk breakage. Gross heating density above the ear averaged 16.3 ± 0.40 MJ kg−1, but with an alkalinity measure of 0.83 g MJ−1, slagging is likely to occur during gasification. Assuming a stover harvest height of 10 cm, the estimated ethanol yield would be >2500 L ha−1, but it would be only 1000 L ha−1 if stover harvest was restricted to the material from above the primary ear. Vertical composition of corn stover is relatively uniform; thus, decision on cutting height may be driven by agronomic, economic and environmental considerations.

  11. Vertical distribution of structural components in corn stover

    Energy Technology Data Exchange (ETDEWEB)

    Jane M. F. Johnson; Douglas L. Karlen; Garold L. Gresham; Keri B. Cantrell; David W. Archer; Brian J. Wienhold; Gary E. Varvel; David A. Laird; John Baker; Tyson E. Ochsner; Jeff M. Novak; Ardell D. Halvorson; Francisco Arriaga; David T. Lightle; Amber Hoover; Rachel Emerson; Nancy W. Barbour

    2014-11-01

    In the United States, corn (Zea mays L.) stover has been targeted for second generation fuel production and other bio-products. Our objective was to characterize sugar and structural composition as a function of vertical distribution of corn stover (leaves and stalk) that was sampled at physiological maturity and about three weeks later from multiple USA locations. A small subset of samples was assessed for thermochemical composition. Concentrations of lignin, glucan, and xylan were about 10% greater at grain harvest than at physiological maturity, but harvestable biomass was about 25% less due to stalk breakage. Gross heating density above the ear averaged 16.3 ± 0.40 MJ kg?¹, but with an alkalinity measure of 0.83 g MJ?¹, slagging is likely to occur during gasification. Assuming a stover harvest height of 10 cm, the estimated ethanol yield would be >2500 L ha?¹, but it would be only 1000 L ha?¹ if stover harvest was restricted to the material from above the primary ear. Vertical composition of corn stover is relatively uniform; thus, decision on cutting height may be driven by agronomic, economic and environmental considerations.

  12. A review on the development and properties of continuous fiber/epoxy/aluminum hybrid composites for aircraft structures

    Directory of Open Access Journals (Sweden)

    Edson Cocchieri Botelho

    2006-09-01

    Full Text Available Weight reduction and improved damage tolerance characteristics were the prime drivers to develop new family of materials for the aerospace/aeronautical industry. Aiming this objective, a new lightweight Fiber/Metal Laminate (FML has been developed. The combination of metal and polymer composite laminates can create a synergistic effect on many properties. The mechanical properties of FML shows improvements over the properties of both aluminum alloys and composite materials individually. Due to their excellent properties, FML are being used as fuselage skin structures of the next generation commercial aircrafts. One of the advantages of FML when compared with conventional carbon fiber/epoxy composites is the low moisture absorption. The moisture absorption in FML composites is slower when compared with polymer composites, even under the relatively harsh conditions, due to the barrier of the aluminum outer layers. Due to this favorable atmosphere, recently big companies such as EMBRAER, Aerospatiale, Boing, Airbus, and so one, starting to work with this kind of materials as an alternative to save money and to guarantee the security of their aircrafts.

  13. Integrated Flight/Structural Mode Control for Very Flexible Aircraft Using L1 Adaptive Output Feedback Controller

    Science.gov (United States)

    Che, Jiaxing; Cao, Chengyu; Gregory, Irene M.

    2012-01-01

    This paper explores application of adaptive control architecture to a light, high-aspect ratio, flexible aircraft configuration that exhibits strong rigid body/flexible mode coupling. Specifically, an L(sub 1) adaptive output feedback controller is developed for a semi-span wind tunnel model capable of motion. The wind tunnel mount allows the semi-span model to translate vertically and pitch at the wing root, resulting in better simulation of an aircraft s rigid body motion. The control objective is to design a pitch control with altitude hold while suppressing body freedom flutter. The controller is an output feedback nominal controller (LQG) augmented by an L(sub 1) adaptive loop. A modification to the L(sub 1) output feedback is proposed to make it more suitable for flexible structures. The new control law relaxes the required bounds on the unmatched uncertainty and allows dependence on the state as well as time, i.e. a more general unmatched nonlinearity. The paper presents controller development and simulated performance responses. Simulation is conducted by using full state flexible wing models derived from test data at 10 different dynamic pressure conditions. An L(sub 1) adaptive output feedback controller is designed for a single test point and is then applied to all the test cases. The simulation results show that the L(sub 1) augmented controller can stabilize and meet the performance requirements for all 10 test conditions ranging from 30 psf to 130 psf dynamic pressure.

  14. Oppor tunistic maintenance for multi-component systems considering structural dependence and economic dependence

    Institute of Scientific and Technical Information of China (English)

    Junbao Geng; Michael Azarian; Michael Pecht

    2015-01-01

    Although opportunistic maintenance strategies are widely used for multi-component systems, al opportunistic mainte-nance strategies only consider economic dependence and do not take structural dependence into account. An opportunistic main-tenance strategy is presented for a multi-component system that considers both structural dependence and economic dependence. The cost relation and time relation among components based on structural dependence are developed. The maintenance strategy for each component of a multi-component system involves one of five maintenance actions, namely, no-maintenance, a minimal maintenance action, an imperfect maintenance action, a perfect maintenance action, and a replacement action. The maintenance action is determined by the virtual age of the component, the life expectancy of the component, and the age threshold values. Monte Carlo simulation is designed to obtain the optimal oppor-tunistic maintenance strategy of the system over its lifetime. The simulation result reveals that the minimum maintenance cost with a strategy that considers structural dependence is less than that with a strategy that does not consider structural dependence. The availability with a strategy that considers structural dependence is greater than that with a strategy that does not consider structural dependence under the same conditions.

  15. Wavlet Decomposition based Diagnostic for Structural Health Monitoring on Metallic Aircrafts: Case of Crack Triangulation and Corrosion Detection

    Directory of Open Access Journals (Sweden)

    jean yves fourniols

    2013-02-01

    Full Text Available This work focus on the structural health monitoring of aircrafts parts specimen structures made of 2024 Aluminum alloys using a reliable Joint Time Frequency Analysis calculation (Joint Temporal Frequency Analysis. In this paper we demonstrate the feasibility of a new non destructive control method capable to probe very large structures within a short time. The method we developed is based through a wide piezoelectric sensors network on a smart comparison between two acoustic signatures: the healthy structure response captured before the commissioning of the plane and “an after flight” response. The sensors network exploits the capability of piezoelectric patches to generate/measure specific Lamb wave’s modes. The system is therefore dynamically configured to localize mechanicals flaws using a triangulation algorithm that operates using different techniques like pitch-catch and pulse-echo. The aim of this paper is to highlight a methodology that is currently being integrated into reconfigurable qualified and certified hardware architecture. The idea behind is to interface the airplane's structure to an integrated modular avionics calculator (IMA.An analytic study is performed and tests to prove the proposed method feasibility on corroded and damaged structures specimens are provided at the end of this paper.

  16. On-line identification, flutter testing and adaptive notching of structural parameters for V-22 tiltrotor aircraft

    Indian Academy of Sciences (India)

    R K Mehra; P O Arambel; A M Sampath; R K Prasanth; T C Parham

    2000-04-01

    New algorithms and results are presented for flutter testing and adaptive notching of structural modes in V-22 tiltrotor aircraft based on simulated and flight-test data from Bell Helicopter Textron, Inc. (BHTI). For flutter testing and the identification of structural mode frequencies, dampings and mode shapes, time domain state space techniques based on Deterministic Stochastic Realization Algorithms (DSRA) are used to accurately identify multiple modessimultaneously from sine sweep and other multifrequency data, resulting in great savings over the conventional Prony method. Two different techniques for adaptive notching are explored in order to design an Integrated Flight Structural Control (IFSC) system. The first technique is based on on-line identification of structural mode parameters using DSRA algorithm and tuning of a notch filter. The second technique is based on decoupling rigid-body and structural modes of the aircraft by means of a Kalman filter and using rigid-body estimates in the feedback control loop. The difference between the two approaches is that on-line identification and adaptive notching in the first approach are entirely based on the knowledge of structural modes, whereas the Kalman filter design in the second approach is based on the rigid-body dynamic model only.In the first IFSC design, on-line identification is necessary for flight envelope expansion and to adjust the notch filter frequencies and suppress aero-servoelastic instabilities due to changing flight conditionssuch as gross weight, sling loads, and airspeed. It isshown that by tuning the notch filterfrequency to the identified frequency, the phase lag is reduced and the corresponding structural mode is effectively suppressed and stability is maintained. In the second IFSC design using Kalman filter design, the structural modes are again effectively suppressed. Furthermore, the rigid-body estimates are found to be fairly insensitive to both natural frequency and damping factor

  17. Development of powder metallurgy Al alloys for high temperature aircraft structural applications, phase 2

    Science.gov (United States)

    Chellman, D. J.

    1982-01-01

    In this continuing study, the development of mechanically alloyed heat resistant aluminum alloys for aircraft were studied to develop higher strength targets and higher service temperatures. The use of higher alloy additions to MA Al-Fe-Co alloys, employment of prealloyed starting materials, and higher extrusion temperatures were investigated. While the MA Al-Fe-Co alloys exhibited good retention of strength and ductility properties at elevated temperatures and excellent stability of properties after 1000 hour exposure at elevated temperatures, a sensitivity of this system to low extrusion strain rates adversely affected the level of strength achieved. MA alloys in the Al-Li family showed excellent notched toughness and property stability after long time exposures at elevated temperatures. A loss of Li during processing and the higher extrusion temperature 482 K (900 F) resulted in low mechanical strengths. Subsequent hot and cold working of the MA Al-Li had only a mild influence on properties.

  18. Integrated Aerodynamic/Structural/Dynamic Analyses of Aircraft with Large Shape Changes

    Science.gov (United States)

    Samareh, Jamshid A.; Chwalowski, Pawel; Horta, Lucas G.; Piatak, David J.; McGowan, Anna-Maria R.

    2007-01-01

    The conceptual and preliminary design processes for aircraft with large shape changes are generally difficult and time-consuming, and the processes are often customized for a specific shape change concept to streamline the vehicle design effort. Accordingly, several existing reports show excellent results of assessing a particular shape change concept or perturbations of a concept. The goal of the current effort was to develop a multidisciplinary analysis tool and process that would enable an aircraft designer to assess several very different morphing concepts early in the design phase and yet obtain second-order performance results so that design decisions can be made with better confidence. The approach uses an efficient parametric model formulation that allows automatic model generation for systems undergoing radical shape changes as a function of aerodynamic parameters, geometry parameters, and shape change parameters. In contrast to other more self-contained approaches, the approach utilizes off-the-shelf analysis modules to reduce development time and to make it accessible to many users. Because the analysis is loosely coupled, discipline modules like a multibody code can be easily swapped for other modules with similar capabilities. One of the advantages of this loosely coupled system is the ability to use the medium-to high-fidelity tools early in the design stages when the information can significantly influence and improve overall vehicle design. Data transfer among the analysis modules are based on an accurate and automated general purpose data transfer tool. In general, setup time for the integrated system presented in this paper is 2-4 days for simple shape change concepts and 1-2 weeks for more mechanically complicated concepts. Some of the key elements briefly described in the paper include parametric model development, aerodynamic database generation, multibody analysis, and the required software modules as well as examples for a telescoping wing, a

  19. A Parametrical Transport Aircraft Fuselage Model for Preliminary Sizing and Beyond

    OpenAIRE

    Schwinn, Dominik; Kohlgrüber, Dieter; Scherer, Julian; Siemann, Martin

    2015-01-01

    Aircraft design generally comprises three consecutive phases: Conceptual, preliminary and detailed design phase. The preliminary design phase is of particular interest as the basic layout of the primary structure is defined. Up to date, semi-analytical methods are widely used in this design stage to estimate the structural mass. Although these methods lead to adequate results for the major aircraft components of standard configurations, the evaluation of new configurations (e.g. box wing, ble...

  20. Analyzing spiral structure in a galactic disk with a gaseous component

    CERN Document Server

    Mata-Chavez,; C., Gomez Gilberto; Puerari,; Ivanio,

    2013-01-01

    Using GADGET2, we performed an SPH+N-body simulation of a galactic disk with stellar and gas particles. This simulation allows to compare the spiral structure in the different disk components. Also, we performed a simulation without gaseous component to explore the effects of the gas in the spiral pattern of the stars.

  1. CMS experiment : animation showing the construction of the main structural components of CMS together

    CERN Multimedia

    CERN Multimedia Production Unit

    2003-01-01

    This 17-minute long animation shows the construction of the main structural components of CMS in the surface hall in Cessy and offers a detailed overview of the installation in the experimental cavern.

  2. CMS experiment : animation showing the construction of the main structural components of CMS together

    CERN Document Server

    2006-01-01

    This 17-minute long animation shows the construction of the main structural components of CMS in the surface hall in Cessy and offers a detailed overview of the installation in the experimental cavern.

  3. Aeroelastic Loads Modeling for Composite Aircraft Design Support

    NARCIS (Netherlands)

    Baluch, H.A.

    2009-01-01

    With regard to the simulation of structural vibrations and consequent aeroelastic loads in aircraft components, the use of elastic axis e.a as reference of vibrations is quite common. The e.a decouples the bending and torsion degrees of freedom (D.o.F) during the dynamic analysis. The use of the e.a

  4. Distributed, Passivity-Based, Aeroservoelastic Control (DPASC) of Structurally Efficient Aircraft in the Presence of Gusts Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Control of extremely lightweight, long endurance aircraft poses a challenging aeroservoelastic (ASE) problem due to significantly increased flexibility, and...

  5. Mapping crustal S-wave velocity structure with SV-component receiver function method

    Institute of Scientific and Technical Information of China (English)

    邹最红; 陈晓非

    2003-01-01

    In this article, we analyze the characters of SV-component receiver function of teleseismic body waves and its advantages in mapping the S-wave velocity structure of crust in detail. Similar to radial receiver function, SV-component receiver function can be obtained by directly deconvolving the P-component from the SV-component of teleseismic recordings. Our analyses indicate that the change of amplitude of SV-component receiver function against the change of epicentral distance is less than that of radial receiver function. Moreover, the waveform of SV-component receiver function is simpler than the radial receiver function and gives prominence to the PS converted phases that are the most sensitive to the shear wave velocity structure in the inversion. The synthetic tests show that the convergence of SV-component receiver function inversion is faster than that of the radial receiver function inversion. As an example, we investigate the S-wave velocity structure beneath HIA station by using the SV-component receiver function inversion method.

  6. Reliability-based aeroelastic optimization of a composite aircraft wing via fluid-structure interaction of high fidelity solvers

    Science.gov (United States)

    Nikbay, M.; Fakkusoglu, N.; Kuru, M. N.

    2010-06-01

    We consider reliability based aeroelastic optimization of a AGARD 445.6 composite aircraft wing with stochastic parameters. Both commercial engineering software and an in-house reliability analysis code are employed in this high-fidelity computational framework. Finite volume based flow solver Fluent is used to solve 3D Euler equations, while Gambit is the fluid domain mesh generator and Catia-V5-R16 is used as a parametric 3D solid modeler. Abaqus, a structural finite element solver, is used to compute the structural response of the aeroelastic system. Mesh based parallel code coupling interface MPCCI-3.0.6 is used to exchange the pressure and displacement information between Fluent and Abaqus to perform a loosely coupled fluid-structure interaction by employing a staggered algorithm. To compute the probability of failure for the probabilistic constraints, one of the well known MPP (Most Probable Point) based reliability analysis methods, FORM (First Order Reliability Method) is implemented in Matlab. This in-house developed Matlab code is embedded in the multidisciplinary optimization workflow which is driven by Modefrontier. Modefrontier 4.1, is used for its gradient based optimization algorithm called NBI-NLPQLP which is based on sequential quadratic programming method. A pareto optimal solution for the stochastic aeroelastic optimization is obtained for a specified reliability index and results are compared with the results of deterministic aeroelastic optimization.

  7. A tabu search evalutionary algorithm for multiobjective optimization: Application to a bi-criterion aircraft structural reliability problem

    Science.gov (United States)

    Long, Kim Chenming

    Real-world engineering optimization problems often require the consideration of multiple conflicting and noncommensurate objectives, subject to nonconvex constraint regions in a high-dimensional decision space. Further challenges occur for combinatorial multiobjective problems in which the decision variables are not continuous. Traditional multiobjective optimization methods of operations research, such as weighting and epsilon constraint methods, are ill-suited to solving these complex, multiobjective problems. This has given rise to the application of a wide range of metaheuristic optimization algorithms, such as evolutionary, particle swarm, simulated annealing, and ant colony methods, to multiobjective optimization. Several multiobjective evolutionary algorithms have been developed, including the strength Pareto evolutionary algorithm (SPEA) and the non-dominated sorting genetic algorithm (NSGA), for determining the Pareto-optimal set of non-dominated solutions. Although numerous researchers have developed a wide range of multiobjective optimization algorithms, there is a continuing need to construct computationally efficient algorithms with an improved ability to converge to globally non-dominated solutions along the Pareto-optimal front for complex, large-scale, multiobjective engineering optimization problems. This is particularly important when the multiple objective functions and constraints of the real-world system cannot be expressed in explicit mathematical representations. This research presents a novel metaheuristic evolutionary algorithm for complex multiobjective optimization problems, which combines the metaheuristic tabu search algorithm with the evolutionary algorithm (TSEA), as embodied in genetic algorithms. TSEA is successfully applied to bicriteria (i.e., structural reliability and retrofit cost) optimization of the aircraft tail structure fatigue life, which increases its reliability by prolonging fatigue life. A comparison for this

  8. Fire resistant aircraft seat program

    Science.gov (United States)

    Fewell, L. A.

    1979-01-01

    Foams, textiles, and thermoformable plastics were tested to determine which materials were fire retardant, and safe for aircraft passenger seats. Seat components investigated were the decorative fabric cover, slip covers, fire blocking layer, cushion reinforcement, and the cushioning layer.

  9. Structural Reliability Methods for Wind Power Converter System Component Reliability Assessment

    DEFF Research Database (Denmark)

    Kostandyan, Erik; Sørensen, John Dalsgaard

    2012-01-01

    is defined by the threshold model. The attention is focused on crack propagation in solder joints of electrical components due to the temperature loadings. Structural Reliability approaches are used to incorporate model, physical and statistical uncertainties. Reliability estimation by means of structural...

  10. Lewis acidic metal catalysed organic transformations by designed multi-component structures and assemblies

    Indian Academy of Sciences (India)

    Afsar Ali; Amit P Singh; Rajeev Gupta

    2010-05-01

    This paper presents the recent developments in designing multi-component structures including metal-organic frameworks containing Lewis acidic metal ions. The emphasis has been given to understand the design elements adopted to synthesize such structures bearing Lewis acidic metal ion. Further, few important Lewis acidic metal catalysed organic transformation reactions have been discussed demonstrating the importance of such materials for practical purposes.

  11. Some Considerations about the RIERA Approach and Missile-Structure Interaction Analysis Method in Aircraft Impact Assessment on Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Byeong Moo; Kim, Young Jin [Daewoo E and C Co. Ltd., Suwon (Korea, Republic of); Jeon, Se Jin [Ajou Univ., Suwon (Korea, Republic of)

    2014-05-15

    In this paper, the classically preferred RIERA approach and the so-called missile-structure interaction (MSI) analysis methods which are indebted by the latest computing power are discussed about their inherent discrepancies. Studies on the safety assessments on the nuclear power plants against large civil aircraft crashes are ongoing actively. In this paper, the classically preferred RIERA approach and the so-called missile-structure interaction (MSI) analysis methods are discussed about their inherent discrepancies especially from the point of view energy balances. More advanced and simplified ways in the safety assessment of nuclear power plants against large civil aircrafts may be possible by understanding the inherent discrepancies of the RIERA approach method and the missile-structure interaction method and reducing the differences of structural responses.

  12. Vlasov Simulation of Electrostatic Solitary Structures in Multi-Component Plasmas

    Science.gov (United States)

    Umeda, Takayuki; Ashour-Abdalla, Maha; Pickett, Jolene S.; Goldstein, Melvyn L.

    2012-01-01

    Electrostatic solitary structures have been observed in the Earth's magnetosheath by the Cluster spacecraft. Recent theoretical work has suggested that these solitary structures are modeled by electron acoustic solitary waves existing in a four-component plasma system consisting of core electrons, two counter-streaming electron beams, and one species of background ions. In this paper, the excitation of electron acoustic waves and the formation of solitary structures are studied by means of a one-dimensional electrostatic Vlasov simulation. The present result first shows that either electron acoustic solitary waves with negative potential or electron phase-space holes with positive potential are excited in four-component plasma systems. However, these electrostatic solitary structures have longer duration times and higher wave amplitudes than the solitary structures observed in the magnetosheath. The result indicates that a high-speed and small free energy source may be needed as a fifth component. An additional simulation of a five-component plasma consisting of a stable four-component plasma and a weak electron beam shows the generation of small and fast electron phase-space holes by the bump-on-tail instability. The physical properties of the small and fast electron phase-space holes are very similar to those obtained by the previous theoretical analysis. The amplitude and duration time of solitary structures in the simulation are also in agreement with the Cluster observation.

  13. Impact imaging of aircraft composite structure based on a model-independent spatial-wavenumber filter.

    Science.gov (United States)

    Qiu, Lei; Liu, Bin; Yuan, Shenfang; Su, Zhongqing

    2016-01-01

    The spatial-wavenumber filtering technique is an effective approach to distinguish the propagating direction and wave mode of Lamb wave in spatial-wavenumber domain. Therefore, it has been gradually studied for damage evaluation in recent years. But for on-line impact monitoring in practical application, the main problem is how to realize the spatial-wavenumber filtering of impact signal when the wavenumber of high spatial resolution cannot be measured or the accurate wavenumber curve cannot be modeled. In this paper, a new model-independent spatial-wavenumber filter based impact imaging method is proposed. In this method, a 2D cross-shaped array constructed by two linear piezoelectric (PZT) sensor arrays is used to acquire impact signal on-line. The continuous complex Shannon wavelet transform is adopted to extract the frequency narrowband signals from the frequency wideband impact response signals of the PZT sensors. A model-independent spatial-wavenumber filter is designed based on the spatial-wavenumber filtering technique. Based on the designed filter, a wavenumber searching and best match mechanism is proposed to implement the spatial-wavenumber filtering of the frequency narrowband signals without modeling, which can be used to obtain a wavenumber-time image of the impact relative to a linear PZT sensor array. By using the two wavenumber-time images of the 2D cross-shaped array, the impact direction can be estimated without blind angle. The impact distance relative to the 2D cross-shaped array can be calculated by using the difference of time-of-flight between the frequency narrowband signals of two different central frequencies and the corresponding group velocities. The validations performed on a carbon fiber composite laminate plate and an aircraft composite oil tank show a good impact localization accuracy of the model-independent spatial-wavenumber filter based impact imaging method.

  14. Essentials of aircraft armaments

    CERN Document Server

    Kaushik, Mrinal

    2017-01-01

    This book aims to provide a complete exposure about armaments from their design to launch from the combat aircraft. The book details modern ammunition and their tactical roles in warfare. The proposed book discusses aerodynamics, propulsion, structural as well as navigation, control, and guidance of aircraft armament. It also introduces the various types of ammunition developed by different countries and their changing trends. The book imparts knowledge in the field of design, and development of aircraft armaments to aerospace engineers and covers the role of the United Nations in peacekeeping and disarmament. The book will be very useful to researchers, students, and professionals working in design and manufacturing of aircraft armaments. The book will also serve air force and naval aspirants, and those interested in working on defence research and developments organizations. .

  15. Boron carbide: Consistency of components, lattice parameters, fine structure and chemical composition makes the complex structure reasonable

    Science.gov (United States)

    Werheit, Helmut

    2016-10-01

    The complex, highly distorted structure of boron carbide is composed of B12 and B11C icosahedra and CBC, CBB and B□B linear elements, whose concentration depends on the chemical composition each. These concentrations are shown to be consistent with lattice parameters, fine structure data and chemical composition. The respective impacts on lattice parameters are estimated and discussed. Considering the contributions of the different structural components to the energy of the overall structure makes the structure and its variation within the homogeneity range reasonable; in particular that of B4.3C representing the carbon-rich limit of the homogeneity range. Replacing in B4.3C virtually the B□B components by CBC yields the hypothetical moderately distorted B4.0C (structure formula (B11C)CBC). The reduction of lattice parameters related is compatible with recently reported uncommonly prepared single crystals, whose compositions deviate from B4.3C.

  16. Aircraft Design

    Science.gov (United States)

    Bowers, Albion H. (Inventor); Uden, Edward (Inventor)

    2016-01-01

    The present invention is an aircraft wing design that creates a bell shaped span load, which results in a negative induced drag (induced thrust) on the outer portion of the wing; such a design obviates the need for rudder control of an aircraft.

  17. Correlation between rheological behavior and structure of multi-component polymer systems

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Rheological measurement has been an effective method to characterize the structure and properties for multiphase/multi-component polymers, owing to its sensitivity to the structure change of hetero geneous systems. In this article, recent progress in the studies on the morphology/structure and rheological properties of heterogeneous systems is summarized, mainly reporting the findings of the authors and their collaborators, involving the correlation between the morphology and viscoelastic relaxation of LCST-type polymer blends, the microstructure and linear/nonlinear viscoelastic behavior of block copolymers, time scaling of shear-induced crystallization and rheological response of polyolefins, and the relationship between the structure/properties and rheological behavior of filled polymer blends. It is suggested that a thorough understanding of the characteristic rheological response to the morphology/structure evolution of multiphase/multi-component polymers facilitates researchers' optimizing the morphology/structure and ultimate mechanical properties of polymer materials.

  18. Correlation between rheological behavior and structure of multi-component polymer systems

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Rheological measurement has been an effective method to characterize the structure and properties for multiphase/multi-component polymers, owing to its sensitivity to the structure change of hetero- geneous systems. In this article, recent progress in the studies on the morphology/structure and rheological properties of heterogeneous systems is summarized, mainly reporting the findings of the authors and their collaborators, involving the correlation between the morphology and viscoelastic relaxation of LCST-type polymer blends, the microstructure and linear/nonlinear viscoelastic behavior of block copolymers, time scaling of shear-induced crystallization and rheological response of poly- olefins, and the relationship between the structure/properties and rheological behavior of filled polymer blends. It is suggested that a thorough understanding of the characteristic rheological response to the morphology/structure evolution of multiphase/multi-component polymers facilitates researchers’ op- timizing the morphology/structure and ultimate mechanical properties of polymer materials.

  19. Large Aircraft Component Transport Based on Omni-Directional Mobile and Multi-Point Supporting%基于全向移动与多点柔性支撑的飞机大部件运输技术

    Institute of Scientific and Technical Information of China (English)

    姚定; 佘晶; 黄翔; 徐燕

    2012-01-01

    为实现飞机大部件车间叛运输机动灵活,基于全向移动技术,提出了一种飞机大部件全向移动运输平台,以满足大尺寸空间、重载条件的运输作业要求;为改变当首企业一车一用、专车专用现象,基于秉性的思想,提出了一种多点柔性支撑系统.结合某型飞机机翼大部件特点,实际研制了一辆全向移动柔性运输架车样车,在此基础上开发了相应控制与离线鳊程系统.研究结果表明:架丰可以实现较高精度的全向移动,具有较大的灵活性,能够满足飞机部件柔性运输要求.%To flexibly transport the large aircraft components in workshops, one type of omni-directional transporting platform of large aircraft component based on omni-directional technology is presented to meet the transportation requirements of large size and heavy load. To change the present condition that one car for a single use, as well as one car for a special use, a novel type of multi-point flexible supporting tool system based on the flexible supporting tool is proposed. Considering the characteristics of one certain type of aircraft wing components, an omni-directional transporting platform prototype is manufactured. And then the corresponding control and programming system is developed. Research result shows that higher accuracy and greater flexibility of transporting can be achieved by using omni-directional technology, and the requirements of aircraft component flexible transporting can be perfectly met.

  20. Preparation of Waterborne Two-Component Polyurethane Coatings for the Aircraft Cabin Interior Decoration%飞机舱内装饰用水性双组分聚氨酯涂料的制备

    Institute of Scientific and Technical Information of China (English)

    董晓蓉

    2015-01-01

    A waterborne two-component polyurethane coatings for the aircraft cabin interior decoration was prepared. The influences of waterborne resin,curing agent,flame retardant,antiscratch agent on the adhesion, flame resistance,stain resistance,scratch resistance of the coatings were discussed.%制备了一种飞机舱内装饰用水性双组分聚氨酯涂料.讨论了水性树脂、固化剂、阻燃剂、抗划伤剂对其附着力、阻燃性、耐沾污性、抗划痕性等性能的影响.

  1. Trimmed simulation of a transport aircraft using fluid-structure coupling

    NARCIS (Netherlands)

    Michler, A.K.; Dwight, R.P.; Heinrich, R.

    2009-01-01

    The accurate prediction of the aerodynamic coefficients under cruise conditions is of major importance for assessing the aircraft’s fuel consumption. To this end, fluid dynamics, structural mechanics and flight mechanics have to be considered: on the one hand, the structure elastically deforms under

  2. Projectiles Impact Assessment of Aircraft Wing Structures with Real Dynamic Load

    Science.gov (United States)

    Han, Lu; Han, Qing; Wang, Changlin

    2015-07-01

    This paper presents an analysis to achieve the impact damage of the wing structure under real dynamic load. MPCCI tools are utilized to convert wing aerodynamic load into structural Finite Element Method (FEM) node load. The ANSYS/LS-DYNA code is also used to simulate the dynamic loading effects of the wing structure hit by several projectiles, including both active damage mechanism and common damage mechanism. In addition, structural node force on the leading edge and the midline is compared to the aerodynamic load separately. Furthermore, the statistical analysis of the penetrating size and the stress concentration around the damage holes indicates that under the same load situation, the structural damage efficiency of active damage mechanism is significantly higher than the one of common damage mechanism.

  3. Two-component injection moulding simulation of ABS-POM micro structured surfaces

    DEFF Research Database (Denmark)

    Tosello, Guido; Hansen, Hans Nørgaard; Islam, Aminul

    2013-01-01

    a pair of thermoplastic materials (ABS and POM) were conducted. Three dimensional process simulations based on the finite element method have been performed to explore the capability of predicting filling pattern shape at component-level and surface micro feature-level in a polymer/polymer overmoulding...... process. Flow front predictions are compared with experimental results using the short shots technique over the whole miniaturized component and within the surface micro structures....

  4. How to Solve Problem of Seal for Aircraft Structure Maintenance%飞机结构密封与失效修理

    Institute of Scientific and Technical Information of China (English)

    王哲

    2014-01-01

    为提高飞机增压舱的密封能力,给出了飞机结构密封失效的修理程序、方法、试验验证、典型结构密封的措施等,以求达到增压舱正常加压和减缓机体腐蚀发生,保证飞机在寿命期内安全飞行。%In order to enhance the sealing capacity of the pressure cabin, a set of proposals regarding the failure of the sealing in the aircraft structure is presented, including maintenance procedures, ways and means, tests, sealing options of typical structures, etc. By doing this, the normal pressurization of the pressure cabin can be ob-tained and the structure eroding can be delayed to ensure the flying security during the aircraft flight life.

  5. Flight dynamics simulation modeling and control of a large flexible tiltrotor aircraft

    Science.gov (United States)

    Juhasz, Ondrej

    A high order rotorcraft mathematical model is developed and validated against the XV-15 and a Large Civil Tiltrotor (LCTR) concept. The mathematical model is generic and allows for any rotorcraft configuration, from single main rotor helicopters to coaxial and tiltrotor aircraft. Rigid-body and inflow states, as well as flexible wing and blade states are used in the analysis. The separate modeling of each rotorcraft component allows for structural flexibility to be included, which is important when modeling large aircraft where structural modes affect the flight dynamics frequency ranges of interest, generally 1 to 20 rad/sec. Details of the formulation of the mathematical model are given, including derivations of structural, aerodynamic, and inertial loads. The linking of the components of the aircraft is developed using an approach similar to multibody analyses by exploiting a tree topology, but without equations of constraints. Assessments of the effects of wing flexibility are given. Flexibility effects are evaluated by looking at the nature of the couplings between rigid-body modes and wing structural modes and vice versa. The effects of various different forms of structural feedback on aircraft dynamics are analyzed. A proportional-integral feedback on the structural acceleration is deemed to be most effective at both improving the damping and reducing the overall excitation of a structural mode. A model following control architecture is then implemented on full order flexible LCTR models. For this aircraft, the four lowest frequency structural modes are below 20 rad/sec, and are thus needed for control law development and analysis. The impact of structural feedback on both Attitude-Command, Attitude-Hold (ACAH) and Translational Rate Command (TRC) response types are investigated. A rigid aircraft model has optimistic performance characteristics, and a control system designed for a rigid aircraft could potentially destabilize a flexible one. The various

  6. Nonlinear Aerodynamics-Structure Time Simulation for HALE Aircraft Design/Analysis Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Time simulation of a nonlinear aerodynamics model (NA) developed at Virginia Tech coupled with a nonlinear structure model (NS) is proposed as a design/analysis...

  7. Innovative Structural and Material Concepts for Low-Weight Low-Drag Aircraft Design Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The overall objective of this multi-phase project is to explore, develop, integrate, and test several innovative structural design concepts and new material...

  8. Seismic Response of Base-Isolated Structures under Multi-component Ground Motion Excitation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An analysis of a base-isolated structure for multi-component random ground motion is presented. The mean square response of the system is obtained under different parametric variations. The effectiveness of main parameters and the torsional component during an earthquake is quantified with the help of the response ratio and the root mean square response with and without base isolation. It is observed that the base isolation has considerable influence on the response and the effect of the torsional component is not ignored.

  9. Flight service evaluation of Kevlar-49/epoxy composite panels in wide-bodied commercial transport aircraft

    Science.gov (United States)

    Stone, R. H.

    1977-01-01

    Kevlar-49 fairing panels, installed as flight service components on three L-1011s, were inspected after three years' service, and found to be performing satisfactorily. There are six Kevlar-49 panels on each aircraft, including sandwich and solid laminate wing-body panels, and 150 C service aft engine fairings. The service history to date indicates that Kevlar-49 epoxy composite materials have satisfactory service characteristics for use in aircraft secondary structure.

  10. Causes of aircraft electrical failures

    Science.gov (United States)

    Galler, Donald; Slenski, George

    1991-08-01

    The results of a survey of data on failures of aircraft electronic and electrical components that was conducted to identify problematic components are reported. The motivation for the work was to determine priorities for future work on the development of accident investigation techniques for aircraft electrical components. The primary source of data was the Airforce Mishap Database, which is maintained by the Directorate of Aerospace Safety at Norton Air Force Base. Published data from the Air Force Avionics Integrity Program (AVIP) and Hughes Aircraft were also reviewed. Statistical data from these three sources are presented. Two major conclusions are that problems with interconnections are major contributors to aircraft electrical equipment failures, and that environmental factors, especially corrosion, are significant contributors to connector problems.

  11. Weibull-Based Design Methodology for Rotating Structures in Aircraft Engines

    Directory of Open Access Journals (Sweden)

    Erwin V. Zaretsky

    2003-01-01

    Full Text Available The NASA Energy-Efficient Engine (E3-Engine is used as the basis of a Weibull-based life and reliability analysis. Each component's life, and thus the engine's life, is defined by high-cycle fatigue or low-cycle fatigue. Knowing the cumulative life distribution of each of the components making up the engine as represented by a Weibull slope is a prerequisite to predicting the life and reliability of the entire engine. As the engine's Weibull slope increases, the predicted life decreases. The predicted engine lives L5 (95% probability of survival of approximately 17,000 and 32,000 hr do correlate with current engine-maintenance practices without and with refurbishment, respectively. The individual high-pressure turbine (HPT blade lives necessary to obtain a blade system life L0.1 (99.9% probability of survival of 9000 hr for Weibull slopes of 3, 6, and 9 are 47,391; 20,652; and 15,658 hr, respectively. For a design life of the HPT disks having probable points of failure equal to or greater than 36,000 hr at a probability of survival of 99.9%, the predicted disk system life L0.1 can vary from 9408 to 24,911 hr.

  12. Innovative fabrication processing of advanced composite materials concepts for primary aircraft structures

    Science.gov (United States)

    Kassapoglou, Christos; Dinicola, Al J.; Chou, Jack C.

    1992-01-01

    The autoclave based THERM-X(sub R) process was evaluated by cocuring complex curved panels with frames and stiffeners. The process was shown to result in composite parts of high quality with good compaction at sharp radius regions and corners of intersecting parts. The structural properties of the postbuckled panels fabricated were found to be equivalent to those of conventionally tooled hand laid-up parts. Significant savings in bagging time over conventional tooling were documented. Structural details such as cocured shear ties and embedded stiffener flanges in the skin were found to suppress failure modes such as failure at corners of intersecting members and skin stiffeners separation.

  13. Isolation and characterization of structural components of Aloe vera L. leaf pulp.

    Science.gov (United States)

    Ni, Y; Turner, D; Yates, K M; Tizard, I

    2004-12-20

    The clear pulp, also known as inner gel, of Aloe vera L. leaf is widely used in various medical, cosmetic and nutraceutical applications. Many beneficial effects of this plant have been attributed to the polysaccharides present in the pulp. However, discrepancies exist regarding the composition of pulp polysaccharide species and an understanding of pulp structure in relation to its chemical composition has been lacking. Thus, we examined pulp structure, isolated structural components and determined their carbohydrate compositions along with analyzing a partially purified pulp-based product (Acemannan hydrogel) used to make Carrisyn hydrogel wound dressing. Light and electron microscopy showed that the pulp consisted of large clear mesophyll cells with a diameter as large as 1000 microm. These cells were composed of cell walls and cell membranes along with a very limited number of degenerated cellular organelles. No intact cellular organelles were found in mesophyll cells. Following disruption of pulp by homogenization, three components were isolated by sequential centrifugation. They were thin clear sheets, microparticles and a viscous liquid gel, which corresponded to cell wall, degenerated cellular organelles and liquid content of mesophyll cells based on morphological and chemical analysis. These three components accounted for 16.2% (+/-3.8), 0.70% (+/-0) and 83.1% of the pulp on a dry weight basis. The carbohydrate composition of each component was distinct; liquid gel contained mannan, microparticles contained galactose-rich polysaccharide(s) and cell walls contained an unusually high level of galacturonic acid (34%, w/w; Gal A). The same three components were also found in Acemannan Hydrogel with mannan as the predominant component. Thus, different pulp structural components are associated with different polysaccharides and thus may potentially be different functionally. These findings may help lay a basis for further studies and development of better

  14. Genetic Structure and Indica/Japonica Component Changes in Major Inbred Rice Varieties in China

    Institute of Scientific and Technical Information of China (English)

    YU Ping; YUAN Xiao-ping; XU Qun; WANG Cai-hong; YU Han-yong; WANG Yi-ping; TANG Sheng-xiang

    2013-01-01

    We used 39 SSR markers to analyze the genetic structure of 304 major Chinese inbred rice varieties,and to compare changes in the indica or japonica components in these varieties that have been widely cultivated from the 1950s to the 1990s in China.The genetic structure analysis showed that these rice varieties were distinctly divided into two populations,indica and japonica.The sub-structure of indica varieties was more complex than that of japonica ones.Among the various lines,late-season indica and early season japonica varieties had simpler genetic backgrounds.The seasonal ecotypes were not quite consistent with the subtypes of genetic structure.Twelve SSR loci with specific differentiation between indica and japonica were used to calculate the indica/japonica components.The differences in indica/japonica components among the five decades were not significant,except for late-season indica varieties in the 1990s,which had a significantly higher japonica component.These results will help to understand the genetic structure of the major Chinese inbred rice varieties and will be useful for indica-japonica hybrid breeding in China.

  15. 基于结构件实例库的飞机机体结构快速建模%Rapid aircraft structure modeling based on structure case base

    Institute of Scientific and Technical Information of China (English)

    冯昊成; 罗明强; 刘虎; 武哲

    2012-01-01

    In order to utilize and study more effectively from existing examples of aircraft structure information,the parametric object-oriented description method of structure instance was studied.The architecture framework of aircraft structure case base was proposed and the prototype system was established.The design method of aircraft structure based on structure case base was studied.The parametric modeling method of fuselage structure and wing structure was represented.The functionality of rapid aircraft structure design based on structure case base was achieved in an open conceptual aircraft design system.An instance is given to illustrate the effectiveness of the system and methods.%为充分利用和借鉴已有的飞机结构件设计方案实例信息,研究了面向对象的参数化结构件实例描述方法,提出了飞机结构件实例库的总体框架并开发了系统的原型.研究了基于实例库的飞机机体结构设计措施及建模方法,提出了翼面结构和机身结构的参数化描述和模型构建方法,并在一个开放式的飞机总体设计环境中完成了基于实例库的飞机结构快速设计功能.最后通过应用示例说明了该系统和方法的有效性.

  16. Optical Properties of One-dimensional Three-component Photonic Band Gap Structure

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Theoretical study of the optical properties of one-dimensional three-component photonic band gap structure, which is composed of three alternating dielectric layers of different refractive indices and thickness in a unit cell, is performed. This one-dimensional photonic band gap structure exhibits the transparency band and forbidden band. We find that there are several mini-bands of the allowed transmission to be created within the photonic band gap region of the structure if a defect designed specially is introduced inside the structure. This characteristic is very important for some practical applications.

  17. PVDF array sensor for Lamb wave reception: Aircraft structural health monitoring

    Science.gov (United States)

    Ren, Baiyang; Lissenden, Cliff J.

    2016-02-01

    Fracture critical structures need structural health monitoring (SHM) to improve safety and reliability as well as reduce downtime and maintenance costs. Lamb waves provide promising techniques for on-line SHM systems because of their large volumetric coverage and good sensitivity to defects. Extensive research has focused on using features derived from time signals obtained at sparse locations distributed across the structure. Commonly used features are wave amplitude, energy, and time of arrival. However, the modal content of received Lamb waves contains valuable information about the existence and characteristics of defects, but cannot be determined from these signal features. Wave scattering at a defect often results in mode conversions in both transmitted and reflected waves. Features like change in time of arrival or amplitude reduction can be interpreted as being a result of mode conversion. This work is focused on the design of a 1D array sensor such that received wave signals at equally spaced locations are available for modal analysis in the wavenumber-frequency domain. PVDF (polyvinylidene fluoride) is selected as the active material of the sensor because of its low interference with wave fields in structures. The PVDF array sensor is fabricated to have 16 independent channels and its capability to detect and characterize different types of defects is demonstrated experimentally.

  18. Aircraft Metal Skin Repair and Honeycomb Structure Repair; Sheet Metal Work 3: 9857.02.

    Science.gov (United States)

    Dade County Public Schools, Miami, FL.

    The course helps students determine types of repairs, compute repair sizes, and complete the repair through surface protection. Course content includes goals, specific objectives, protection of metals, repairs to metal skin, and honeycomb structure repair. A bibliography and post-test are appended. A prerequisite for this course is mastery of the…

  19. Corrosion on Fatigue and Fatigue Crack Growth in Aircraft Structural Materials

    Science.gov (United States)

    1979-06-01

    microplastic flow or constraint to flow or both. The physical flow or fracture processes that may ]cad to the development of a Mode I (Forsyth-Stage Ii...have a significant impact I upon the life prediction of a pitted structure due to the a/2c effect upon the stress intensity. 6.2.4 Results and

  20. Numerical Modeling of Inverse Problems under Uncertainty for Damage Detection in Aircraft Structures

    Science.gov (United States)

    2013-08-01

    Banks, HT; Inman, DJ; Leo, DJ & Wang, Y (1996): An experimentally validated damage detection theory in smart structures, Journal of Sound and...Aeroelastic Coupling (in Portuguese) (Otimização Estocástica Multi- Objetivos em Estrutura Aeronáutica sujeita a Carregamentos Aerodinâmicos, com

  1. Mapping snow depth from manned aircraft on landscape scales at centimeter resolution using structure-from-motion photogrammetry

    Science.gov (United States)

    Nolan, M.; Larsen, C.; Sturm, M.

    2015-08-01

    Airborne photogrammetry is undergoing a renaissance: lower-cost equipment, more powerful software, and simplified methods have significantly lowered the barriers to entry and now allow repeat mapping of cryospheric dynamics at spatial resolutions and temporal frequencies that were previously too expensive to consider. Here we apply these advancements to the measurement of snow depth from manned aircraft. Our main airborne hardware consists of a consumer-grade digital camera directly coupled to a dual-frequency GPS; no inertial motion unit (IMU) or on-board computer is required, such that system hardware and software costs less than USD 30 000, exclusive of aircraft. The photogrammetric processing is done using a commercially available implementation of the structure from motion (SfM) algorithm. The system is simple enough that it can be operated by the pilot without additional assistance and the technique creates directly georeferenced maps without ground control, further reducing overall costs. To map snow depth, we made digital elevation models (DEMs) during snow-free and snow-covered conditions, then subtracted these to create difference DEMs (dDEMs). We assessed the accuracy (real-world geolocation) and precision (repeatability) of our DEMs through comparisons to ground control points and to time series of our own DEMs. We validated these assessments through comparisons to DEMs made by airborne lidar and by a similar photogrammetric system. We empirically determined that our DEMs have a geolocation accuracy of ±30 cm and a repeatability of ±8 cm (both 95 % confidence). We then validated our dDEMs against more than 6000 hand-probed snow depth measurements at 3 separate test areas in Alaska covering a wide-variety of terrain and snow types. These areas ranged from 5 to 40 km2 and had ground sample distances of 6 to 20 cm. We found that depths produced from the dDEMs matched probe depths with a 10 cm standard deviation, and were statistically identical at 95

  2. Mapping snow-depth from manned-aircraft on landscape scales at centimeter resolution using Structure-from-Motion photogrammetry

    Science.gov (United States)

    Nolan, M.; Larsen, C. F.; Sturm, M.

    2015-01-01

    Airborne photogrammetry is undergoing a renaissance: lower-cost equipment, more powerful software, and simplified methods have significantly lowered the barriers-to-entry and now allow repeat-mapping of cryospheric dynamics at spatial resolutions and temporal frequencies that were previously too expensive to consider. Here we apply these techniques to the measurement of snow depth from manned aircraft. The main airborne hardware consists of a consumer-grade digital camera coupled to a dual-frequency GPS. The photogrammetric processing is done using a commercially-available implementation of the Structure from Motion (SfM) algorithm. The system hardware and software, exclusive of aircraft, costs less than USD 30 000. The technique creates directly-georeferenced maps without ground control, further reducing costs. To map snow depth, we made digital elevation models (DEMs) during snow-free and snow-covered conditions, then subtracted these to create difference DEMs (dDEMs). We assessed the accuracy (geolocation) and precision (repeatability) of our DEMs through comparisons to ground control points and to time-series of our own DEMs. We validated these assessments through comparisons to DEMs made by airborne lidar and by another photogrammetric system. We empirically determined an accuracy of ± 30 cm and a precision of ± 8 cm (both 95% confidence) for our methods. We then validated our dDEMs against more than 6000 hand-probed snow depth measurements at 3 test areas in Alaska covering a wide-variety of terrain and snow types. These areas ranged from 5 to 40 km2 and had ground sample distances of 6 to 20 cm. We found that depths produced from the dDEMs matched probe depths with a 10 cm standard deviation, and these depth distributions were statistically identical at 95% confidence. Due to the precision of this technique, other real changes on the ground such as frost heave, vegetative compaction by snow, and even footprints become sources of error in the measurement of

  3. Mapping snow-depth from manned-aircraft on landscape scales at centimeter resolution using Structure-from-Motion photogrammetry

    Directory of Open Access Journals (Sweden)

    M. Nolan

    2015-01-01

    Full Text Available Airborne photogrammetry is undergoing a renaissance: lower-cost equipment, more powerful software, and simplified methods have significantly lowered the barriers-to-entry and now allow repeat-mapping of cryospheric dynamics at spatial resolutions and temporal frequencies that were previously too expensive to consider. Here we apply these techniques to the measurement of snow depth from manned aircraft. The main airborne hardware consists of a consumer-grade digital camera coupled to a dual-frequency GPS. The photogrammetric processing is done using a commercially-available implementation of the Structure from Motion (SfM algorithm. The system hardware and software, exclusive of aircraft, costs less than USD 30 000. The technique creates directly-georeferenced maps without ground control, further reducing costs. To map snow depth, we made digital elevation models (DEMs during snow-free and snow-covered conditions, then subtracted these to create difference DEMs (dDEMs. We assessed the accuracy (geolocation and precision (repeatability of our DEMs through comparisons to ground control points and to time-series of our own DEMs. We validated these assessments through comparisons to DEMs made by airborne lidar and by another photogrammetric system. We empirically determined an accuracy of ± 30 cm and a precision of ± 8 cm (both 95% confidence for our methods. We then validated our dDEMs against more than 6000 hand-probed snow depth measurements at 3 test areas in Alaska covering a wide-variety of terrain and snow types. These areas ranged from 5 to 40 km2 and had ground sample distances of 6 to 20 cm. We found that depths produced from the dDEMs matched probe depths with a 10 cm standard deviation, and these depth distributions were statistically identical at 95% confidence. Due to the precision of this technique, other real changes on the ground such as frost heave, vegetative compaction by snow, and even footprints become sources of error in the

  4. Amphibious Aircraft

    Data.gov (United States)

    National Aeronautics and Space Administration — A brief self composed research article on Amphibious Aircrafts discussing their use, origin and modern day applications along with their advantages and disadvantages...

  5. Bayesian Framework based Damage Segmentation (BFDS) with Time-Reversal Tomography (TRT) for Damage Characterization in Complex Aircraft Structures Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To meet the NASA's need for innovative technologies that decrease turn-around time for inspections and assessments for safe operations of aircraft and spacecraft,...

  6. STRUCTURE OF CONSORTIUM DESTRUCTIVE COMPONENTS IN THE INDUSTRIAL AREA OF KRIVYI RIG BASIN

    Directory of Open Access Journals (Sweden)

    V. V. Kachinskaya

    2014-07-01

    Full Text Available Тhe structural organization and a biological variety of ground mesofauna on consortium level of the organization of ecosystems are considered. The analysis of indicators of the structural organization and a biodiversity of ground mesofauna in consortium Ulmus and Populus in the conditions of territories of industrial mining – metallurgical complex of Krivyi Rig Basin is carried out. It is established that taxonomical structure of ground mesofauna is characterized by insignificant number and quantity of taxonomical groups. Prevalence in morfo-ecological structure of hortobiontes and herpetobiontes testifies about faunae considerable attachment to consortium determinants and influences of a steppe climate on its structure. Prevalence of phytophages and polyphages in trophic structure is caused by combination of determinants specificity of consortium and zone source of fauna formations. The structural organization of ground mesofauna in consortium Ulmus and Populus in the conditions of industrial sites is characterized simplified taxonomical structure with a low biodiversity at all levels. It was suggested that structural and functional organization of destructive components of the block consortium of Ulmus and Populus in the conditions of industrial sites are simplified and determined by biogeochemical patterns of pedogenic and leaf litter layer of consortium and type of anthropogenic impact. Management and sustainable use of consortium under technogenic pressure should be based on the effects of extreme and critical components in the evolution of consortium. These critical points are the type of leading man-made factors and pedogenic and leaf litter biogeochemical conditions of consortium determinants, which results in inhibition of development and simplification of the structural and functional organization of destructive components of the block. The elaboration of measures to restore and maintain that structural and functional organization

  7. Sensor-Only System Identification for Structural Health Monitoring of Advanced Aircraft

    Science.gov (United States)

    Kukreja, Sunil L.; Bernstein, Dennis S.

    2012-01-01

    Environmental conditions, cyclic loading, and aging contribute to structural wear and degradation, and thus potentially catastrophic events. The challenge of health monitoring technology is to determine incipient changes accurately and efficiently. This project addresses this challenge by developing health monitoring techniques that depend only on sensor measurements. Since actively controlled excitation is not needed, sensor-to-sensor identification (S2SID) provides an in-flight diagnostic tool that exploits ambient excitation to provide advance warning of significant changes. S2SID can subsequently be followed up by ground testing to localize and quantify structural changes. The conceptual foundation of S2SID is the notion of a pseudo-transfer function, where one sensor is viewed as the pseudo-input and another is viewed as the pseudo-output, is approach is less restrictive than transmissibility identification and operational modal analysis since no assumption is made about the locations of the sensors relative to the excitation.

  8. High-strain fiber bragg gratings for structural fatigue testing of military aircraft

    Science.gov (United States)

    Davis, Claire; Tejedor, Silvia; Grabovac, Ivan; Kopczyk, James; Nuyens, Travis

    2012-09-01

    This paper reports on an experimental program of work which investigates the reliability, durability, and packaging of fiber Bragg gratings (FBGs) for application as distributed strain sensors during structural fatigue testing of military platforms. The influence of the FBG fabrication process on sensor reliability is investigated. In addition, methodologies for broad-area packaging and surface-mounting of FBG sensing arrays to defense platforms are developed and tested.

  9. A Review of Research and Development in Crashworthiness of General Aviation Aircraft: Seats, Restraints and Floor Structures

    Science.gov (United States)

    1990-02-01

    accident rates in general aviation. 3 q’ ) RtSUM~k Une recherche documentaire a W effectude afin de determiner l’dtat de nos connaissances sur les aspects...extensive computer analyses are necessary because the costs of full-scale aircraft tests are prohibitive. Wittlin 4 1) briefly outlined aircraft crash...subfloors. These analyses are required to defint the requirements for retrofit and new designs. The introduction of the FAA regulations [681 on dynamic

  10. Wearproof composition coatings on the basis of SiC-AL2O3 for restoration and reiforcement of the components of aircraft ground support equipment

    Directory of Open Access Journals (Sweden)

    О. П. Уманський

    2013-07-01

    Full Text Available On the ground of research of a contact interaction of the melts of the system Ni–Al with the ceramics of SiC–Al2O3 content, the possibility of wearproof coating deposition of the system SiC–Al2O3–Ni–Al by gas-flame techniques has been proved. Technological features of their acquisition also have been studied. The structure of coatings from composition material that contains the SiC–Al2O3 wearproof component and Ni–Al metallic binder, deposited by the method of high velocity air fuel deposition (HVAF on medium-carbon steel steels has been researched. Tribotechnical descriptions of the deposited coatings under the conditions of friction without lubricating materials in the air environment in wide range of speed-load modes of the “pin–on–disk” layout have been studied. The features and regularities of their wear mechanisms retaining the constant speed and constant load have been determined

  11. Structure Analysis of Network Traffic Matrix Based on Relaxed Principal Component Pursuit

    CERN Document Server

    Wang, Zhe; Xu, Ke; Yin, Baolin

    2011-01-01

    The network traffic matrix is a kind of flow-level Internet traffic data and is widely applied to network operation and management. It is a crucial problem to analyze the composition and structure of traffic matrix; some mathematical approaches such as Principal Component Analysis (PCA) were used to handle that problem. In this paper, we first argue that PCA performs poorly for analyzing traffic matrixes polluted by large volume anomalies, then propose a new composition model of the network traffic matrix. According to our model, structure analysis can be formally defined as decomposing a traffic matrix into low-rank, sparse, and noise sub-matrixes, which is equal to the Robust Principal Component Analysis (RPCA) problem defined in [13]. Based on the Relaxed Principal Component Pursuit (Relaxed PCP) method and the Accelerated Proximal Gradient (APG) algorithm, an iterative algorithm for decomposing a traffic matrix is presented, and our experiment results demonstrate its efficiency and flexibility. At last, f...

  12. Crashworthiness Optimization of Civil Aircraft Subfloor Structure%民机机身下部结构耐撞性优化设计

    Institute of Scientific and Technical Information of China (English)

    郑建强; 向锦武; 罗漳平; 任毅如

    2012-01-01

    针对含多设计参数的典型民机机身下部结构耐撞性设计,提出了一种设计方法,该方法以最小化客舱地板的初始加速度峰值与最大化参考压溃状态的结构内能为优化双目标,通过Kriging模型对结构的冲击响应进行预测,采用非支配排序遗传算法Ⅱ(NSGA-Ⅱ)对双目标进行优化,进而由Nash-Pareto策略获得最优方案.为了得到最优设计方案,同时研究设计参数对机身结构耐撞性的影响,提出最大化期望提高与最大化预测方差同步加点准则建立代理模型.采用该设计方法,以典型民机机身下部结构设计问题为算例,对客舱地板支撑结构、货舱地板和泡沫构件形状参数进行优化.结果表明,相对原始设计客舱地板的加速度峰值降低约18.3%,次高加速度峰值也得到有效降低,改善了机身结构的耐撞性;Kriging模型预测响应与有限元分析结果误差小于1%,说明了设计方法的有效性.%For a typical civil aircraft fuselage structural crashworthiness design with several design parameters, a design approach is proposed to minimize the peak acceleration of the cabin floor and maximize the internal energy of the structure at a certain crushing state. A Kriging surrogate model is adopted for impact response approximation, a nondominated sorting genetic algorithm II (NSGA-II) for dual objective optimization, and Nash-Pareto strategy for the optimum design selection. In order to obtain the effect of design parameters on crashworthiness as well as the optimum design, a synchronous sampling criterion of the maximum expected improvement and the maximum predicted variance Is suggested to construct a surrogate model. Using this design approach, a typical civil aircraft fuselage structural design with the shape parameters of the cabin floor struts, cargo floor and foam components is studied as a design case. The results indicate that the peak acceleration of the cabin floor is reduced by

  13. 飞机机身结构的腐蚀及防护方法%Structure Corrosion and Protective Measures for Aircraft Fuselage

    Institute of Scientific and Technical Information of China (English)

    郭小波

    2013-01-01

    Structure corrosion of aircraft fuselage is inevitable. This paper analyzes the causes of corrosion, and put out the measures and remedies how to prevent and delay the occurrence of corrosion.%  飞机机身结构腐蚀不可避免,本文通过分析腐蚀产生的原因,提出了如何预防和延缓腐蚀发生的措施及补救方法。

  14. Studying the mesoscale structure of inhomogeneities within the high-latitude stratosphere during the evolution of the circumpolar vortex on the basis of aircraft measurements

    Science.gov (United States)

    Shur, G. N.; Volkov, V. V.; Sitnikov, N. M.; Ulanovskii, A. E.; Sitnikova, V. I.

    2014-03-01

    Mesoscale inhomogeneities in the fields of wind, temperature, and ozone concentrations have been studied on the basis of aircraft measurements performed within the international EUPLEX and RECONCILE projects in the northern polar region in the presence of the circumpolar vortex. Data have been obtained on the structure of turbulence inside and outside the circumpolar vortex. The zones of enhanced turbulence have been studied. The spectrum of coherence between ozone and wind velocity are found to have high values.

  15. [Isolation and partial structural characteristics of major toxic components of Latrodectus pallidus venom].

    Science.gov (United States)

    Charakha, A R; Shevchenko, L V; Molodkin, A K; Pluzhnikov, K A; Volkova, T M; Grishin, E V

    1997-03-01

    Toxic components of the Latrodectus pallidus spider venom were isolated and characterized. The venom was shown to contain a toxin specific for mammals and at least one insectospecific toxin. Partial amino acid sequences of both toxins were determined, and their high structural homology with previously studied alpha-latrotoxin and alpha-latroinsectotoxin from L. mactans tredecimguttatus was found.

  16. Cyberlexicography in LSP: New Aspects of Components and Structures in the Dictionary

    DEFF Research Database (Denmark)

    Laursen, Anne Lise; Duvå, Grete

    2005-01-01

    to have been established. In this paper, we shall focus on the strengths and weaknesses of a number of existing electronic dictionaries, and we shall make some suggestions as to how to reach an optimum and how to change the components and the structures of the internet dictionary accordingly....

  17. Peroxynitrous acid induces structural and functional modifications to basement membranes and its key component, laminin

    DEFF Research Database (Denmark)

    Degendorfer, Georg; Chuang, Christine Y.; Hammer, Astrid;

    2015-01-01

    Basement membranes (BM) are specialized extracellular matrices underlying endothelial cells in the artery wall. Laminin, the most abundant BM glycoprotein, is a structural and biologically active component. Peroxynitrous acid (ONOOH), a potent oxidizing and nitrating agent, is formed in vivo at s...

  18. Equilibrium structure of the multi-component screened charged hard-sphere fluid.

    Science.gov (United States)

    Sánchez-Díaz, Luis E; Mendez-Maldonado, Gloria A; González-Melchor, Minerva; Ruiz-Estrada, Honorina; Medina-Noyola, Magdaleno

    2011-07-07

    The generalized mean spherical approximation of the structural properties of the binary charge-symmetric fluid of screened charged hard-spheres of the same diameter, i.e., the screened restricted primitive model, is extended to include binary charge-asymmetric and multi-component fluids. Molecular dynamics simulation data are generated to assess the accuracy of the corresponding theoretical predictions.

  19. 78 FR 15755 - Proposed Revision to Design of Structures, Components, Equipment and Systems; Correction

    Science.gov (United States)

    2013-03-12

    ... of New Reactors, U.S. Nuclear Regulatory Commission, Washington, DC 20555- 0001; telephone: 301-415... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Proposed Revision to Design of Structures, Components, Equipment and Systems; Correction...

  20. 78 FR 48727 - Proposed Revisions to Design of Structures, Components, Equipment and Systems

    Science.gov (United States)

    2013-08-09

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Proposed Revisions to Design of Structures, Components, Equipment and Systems AGENCY: Nuclear.... FOR FURTHER INFORMATION CONTACT: Jonathan DeGange, Office of New Reactors, U.S. Nuclear...

  1. Structure and Mechanism of the S Component of a Bacterial ECF Transporter

    Energy Technology Data Exchange (ETDEWEB)

    P Zhang; J Wang; Y Shi

    2011-12-31

    The energy-coupling factor (ECF) transporters, responsible for vitamin uptake in prokaryotes, are a unique family of membrane transporters. Each ECF transporter contains a membrane-embedded, substrate-binding protein (known as the S component), an energy-coupling module that comprises two ATP-binding proteins (known as the A and A' components) and a transmembrane protein (known as the T component). The structure and transport mechanism of the ECF family remain unknown. Here we report the crystal structure of RibU, the S component of the ECF-type riboflavin transporter from Staphylococcus aureus at 3.6-{angstrom} resolution. RibU contains six transmembrane segments, adopts a previously unreported transporter fold and contains a riboflavin molecule bound to the L1 loop and the periplasmic portion of transmembrane segments 4-6. Structural analysis reveals the essential ligand-binding residues, identifies the putative transport path and, with sequence alignment, uncovers conserved structural features and suggests potential mechanisms of action among the ECF transporters.

  2. X-ray Crystal Structure of the B Component of Hemolysin BL from Bacillus cereus

    Energy Technology Data Exchange (ETDEWEB)

    Madegowda,M.; Eswaramoorthy, S.; Burley, S.; Swaminathan, S.

    2008-01-01

    Bacillus cereus Hemolysin BL enterotoxin, a ternary complex of three proteins, is the causative agent of food poisoning and requires all three components for virulence. The X-ray structure of the binding domain of HBL suggests that it may form a pore similar to other soluble channel forming proteins. A putative pathway of pore formation is discussed.

  3. STRUCTURE OF CONSORTIUM DESTRUCTIVE COMPONENTS IN THE INDUSTRIAL AREA OF KRIVYI RIG BASIN

    Directory of Open Access Journals (Sweden)

    Kachinskaya V.V.

    2014-08-01

    Full Text Available Тhe structural organization and a biological variety of ground mesofauna on consortium level of the organization of ecosystems are considered. The analysis of indicators of the structural organization and a biodiversity of ground mesofauna in consortium Ulmus and Populus in the conditions of territories of industrial mining – metallurgical complex of Krivyi Rig Basin is carried out. It is established that taxonomical structure of ground mesofauna is characterized by insignificant number and quantity of taxonomical groups. Prevalence in morfo-ecological structure of hortobiontes and herpetobiontes testifies about faunae considerable attachment to consortium determinants and influences of a steppe climate on its structure. Prevalence of phytophages and polyphages in trophic structure is caused by combination of determinants specificity of consortium and zone source of fauna formations. The structural organization of ground mesofauna in consortium Ulmus and Populus in the conditions of industrial sites is characterized simplified taxonomical structure with a low biodiversity at all levels. It was suggested that structural and functional organization of destructive components of the block consortium of Ulmus and Populus in the conditions of industrial sites are simplified and determined by biogeochemical patterns of pedogenic and leaf litter layer of consortium and type of anthropogenic impact. Management and sustainable use of consortium under technogenic pressure should be based on the effects of extreme and critical components in the evolution of consortium. These critical points are the type of leading man-made factors and pedogenic and leaf litter biogeochemical conditions of consortium determinants, which results in inhibition of development and simplification of the structural and functional organization of destructive components of the block. The elaboration of measures to restore and maintain that structural and functional organization

  4. Multilevel probabilistic approach to evaluate manufacturing defect in composite aircraft structures

    Science.gov (United States)

    Caracciolo, Paola

    2014-05-01

    In this work it is developed a reliable approach and its feasibility to the design and analysis of a composite structures. The metric is compared the robustness and reliability designs versus the traditional design, to demonstrate the gain that can be achieved with a probabilistic approach. The use of the stochastic approach of the uncertain parameteters in combination with the multi-scale levels analysis is the main objective of this paper. The work is dedicated to analyze the uncertainties in the design, tests, manufacturing process, and key gates such as materials characteristic.

  5. Multilevel probabilistic approach to evaluate manufacturing defect in composite aircraft structures

    Energy Technology Data Exchange (ETDEWEB)

    Caracciolo, Paola, E-mail: paola.caracciolo@airbus.com [AIRBUS INDUSTRIES Germany, Department of Airframe Architecture and Integration-Research and Technology-Kreetslag, 10, D-21129, Hamburg (Germany)

    2014-05-15

    In this work it is developed a reliable approach and its feasibility to the design and analysis of a composite structures. The metric is compared the robustness and reliability designs versus the traditional design, to demonstrate the gain that can be achieved with a probabilistic approach. The use of the stochastic approach of the uncertain parameteters in combination with the multi-scale levels analysis is the main objective of this paper. The work is dedicated to analyze the uncertainties in the design, tests, manufacturing process, and key gates such as materials characteristic.

  6. Robots for Aircraft Maintenance

    Science.gov (United States)

    1993-01-01

    Marshall Space Flight Center charged USBI (now Pratt & Whitney) with the task of developing an advanced stripping system based on hydroblasting to strip paint and thermal protection material from Space Shuttle solid rocket boosters. A robot, mounted on a transportable platform, controls the waterjet angle, water pressure and flow rate. This technology, now known as ARMS, has found commercial applications in the removal of coatings from jet engine components. The system is significantly faster than manual procedures and uses only minimal labor. Because the amount of "substrate" lost is minimal, the life of the component is extended. The need for toxic chemicals is reduced, as is waste disposal and human protection equipment. Users of the ARMS work cell include Delta Air Lines and the Air Force, which later contracted with USBI for development of a Large Aircraft Paint Stripping system (LARPS). LARPS' advantages are similar to ARMS, and it has enormous potential in military and civil aircraft maintenance. The technology may also be adapted to aircraft painting, aircraft inspection techniques and paint stripping of large objects like ships and railcars.

  7. "Structuration" by Intellectual Organization: The Configuration of Knowledge in Relations among Structural Components in Networks of Science

    CERN Document Server

    Leydesdorff, Loet

    2010-01-01

    Using aggregated journal-journal citation networks, the measurement of the knowledge base in empirical systems is factor-analyzed in two cases of interdisciplinary developments during the period 1995-2005: (i) the development of nanotechnology in the natural sciences and (ii) the development of communication studies as an interdiscipline between social psychology and political science. The results are compared with a case of stable development: the citation networks of core journals in chemistry. These citation networks are intellectually organized by networks of expectations in the knowledge base at the specialty (that is, above-journal) level. This "structuration" of structural components (over time) can be measured as configurational information. The latter is compared with the Shannon-type information generated in the interactions among structural components: the difference between these two measures provides us with a measure for the redundancy generated by the specification of a model in the knowledge b...

  8. Variations of Structural Components: Specific Intercultural Differences in Facial Morphology, Skin Type, and Structures

    OpenAIRE

    McKnight, Aisha; Momoh, Adeyiza O.; Bullocks, Jamal M.

    2009-01-01

    Analysis of the differences in facial morphology and skin structure and tone among ethnic groups within the realm of plastic surgery is relevant due to the increasing number of ethnic individuals seeking cosmetic surgery. Previous classifications of ideal facial morphologic characteristics have been revised and challenged over the years to accurately reflect the differences in facial structure that are aesthetically pleasing to individuals of differing ethnic groups. The traditional neoclassi...

  9. Aircraft modifications: Assessing the current state of Air Force aircraft modifications and the implications for future military capability

    Science.gov (United States)

    Hill, Owen Jacob

    How prepared is the U.S. Air Force to modify its aircraft fleet in upcoming years? Aircraft modernization is a complex interaction of new and legacy aircraft, organizational structure, and planning policy. This research will take one component of modernization: aircraft modification, and apply a new method of analysis in order to help formulate policy to promote modernization. Departing from previous small-sample studies dependent upon weight as a chief explanatory variable, this dissertation incorporates a comprehensive dataset that was constructed for this research of all aircraft modifications from 1996 through 2005. With over 700 modification programs, this dataset is used to examine changes to the current modification policy using policy-response regression models. These changes include separating a codependent procurement and installation schedule, reducing the documentation requirements for safety modifications, and budgeting for aging aircraft modifications. The research then concludes with predictive models for the F-15 and F-16 along with their replacements: the F-22 and F-35 Joint Strike Fighter.

  10. The influence of the stray-light component in determining coronal temperature structures

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    We use a few solar partial eclipse observations made by XRT/Hinode to estimate the influence of stray-light component in determining coronal temperature structures. Our analysis shows that the stray light will largely affect the estimation of coronal temperature and change the estimated temperature structure in one coronal hole region. The stray lights mildly influence the estimated temperatures in one quiet Sun region and do not change the estimated temperature structure. This implies that the influence of stray lights differs from one region to another, and definitely needs to be considered in some regions. Whereas a carefully estimated point-spread-function is needed to remove the stray light component, our study shows that by a simple approach such as subtracting the average intensity of distant (e.g. >1.4 solar radius) points from the data values, the influence of stray light can be largely removed, at least for the two regions we study here.

  11. Knowledge-based System Prototype in Structural Component Design Based on FM

    Institute of Scientific and Technical Information of China (English)

    JIANG; Tao; LI; Qing-fen; LI; Ming; FU; Wei

    2002-01-01

    A knowledge-based system in structural component design based on fracture mechanics is developed in this paper. The system consists of several functional parts: a general inference engine, a set of knowledge bases and data-bases, an interpretation engine, a bases administration system and the interface. It can simulate a human expert to make analysis and design scheme mainly for four kinds of typical structural components widely used in shipbuilding industry: pressure vessels, huge rotation constructions, pump-rod and welded structures. It is an open system which may be broadened and perfected to cover a wider range of engineering application through the modification and enlargement of knowledge bases and data-bases. It has a natural and friendly interface that may be easily operated. An on-line help service is also provided.

  12. The influence of the stray-light component in determining coronal temperature structures

    Institute of Scientific and Technical Information of China (English)

    HAO Juan; ZHANG Mei

    2009-01-01

    We use a few solar partial eclipse observations made by XRT/Hinode to estimate the influence of stray-light component in determining coronal temperature structures. Our analysis shows that the stray light will largely affect the estimation of coronal temperature and change the estimated temperature structure in one coronal hole region. The stray lights mildly influence the estimated temperatures in one quiet Sun region and do not change the estimated temperature structure. This implies that the influence of stray lights differs from one region to another, and definitely needs to be considered in some regions. Whereas a carefully estimated point-spread-function Is needed to remove the stray light component, our study shows that by a simple approach such as subtracting the average intensity of distant (e.g. >1.4 solar radius) points from the data values, the influence of stray light can be largely removed, at least for the two regions we study here.

  13. Chitosan facilitates structure formation of the salivary gland by regulating the basement membrane components.

    Science.gov (United States)

    Yang, Tsung-Lin; Hsiao, Ya-Chuan

    2015-10-01

    Tissue structure is important for inherent physiological function and should be recapitulated during tissue engineering for regenerative purposes. The salivary gland is a branched organ that is responsible for saliva secretion and regulation. The salivary glands develop from epithelial-mesenchymal interactions, and depend on the support of the basement membrane (BM). Chitosan-based biomaterials have been demonstrated to be competent in facilitating the formation of salivary gland tissue structure. However, the underlying mechanisms have remained elusive. In the developing submandibular gland (SMG), the chitosan effect was found to diminish when collagen and laminin were removed from cultured SMG explants. Chitosan increased the expression of BM components including collagen, laminin, and heparan sulfate proteoglycan, and also facilitated BM components and the corresponding receptors to be expressed in tissue-specific patterns beneficial for SMG branching. The chitosan effect decreased when either laminin components or receptors were inhibited, as well when the downstream signaling was blocked. Our results revealed that chitosan promotes salivary glands branching through the BM. By regulating BM components and receptors, chitosan efficiently stimulated downstream signaling to facilitate salivary gland branching. The present study revealed the underlying mechanism of the chitosan effect in engineering SMG structure formation.

  14. Full-scale flight tests of aircraft morphing structures using SMA actuators

    Science.gov (United States)

    Mabe, James H.; Calkins, Frederick T.; Ruggeri, Robert T.

    2007-04-01

    In August of 2005 The Boeing Company conducted a full-scale flight test utilizing Shape Memory Alloy (SMA) actuators to morph an engine's fan exhaust to correlate exhaust geometry with jet noise reduction. The test was conducted on a 777-300ER with GE-115B engines. The presence of chevrons, serrated aerodynamic surfaces mounted at the trailing edge of the thrust reverser, have been shown to greatly reduce jet noise by encouraging advantageous mixing of the free, and fan streams. The morphing, or Variable Geometry Chevrons (VGC), utilized compact, light weight, and robust SMA actuators to morph the chevron shape to optimize the noise reduction or meet acoustic test objectives. The VGC system was designed for two modes of operation. The entirely autonomous operation utilized changes in the ambient temperature from take-off to cruise to activate the chevron shape change. It required no internal heaters, wiring, control system, or sensing. By design this provided one tip immersion at the warmer take-off temperatures to reduce community noise and another during the cooler cruise state for more efficient engine operation, i.e. reduced specific fuel consumption. For the flight tests a powered mode was added where internal heaters were used to individually control the VGC temperatures. This enabled us to vary the immersions and test a variety of chevron configurations. The flight test demonstrated the value of SMA actuators to solve a real world aerospace problem, validated that the technology could be safely integrated into the airplane's structure and flight system, and represented a large step forward in the realization of SMA actuators for production applications. In this paper the authors describe the development of the actuator system, the steps required to integrate the morphing structure into the thrust reverser, and the analysis and testing that was required to gain approval for flight. Issues related to material strength, thermal environment, vibration

  15. Investigation on Spectral Structure of Gearbox Vibration Signals by Principal Component Analysis for Condition Monitoring Purposes

    Energy Technology Data Exchange (ETDEWEB)

    Zimroz, Radoslaw [Wroclaw University of Technology, Diagnostics and Vibro-Acoustics Science Laboratory (Poland); Bartkowiak, Anna, E-mail: radoslaw.zimroz@pwr.wroc.pl, E-mail: aba@ii.uni.wroc.pl [University of Wroclaw, Institute of Computer Science, Wroclaw (Poland)

    2011-07-19

    Spectral analysis is well-established analysis of vibrations used in diagnostics both in academia and industry. In general, one may identify components related to particular stages in the gearbox and analyze amplitudes of these components with a simple rule for decision-making: if amplitudes are increasing the condition becomes worse. However, usually one should analyze not single amplitude but at least several components, but: how to analyze them simultaneously? We have provided an example (case study) for planetary gearboxes in good and bad conditions (case B and case A). As diagnostic features we have used 15 amplitudes of spectral components related to fundamental planetary mesh frequency and its harmonics. Using Principal Component Analysis (PCA), it has been shown that amplitudes don't vary in the same way; change of condition affects not only amplitudes of all components in that sense, but also relation between them. We have investigated geometry of the data and it has been shown that the proportions of the explained total inertia of the three data sets ('good', 'bad' and mixed good/bad) are different. We claim that it may be a novel diagnostic approach to employ multidimensional analysis for accounting not only directly observed values but also interrelations both within and between the two groups of data. Different structure of the data is associated with different condition of the machines and such assumption is specified for the first time in the literature. Obviously it requires more studies.

  16. Model updating of complex structures using the combination of component mode synthesis and Kriging predictor.

    Science.gov (United States)

    Liu, Yang; Li, Yan; Wang, Dejun; Zhang, Shaoyi

    2014-01-01

    Updating the structural model of complex structures is time-consuming due to the large size of the finite element model (FEM). Using conventional methods for these cases is computationally expensive or even impossible. A two-level method, which combined the Kriging predictor and the component mode synthesis (CMS) technique, was proposed to ensure the successful implementing of FEM updating of large-scale structures. In the first level, the CMS was applied to build a reasonable condensed FEM of complex structures. In the second level, the Kriging predictor that was deemed as a surrogate FEM in structural dynamics was generated based on the condensed FEM. Some key issues of the application of the metamodel (surrogate FEM) to FEM updating were also discussed. Finally, the effectiveness of the proposed method was demonstrated by updating the FEM of a real arch bridge with the measured modal parameters.

  17. Model Updating of Complex Structures Using the Combination of Component Mode Synthesis and Kriging Predictor

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2014-01-01

    Full Text Available Updating the structural model of complex structures is time-consuming due to the large size of the finite element model (FEM. Using conventional methods for these cases is computationally expensive or even impossible. A two-level method, which combined the Kriging predictor and the component mode synthesis (CMS technique, was proposed to ensure the successful implementing of FEM updating of large-scale structures. In the first level, the CMS was applied to build a reasonable condensed FEM of complex structures. In the second level, the Kriging predictor that was deemed as a surrogate FEM in structural dynamics was generated based on the condensed FEM. Some key issues of the application of the metamodel (surrogate FEM to FEM updating were also discussed. Finally, the effectiveness of the proposed method was demonstrated by updating the FEM of a real arch bridge with the measured modal parameters.

  18. Algorithm for Multi-Axis Cooperative Control of Aircraft Component Flexible Assembly%飞机部件柔性装配多轴协同控制算法研究

    Institute of Scientific and Technical Information of China (English)

    黄果; 王仲奇; 康永刚; 胡玉龙

    2013-01-01

    根据飞机部件柔性装配多轴协同控制的需求,采用模糊自整定PID算法进行实时控制.依据模糊自整定PID控制策略和PID参数的整定原则,结合MATLAB软件,用MATLAB语言编程与SIMULINK相结合的方法实现了一种飞机部件柔性装配模糊自整定PID控制器的设计、分析与仿真.%According to the aircraft component flexible assembly multi-axis cooperative control requirements, fuzzy self-tuning PID algorithm is used for realtime control. Based on fuzzy self-tuning PID control strategy and PID parameters setting principle, combined with the MATLAB software, MATLAB language programming and SIMULINK is combined to realize a kind of aircraft parts flexible assembly fuzzy self-tuning PID controller design, analysis and simulation.

  19. NASA-UVA Light Aerospace Alloy and Structure Technology Program Supplement: Aluminum-Based Materials for High Speed Aircraft. Final report, 1 December 1991-31 March 1996

    Energy Technology Data Exchange (ETDEWEB)

    Starke, E.A. Jr.

    1996-05-01

    This is the final report of the study `Aluminum-Based Materials for high Speed Aircraft` which had the objectives (1) to identify the most promising aluminum-based materials with respect to major structural use on the HSCT and to further develop those materials and (2) to assess the materials through detailed trade and evaluation studies with respect to their structural efficiency on the HSCT. The research team consisted of ALCOA, Allied-Signal, Boeing, McDonnell Douglas, Reynolds Metals and the University of Virginia. Four classes of aluminum alloys were investigated: (1) I/M 2XXX containing Li and I/M 2XXX with Li, (2) I/M 6XXX, (3) two P/M 2XXX alloys and (4) two different aluminum-based metal matrix composites (MMC). The I/M alloys were targeted for a Mach 2.0 aircraft and the P/M and MMC alloys were targeted for a Mach 2.4 aircraft. Design studies were conducted using several different concepts including skin/stiffener (baseline), honeycomb sandwich, integrally stiffened and hybrid adaptations (conventionally stiffened thin-sandwich skins). Alloy development included fundamental studies of coarsening behavior, the effect of stress on nucleation and growth of precipitates, and fracture toughness as a function of temperature were an integral part of this program. The details of all phases of the research are described in this final report.

  20. Structural Framework for Flight: NASA's Role in Development of Advanced Composite Materials for Aircraft and Space Structures

    Science.gov (United States)

    Tenney, Darrel R.; Davis, John G., Jr.; Johnston, Norman J.; Pipes, R. Byron; McGuire, Jack F.

    2011-01-01

    This serves as a source of collated information on Composite Research over the past four decades at NASA Langley Research Center, and is a key reference for readers wishing to grasp the underlying principles and challenges associated with developing and applying advanced composite materials to new aerospace vehicle concepts. Second, it identifies the major obstacles encountered in developing and applying composites on advanced flight vehicles, as well as lessons learned in overcoming these obstacles. Third, it points out current barriers and challenges to further application of composites on future vehicles. This is extremely valuable for steering research in the future, when new breakthroughs in materials or processing science may eliminate/minimize some of the barriers that have traditionally blocked the expanded application of composite to new structural or revolutionary vehicle concepts. Finally, a review of past work and identification of future challenges will hopefully inspire new research opportunities and development of revolutionary materials and structural concepts to revolutionize future flight vehicles.

  1. Synergistic proinflammatory interactions of microbial toxins and structural components characteristic to moisture-damaged buildings.

    Science.gov (United States)

    Korkalainen, M; Täubel, M; Naarala, J; Kirjavainen, P; Koistinen, A; Hyvärinen, A; Komulainen, H; Viluksela, M

    2017-01-01

    Indoor exposure to microbes and their structural and metabolic compounds is notoriously complex. To study proinflammatory interactions between the multiple microbial agents, macrophages derived from human THP-1 monocytic cells were exposed to several concentrations of microbial toxins alone (emodin, enniatin B, physcion, sterigmatocystin, valinomycin) and in combination with microbial structural components (bacterial lipopolysaccharide [LPS] or fungal β-glucan). While the expression of proinflammatory cytokines TNFα and IL-1β to single toxins alone was modest, low-dose co-exposure with structural components increased the responses of emodin, enniatin B, and valinomycin synergistically, both at the mRNA and protein level, as measured by RT-qPCR and ELISA, respectively. Co-exposure of toxins and β-glucan resulted in consistent synergistically increased expression of several inflammation-related genes, while some of the responses with LPS were also inhibitory. Co-exposure of toxins with either β-glucan or LPS induced also mitochondrial damage and autophagocytosis. The results demonstrate that microbial toxins together with bacterial and fungal structural components characteristic to moisture-damaged buildings can have drastic synergistic proinflammatory interactions at low exposure levels.

  2. Research situation of multiple site damages aircraft structure%飞机结构多处损伤研究现状

    Institute of Scientific and Technical Information of China (English)

    李郑琦; 胡建军; 陈跃良

    2011-01-01

    多损伤是老龄飞机最主要的损伤形式,在文中介绍了多损伤应力强度因子的计算方法和多裂纹连通准则,飞机结构多损伤裂纹扩展模型和可靠性分析研究现状.%Multiple site damages (MSD) is the major aging damage forms of aircraft. It was introduced Calculation method of damage stress intensity factor and crack connected criteria for aircraft structure were introduced in this paper, and MSD crack propagation model and situation of its reliability analysis were also presented.

  3. VTOL to Transonic Aircraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The cyclogyro, an aircraft propulsion concept with the potential for VTOL to the lower bounds of transonic flight, is conceptually simple but structurally and...

  4. 13C NMR spectra of tectonic coals and the effects of stress on structural components

    Institute of Scientific and Technical Information of China (English)

    JU Yiwen; JIANG Bo; HOU Quanlin; WANG Guiliang; NI Shanqin

    2005-01-01

    High-resolution 13C Nuclear Magnetic Resonance (NMR) spectra of different kinds of tectonic coals were obtained using the NMR (CP/MAS+TOSS) method. On the basis of this, after simulation synthesis and division of spectra, the relative contents of carbon functional groups were calculated. Combined with results of Ro, max, XRD testing and element analysis, stress effects on the composition of macromolecular structures in tectonic coals were studied further. The results showed that Ro, max was not only the important index for describing coal rank, but was also effective for estimating the stress effect of tectonic coals. Under tectonic stress action, Ro, max was the most direct indicator of the coal structure and chemical components. Changes in the stacking Lc of the coal basic structure unit (BSU) and La/Lc parameters could distinguish the temperature and stress effects on metamorphic-deformed environments, and reflected the degree of structural deformation. Therefore, on the whole, Lc and La/Lc can be used to index of the degree of structural deformation of tectonic coals. In different metamorphic and deformed environments, different kinds of tectonic coals are formed under structural stress. The changes in characteristics of the macromolecular structure and chemical composition are such that as the increase in structural deformation becomes stronger, from the brittle deformation coal to ductile deformation coal, the ratio of width at the half height of the aromatic carbon and aliphatic carbon peaks (Hfa/Hfal ) was increased. As carbon aromaticity was raised further, carbon aliphaticity reduced obviously and different compositions of macromolecular structure appeared as a jump and wave pattern except for in wrinkle structure coal, which might result chiefly from stress effects on the macromolecular structure of different kinds of tectonic coals. The macromoecular changes of wrinkle structure coal are reflected mainly on physical structure. In the metamorphic and

  5. A Kernel Time Structure Independent Component Analysis Method for Nonlinear Process Monitoring☆

    Institute of Scientific and Technical Information of China (English)

    Lianfang Cai; Xuemin Tian; Ni Zhang

    2014-01-01

    Kernel independent component analysis (KICA) is a newly emerging nonlinear process monitoring method, which can extract mutually independent latent variables cal ed independent components (ICs) from process var-iables. However, when more than one IC have Gaussian distribution, it cannot extract the IC feature effectively and thus its monitoring performance will be degraded drastical y. To solve such a problem, a kernel time struc-ture independent component analysis (KTSICA) method is proposed for monitoring nonlinear process in this paper. The original process data are mapped into a feature space nonlinearly and then the whitened data are calculated in the feature space by the kernel trick. Subsequently, a time structure independent component analysis algorithm, which has no requirement for the distribution of ICs, is proposed to extract the IC feature. Finally, two monitoring statistics are built to detect process faults. When some fault is detected, a nonlinear fault identification method is developed to identify fault variables based on sensitivity analysis. The proposed monitoring method is applied in the Tennessee Eastman benchmark process. Applications demonstrate the superiority of KTSICA over KICA.

  6. Building Block Approach' for Structural Analysis of Thermoplastic Composite Components for Automotive Applications

    Science.gov (United States)

    Carello, M.; Amirth, N.; Airale, A. G.; Monti, M.; Romeo, A.

    2017-02-01

    Advanced thermoplastic prepreg composite materials stand out with regard to their ability to allow complex designs with high specific strength and stiffness. This makes them an excellent choice for lightweight automotive components to reduce mass and increase fuel efficiency, while maintaining the functionality of traditional thermosetting prepreg (and mechanical characteristics) and with a production cycle time and recyclability suited to mass production manufacturing. Currently, the aerospace and automotive sectors struggle to carry out accurate Finite Elements (FE) component analyses and in some cases are unable to validate the obtained results. In this study, structural Finite Elements Analysis (FEA) has been done on a thermoplastic fiber reinforced component designed and manufactured through an integrated injection molding process, which consists in thermoforming the prepreg laminate and overmolding the other parts. This process is usually referred to as hybrid molding, and has the provision to reinforce the zones subjected to additional stresses with thermoformed themoplastic prepreg as required and overmolded with a shortfiber thermoplastic resin in single process. This paper aims to establish an accurate predictive model on a rational basis and an innovative methodology for the structural analysis of thermoplastic composite components by comparison with the experimental tests results.

  7. Comprehensive Evaluation on Consumption Structure of Rural Residents with Principal Component Analysis in China

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    In order to make analysis on consumption structure of rural residents,the paper makes a principle component analysis on consumption expenditure per capita of rural residents in different areas of 2009 based on statistics of China statistical yearbook of 2010.Selecting a principal component,the paper arranges 31 provinces in China in order.Shanghai lists the 1st place with highest marks;coastal provinces in southeastern part,the Northeast,Beijing and Tianjin are at the top;the northern and central parts with Hebei,Shanxi,Hubei as representatives scores minus which is a little lower than that of average;the western part,such as Guizhou,Xizang,Gansu and so on are in far behind.The paper also makes analysis on the consumption structure of rural residents and proposes suggestions on how to accelerate consumption of rural residents.

  8. Independent component analysis reveals new and biologically significant structures in micro array data

    Directory of Open Access Journals (Sweden)

    Veerla Srinivas

    2006-06-01

    Full Text Available Abstract Background An alternative to standard approaches to uncover biologically meaningful structures in micro array data is to treat the data as a blind source separation (BSS problem. BSS attempts to separate a mixture of signals into their different sources and refers to the problem of recovering signals from several observed linear mixtures. In the context of micro array data, "sources" may correspond to specific cellular responses or to co-regulated genes. Results We applied independent component analysis (ICA to three different microarray data sets; two tumor data sets and one time series experiment. To obtain reliable components we used iterated ICA to estimate component centrotypes. We found that many of the low ranking components indeed may show a strong biological coherence and hence be of biological significance. Generally ICA achieved a higher resolution when compared with results based on correlated expression and a larger number of gene clusters with significantly enriched for gene ontology (GO categories. In addition, components characteristic for molecular subtypes and for tumors with specific chromosomal translocations were identified. ICA also identified more than one gene clusters significant for the same GO categories and hence disclosed a higher level of biological heterogeneity, even within coherent groups of genes. Conclusion Although the ICA approach primarily detects hidden variables, these surfaced as highly correlated genes in time series data and in one instance in the tumor data. This further strengthens the biological relevance of latent variables detected by ICA.

  9. Relay Channel with Orthogonal Components and Structured Interference Known at the Source

    OpenAIRE

    Bakanoglu, Kagan; Erkip, Elza; Simeone, Osvaldo; Shamai, Sholomo

    2012-01-01

    A relay channel with orthogonal components that is affected by an interference signal that is noncausally available only at the source is studied. The interference signal has structure in that it is produced by another transmitter communicating with its own destination. Moreover, the interferer is not willing to adjust its communication strategy to minimize the interference. Knowledge of the interferer's signal may be acquired by the source, for instance, by exploiting HARQ retransmissions on...

  10. Cross-section of subsea umbilical and stress prediction of its structural components

    OpenAIRE

    Solovev V. V.; Zyatikov P. N.; Kozyrev I. N.

    2017-01-01

    It is presented in this article analysis of two models of subsea umbilicals under axial stress. Subsea umbilicals play a crucial role in offshore petroleum production and are designed to withstand all the environmental dynamic loads during the production period as long as 25 years. Apart from dynamic loads subsea umbilicals are under thermal loads as well having impact on the structural components and changing the material properties in some cases. The cross-section arrangement is a major par...

  11. The influence of cellular structures on flow stress of high strength components manufactured using SLM

    DEFF Research Database (Denmark)

    Mahshid, Rasoul; Hansen, Hans Nørgaard; Loft Højbjerre, Klaus

    2016-01-01

    Additive manufacturing has shown significant improvement in material and machines for high-quality solid freeform fabrication processes such as selective laser melting (SLM). In particular, manufacturing lattice structures using the SLM procedure is of interest. This research examines the effect...... of cellular materials on compression strength. The specimens are manufactured additively using industrial 3D printing systems from high-strength alloy. The material has the right mechanical properties for manufacturing tool components. This includes samples with solid and lattice structures. The Compression...

  12. Silicon grating structures for optical fiber interfacing and III-V/silicon opto-electronic components

    Science.gov (United States)

    Roelkens, Gunther; Vermeulen, Diedrik; Li, Yanlu; Muneeb, Muhammad; Hattasan, Nannicha; Ryckeboer, Eva; Deconinck, Yannick; Van Thourhout, Dries; Baets, Roel

    2013-02-01

    In this paper, we review our work on efficient, broadband and polarization independent interfaces between a silicon-on-insulator photonic IC and a single-mode optical fiber based on grating structures. The high alignment tolerance and the fact that the optical fiber interface is out-of-plane provide opportunities for easy packaging and wafer-scale testing of the photonic IC. Next to fiber-chip interfaces we will discuss the use of silicon grating structures in III-V on silicon optoelectronic components such as integrated photodetectors and microlasers.

  13. Structural analysis of proteinaceous components in Byssal threads of the mussel Mytilus galloprovincialis.

    Science.gov (United States)

    Hagenau, Anja; Scheidt, Holger A; Serpell, Louise; Huster, Daniel; Scheibel, Thomas

    2009-02-11

    The mussel byssus is a unique holdfast structure employed by marine mussels to colonize diverse substrates. The byssus consists of extracellular threads with mainly proteinaceous components. Individual threads reveal high tensile strength at their distal end and high elasticity in their proximal portion. Our studies show that proteins of the distal part are oriented along the thread axis and are well-ordered with a high beta-structural content. In contrast, proteins of the proximal part are less ordered and are not as well-oriented with primarily alpha-helical structure. The detected differences in the structural features of the proteins along a byssus thread are likely an important basis for its gradual mechanical properties.

  14. A Method of Clustering Components into Modules Based on Products' Functional and Structural Analysis

    Institute of Scientific and Technical Information of China (English)

    MENG Xiang-hui; JIANG Zu-hua; ZHENG Ying-fei

    2006-01-01

    Modularity is the key to improving the cost-variety trade-off in product development. To achieve the functional independency and structural independency of modules, a method of clustering components to identify modules based on functional and structural analysis was presented. Two stages were included in the method. In the first stage the products' function was analyzed to determine the primary level of modules. Then the objective function for modules identifying was formulated to achieve functional independency of modules. Finally the genetic algorithm was used to solve the combinatorial optimization problem in modules identifying to form the primary modules of products. In the second stage the cohesion degree of modules and the coupling degree between modules were analyzed. Based on this structural analysis the modular scheme was refined according to the thinking of structural independency. A case study on the gear reducer was conducted to illustrate the validity of the presented method.

  15. Sensor fault diagnosis of nonlinear processes based on structured kernel principal component analysis

    Institute of Scientific and Technical Information of China (English)

    Kechang FU; Liankui DAI; Tiejun WU; Ming ZHU

    2009-01-01

    A new sensor fault diagnosis method based on structured kernel principal component analysis (KPCA) is proposed for nonlinear processes.By performing KPCA on subsets of variables,a set of structured residuals,i.e.,scaled powers of KPCA,can be obtained in the same way as partial PCA.The structured residuals are utilized in composing an isolation scheme for sensor fault diagnosis,according to a properly designed incidence matrix.Sensor fault sensitivity and critical sensitivity are defined,based on which an incidence matrix optimization algorithm is proposed to improve the performance of the structured KPCA.The effectiveness of the proposed method is demonstrated on the simulated continuous stirred tank reactor (CSTR) process.

  16. Structural modeling and optimization of a joined-wing configuration of a High-Altitude Long-Endurance (HALE) aircraft

    Science.gov (United States)

    Kaloyanova, Valentina B.

    Recent research trends have indicated an interest in High-Altitude, Long-Endurance (HALE) aircraft as a low-cost alternative to certain space missions, such as telecommunication relay, environmental sensing and military reconnaissance. HALE missions require a light vehicle flying at low speed in the stratosphere at altitudes of 60,000-80,000 ft, with a continuous loiter time of up to several days. To provide high lift and low drag at these high altitudes, where the air density is low, the wing area should be increased, i.e., high-aspect-ratio wings are necessary. Due to its large span and lightweight, the wing structure is very flexible. To reduce the structural deformation, and increase the total lift in a long-spanned wing, a sensorcraft model with a joined-wing configuration, proposed by AFRL, is employed. The joined-wing encompasses a forward wing, which is swept back with a positive dihedral angle, and connected with an aft wing, which is swept forward. The joined-wing design combines structural strength, high aerodynamic performance and efficiency. As a first step to study the joined-wing structural behavior an 1-D approximation model is developed. The 1-D approximation is a simple structural model created using ANSYS BEAM4 elements to present a possible approach for the aerodynamics-structure coupling. The pressure loads from the aerodynamic analysis are integrated numerically to obtain the resultant aerodynamic forces and moments (spanwise lift and pitching moment distributions, acting at the aerodynamic center). These are applied on the 1-D structural model. A linear static analysis is performed under this equivalent load, and the deformed shape of the 1-D model is used to obtain the deformed shape of the actual 3-D joined wing, i.e. deformed aerodynamic surface grid. To date in the existing studies, only simplified structural models have been examined. In the present work, in addition to the simple 1-D beam model, a semi-monocoque structural model is

  17. A review on the coordinative structure of human walking and the application of principal component analysis

    Institute of Scientific and Technical Information of China (English)

    Xinguang Wang; Nicholas O'Dwyer; Mark Halaki

    2013-01-01

    Walking is a complex task which includes hundreds of muscles, bones and joints working together to deliver smooth movements. With the complexity, walking has been widely investigated in order to identify the pattern of multi-segment movement and reveal the control mechanism. The degree of freedom and dimensional properties provide a view of the coordinative structure during walking, which has been extensively studied by using dimension reduction technique. In this paper, the studies related to the coordinative structure, dimensions detection and pattern reorganization during walking have been reviewed. Principal component analysis, as a popular technique, is widely used in the processing of human movement data. Both the principle and the outcomes of principal component analysis were introduced in this paper. This technique has been reported to successfully reduce the redundancy within the original data, identify the physical meaning represented by the extracted principal components and discriminate the different patterns. The coordinative structure during walking assessed by this technique could provide further information of the body control mechanism and correlate walking pattern with injury.

  18. Effects of the gene carrier polyethyleneimines on structure and function of blood components.

    Science.gov (United States)

    Zhong, Dagen; Jiao, Yanpeng; Zhang, Yi; Zhang, Wei; Li, Nan; Zuo, Qinhua; Wang, Qian; Xue, Wei; Liu, Zonghua

    2013-01-01

    As a synthetic polycation, polyethylenimine (PEI) is currently one of the most effective non-viral gene carriers. For in vivo applications, PEI will enter systemic circulation and interact with various blood components and then affect their individual bio-functions. Up to now, overall and systematic investigation on the interaction of PEI with multiple blood components at cellular, membrane, and molecular levels is lacking, even though it is critically important for the in vivo safety of PEI. To learn a structure-activity relationship, we investigated the effects of PEI with different molecular weight (MW) and shape (branched or linear) on key blood components and function, specifically, on RBC aggregation and morphological change, platelet activation, conformation change of albumin (as a representative of plasma proteins), and blood coagulation process. Additionally, more proteins from plasma were screened and identified to have associations with PEI by a proteomic analysis. It was found that, the PEIs have severe impact on RBC membrane structure, albumin conformation, and blood coagulation process, but do not significantly activate platelets at low concentrations. Furthermore, 41 plasma proteins were identified to have some interaction with PEI. This indicates that, besides albumin, PEI does interact with a variety of blood plasma proteins, and could have unexplored effects on their structures and bio-functions. The results provide good insight into the molecular design and blood safety of PEI and other polycations for in vivo applications.

  19. DEVELOPMENT OF METHODOLOGY FOR DESIGNING TESTABLE COMPONENT STRUCTURE OF DISCIPLINARY COMPETENCE

    Directory of Open Access Journals (Sweden)

    Vladimir I. Freyman

    2014-01-01

    Full Text Available The aim of the study is to present new methods of quality results assessment of the education corresponding to requirements of Federal State Educational Standards (FSES of the Third Generation developed for the higher school. The urgency of search of adequate tools for quality competency measurement and its elements formed in the course of experts’ preparation are specified. Methods. It is necessary to consider interference of competency components such as knowledge, abilities, possession in order to make procedures of assessment of students’ achievements within the limits of separate discipline or curriculum section more convenient, effective and exact. While modeling of component structure of the disciplinary competence the testable design of components is used; the approach borrowed from technical diagnostics. Results. The research outcomes include the definition and analysis of general iterative methodology for testable designing component structure of the disciplinary competence. Application of the proposed methodology is illustrated as the example of an abstract academic discipline with specified data and index of labour requirement. Methodology restrictions are noted; practical recommendations are given. Scientific novelty. Basic data and a detailed step-by-step implementation phase of the proposed common iterative approach to the development of disciplinary competence testable component structure are considered. Tests and diagnostic tables for different options of designing are proposed. Practical significance. The research findings can help promoting learning efficiency increase, a choice of adequate control devices, accuracy of assessment, and also efficient use of personnel, temporal and material resources of higher education institutions. Proposed algorithms, methods and approaches to procedure of control results organization and realization of developed competences and its components can be used as methodical base while

  20. Novel structural components of the ventral disc and lateral crest in Giardia intestinalis.

    Directory of Open Access Journals (Sweden)

    Kari D Hagen

    2011-12-01

    Full Text Available Giardia intestinalis is a ubiquitous parasitic protist that is the causative agent of giardiasis, one of the most common protozoan diarrheal diseases in the world. Giardia trophozoites attach to the intestinal epithelium using a specialized and elaborate microtubule structure, the ventral disc. Surrounding the ventral disc is a less characterized putatively contractile structure, the lateral crest, which forms a continuous perimeter seal with the substrate. A better understanding of ventral disc and lateral crest structure, conformational dynamics, and biogenesis is critical for understanding the mechanism of giardial attachment to the host. To determine the components comprising the ventral disc and lateral crest, we used shotgun proteomics to identify proteins in a preparation of isolated ventral discs. Candidate disc-associated proteins, or DAPs, were GFP-tagged using a ligation-independent high-throughput cloning method. Based on disc localization, we identified eighteen novel DAPs, which more than doubles the number of known disc-associated proteins. Ten of the novel DAPs are associated with the lateral crest or outer edge of the disc, and are the first confirmed components of this structure. Using Fluorescence Recovery After Photobleaching (FRAP with representative novel DAP::GFP strains we found that the newly identified DAPs tested did not recover after photobleaching and are therefore structural components of the ventral disc or lateral crest. Functional analyses of the novel DAPs will be central toward understanding the mechanism of ventral disc-mediated attachment and the mechanism of disc biogenesis during cell division. Since attachment of Giardia to the intestine via the ventral disc is essential for pathogenesis, it is possible that some proteins comprising the disc could be potential drug targets if their loss or disruption interfered with disc biogenesis or function, preventing attachment.

  1. Principal component regression and linear mixed model in association analysis of structured samples: competitors or complements?

    Science.gov (United States)

    Zhang, Yiwei; Pan, Wei

    2015-03-01

    Genome-wide association studies (GWAS) have been established as a major tool to identify genetic variants associated with complex traits, such as common diseases. However, GWAS may suffer from false positives and false negatives due to confounding population structures, including known or unknown relatedness. Another important issue is unmeasured environmental risk factors. Among many methods for adjusting for population structures, two approaches stand out: one is principal component regression (PCR) based on principal component analysis, which is perhaps the most popular due to its early appearance, simplicity, and general effectiveness; the other is based on a linear mixed model (LMM) that has emerged recently as perhaps the most flexible and effective, especially for samples with complex structures as in model organisms. As shown previously, the PCR approach can be regarded as an approximation to an LMM; such an approximation depends on the number of the top principal components (PCs) used, the choice of which is often difficult in practice. Hence, in the presence of population structure, the LMM appears to outperform the PCR method. However, due to the different treatments of fixed vs. random effects in the two approaches, we show an advantage of PCR over LMM: in the presence of an unknown but spatially confined environmental confounder (e.g., environmental pollution or lifestyle), the PCs may be able to implicitly and effectively adjust for the confounder whereas the LMM cannot. Accordingly, to adjust for both population structures and nongenetic confounders, we propose a hybrid method combining the use and, thus, strengths of PCR and LMM. We use real genotype data and simulated phenotypes to confirm the above points, and establish the superior performance of the hybrid method across all scenarios.

  2. Structure Measurements of Leaf and Woody Components of Forests with Dual-Wavelength Lidar Scanning Data

    Science.gov (United States)

    Strahler, A. H.; Li, Z.; Schaaf, C.; Howe, G.; Martel, J.; Hewawasam, K.; Douglas, E. S.; Chakrabarti, S.; Cook, T.; Paynter, I.; Saenz, E. J.; Wang, Z.; Woodcock, C. E.; Jupp, D. L. B.; Schaefer, M.; Newnham, G.

    2014-12-01

    Forest structure plays a critical role in the exchange of energy, carbon and water between land and atmosphere and nutrient cycle. We can provide detailed forest structure measurements of leaf and woody components with the Dual Wavelength Echidna® Lidar (DWEL), which acquires full-waveform scans at both near-infrared (NIR, 1064 nm) and shortwave infrared (SWIR, 1548 nm) wavelengths from simultaneous laser pulses. We collected DWEL scans at a broadleaf forest stand and a conifer forest stand at Harvard Forest in June 2014. Power returned from leaves is much lower than from woody materials such as trunks and branches at the SWIR wavelength due to the liquid water absorption by leaves, whereas returned power at the NIR wavelength is similar from both leaves and woody materials. We threshold a normalized difference index (NDI), defined as the difference between returned power at the two wavelengths divided by their sum, to classify each return pulse as a leaf or trunk/branch hit. We obtain leaf area index (LAI), woody area index (WAI) and vertical profiles of leaf and woody components directly from classified lidar hits without empirical wood-to-total ratios as are commonly used in optical methods of LAI estimation. Tree heights, diameter at breast height (DBH), and stem count density are the other forest structure parameters estimated from our DWEL scans. The separation of leaf and woody components in tandem with fine-scale forest structure measurements will benefit studies on carbon allocation of forest ecosystems and improve our understanding of the effects of forest structure on ecosystem functions. This research is supported by NSF grant, MRI-0923389

  3. Aircraft cybernetics

    Science.gov (United States)

    1977-01-01

    The use of computers for aircraft control, flight simulation, and inertial navigation is explored. The man-machine relation problem in aviation is addressed. Simple and self-adapting autopilots are described and the assets and liabilities of digital navigation techniques are assessed.

  4. Principal component analysis for surface reflection components and structure in the facial image and synthesis of the facial image in various ages

    Science.gov (United States)

    Hirose, Misa; Toyota, Saori; Ojima, Nobutoshi; Ogawa-Ochiai, Keiko; Tsumura, Norimichi

    2015-03-01

    In this paper, principal component analysis is applied to pigmentation distributions, surface reflectance components and facial landmarks in the whole facial images to obtain feature values. Furthermore, the relationship between the obtained feature vectors and age is estimated by multiple regression analysis to modulate facial images in woman of ages 10 to 70. In our previous work, we analyzed only pigmentation distributions and the reproduced images looked younger than the reproduced age by the subjective evaluation. We considered that this happened because we did not modulate the facial structures and detailed surfaces such as wrinkles. By analyzing landmarks represented facial structures and surface reflectance components, we analyzed the variation of facial structures and fine asperity distributions as well as pigmentation distributions in the whole face. As a result, our method modulate the appearance of a face by changing age more appropriately.

  5. Development of New Material for Fast Repair of Aircraft Structure%一种飞机结构快速修理新材料的研究

    Institute of Scientific and Technical Information of China (English)

    魏东; 韩斐; 刘成武

    2011-01-01

    光固化复合材料修理补片是一种用于飞机结构快速修理的新材料。运用光敏树脂浸渍纤维增强材料制成了预浸料修理补片,采用正交设计方法确定了制备补片的最佳工艺条件,进而对补片的相关特性进行了分析与实验;最终通过模拟某歼击机机翼下蒙皮应力水平最高处的试验;得出结论:使用该材料对飞机结构进行修理所需设备少、结构增重小、修补强度高、通用性强,可适用于多种材质、多种损伤模式下复杂结构的快速修理。%Light-cured complex material repair patch is a kind of new fast repair material for aircraft structure. A reinforcing material of light-sensitive resin impregnated fiber was used to make a flexible prepare repair patch. Orthogonal design was applied in determining the best technical condition to fabricate the patch, and the characteristic of the patch was analyzed. The experiment of aircraft under wing covering stress with the patch showed that the patch for aircraft structure repair has the features of fewer types of equipment needed, light structural weight, high repair strength, and strong universal property, which is suitable for complex structure fast repair with various material and multiple damage models.

  6. Strength Evaluation System for Aircraft Panel Structures Based on MSC.Patran%基于MSC.Patran的飞机壁板结构强度校核系统

    Institute of Scientific and Technical Information of China (English)

    汤超; 乔玉炜

    2012-01-01

    After getting the result from FEA in the aircraft panel structure model, one should add the engineering calculate method into this result to get the final strength evaluation for this panel structures. To implement the strength evaluation system for aircraft panel structures by modularization method, a program based on commercial software MSC. Patran is developed by using PCL language provided by MSC. Patran and journal file. The program is accomplished with start-up file, user self-defined menu and graphical interface, automatically running the analysis and reading results methods. Several typical cases are analyzed by the program and the results showed that the program can not only meet the variety requirement of aircraft panel structure evaluation, but also improve the efficiencies.%在得到飞机璧板结构的有限元分析结果之后,需要利用工程方法对此计算结果进行评估,最终得到壁板结构的强度评估结果.以有限元软件MSC.Patran为平台,利用其二次开发语言PCL( PATRAN Command Language),通过自动加载编译函数文件、用户自定义菜单和图形界面和读取结果等技术,开发了飞机壁板结构强度校核系统.使用此系统对某些典型的壁板结构案例进行了分析,结果表明该程序不仅能够满足较大范围内的各种飞机壁板结构的强度校核要求,而且还可以大大提高飞机设计者的工作效率.

  7. Two-Component Structure of the Hbeta Broad-Line Region in Quasars. I. Evidence from Spectral Principal Component Analysis

    CERN Document Server

    Hu, Chen; Ho, Luis C; Ferland, Gary J; Baldwin, Jack A; Wang, Ye

    2012-01-01

    We report on a spectral principal component analysis (SPCA) of a sample of 816 quasars, selected to have small Fe II velocity shifts with spectral coverage in the rest wavelength range 3500--5500 \\AA. The sample is explicitly designed to mitigate spurious effects on SPCA induced by Fe II velocity shifts. We improve the algorithm of SPCA in the literature and introduce a new quantity, \\emph{the fractional-contribution spectrum}, that effectively identifies the emission features encoded in each eigenspectrum. The first eigenspectrum clearly records the power-law continuum and very broad Balmer emission lines. Narrow emission lines dominate the second eigenspectrum. The third eigenspectrum represents the Fe II emission and a component of the Balmer lines with kinematically similar intermediate velocity widths. Correlations between the weights of the eigenspectra and parametric measurements of line strength and continuum slope confirm the above interpretation for the eigenspectra. Monte Carlo simulations demonstr...

  8. Numerical modeling and experimental validation of the acoustic transmission of aircraft's double-wall structures including sound package

    Science.gov (United States)

    Rhazi, Dilal

    In the field of aeronautics, reducing the harmful effects of acoustics constitutes a major concern at the international level and justifies the call for further research, particularly in Canada where aeronautics is a key economic sector, which operates in a context of global competition. Aircraft sidewall structure is usually of a double wall construction with a curved ribbed metallic skin and a lightweight composite or sandwich trim separated by a cavity filled with a noise control treatment. The latter is of a great importance in the transport industry, and continues to be of interest in many engineering applications. However, the insertion loss noise control treatment depends on the excitation of the supporting structure. In particular, Turbulent Boundary Layer is of interest to several industries. This excitation is difficult to simulate in laboratory conditions, given the prohibiting costs and difficulties associated with wind tunnel and in-flight tests. Numerical simulation is the only practical way to predict the response to such excitations and to analyze effects of design changes to the response to such excitation. Another kinds of excitations encountered in industrial are monopole, rain on the Roof and diffuse acoustic field. Deterministic methods can calculate in each point the spectral response of the system. Most known are numerical methods such as finite elements and boundary elements methods. These methods generally apply to the low frequency where modal behavior of the structure dominates. However, the high limit of calculation in frequency of these methods cannot be defined in a strict way because it is related to the capacity of data processing and to the nature of the studied mechanical system. With these challenges in mind, and with limitations of the main numerical codes on the market, the manufacturers have expressed the need for simple models immediately available as early as the stage of preliminary drafts. This thesis represents an attempt

  9. Experimental shielding evaluation of the radiation protection provided by the structurally significant components of residential structures.

    Science.gov (United States)

    Dickson, E D; Hamby, D M

    2014-03-01

    The human health and environmental effects following a postulated accidental release of radioactive material to the environment have been a public and regulatory concern since the early development of nuclear technology. These postulated releases have been researched extensively to better understand the potential risks for accident mitigation and emergency planning purposes. The objective of this investigation is to provide an updated technical basis for contemporary building shielding factors for the US housing stock. Building shielding factors quantify the protection from ionising radiation provided by a certain building type. Much of the current data used to determine the quality of shielding around nuclear facilities and urban environments is based on simplistic point-kernel calculations for 1950s era suburbia and is no longer applicable to the densely populated urban environments realised today. To analyse a building's radiation shielding properties, the ideal approach would be to subject a variety of building types to various radioactive sources and measure the radiation levels in and around the building. While this is not entirely practicable, this research analyses the shielding effectiveness of ten structurally significant US housing-stock models (walls and roofs) important for shielding against ionising radiation. The experimental data are used to benchmark computational models to calculate the shielding effectiveness of various building configurations under investigation from two types of realistic environmental source terms. Various combinations of these ten shielding models can be used to develop full-scale computational housing-unit models for building shielding factor calculations representing 69.6 million housing units (61.3%) in the United States. Results produced in this investigation provide a comparison between theory and experiment behind building shielding factor methodology.

  10. 某机载电子设备总体结构设计%Structure Design of Airborne Electronic Equipment for a Certain Aircraft

    Institute of Scientific and Technical Information of China (English)

    南雁; 郭建平; 张娅妮

    2011-01-01

    从结构设计角度出发,根据航空平台的工作模式和环境空间要求,针对某机载电子设备的标准化设计、热设计、电磁兼容性设计、防冲击、振动、"三防"设计等方面进行了论述.结合型号设计的工程经验,以航空电子设备结构设计的特点和原则为重点,对机载电子设备的结构设计进行了阐述,通过合理的布局设计和仿真计算来实现结构设计要求.介绍机载电子设备结构设计的经验,可供同行参考.%From the point of structure design,according to work and environment requisition for the aircraft flat ,described delailed such as the standardization, heat, EMC,impact and vibration prevention,three proofing designing for a certain aircraft. Focus on the characteristic and principle for aeronauticat electronic equipment,expatiate the structure design from Many- sided ,and guidance thc structure design by logical position and simulation with engineering experience. Pool the experience for structure design and offer the experience for craft brother discuss.

  11. Structural components of the nuclear body in nuclei of Allium cepa cells

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Nuclear bodies have long been noted in interphase nuclei of plant cells,but their structural component,origin and function are still unclear by now.The present work showed in onion cells the nuclear bodies appeared as a spherical structure about 0.3 to 0.8 μm in diameter.They possibly were formed in nucleolus and subsequently released,and entered into nucleoplasm.Observation through cytochemical staining method at the ultrastructural level confirmed that nuclear bodies consisted of ribonucleoproteins (RNPs) and silver-stainable proteins.Immunocytochemical results revealed that nuclear bodies contained no DNA and ribosomal gene transcription factor (UBF).Based on these data,we suggested that nuclear bodies are not related to the ribosome or other gene transcription activities,instead they may act as subnuclear structures for RNPs transport from nucleolus to cytoplasm,and may also be involved in splicing of pre-mRNAs.

  12. The structure of bovine complement component 3 reveals the basis for thioester function

    DEFF Research Database (Denmark)

    Fredslund, Folmer; Jenner, Lasse Bohl; Husted, Lise Bjerre;

    2006-01-01

    The third component of complement (C3) is a 190 kDa glycoprotein essential for eliciting the complement response. The protein consists of two polypeptide chains (α and β) held together with a single disulfide bridge. The β-chain is made up of six MG domains of which one of which is shared...... but not in C5) is cleaved during complement activation. This mediates covalent attachment of the activated C3b to immune complexes and invading microorganisms hereby opsonising the target. We present the structure of bovine C3 determined at 3 Å resolution. The structure shows that the ester is deeply buried...... activation. This rearrangement is proposed to be the basis for the high reactivity of the thioester group. A strictly conserved glutamate is suggested to function catalytically in thioester proteins. Structure based design of inhibitors of C3 activation may target a conserved pocket between the α- and the β...

  13. Secondary structure, a missing component of sequence-based minimotif definitions.

    Directory of Open Access Journals (Sweden)

    David P Sargeant

    Full Text Available Minimotifs are short contiguous segments of proteins that have a known biological function. The hundreds of thousands of minimotifs discovered thus far are an important part of the theoretical understanding of the specificity of protein-protein interactions, posttranslational modifications, and signal transduction that occur in cells. However, a longstanding problem is that the different abstractions of the sequence definitions do not accurately capture the specificity, despite decades of effort by many labs. We present evidence that structure is an essential component of minimotif specificity, yet is not used in minimotif definitions. Our analysis of several known minimotifs as case studies, analysis of occurrences of minimotifs in structured and disordered regions of proteins, and review of the literature support a new model for minimotif definitions that includes sequence, structure, and function.

  14. Structural parameter for estimating durability of composite materials with polymer components in strong electric fields

    Science.gov (United States)

    Minakova, N. N.; Ushakov, V. Ya.

    2016-11-01

    The purpose of the present work is to reveal and to substantiate the structural parameter for estimation of the durability of composite materials with polymeric components in strong electric fields. Rubbers filled with technical carbon are chosen as objects of research. They possess almost zero water absorption, resistance to aggressive media, high electrical and mechanical strengths, capability of acquiring practically any form, etc. Because of this, they are widely used in high-voltage electrophysics and electrical engineering. Composite materials are represented by an equivalent circuit of a series-parallel connection of a set of individual contacts conductive phase-dielectric-conductive phase formed by an electroconductive grid. The processes in the materials are considered on three hierarchical levels: individual contact conductive phase-dielectric-conductive phase, distribution of the set of individual contacts over their properties taking into account the dispersion of their parameters depending on the employed initial components, macrostructural level—the electricoconductive grid imbedded into a polymer matrix. As a result of our investigations, the structural parameter—the entropy of the textural parameter that can be used to estimate the durability of composite materials with polymer components in strong electric fields—has been chosen.

  15. Components of Appearance in the Structure of Perception of Visual Representations of Age

    Directory of Open Access Journals (Sweden)

    Shkurko T.A.

    2015-12-01

    Full Text Available The article discusses the problem of perception of age (one’s own and that of other people, which is regarded as a special case of social perception. The aim of this study was to analyze the components of another person’s appearance in the structure of perception of visual representations of age. For these purposes the authors created a special technique, “Identifying Age through Photo Visualization” (Shkurko T.A., Nikolaeva E. G.. The study enrolled 20 individuals (10 men, 10 women aged 18 to 58 years as “models” (i.e. objects of perception and 60 individuals (47 women and 13 men aged 18 to 77 years as subjects of perception. The paper shows that in the structure of perception of visual representations of age the most important are stable, moderately stable and dynamic components of appearance, among which the stable parameters prevail. The face as the focus of the stable, moderately stable and dynamic components of appearance is the key element of appearance in one’s perception of other people’s age.

  16. Aircraft family design using enhanced collaborative optimization

    Science.gov (United States)

    Roth, Brian Douglas

    Significant progress has been made toward the development of multidisciplinary design optimization (MDO) methods that are well-suited to practical large-scale design problems. However, opportunities exist for further progress. This thesis describes the development of enhanced collaborative optimization (ECO), a new decomposition-based MDO method. To support the development effort, the thesis offers a detailed comparison of two existing MDO methods: collaborative optimization (CO) and analytical target cascading (ATC). This aids in clarifying their function and capabilities, and it provides inspiration for the development of ECO. The ECO method offers several significant contributions. First, it enhances communication between disciplinary design teams while retaining the low-order coupling between them. Second, it provides disciplinary design teams with more authority over the design process. Third, it resolves several troubling computational inefficiencies that are associated with CO. As a result, ECO provides significant computational savings (relative to CO) for the test cases and practical design problems described in this thesis. New aircraft development projects seldom focus on a single set of mission requirements. Rather, a family of aircraft is designed, with each family member tailored to a different set of requirements. This thesis illustrates the application of decomposition-based MDO methods to aircraft family design. This represents a new application area, since MDO methods have traditionally been applied to multidisciplinary problems. ECO offers aircraft family design the same benefits that it affords to multidisciplinary design problems. Namely, it simplifies analysis integration, it provides a means to manage problem complexity, and it enables concurrent design of all family members. In support of aircraft family design, this thesis introduces a new wing structural model with sufficient fidelity to capture the tradeoffs associated with component

  17. 77 FR 74883 - Aging Management of Stainless Steel Structures and Components in Treated Borated Water; Revision 1

    Science.gov (United States)

    2012-12-18

    ... COMMISSION Aging Management of Stainless Steel Structures and Components in Treated Borated Water; Revision 1... corrects License Renewal Interim Staff Guidance, LR-ISG-2011-01, ``Aging Management of Stainless Steel Structures and Components in Treated Borated Water,'' which was announced in the Federal Register on May...

  18. Prediction of UHPFRC panels thickness subjected to aircraft engine impact

    Directory of Open Access Journals (Sweden)

    Duc-Kien Thai

    2016-06-01

    Full Text Available In the practical design of nuclear building structures subjected to an aircraft crash, the structures are required to prevent scabbing and perforation. NEI 07-13 provided the formulas to predict the minimum reinforced concrete (RC wall thickness to prevent the local damage caused by aircraft engine impact. However, these formulas may not be suitable for predicting the thickness of the ultra-high performance fiber reinforced concrete (UHPFRC wall. In this study, the local damage of a UHPFRC wall caused by the impact of aircraft engine missile is investigated using a finite element program LS-DYNA. The structural components of the UHPFRC panel, aircraft engine model, and their contacts are fully modeled. The analysis results are verified with the test results. A parametric study with varying panel thickness, fiber type and content, and impact velocity is performed to investigate the local damage of the UHPFRC panel. Based on a comparison with the given formulas, the modified equations of Chang and Degen are proposed to predict the minimum wall thickness to prevent scabbing and perforation in the case in which the UHPFRC structure is used.

  19. A new process monitoring method based on noisy time structure independent component analysis

    Institute of Scientific and Technical Information of China (English)

    Lianfang Cai; Xuemin Tian

    2015-01-01

    Conventional process monitoring method based on fast independent component analysis (FastICA) cannot take the ubiquitous measurement noises into account and may exhibit degraded monitoring performance under the adverse effects of the measurement noises. In this paper, a new process monitoring approach based on noisy time structure ICA (NoisyTSICA) is proposed to solve such problem. A NoisyTSICA algorithm which can consider the measurement noises explicitly is firstly developed to estimate the mixing matrix and extract the independent components (ICs). Subsequently, a monitoring statistic is built to detect process faults on the basis of the recur-sive kurtosis estimations of the dominant ICs. Lastly, a contribution plot for the monitoring statistic is constructed to identify the fault variables based on the sensitivity analysis. Simulation studies on the continuous stirred tank reactor system demonstrate that the proposed NoisyTSICA-based monitoring method outperforms the conven-tional FastICA-based monitoring method.

  20. Structural design of cryogenic component support for EAST (HT-7U)

    Institute of Scientific and Technical Information of China (English)

    CHEN Xian-Zhong; WU Song-Tao

    2005-01-01

    EAST is a full superconducting tokamak with an elongated plasma cross-section. It consists of superconducting poloidal field (PF) magnet system, toroidal field (TF) magnet system, vacuum vessel with inner parts, ther mal shields and cryostat vessel. The mission of the project is to widely investigate both physics and technologies of advanced tokamak operations, especially the mechanism of power and particle handling for steady-state operations.The cryogenic component is mainly composed of superconducting TF and superconducting PF coils that ensure the ability of sustaining magnetic field for plasma confinement, control and shaping in steady-state. This report describes the process of the structure design of cryogenic component support for EAST.

  1. Analysis of complex elastic structures by a Rayleigh-Ritz component modes method using Lagrange multipliers. Ph.D. Thesis

    Science.gov (United States)

    Klein, L. R.

    1974-01-01

    The free vibrations of elastic structures of arbitrary complexity were analyzed in terms of their component modes. The method was based upon the use of the normal unconstrained modes of the components in a Rayleigh-Ritz analysis. The continuity conditions were enforced by means of Lagrange Multipliers. Examples of the structures considered are: (1) beams with nonuniform properties; (2) airplane structures with high or low aspect ratio lifting surface components; (3) the oblique wing airplane; and (4) plate structures. The method was also applied to the analysis of modal damping of linear elastic structures. Convergence of the method versus the number of modes per component and/or the number of components is discussed and compared to more conventional approaches, ad-hoc methods, and experimental results.

  2. Using structural information to change the phosphotransfer specificity of a two-component chemotaxis signalling complex.

    Directory of Open Access Journals (Sweden)

    Christian H Bell

    2010-02-01

    Full Text Available Two-component signal transduction pathways comprising histidine protein kinases (HPKs and their response regulators (RRs are widely used to control bacterial responses to environmental challenges. Some bacteria have over 150 different two-component pathways, and the specificity of the phosphotransfer reactions within these systems is tightly controlled to prevent unwanted crosstalk. One of the best understood two-component signalling pathways is the chemotaxis pathway. Here, we present the 1.40 A crystal structure of the histidine-containing phosphotransfer domain of the chemotaxis HPK, CheA(3, in complex with its cognate RR, CheY(6. A methionine finger on CheY(6 that nestles in a hydrophobic pocket in CheA(3 was shown to be important for the interaction and was found to only occur in the cognate RRs of CheA(3, CheY(6, and CheB(2. Site-directed mutagenesis of this methionine in combination with two adjacent residues abolished binding, as shown by surface plasmon resonance studies, and phosphotransfer from CheA(3-P to CheY(6. Introduction of this methionine and an adjacent alanine residue into a range of noncognate CheYs, dramatically changed their specificity, allowing protein interaction and rapid phosphotransfer from CheA(3-P. The structure presented here has allowed us to identify specificity determinants for the CheA-CheY interaction and subsequently to successfully reengineer phosphotransfer signalling. In summary, our results provide valuable insight into how cells mediate specificity in one of the most abundant signalling pathways in biology, two-component signal transduction.

  3. Research on MA700 Aircraft Work Breakdown Structure Method%MA700飞机工作分解结构方法研究

    Institute of Scientific and Technical Information of China (English)

    肖君

    2014-01-01

    This paper introduces the concept of work breakdown structure and its application in the aviation field ,and puts forward the corresponding solutions to problems that MA 700 aircraft is likely to encounter .%介绍了项目工作分解的概念,以及航空领域的应用情况。针对M A700飞机可能遇到的问题,提出相应的解决思路。

  4. Structure and assembly of the essential RNA ring component of a viral DNA packaging motor

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Fang; Lu, Changrui; Zhao, Wei; Rajashankar, Kanagalaghatta R.; Anderson, Dwight L.; Jardine, Paul J.; Grimes, Shelley; Ke, Ailong (Cornell); (UMM)

    2011-07-25

    Prohead RNA (pRNA) is an essential component in the assembly and operation of the powerful bacteriophage {psi}29 DNA packaging motor. The pRNA forms a multimeric ring via intermolecular base-pairing interactions between protomers that serves to guide the assembly of the ring ATPase that drives DNA packaging. Here we report the quaternary structure of this rare multimeric RNA at 3.5 {angstrom} resolution, crystallized as tetrameric rings. Strong quaternary interactions and the inherent flexibility helped rationalize how free pRNA is able to adopt multiple oligomerization states in solution. These characteristics also allowed excellent fitting of the crystallographic pRNA protomers into previous prohead/pRNA cryo-EM reconstructions, supporting the presence of a pentameric, but not hexameric, pRNA ring in the context of the DNA packaging motor. The pentameric pRNA ring anchors itself directly to the phage prohead by interacting specifically with the fivefold symmetric capsid structures that surround the head-tail connector portal. From these contacts, five RNA superhelices project from the pRNA ring, where they serve as scaffolds for binding and assembly of the ring ATPase, and possibly mediate communication between motor components. Construction of structure-based designer pRNAs with little sequence similarity to the wild-type pRNA were shown to fully support the packaging of {psi}29 DNA.

  5. Crystal structure of the terminal oxygenase component of cumene dioxygenase from Pseudomonas fluorescens IP01.

    Science.gov (United States)

    Dong, Xuesong; Fushinobu, Shinya; Fukuda, Eriko; Terada, Tohru; Nakamura, Shugo; Shimizu, Kentaro; Nojiri, Hideaki; Omori, Toshio; Shoun, Hirofumi; Wakagi, Takayoshi

    2005-04-01

    The crystal structure of the terminal component of the cumene dioxygenase multicomponent enzyme system of Pseudomonas fluorescens IP01 (CumDO) was determined at a resolution of 2.2 A by means of molecular replacement by using the crystal structure of the terminal oxygenase component of naphthalene dioxygenase from Pseudomonas sp. strain NCIB 9816-4 (NphDO). The ligation of the two catalytic centers of CumDO (i.e., the nonheme iron and Rieske [2Fe-2S] centers) and the bridging between them in neighboring catalytic subunits by hydrogen bonds through a single amino acid residue, Asp231, are similar to those of NphDO. An unidentified external ligand, possibly dioxygen, was bound at the active site nonheme iron. The entrance to the active site of CumDO is different from the entrance to the active site of NphDO, as the two loops forming the lid exhibit great deviation. On the basis of the complex structure of NphDO, a biphenyl substrate was modeled in the substrate-binding pocket of CumDO. The residues surrounding the modeled biphenyl molecule include residues that have already been shown to be important for its substrate specificity by a number of engineering studies of biphenyl dioxygenases.

  6. A cold component and the complex velocity structure of DLA1331+170

    CERN Document Server

    Carswell, R F; Wolfe, A M; Murphy, M T

    2010-01-01

    [ABRIDGED] We examine the velocity structure in the gas associated with \\ion{H}{1} in the damped Ly$\\alpha$ absorption system at redshift $z=1.7764$ towards the QSO $1331+170$ using 21cm data, optical and STIS spectra. We find at least two, and possibly three, components showing \\ion{C}{1} lines. One of these has Doppler parameter $b=0.55${\\kms}, corresponding to a kinetic temperature of 220K if the broadening is thermal. We re-examine the H$_2$ analysis undertaken by \\citet{Cui05} using the neutral carbon velocity structure, and find a model which is, consistent with a mixture of collisional and background radiation excitation of the observed H$_2$ rotational levels. For singly ionized heavy elements we find eight components covering a velocity range of $\\sim 110$ {\\kms}. The \\ion{H}{1} structure is expected to follow some combination of the singly ionized and neutral gas, but the 21cm absorption profile is considerably different. This may be because of the different extent and brightness distributions of th...

  7. Mining the physical infrastructure: Opportunities, barriers and interventions in promoting structural components reuse.

    Science.gov (United States)

    Iacovidou, Eleni; Purnell, Phil

    2016-07-01

    Construction is the most resource intensive sector in the world. It consumes more than half of the total global resources; it is responsible for more than a third of the total global energy use and associated emissions; and generates the greatest and most voluminous waste stream globally. Reuse is considered to be a material and carbon saving practice highly recommended in the construction sector as it can address both waste and carbon emission regulatory targets. This practice offers the possibility to conserve resources through the reclamation of structural components and the carbon embedded in them, as well as opportunities for the development of new business models and the creation of environmental, economic, technical and social value. This paper focuses on the identification and analysis of existing interventions that can promote the reuse of construction components, and outlines the barriers and opportunities arising from this practice as depicted from the global literature. The main conclusions that derive from this study are that the combination of incentives that promote reuse of construction components and recycling of the rest of the construction materials with the provision of specialised education, skills and training would transform the way construction sector currently operates and create opportunities for new business development. Moreover, a typology system developed based on the properties and lifetime of construction components is required in order to provide transparency and guidance in the way construction components are used and reused, in order to make them readily available to designers and contractors. Smart technologies carry the potential to aid the development and uptake of this system by enabling efficient tracking, storage and archiving, while providing information relevant to the environmental and economic savings that can be regained, enabling also better decision-making during construction and deconstruction works. However, further

  8. The thematic structure of passenger comfort experience and its relationship to the context features in the aircraft cabin.

    Science.gov (United States)

    Ahmadpour, Naseem; Lindgaard, Gitte; Robert, Jean-Marc; Pownall, Bernard

    2014-01-01

    This paper describes passenger comfort as an experience generated by the cabin interior features. The findings of previous studies are affirmed regarding a set of 22 context features. Passengers experience a certain level of comfort when these features impact their body and elicit subjective perceptions. New findings characterise these perceptions in the form of eight themes and outline their particular eliciting features. Comfort is depicted as a complex construct derived by passengers' perceptions beyond the psychological (i.e. peace of mind) and physical (i.e. physical well-being) aspects, and includes perceptual (e.g. proxemics) and semantic (e.g. association) aspects. The seat was shown to have a focal role in eliciting seven of those themes and impacting comfort through its diverse characteristics. In a subsequent study, a group of aircraft cabin interior designers highlighted the possibility of employing the eight themes and their eliciting features as a framework for design and evaluation of new aircraft interiors.

  9. Multiparameter radar and aircraft based studies of microphysical, kinematic, and electrical structure of convective clouds during CaPE

    Science.gov (United States)

    Bringi, V. N.

    1994-03-01

    Two storms from the 9 August, 1991 CaPE case were analyzed in-depth focusing on multiparameter radar signature evolution over 60 min. in coordination with 24 aircraft penetrations which provided particle image and electric field data together with vertical air motion, cloud water and other state parameters. A total of five discrete 'cells' were identified in the two storms and their life cycle fully documented. Collaboration with South Dakota School of Mines and University of Alabama at Huntsville has resulted in a full integration of aircraft image and field mill data (from SDSM&T T-28 aircraft) with vertical air motion from dual-Doppler wind synthesis (UAH). The cellular evolution starts with a warm rain phase where updrafts and a very low concentration of large drops dominate the cloud. As the supercooled drops rise in the updraft they freeze and acquire a water-coat possibly by collisions with other liquid drops. The multi-parameter radar signatures clearly identify this mixed-phase zone. The cloud thereafter gets electrified which may intensify to produce lightning depending on cloud vertical growth, and generation of updraft/ downdrafts.

  10. Towards Prognostics for Electronics Components

    Data.gov (United States)

    National Aeronautics and Space Administration — Electronics components have an increasingly critical role in avionics systems and in the development of future aircraft systems. Prognostics of such components is...

  11. Effects of inulin on the structure and emulsifying properties of protein components in dough.

    Science.gov (United States)

    Liu, Juan; Luo, Denglin; Li, Xuan; Xu, Baocheng; Zhang, Xiaoyu; Liu, Jianxue

    2016-11-01

    High-purity gliadin, glutenin and gluten fractions were extracted from wheat gluten flour. To investigate the effects of three types of inulin with different degrees of polymerization (DP) on the emulsifying properties, disulfide contents, secondary structures and microstructures of these fractions, Turbidimetry, spectrophotometer, Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) were used in this study. The results showed that the emulsifying activity of gliadin was higher than that of glutenin and gluten, but its emulsion stability was lower than that of glutenin. Adding inulin increased the emulsifying activity of the three protein fractions and emulsion stability of gliadin and gluten, but decreased the emulsion stability of glutenin and disulfide bond contents of glutenin and gluten. In the presence of inulin, the α-helical structure of the three proteins had no significant change, whereas the β-turn structure decreased and β-sheet structure increased. The SEM images showed that inulin had the most significant effect on the glutenin microstructure. In general, inulin with a higher DP had greater effects on the structure and emulsifying properties of protein components in dough.

  12. Structure, dynamics, evolution, and function of a major scaffold component in the nuclear pore complex.

    Science.gov (United States)

    Sampathkumar, Parthasarathy; Kim, Seung Joong; Upla, Paula; Rice, William J; Phillips, Jeremy; Timney, Benjamin L; Pieper, Ursula; Bonanno, Jeffrey B; Fernandez-Martinez, Javier; Hakhverdyan, Zhanna; Ketaren, Natalia E; Matsui, Tsutomu; Weiss, Thomas M; Stokes, David L; Sauder, J Michael; Burley, Stephen K; Sali, Andrej; Rout, Michael P; Almo, Steven C

    2013-04-02

    The nuclear pore complex, composed of proteins termed nucleoporins (Nups), is responsible for nucleocytoplasmic transport in eukaryotes. Nuclear pore complexes (NPCs) form an annular structure composed of the nuclear ring, cytoplasmic ring, a membrane ring, and two inner rings. Nup192 is a major component of the NPC's inner ring. We report the crystal structure of Saccharomyces cerevisiae Nup192 residues 2-960 [ScNup192(2-960)], which adopts an α-helical fold with three domains (i.e., D1, D2, and D3). Small angle X-ray scattering and electron microscopy (EM) studies reveal that ScNup192(2-960) could undergo long-range transition between "open" and "closed" conformations. We obtained a structural model of full-length ScNup192 based on EM, the structure of ScNup192(2-960), and homology modeling. Evolutionary analyses using the ScNup192(2-960) structure suggest that NPCs and vesicle-coating complexes are descended from a common membrane-coating ancestral complex. We show that suppression of Nup192 expression leads to compromised nuclear transport and hypothesize a role for Nup192 in modulating the permeability of the NPC central channel.

  13. Trajectory Control for Very Flexible Aircraft

    Science.gov (United States)

    2006-10-30

    total airspeed and the classic aircraft longitudinal , lateral, and vertical velocity components are u positive out the nose, v positive out the right...wing flexibility is a secondary and minimal contribution to aircraft longitudinal motion. Using this assumption and the previous assumptions of

  14. Cycle Counting Methods of the Aircraft Engine

    Science.gov (United States)

    Fedorchenko, Dmitrii G.; Novikov, Dmitrii K.

    2016-01-01

    The concept of condition-based gas turbine-powered aircraft operation is realized all over the world, which implementation requires knowledge of the end-of-life information related to components of aircraft engines in service. This research proposes an algorithm for estimating the equivalent cyclical running hours. This article provides analysis…

  15. Structural Molecular Components of Septate Junctions in Cnidarians Point to the Origin of Epithelial Junctions in Eukaryotes

    KAUST Repository

    Ganot, P.

    2014-09-21

    Septate junctions (SJs) insure barrier properties and control paracellular diffusion of solutes across epithelia in invertebrates. However, the origin and evolution of their molecular constituents in Metazoa have not been firmly established. Here, we investigated the genomes of early branching metazoan representatives to reconstruct the phylogeny of the molecular components of SJs. Although Claudins and SJ cytoplasmic adaptor components appeared successively throughout metazoan evolution, the structural components of SJs arose at the time of Placozoa/Cnidaria/Bilateria radiation. We also show that in the scleractinian coral Stylophora pistillata, the structural SJ component Neurexin IV colocalizes with the cortical actin network at the apical border of the cells, at the place of SJs. We propose a model for SJ components in Cnidaria. Moreover, our study reveals an unanticipated diversity of SJ structural component variants in cnidarians. This diversity correlates with gene-specific expression in calcifying and noncalcifying tissues, suggesting specific paracellular pathways across the cell layers of these diploblastic animals.

  16. [Establishment of industry promotion technology system in Chinese medicine secondary exploitation based on "component structure theory"].

    Science.gov (United States)

    Cheng, Xu-Dong; Feng, Liang; Zhang, Ming-Hua; Gu, Jun-Fei; Jia, Xiao-Bin

    2014-10-01

    The purpose of the secondary exploitation of Chinese medicine is to improve the quality of Chinese medicine products, enhance core competitiveness, for better use in clinical practice, and more effectively solve the patient suffering. Herbs, extraction, separation, refreshing, preparation and quality control are all involved in the industry promotion of Chinese medicine secondary exploitation of industrial production. The Chinese medicine quality improvement and industry promotion could be realized with the whole process of process optimization, quality control, overall processes improvement. Based on the "component structure theory", "multi-dimensional structure & process dynamic quality control system" and systematic and holistic character of Chinese medicine, impacts of whole process were discussed. Technology systems of Chinese medicine industry promotion was built to provide theoretical basis for improving the quality and efficacy of the secondary development of traditional Chinese medicine products.

  17. Fungal glucosylceramides: from structural components to biologically active targets of new antimicrobials

    Directory of Open Access Journals (Sweden)

    Leonardo eNimrichter

    2011-10-01

    Full Text Available The first work reporting synthesis of glucosylceramide (cerebrin, GlcCer by yeasts was published in 1930. During approximately 70 years members of this class of glycosphingolipids (GSL were considered merely structural components of plasma membrane in fungi. However, in the last decade GlcCer was reported to be involved with fungal growth, differentiation, virulence, immunogenicity and lipid raft architecture in at least two human pathogens. Fungal GlcCer are structurally distinct from their mammalian counterparts and enriched at the cell wall, which makes this molecule an effective target for antifungal activity of specific ligands (peptides and antibodies to GlcCer. Therefore, GSL are promising targets for new drugs to combat fungal diseases. This review discusses the most recent information on biosynthesis and role of GlcCer in fungal pathogens.

  18. Carbohydrate components and crystalline structure of organosolv hemp (Cannabis sativa L.) bast fibers pulp.

    Science.gov (United States)

    Gümüşkaya, Esat; Usta, Mustafa; Balaban, Mualla

    2007-02-01

    Changes in carbohydrate components and crystalline structure of hemp bast fibers during organosolv pulping were investigated by X-ray diffractometry, FT-IR spectroscopy and high performance liquid chromatography (HPLC). The reasons for defibrillation and beating problems with organosolv hemp bast fiber pulp were investigated with reference to these properties of pulp samples. Hemp bast fibers and organosolv pulp samples had low hemicellulose contents and high cellulose contents. It was found that the disorder parameter of cellulose in hemp bast fibers was very low, when crystalline cellulose ratio was high and the crystalline structure of cellulose in hemp bast fibers was very stable. These properties affected defibrillation and beating of organosolv hemp bast fibers pulp negatively.

  19. Star PolyMOCs with Diverse Structures, Dynamics, and Functions by Three-Component Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yufeng [Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue Cambridge MA USA; Department of Chemistry, the University of Hong Kong, Pokfulam Road Hong Kong SAR China; Gu, Yuwei [Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue Cambridge MA USA; Keeler, Eric G. [Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue Cambridge MA USA; Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, 77 Massachusetts Avenue Cambridge MA USA; Park, Jiwon V. [Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue Cambridge MA USA; Griffin, Robert G. [Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue Cambridge MA USA; Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, 77 Massachusetts Avenue Cambridge MA USA; Johnson, Jeremiah A. [Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue Cambridge MA USA

    2016-12-05

    We report star polymer metal–organic cage (polyMOC) materials whose structures, mechanical properties, functionalities, and dynamics can all be precisely tailored through a simple three-component assembly strategy. The star polyMOC network is composed of tetra-arm star polymers functionalized with ligands on the chain ends, small molecule ligands, and palladium ions; polyMOCs are formed via metal–ligand coordination and thermal annealing. The ratio of small molecule ligands to polymer-bound ligands determines the connectivity of the MOC junctions and the network structure. The use of large M12L24 MOCs enables great flexibility in tuning this ratio, which provides access to a rich spectrum of material properties including tunable moduli and relaxation dynamics.

  20. Star PolyMOCs with Diverse Structures, Dynamics, and Functions by Three-Component Assembly.

    Science.gov (United States)

    Wang, Yufeng; Gu, Yuwei; Keeler, Eric G; Park, Jiwon V; Griffin, Robert G; Johnson, Jeremiah A

    2017-01-02

    We report star polymer metal-organic cage (polyMOC) materials whose structures, mechanical properties, functionalities, and dynamics can all be precisely tailored through a simple three-component assembly strategy. The star polyMOC network is composed of tetra-arm star polymers functionalized with ligands on the chain ends, small molecule ligands, and palladium ions; polyMOCs are formed via metal-ligand coordination and thermal annealing. The ratio of small molecule ligands to polymer-bound ligands determines the connectivity of the MOC junctions and the network structure. The use of large M12 L24 MOCs enables great flexibility in tuning this ratio, which provides access to a rich spectrum of material properties including tunable moduli and relaxation dynamics.

  1. Metallized Coatings for Corrosion Control of Naval Ship Structures and Components.

    Science.gov (United States)

    1983-02-01

    Deutschen Normen n.d.; Petersen 1969; Hermanek 1978; Pratt and Whitney Aircraft Group 1968; Lyashenko et al. 1969a,b) have been devised that are based on a...Naval ships. Report DoD-STD-2138(SH). Washington, D.C. Deutschen Normen (German standard). n.d. Prufung Termisch Gesprtizler Metallischer Schichten

  2. Dissecting the molecular structure of the Orion B cloud: insight from principal component analysis

    Science.gov (United States)

    Gratier, Pierre; Bron, Emeric; Gerin, Maryvonne; Pety, Jérôme; Guzman, Viviana V.; Orkisz, Jan; Bardeau, Sébastien; Goicoechea, Javier R.; Le Petit, Franck; Liszt, Harvey; Öberg, Karin; Peretto, Nicolas; Roueff, Evelyne; Sievers, Albrech; Tremblin, Pascal

    2017-03-01

    Context. The combination of wideband receivers and spectrometers currently available in (sub-)millimeter observatories deliver wide-field hyperspectral imaging of the interstellar medium. Tens of spectral lines can be observed over degree wide fields in about 50 h. This wealth of data calls for restating the physical questions about the interstellar medium in statistical terms. Aims: We aim to gain information on the physical structure of the interstellar medium from a statistical analysis of many lines from different species over a large field of view, without requiring detailed radiative transfer or astrochemical modeling. Methods: We coupled a non-linear rescaling of the data with one of the simplest multivariate analysis methods, namely the principal component analysis, to decompose the observed signal into components that we interpret first qualitatively and then quantitatively based on our deep knowledge of the observed region and of the astrochemistry at play. Results: We identify three principal components, linear compositions of line brightness temperatures, that are correlated at various levels with the column density, the volume density and the UV radiation field. Conclusions: When sampling a sufficiently diverse mixture of physical parameters, it is possible to decompose the molecular emission in order to gain physical insight on the observed interstellar medium. This opens a new avenue for future studies of the interstellar medium. Based on observations carried out at the IRAM-30 m single-dish telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain).

  3. Structure of the poly-C9 component of the complement membrane attack complex.

    Science.gov (United States)

    Dudkina, Natalya V; Spicer, Bradley A; Reboul, Cyril F; Conroy, Paul J; Lukoyanova, Natalya; Elmlund, Hans; Law, Ruby H P; Ekkel, Susan M; Kondos, Stephanie C; Goode, Robert J A; Ramm, Georg; Whisstock, James C; Saibil, Helen R; Dunstone, Michelle A

    2016-02-04

    The membrane attack complex (MAC)/perforin-like protein complement component 9 (C9) is the major component of the MAC, a multi-protein complex that forms pores in the membrane of target pathogens. In contrast to homologous proteins such as perforin and the cholesterol-dependent cytolysins (CDCs), all of which require the membrane for oligomerisation, C9 assembles directly onto the nascent MAC from solution. However, the molecular mechanism of MAC assembly remains to be understood. Here we present the 8 Å cryo-EM structure of a soluble form of the poly-C9 component of the MAC. These data reveal a 22-fold symmetrical arrangement of C9 molecules that yield an 88-strand pore-forming β-barrel. The N-terminal thrombospondin-1 (TSP1) domain forms an unexpectedly extensive part of the oligomerisation interface, thus likely facilitating solution-based assembly. These TSP1 interactions may also explain how additional C9 subunits can be recruited to the growing MAC subsequent to membrane insertion.

  4. Evidence for a Meteoritic Component in Impact Melt Rock from the Chicxulub Structure

    Science.gov (United States)

    Koeberl, Christian; Sharpton, Virgil L.; Schuraytz, Benjamin C.; Shirey, Steven B.; Blum, Joel D.; Marin, Luis E.

    1994-01-01

    The Chicxulub structure in Yucatan, Mexico, has recently been recognized as a greater then 200-km-diameter multi-ring impact crater of K-T boundary age. Crystalline impact melt rocks and breccias from within the crater, which have compositions similar to those of normal continental crustal rocks and which show shock metamorphic effects, have been studied for trace element and Re-Os isotope compositions. Re-Os isotope systematics allow the sensitive and selective determination of an extraterrestrial component in impact-derived rocks. A melt rock sample shows elevated iridium concentrations, an osmium concentration of 25 ppb, and a low Os-187/Os-188 ratio of 0.113, which are incompatible with derivation from the continental crust. Even though the Os-187/Os-188 ratio is slightly lower than the range so far measured in meteorites, a mantle origin seems unlikely for mass balance reasons and because the cratering event is unlikely to have excavated mantle material. The data support the hypothesis of a heterogeneously distributed meteoritic component in the Chicxulub melt rock. A sample of impact glass from the Haitian K-T boundary at Beloc yielded about 0.1 ppb osmium and an Os-187/0s-188 ratio of 0.251, indicating the presence of a small meteoritic component in the impact ejecta as well.

  5. Advanced technology components for model GTP305-2 aircraft auxiliary power system. Final report 6 May 75-15 Jul 79

    Energy Technology Data Exchange (ETDEWEB)

    Kidwell, J.R.; Large, G.D.

    1980-02-01

    The GTP305-2 Advanced APU is a single shaft, all shaft power engine incorporating an axial-centrifugal compressor, a reverse flow annular combustor and a radial-axial turbine. Cycle analyses indicated a 10-percent high pressure compressor flow increase improved matching characteristics with the low pressure compressor. The combustion system is a reverse flow annular combustor with an air-assist/airblast fuel injection system. The radial-axial turbine stage is characterized by an integrally cast turbine rotor and a cast exhaust duct assembly. The Integrated Components Assembly (ICA) rig consists of the combustor and turbines with a dummy mass on the shaft to simulate the compressor. ICA testing was conducted to establish component performance at design operating conditions. ICA and cold air aerodynamic testing of the turbine stage and cooling flow effects, indicates design efficiency goals were exceeded. ICA test results, cold-air testing and combustion system parameters were input to the cycle model. Room temperature strain-control LCF tests were performed and results analyzed on a Weibull distribution. Data analysis indicated LCF life improvement was obtained through HIP and heat treatment.

  6. Discriminant analysis of principal components: a new method for the analysis of genetically structured populations

    Directory of Open Access Journals (Sweden)

    Balloux François

    2010-10-01

    Full Text Available Abstract Background The dramatic progress in sequencing technologies offers unprecedented prospects for deciphering the organization of natural populations in space and time. However, the size of the datasets generated also poses some daunting challenges. In particular, Bayesian clustering algorithms based on pre-defined population genetics models such as the STRUCTURE or BAPS software may not be able to cope with this unprecedented amount of data. Thus, there is a need for less computer-intensive approaches. Multivariate analyses seem particularly appealing as they are specifically devoted to extracting information from large datasets. Unfortunately, currently available multivariate methods still lack some essential features needed to study the genetic structure of natural populations. Results We introduce the Discriminant Analysis of Principal Components (DAPC, a multivariate method designed to identify and describe clusters of genetically related individuals. When group priors are lacking, DAPC uses sequential K-means and model selection to infer genetic clusters. Our approach allows extracting rich information from genetic data, providing assignment of individuals to groups, a visual assessment of between-population differentiation, and contribution of individual alleles to population structuring. We evaluate the performance of our method using simulated data, which were also analyzed using STRUCTURE as a benchmark. Additionally, we illustrate the method by analyzing microsatellite polymorphism in worldwide human populations and hemagglutinin gene sequence variation in seasonal influenza. Conclusions Analysis of simulated data revealed that our approach performs generally better than STRUCTURE at characterizing population subdivision. The tools implemented in DAPC for the identification of clusters and graphical representation of between-group structures allow to unravel complex population structures. Our approach is also faster than

  7. Free vibration analysis of civil engineering structures by component-wise models

    Science.gov (United States)

    Carrera, Erasmo; Pagani, Alfonso

    2014-09-01

    Higher-order beam models are used in this paper to carry out free vibration analysis of civil engineering structures. Refined kinematic fields are developed using the Carrera Unified Formulation (CUF), which allows for the implementation of any-order theory without the need for ad hoc formulations. The principle of virtual displacements in conjunction with the finite element method (FEM) is used to formulate stiffness and mass matrices in terms of fundamental nuclei. The nuclei depend neither on the adopted class of beam theory nor on the FEM approximation along the beam axis. This paper focuses on a particular class of CUF models that makes use of Lagrange polynomials to discretize cross-sectional displacement variables. This class of models are referred to as component-wise (CW) in recent works. According to the CW approach, each structural component (e.g. columns, walls, frame members, and floors) can be modeled by means of the same 1D formulation. A number of typical civil engineering structures (e.g. simple beams, arches, truss structures, and complete industrial and civil buildings) are analyzed and CW results are compared to classical beam theories (Euler-Bernoulli and Timoshenko), refined beam models based on Taylor-like expansions of the displacements on the cross-section, and classical solid/shell FEM solutions from the commercial code MSC Nastran. The results highlight the enhanced capabilities of the proposed formulation. It is in fact demonstrated that CW models are able to replicate 3D solid results with very low computational efforts.

  8. Identifying coordinative structure using principal component analysis based on coherence derived from linear systems analysis.

    Science.gov (United States)

    Wang, Xinguang; O'Dwyer, Nicholas; Halaki, Mark; Smith, Richard

    2013-01-01

    Principal component analysis is a powerful and popular technique for capturing redundancy in muscle activity and kinematic patterns. A primary limitation of the correlations or covariances between signals on which this analysis is based is that they do not account for dynamic relations between signals, yet such relations-such as that between neural drive and muscle tension-are widespread in the sensorimotor system. Low correlations may thus be obtained and signals may appear independent despite a dynamic linear relation between them. To address this limitation, linear systems analysis can be used to calculate the matrix of overall coherences between signals, which measures the strength of the relation between signals taking dynamic relations into account. Using ankle, knee, and hip sagittal-plane angles from 6 healthy subjects during ~50% of total variance in the data set, while with overall coherence matrices the first component accounted for > 95% of total variance. The results demonstrate that the dimensionality of the coordinative structure can be overestimated using conventional correlation, whereas a more parsimonious structure is identified with overall coherence.

  9. Asymmetric segregation of damaged cellular components in spatially structured multicellular organisms.

    Directory of Open Access Journals (Sweden)

    Charlotte Strandkvist

    Full Text Available The asymmetric distribution of damaged cellular components has been observed in species ranging from fission yeast to humans. To study the potential advantages of damage segregation, we have developed a mathematical model describing ageing mammalian tissue, that is, a multicellular system of somatic cells that do not rejuvenate at cell division. To illustrate the applicability of the model, we specifically consider damage incurred by mutations to mitochondrial DNA, which are thought to be implicated in the mammalian ageing process. We show analytically that the asymmetric distribution of damaged cellular components reduces the overall damage level and increases the longevity of the cell population. Motivated by the experimental reports of damage segregation in human embryonic stem cells, dividing symmetrically with respect to cell-fate, we extend the model to consider spatially structured systems of cells. Imposing spatial structure reduces, but does not eliminate, the advantage of asymmetric division over symmetric division. The results suggest that damage partitioning could be a common strategy for reducing the accumulation of damage in a wider range of cell types than previously thought.

  10. 民机典型前缘结构抗鸟撞分析研究%Study of Bird Impact Resistance for Typical Civil Aircraft Leading Edge Structure

    Institute of Scientific and Technical Information of China (English)

    何瑞

    2013-01-01

    为保障飞行安全,CCAR25部对民机结构抗鸟撞性能提出了严格的指令性要求,须对机翼前缘、平尾前缘和垂尾前缘等典型前缘结构进行鸟撞分析。鸟撞分析涉及到结构的动力学分析、鸟体的本构关系模拟、材料的高速非线性效应以及结构大变形等多方面因素的影响,相关的计算复杂,会耗费结构设计人员大量的精力和时间。通过采用经验公式和仿真分析方法对前缘结构抗鸟撞性能进行快速的分析,可达到对结构的抗鸟撞能力进行快速预估并从而指导设计的目的。%For flying safety, leading edge structures include wing leading edge horizontal leading edge and vertical leading edge, which are very typical structures in civil aircraft. Bird impact analysis has relations with the structure dynamic analysis the physical model of bird the high speed non-linear influences of material and the structure large displacements. It will cost many energies and much time to accurately analyze bird impact resistance's properties of the structure, and will reduce the work efficiency. In the paper, experienced formula and simulation to quickly an-alyze the bird impact resistance of the aircraft leading edge is employed, then according to the analysis estimates the structure's bird impact resistance, finally depending on the estimation we can quickly revise the design to achieve the aim at the analysis guiding design.

  11. Damage prognosis of adhesively-bonded joints in laminated composite structural components of unmanned aerial vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Farrar, Charles R [Los Alamos National Laboratory; Gobbato, Maurizio [UCSD; Conte, Joel [UCSD; Kosmatke, John [UCSD; Oliver, Joseph A [UCSD

    2009-01-01

    The extensive use of lightweight advanced composite materials in unmanned aerial vehicles (UAVs) drastically increases the sensitivity to both fatigue- and impact-induced damage of their critical structural components (e.g., wings and tail stabilizers) during service life. The spar-to-skin adhesive joints are considered one of the most fatigue sensitive subcomponents of a lightweight UAV composite wing with damage progressively evolving from the wing root. This paper presents a comprehensive probabilistic methodology for predicting the remaining service life of adhesively-bonded joints in laminated composite structural components of UAVs. Non-destructive evaluation techniques and Bayesian inference are used to (i) assess the current state of damage of the system and, (ii) update the probability distribution of the damage extent at various locations. A probabilistic model for future loads and a mechanics-based damage model are then used to stochastically propagate damage through the joint. Combined local (e.g., exceedance of a critical damage size) and global (e.g.. flutter instability) failure criteria are finally used to compute the probability of component failure at future times. The applicability and the partial validation of the proposed methodology are then briefly discussed by analyzing the debonding propagation, along a pre-defined adhesive interface, in a simply supported laminated composite beam with solid rectangular cross section, subjected to a concentrated load applied at mid-span. A specially developed Eliler-Bernoulli beam finite element with interlaminar slip along the damageable interface is used in combination with a cohesive zone model to study the fatigue-induced degradation in the adhesive material. The preliminary numerical results presented are promising for the future validation of the methodology.

  12. Floor Response Evaluation for Auxiliary Building Subjected to Aircraft Impact Loading

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Sang Shup; Hahm, Daegi; Choi, Inkil [Korea Atomic Energy Research institute, Daejeon (Korea, Republic of)

    2014-05-15

    These studies have been aimed to verify and ensure the safety of the targeted walls and structures especially in the viewpoint of the deterministic approach. However, a probabilistic safety assessment as well as deterministic approach for the damage of the internal component in the nuclear power plants (NPPs) subjected to aircraft crash is also needed. A probabilistic safety assessment for aircraft crash includes many uncertainties such as impact velocity, mass, impact location, shape, size, material etc. of aircraft. In this paper, an impact location was selected among the various parameters. This paper found the acceleration floor response spectra at specified locations (safety related components) on the target structure that assumed to be impact velocity 150m/s and maximum fuel for the specified aircraft model. In order to obtain the floor response in case of the crash with a various locations, the analyses for the auxiliary building subjected to aircraft impact were performed using Riera force history method and missile-target interaction method. The difference between responses in case of the building floor subjected to impact was occurred. Thus, in order to obtain the more accurate results, missile-target interaction method was used. This paper found the response at the selected point (node point No. 51). In order to probabilistic assessment for the safety related components, the assessment for a various parameters (velocity, mass, materials etc.) as well as impact locations should be needed.

  13. Complete primary structure of the major component myoglobin of California gray whale (Eschrichtius gibbosus).

    Science.gov (United States)

    Bogardt, R A; Dwulet, F E; Lehman, L D; Jones, B N; Gurd, F R

    1976-06-15

    The complete primary structure of the major component myoglobin from the California gray whale, Eschrichtius gibbosus, was determined by specific cleavage of the protein to obtain large peptides for degradation by the automatic sequenator. Cleavage at the two methionine residues of the apomyoglobin with cyanogen bromide and at the three arginine residues of the methyl acetimidated protein with trypsin resulted in three and four easily separable peptides, respectively, which when sequenced accounted for 85% of the primary structure. The remainder of the covalent structure was obtained by further digestion of the central cyanogen bromide peptide with trypsin and S. aureus strain V8 protease. This protein differs from that of the sperm whale, Physeter catodon, at 12 positions, from that of the common porpoise, Phocoena phocoena, and the Black Sea dolphin, Delphinus delphis, at 14 positions, and from that of the Amazon River dolphin, Inia geoffrensis, at 7 positions. All substitutions observed in this sequence fit easily into the tertiary structure of sperm whale myoglobin.

  14. Neuromelanins of human brain have soluble and insoluble components with dolichols attached to the melanic structure.

    Directory of Open Access Journals (Sweden)

    Mireille Engelen

    Full Text Available Neuromelanins (NMs are neuronal pigments of melanic-lipidic type which accumulate during aging. They are involved in protective and degenerative mechanisms depending on the cellular context, however their structures are still poorly understood. NMs from nine human brain areas were analyzed in detail. Elemental analysis led to identification of three types of NM, while infrared spectroscopy showed that NMs from neurons of substantia nigra and locus coeruleus, which selectively degenerate in Parkinson's disease, have similar structure but different from NMs from brain regions not targeted by the disease. Synthetic melanins containing Fe and bovine serum albumin were prepared to model the natural product and help clarifying the structure of NMs. Extensive nuclear magnetic resonance spectroscopy studies showed the presence of dolichols both in the soluble and insoluble parts of NM. Diffusion measurements demonstrated that the dimethyl sulfoxide soluble components consist of oligomeric precursors with MWs in the range 1.4-52 kDa, while the insoluble part contains polymers of larger size but with a similar composition. These data suggest that the selective vulnerability of neurons of substantia nigra and locus coeruleus in Parkinson's disease might depend on the structure of the pigment. Moreover, they allow to propose a pathway for NM biosynthesis in human brain.

  15. Smart Sensor System for NDE or Corrosion in Aging Aircraft

    Science.gov (United States)

    Bar-Cohen, Y.; Marzwell, N.; Osegueda, R.; Ferregut, C.

    1998-01-01

    The extension of the operation life of military and civilian aircraft rather than replacing them with new ones is increasing the probability of aircraft component failure as a result of aging. Aircraft that already have endured a long srvice life of more than 40 years are now being considered for another 40 years of service.

  16. Micro-mechanical damage accumulation in airframe materials and structural components

    Science.gov (United States)

    Tiku, Sanjay

    A simple and flexible ACPD probe design methodology incorporating current focusing technique was developed for on-line as well as off-line measurements in laboratory and industrial scale test environments. The effectiveness of the current focusing technique and the resulting three-dimensional control of the current density distribution was demonstrated. The ACPD technique was successfully used to obtain strain calibration and crack calibration curves in 7075 Al alloys. This also included quantifying the effect of residual stresses on ACPD signal. The smallest crack depth detected was 140 mum at 120 kHz, 5 amp. and 3000 gain. A quadratic relation was found to correlate crack depth with potential change. The ACPD sensors were installed on a F-18 aircraft undergoing full scale test at Canadair. The sensors were able to measure the response of the structure to spectrum loading. A crack was detected by the ACPD sensors only after 3400 SFH and it was established that ACPD probes were able to detect the crack long before (˜2500 SFH) any other established techniques utilized by DND/Canadair was able to detect the crack. The technique was successfully used to characterize short crack growth behaviour of naturally initiated fatigue cracks in Al alloys from 40 mum crack depth onwards. The cracks were semi-elliptical in shape and crack growth along the notch root was faster than crack growth into the specimen. The effect of various grain orientations on short crack growth behaviour was studied. The crack tip interactions with grain boundaries were shown to control the SCG behaviour of Al alloys even at notch root peak stresses close to yield stress of the material. This effect was less prominent at notch root peak stresses considerably higher than yield stresses. The fatigue crack growth rates were correlated with the SIF (K) calculated using Newman's model for thumb nail cracks. This correlation resulted in a very large scatter in the data. The fatigue crack growth rate data

  17. CAD System for Aircraft Structure Static Test Design%飞机结构静力试验 CAD 系统

    Institute of Scientific and Technical Information of China (English)

    侯同济; 张建锋; 滕申科

    2013-01-01

      飞机结构静力试验设计系统(Aircraft Structure Static Test Design System-ASSTDS)是用于全尺寸飞机结构静力试验设计的、图形交互式的计算机辅助设计(CAD)软件系统。本文介绍了基于面向对象技术完成的软件系统需求分析、功能分解和对象抽象,软件开发过程中建立的系统对象体系以及主要对象和它们之间的相互关系。飞机结构静力试验设计系统采用 VC++编程语言在 Windows 操作系统上开发完成的。%The ASSTDS system is a special graphical interactive CAD software for the aircraft structure static test design. The paper introduces the requesting analysis, function decomposing and object abstracting for the sofeware based on object-oriented technology and the object architecture in the software development. The main objects and their relationships are also described. ASSTDS is developed in the programming language VC++ on the Windows operation system.

  18. Development of Probabilistic Risk Assessment Procedure of Nuclear Power Plant under Aircraft Impact Loadings

    Energy Technology Data Exchange (ETDEWEB)

    Hahm, Daegi; Shin, Sangshup; Park, Jin Hee; Choi, Inkil [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    In this paper, the total technical roadmap and the procedure to assess the aircraft impact risk will be introduced. In the first year of the research project, 2012, we developed aircraft impact accident scenario and performed preliminary fragility analysis of the local failure of the targeted wall by aircraft impact. An aircraft impact event can be characterized by the appropriate load parameters (i. e., aircraft type, mass, velocity, angle of crash, etc.). Therefore, the reference parameter should be selected to represent each load effect in order to evaluate the capacity/fragility of SSCs using deterministic or probabilistic methods. This is similar to the use of the peak ground acceleration (PGA) to represent the ground motion spectrum of the earthquake in the seismic probabilistic risk assessment (SPRA) approach. We developed the methodology to decide on the reference parameter for the aircraft impact risk quantification among some reasonable candidates, which can represent many uncertain loading parameters. To detect the response and the damage of the target structure, missile-target interaction method and Riera's time-history analysis method have been used primarily in the aircraft impact research area. To define the reference loading parameter, we need to perform repetitive simulations for many analysis cases. Thus, we applied a revised version of Riera's method, which is appropriate for a simplified impact simulation. The target NPP to determine the reference parameter and evaluate the preliminary assessment of aircraft impact risk was selected among the typical Korean PWR NPPs. The response has been calculated for pre-stressed concrete containment buildings subjected to aircraft impact loading, and the responses according to each reference parameter have been analyzed. Recently, we also evaluated the floor response spectra for the locations of important components for the estimation of the failure probabilities and fragility functions of

  19. Relationship between structures of sprite streamers and inhomogeneity of preceding halos captured by high-speed camera during a combined aircraft and ground-based campaign

    Science.gov (United States)

    Takahashi, Y.; Sato, M.; Kudo, T.; Shima, Y.; Kobayashi, N.; Inoue, T.; Stenbaek-Nielsen, H. C.; McHarg, M. G.; Haaland, R. K.; Kammae, T.; Yair, Y.; Lyons, W. A.; Cummer, S. A.; Ahrns, J.; Yukman, P.; Warner, T. A.; Sonnenfeld, R. G.; Li, J.; Lu, G.

    2011-12-01

    The relationship between diffuse glows such as elves and sprite halos and subsequent discrete structure of sprite streamers is considered to be one of the keys to solve the mechanism causing a large variation of sprite structures. However, it's not easy to image at high frame rate both the diffuse and discrete structures simultaneously, since it requires high sensitivity, high spatial resolution and high signal-to-noise ratio. To capture the real spatial structure of TLEs without influence of atmospheric absorption, spacecraft would be the best solution. However, since the imaging observation from space is mostly made for TLEs appeared near the horizon, the range from spacecraft to TLEs becomes large, such as few thousand km, resulting in low spatial resolution. The aircraft can approach thunderstorm up to a few hundred km or less and can carry heavy high-speed cameras with huge size data memories. In the period of June 27 - July 10, 2011, a combined aircraft and ground-based campaign, in support of NHK Cosmic Shore project, was carried with two jet airplanes under collaboration between NHK (Japan Broadcasting Corporation) and universities. On 8 nights out of 16 standing-by, the jets took off from the airport near Denver, Colorado, and an airborne high speed camera captured over 40 TLE events at a frame rate of 8300 /sec. Here we introduce the time development of sprite streamers and the both large and fine structures of preceding halos showing inhomogeneity, suggesting a mechanism to cause the large variation of sprite types, such as crown like sprites.

  20. Dynamic Response Analysis of Storage Cask Lid Structure Subjected to Lateral Impact Load of Aircraft Engine Crash

    Energy Technology Data Exchange (ETDEWEB)

    Almomania, Belal; Kang, Hyun Gook [KAIST, Daejeon (Korea, Republic of); Lee, Sanghoon [Keimyung Univ., Daegu (Korea, Republic of)

    2015-10-15

    Several numerical methods and tests have been carried out to measure the capability of storage cask to withstand extreme impact loads. Testing methods are often constrained by cost, and difficulty in preparation for several impact conditions with different applied loads, and areas of impact. Instead, analytic method is an acceptable process that can easily apply different impact conditions for the evaluation of cask integrity. The aircraft engine impact is considered as one of the most critical impact accidents on the storage cask that significantly affects onto the lid closure system and may cause a considerable release of radioactive materials. This paper presents a method for evaluating the dynamic responses of one upper metal cask lid closure without impact limiters subjected to lateral impact of an aircraft engine with respect to variation of the impact velocity. An assessment method to predict damage response due to the lateral engine impact onto metal storage cask has been studied by using computer code LS-DYNA. The dynamic behavior of the lid movements was successfully calculated by utilizing a simplified finite element cask model, which showed a good agreement with the previous research. The simulation analyses results showed that no significant plastic deformation for bolts, lid, and the cask body. In this study, the lid opening and sliding displacements are considered as the major factors in initiating the leakage path. This analysis may be useful for evaluating the instantaneous leakage rates in a connection with the sliding and opening displacements between the lid and the flange to ensure that the radiological consequences caused by an aircraft engine crash accident during the storage phase are within the permissible level.

  1. Principal component and causal analysis of structural and acute in vitro toxicity data for nanoparticles.

    Science.gov (United States)

    Wang, Xue Z; Yang, Yang; Li, Ruifa; McGuinnes, Catherine; Adamson, Janet; Megson, Ian L; Donaldson, Kenneth

    2014-08-01

    Structure toxicity relationship analysis was conducted using principal component analysis (PCA) for a panel of nanoparticles that included dry powders of oxides of titanium, zinc, cerium and silicon, dry powders of silvers, suspensions of polystyrene latex beads and dry particles of carbon black, nanotubes and fullerene, as well as diesel exhaust particles. Acute in vitro toxicity was assessed by different measures of cell viability, apoptosis and necrosis, haemolytic effects and the impact on cell morphology, while structural properties were characterised by particle size and size distribution, surface area, morphology, metal content, reactivity, free radical generation and zeta potential. Different acute toxicity measures were processed using PCA that classified the particles and identified four materials with an acute toxicity profile: zinc oxide, polystyrene latex amine, nanotubes and nickel oxide. PCA and contribution plot analysis then focused on identifying the structural properties that could determine the acute cytotoxicity of these four materials. It was found that metal content was an explanatory variable for acute toxicity associated with zinc oxide and nickel oxide, while high aspect ratio appeared the most important feature in nanotubes. Particle charge was considered as a determinant for high toxicity of polystyrene latex amine.

  2. Phylogenetic, functional, and structural components of variation in bone growth rate of amniotes.

    Science.gov (United States)

    Cubo, Jorge; Legendre, Pierre; de Ricqlès, Armand; Montes, Laëtitia; de Margerie, Emmanuel; Castanet, Jacques; Desdevises, Yves

    2008-01-01

    The biological features observed in every living organism are the outcome of three sets of factors: historical (inherited by homology), functional (biological adaptation), and structural (properties inherent to the materials with which organs are constructed, and the morphogenetic rules by which they grow). Integrating them should bring satisfactory causal explanations of empirical data. However, little progress has been accomplished in practice toward this goal, because a methodologically efficient tool was lacking. Here we use a new statistical method of variation partitioning to analyze bone growth in amniotes. (1) Historical component. The variation of bone growth rates contains a significant phylogenetic signal, suggesting that the observed patterns are partly the outcome of shared ancestry. (2) Functional causation. High growth rates, although energy costly, may be adaptive (i.e., they may increase survival rates) in taxa showing short growth periods (e.g., birds). In ectothermic amniotes, low resting metabolic rates may limit the maximum possible growth rates. (3) Structural constraint. Whereas soft tissues grow through a multiplicative process, growth of mineralized tissues is accretionary (additive, i.e., mineralization fronts occur only at free surfaces). Bone growth of many amniotes partially circumvents this constraint: it is achieved not only at the external surface of the bone shaft, but also within cavities included in the bone cortex as it grows centrifugally. Our approach contributes to the unification of historicism, functionalism, and structuralism toward a more integrated evolutionary biology.

  3. Crystal structure of the type IV secretion system component CagX from Helicobacter pylori

    Science.gov (United States)

    Zhang, Jin; Fan, Fei; Zhao, Yanhe; Sun, Lifang; Liu, Yadan; Wu, Yunkun

    2017-01-01

    Helicobacter pylori, a Gram-negative bacterial pathogen prevalent in the human population, is the causative agent of severe gastric diseases. An H. pylori type IV secretion (T4S) system encoded by the cytotoxin-associated gene pathogenicity island (cagPAI) is responsible for communication with host cells. As a component of the cagPAI T4S system core complex, CagX plays an important role in virulence-protein translocation into the host cells. In this work, the crystal structure of the C-terminal domain of CagX (CagXct), which is a homologue of the VirB9 protein from the VirB/D4 T4S system, is presented. CagXct is only the second three-dimensional structure to be elucidated of a VirB9-like protein. Another homologue, TraO, which is encoded on the Escherichia coli conjugative plasmid pKM101, shares only 19% sequence identity with CagXct; however, there is a remarkable similarity in tertiary structure between these two β-sandwich protein domains. Most of the residues that are conserved between CagXct and TraO are located within the protein core and appear to be responsible for the preservation of this domain fold. The studies presented here will contribute to our understanding of different bacterial T4S systems. PMID:28291753

  4. Fundamental Understanding of Crack Growth in Structural Components of Generation IV Supercritical Light Water Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Iouri I. Balachov; Takao Kobayashi; Francis Tanzella; Indira Jayaweera; Palitha Jayaweera; Petri Kinnunen; Martin Bojinov; Timo Saario

    2004-11-17

    This work contributes to the design of safe and economical Generation-IV Super-Critical Water Reactors (SCWRs) by providing a basis for selecting structural materials to ensure the functionality of in-vessel components during the entire service life. During the second year of the project, we completed electrochemical characterization of the oxide film properties and investigation of crack initiation and propagation for candidate structural materials steels under supercritical conditions. We ranked candidate alloys against their susceptibility to environmentally assisted degradation based on the in situ data measure with an SRI-designed controlled distance electrochemistry (CDE) arrangement. A correlation between measurable oxide film properties and susceptibility of austenitic steels to environmentally assisted degradation was observed experimentally. One of the major practical results of the present work is the experimentally proven ability of the economical CDE technique to supply in situ data for ranking candidate structural materials for Generation-IV SCRs. A potential use of the CDE arrangement developed ar SRI for building in situ sensors monitoring water chemistry in the heat transport circuit of Generation-IV SCWRs was evaluated and proved to be feasible.

  5. Noise of High Performance Aircraft at Afterburner

    Science.gov (United States)

    2016-02-10

    aircraft carrier, navy personnel work in close proximity to high performance jets at takeoffs and landings. The noise level emitted by these jets is...any major differences between the dominant noise components of these jets and those of a standard high temperature laboratory supersonic jet . It is...noise. For the F18E aircraft, we find that its noise, at high engine power settings, also includes new noise components in addition to the usual fine

  6. Cross-section of subsea umbilical and stress prediction of its structural components

    Directory of Open Access Journals (Sweden)

    Solovev V. V.

    2017-01-01

    Full Text Available It is presented in this article analysis of two models of subsea umbilicals under axial stress. Subsea umbilicals play a crucial role in offshore petroleum production and are designed to withstand all the environmental dynamic loads during the production period as long as 25 years. Apart from dynamic loads subsea umbilicals are under thermal loads as well having impact on the structural components and changing the material properties in some cases. The cross-section arrangement is a major part of the entire process of subsea umbilicals design. That is why this research is focused on the design of cross-section and has an aim to calculate main impacts subsea umbilicals facing during exploitation.

  7. State-of-the-art review on fracture analysis of concrete structural components

    Indian Academy of Sciences (India)

    A Rama Chandra Murthy; G S Palani; Nagesh R Iyer

    2009-04-01

    This paper presents a critical review of literature on fracture analysis of concrete structural components. Review includes various fracture models, tension softening models, methodologies for crack growth analysis and remaining life prediction. The widely used fracture models which are based on fictitious crack approach and effective elastic crack approach have been explained. Various tension softening models such as linear, bi-linear, tri-linear, etc. have been presented with appropriate expressions. From the critical review of models, it has been observed that some of the models have complex expressions involving many parameters. There is a need to develop some more generalised models. Studies have been conducted on crack growth analysis and remaining life prediction using linear elastic fracture mechanics (LEFM) principles. From the studies, it has been observed that there is significant difference between predicted and experimental observations. The difference in the values is attributed to not considering the tension softening effect in the analysis.

  8. Advanced Aerostructural Optimization Techniques for Aircraft Design

    OpenAIRE

    Yingtao Zuo; Pingjian Chen; Lin Fu; Zhenghong Gao; Gang Chen

    2015-01-01

    Traditional coupled aerostructural design optimization (ASDO) of aircraft based on high-fidelity models is computationally expensive and inefficient. To improve the efficiency, the key is to predict aerostructural performance of the aircraft efficiently. The cruise shape of the aircraft is parameterized and optimized in this paper, and a methodology named reverse iteration of structural model (RISM) is adopted to get the aerostructural performance of cruise shape efficiently. A new mathematic...

  9. Fast plasma sintering delivers functional graded materials components with macroporous structures and osseointegration properties.

    Science.gov (United States)

    Godoy, R F; Coathup, M J; Blunn, G W; Alves, A L; Robotti, P; Goodship, A E

    2016-04-13

    We explored the osseointegration potential of two macroporous titanium surfaces obtained using fast plasma sintering (FPS): Ti macroporous structures with 400-600 µmØ pores (TiMac400) and 850-1000 µmØ pores (TiMac850). They were compared against two surfaces currently in clinical use: Ti-Growth® and air plasma spray (Ti-Y367). Each surface was tested, once placed over a Ti-alloy and once onto a CoCr bulk substrate. Implants were placed in medial femoral condyles in 24 sheep. Samples were explanted at four and eight weeks after surgery. Push-out loads were measured using a material-testing system. Bone contact and ingrowth were assessed by histomorphometry and SEM and EDX analyses. Histology showed early osseointegration for all the surfaces tested. At 8 weeks, TiMac400, TiMac850 and Ti-Growth® showed deep bone ingrowth and extended colonisation with newly formed bone. The mechanical push-out force was equal in all tested surfaces. Plasma spray surfaces showed greater bone-implant contact and higher level of pores colonisation with new bone than FPS produced surfaces. However, the void pore area in FPS specimens was significantly higher, yet the FPS porous surfaces allowed a deeper osseointegration of bone to implant. FPS manufactured specimens showed similar osseointegration potential to the plasma spray surfaces for orthopaedic implants. FPS is a useful technology for manufacturing macroporous titanium surfaces. Furthermore, its capability to combine two implantable materials, using bulk CoCr with macroporous titanium surfaces, could be of interest as it enables designers to conceive and manufacture innovative components. FPS delivers functional graded materials components with macroporous structures optimised for osseointegration.

  10. The potential of small unmanned aircraft systems and structure-from-motion for topographic surveys: A test of emerging integrated approaches at Cwm Idwal, North Wales

    Science.gov (United States)

    Tonkin, T. N.; Midgley, N. G.; Graham, D. J.; Labadz, J. C.

    2014-12-01

    Novel topographic survey methods that integrate both structure-from-motion (SfM) photogrammetry and small unmanned aircraft systems (sUAS) are a rapidly evolving investigative technique. Due to the diverse range of survey configurations available and the infancy of these new methods, further research is required. Here, the accuracy, precision and potential applications of this approach are investigated. A total of 543 images of the Cwm Idwal moraine-mound complex were captured from a light (< 5 kg) semi-autonomous multi-rotor unmanned aircraft system using a consumer-grade 18 MP compact digital camera. The images were used to produce a DSM (digital surface model) of the moraines. The DSM is in good agreement with 7761 total station survey points providing a total vertical RMSE value of 0.517 m and vertical RMSE values as low as 0.200 m for less densely vegetated areas of the DSM. High-precision topographic data can be acquired rapidly using this technique with the resulting DSMs and orthorectified aerial imagery at sub-decimetre resolutions. Positional errors on the total station dataset, vegetation and steep terrain are identified as the causes of vertical disagreement. Whilst this aerial survey approach is advocated for use in a range of geomorphological settings, care must be taken to ensure that adequate ground control is applied to give a high degree of accuracy.

  11. Structural studies of the activation of the two component receiver domain NTRC by multidimensional heteronuclear NMR

    Energy Technology Data Exchange (ETDEWEB)

    Nohaile, M J [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry

    1996-05-01

    Multidimensional heteronuclear NMR spectroscopy was used to investigate the N-terminal domain of the transcriptional enhancer NTRC (NiTrogen Regulatory protein C). This domain belongs to the family of receiver domains of two-component regulatory systems involved in signal transduction. Phosphorylation of NTRC at D54 leads to an activated form of the molecule which stimulates transcription of genes involved in nitrogen regulation. Three and four dimensional NMR techniques were used to determine an intermediate resolution structure of the unphosphorylated, inactive form of the N-terminal domain of NTRC. The structure is comprised of five {alpha}-helices and a five-stranded {beta}-sheet in a ({beta}/{alpha}){sub 5} topology. Analysis of the backbone dynamics of NTRC indicate that helix 4 and strand 5 are significantly more flexible than the rest of the secondary structure of the protein and that the loops making up the active site are flexible. The short lifetime of phospho-NTRC hampers the study of this form. However, conditions for determining the resonance assignments and, possibly, the three dimensional structure of phosphorylated NTRC have been obtained. Tentative assignments of the phosphorylated form indicate that the majority of the changes that NTRC experiences upon phosphorylation occur in helix 3, strand 4, helix 4, strand 5, and the loop between strand 5 and helix 5 (the 3445 face of NTRC) as well as near the site of phosphorylation. In order to examine a stable, activated form of the protein, constitutively active mutants of NTRC were investigated.

  12. Crystal structure of prunin-1, a major component of the almond (Prunus dulcis) allergen amandin.

    Science.gov (United States)

    Jin, Tengchuan; Albillos, Silvia M; Guo, Feng; Howard, Andrew; Fu, Tong-Jen; Kothary, Mahendra H; Zhang, Yu-Zhu

    2009-09-23

    Seed storage proteins are accumulated during seed development and act as a reserve of nutrition for seed germination and young sprout growth. Plant seeds play an important role in human nutrition by providing a relatively inexpensive source of protein. However, many plant foods contain allergenic proteins, and the number of people suffering from food allergies has increased rapidly in recent years. The 11S globulins are the most widespread seed storage proteins, present in monocotyledonous and dicotyledonous seeds as well as in gymnosperms (conifers) and other spermatophytes. This family of proteins accounts for a number of known major food allergens. They are of interest to both the public and industry due to food safety concerns. Because of the interests in the structural basis of the allergenicity of food allergens, we sought to determine the crystal structure of Pru1, the major component of the 11 S storage protein from almonds. The structure was refined to 2.4 A, and the R/Rfree for the final refined structure is 17.2/22.9. Pru1 is a hexamer made of two trimers. Most of the back-to-back trimer-trimer association was contributed by monomer-monomer interactions. An alpha helix (helix 6) at the C-terminal end of the acidic domain of one of the interacting monomers lies at the cleft of the two protomers. The residues in this helix correspond to a flexible region in the peanut allergen Ara h 3 that encompasses a previously defined linear IgE epitope.

  13. Crystal Structure of Prunin-1, a Major Component of the Almond (Prunus dulcis) Allergen Amandin

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Tengchuan; Albillos, Silvia M.; Guo, Feng; Howard, Andrew; Fu, Tong-Jen; Kothary, Mahendra H.; Zhang, Yu-Zhu; (IIT); (US-FDA); (IT)

    2010-10-28

    Seed storage proteins are accumulated during seed development and act as a reserve of nutrition for seed germination and young sprout growth. Plant seeds play an important role in human nutrition by providing a relatively inexpensive source of protein. However, many plant foods contain allergenic proteins, and the number of people suffering from food allergies has increased rapidly in recent years. The 11S globulins are the most widespread seed storage proteins, present in monocotyledonous and dicotyledonous seeds as well as in gymnosperms (conifers) and other spermatophytes. This family of proteins accounts for a number of known major food allergens. They are of interest to both the public and industry due to food safety concerns. Because of the interests in the structural basis of the allergenicity of food allergens, we sought to determine the crystal structure of Pru1, the major component of the 11 S storage protein from almonds. The structure was refined to 2.4 {angstrom}, and the R/Rfree for the final refined structure is 17.2/22.9. Pru1 is a hexamer made of two trimers. Most of the back-to-back trimer-trimer association was contributed by monomer-monomer interactions. An {alpha} helix (helix 6) at the C-terminal end of the acidic domain of one of the interacting monomers lies at the cleft of the two protomers. The residues in this helix correspond to a flexible region in the peanut allergen Ara h 3 that encompasses a previously defined linear IgE epitope.

  14. Structural studies of the activation of the two component receiver domain NTRC by multidimensional heteronuclear NMR

    Energy Technology Data Exchange (ETDEWEB)

    Nohaile, Michael James [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry

    1996-05-01

    Multidimensional heteronuclear NMR spectroscopy was used to investigate the N-terminal domain of the transcriptional enhancer NTRC (NiTrogen Regulatory protein C). This domain belongs to the family of receiver domains of two-component regulatory systems involved in signal transduction. Phosphorylation of NTRC at D54 leads to an activated form of the molecule which stimulates transcription of genes involved in nitrogen regulation. Three and four dimensional NMR techniques were used to determine an intermediate resolution structure of the unphosphorylated, inactive form of the N-terminal domain of NTRC. The structure is comprised of five α-helices and a five-stranded β-sheet in a (β/α)5 topology. Analysis of the backbone dynamics of NTRC indicate that helix 4 and strand 5 are significantly more flexible than the rest of the secondary structure of the protein and that the loops making up the active site are flexible. The short lifetime of phospho-NTRC hampers the study of this form. However, conditions for determining the resonance assignments and, possibly, the three dimensional structure of phosphorylated NTRC have been obtained. Tentative assignments of the phosphorylated form indicate that the majority of the changes that NTRC experiences upon phosphorylation occur in helix 3, strand 4, helix 4, strand 5, and the loop between strand 5 and helix 5 (the 3445 face of NTRC) as well as near the site of phosphorylation. In order to examine a stable, activated form of the protein, constitutively active mutants of NTRC were investigated.

  15. Component Structure of Individual Differences in True and False Recognition of Faces

    Science.gov (United States)

    Bartlett, James C.; Shastri, Kalyan K.; Abdi, Herve; Neville-Smith, Marsha

    2009-01-01

    Principal-component analyses of 4 face-recognition studies uncovered 2 independent components. The first component was strongly related to false-alarm errors with new faces as well as to facial "conjunctions" that recombine features of previously studied faces. The second component was strongly related to hits as well as to the conjunction/new…

  16. Noninvasive MR characterization of structural and functional components of reperfused infarct

    Energy Technology Data Exchange (ETDEWEB)

    Saeed, Maythem; Martin, Alastair J.; Saloner, David; Loi Do; Wilson, Mark (Dept. of Radiology and Biomedical Imaging, Univ. of California San Francisco, San Francisco, CA (United States)), e-mail: Maythem.Saeed@radiology.ucsf.edu

    2010-12-15

    Background: Left ventricular (LV) remodeling is a highly complex phenomenon that starts soon after infarction and progresses to extensive regional and global architectural changes over time. Purpose: To noninvasively comprehensively characterize transient (edema, hemorrhage, microvascular obstruction (MO)) and persistent structural (infarct size) components of reperfused infarct up to 10 weeks and to determine their relation to LV function. Material and Methods: Farm pigs were used for the study. Under fluoroscopy the left anterior descending (LAD) coronary artery was occluded for 90 min. MR imaging was performed at 3 days (n=14 pigs), 5 weeks (n=10), and 10 weeks (n=6) after reperfusion. The following MR imaging sequences were used: (i) cine; (ii) T2-weighted turbo spin echo; (iii) T2-weighted turbo spin echo; (iv) tagged; (v) phase-contrast velocity-encoded; (vi) first-pass perfusion; and (vii) delayed contrast-enhanced (DE-MR imaging). After imaging, animals were euthanized at 3 days (n=4), 5 weeks (n=4), and 10 weeks (n=6) and hearts were stained with triphenyltetrazolium chloride to define acute, subacute, and scar infarct and interstitial hemorrhage. Results: T2, T2, and DE-MR imaging demonstrated transient interstitial edema, interstitial hemorrhage, and MO, respectively. MO was observed in 85% of animals and 60% of these showed hemorrhages. Cine, tagged, and phase-contrast velocity-encoded images documented the persistent impairment in 3D strain of infarcted segments, which on first-pass perfusion showed persistent perfusion deficit. MR imaging demonstrated the progressive increase in LV volumes and decreased ejection fraction over time. The changes in LV between 5 and 10 weeks were not related to the presence of interstitial edema, interstitial hemorrhage, MO or increase in infarct size. Conclusion: The various MR sequences described in this study allowed the demonstration of transient and persistent components of reperfused infarct. The progressive

  17. A simple iterative independent component analysis algorithm for vibration source signal identification of complex structures

    Directory of Open Access Journals (Sweden)

    Lee Dong-Sup

    2015-01-01

    Full Text Available Independent Component Analysis (ICA, one of the blind source separation methods, can be applied for extracting unknown source signals only from received signals. This is accomplished by finding statistical independence of signal mixtures and has been successfully applied to myriad fields such as medical science, image processing, and numerous others. Nevertheless, there are inherent problems that have been reported when using this technique: instability and invalid ordering of separated signals, particularly when using a conventional ICA technique in vibratory source signal identification of complex structures. In this study, a simple iterative algorithm of the conventional ICA has been proposed to mitigate these problems. The proposed method to extract more stable source signals having valid order includes an iterative and reordering process of extracted mixing matrix to reconstruct finally converged source signals, referring to the magnitudes of correlation coefficients between the intermediately separated signals and the signals measured on or nearby sources. In order to review the problems of the conventional ICA technique and to validate the proposed method, numerical analyses have been carried out for a virtual response model and a 30 m class submarine model. Moreover, in order to investigate applicability of the proposed method to real problem of complex structure, an experiment has been carried out for a scaled submarine mockup. The results show that the proposed method could resolve the inherent problems of a conventional ICA technique.

  18. ANALISIS DERAJAT KESEHATAN MASYARAKAT PROVINSI BALI DENGAN MENGGUNAKAN METODE GENERALIZED STRUCTURED COMPONENT ANALYSIS (GSCA

    Directory of Open Access Journals (Sweden)

    PUTU NOPITA PURNAMA NINGSIH

    2013-09-01

    Full Text Available The aim of this research is to determine the relationship between environmental, behavioral, health services, education, and economic variables to health status in the Province of Bali. These variables are constructs (latents that can not be measured directly by observation. If there was a relationship between latent and its indicators, it is recomended to use Structural Equation Modeling (SEM. In this research we used variance-based SEM i.e. Generalized Structured Component Analysis (GSCA. This method not based on many assumptions such as the data does not have a multivariate normal distribution, the sample size does is not necessary large. Moreover, GSCA provides by overall goodness-fit of the model. The result of this research indicates that the environmental, behavioral, economic and educational variable influenced health status, but health service does not significantly affect the health status; economic does not significantly affect the environment; and education does not significantly affect the behavior. The result of the FIT value ?0.450 and the AFIT value 0.429 showed that overall model in this research is not good enough because of both of these values are under 0.50.

  19. Characterization of ABS specimens produced via the 3D printing technology for drone structural components

    Science.gov (United States)

    Ferro, Carlo Giovanni; Brischetto, Salvatore; Torre, Roberto; Maggiore, Paolo

    2016-07-01

    The Fused Deposition Modelling (FDM) technology is widely used in rapid prototyping. 3D printers for home desktop applications are usually employed to make non-structural objects. When the mechanical stresses are not excessive, this technology can also be successfully employed to produce structural objects, not only in prototyping stage but also in the realization of series pieces. The innovative idea of the present work is the application of this technology, implemented in a desktop 3D printer, to the realization of components for aeronautical use, especially for unmanned aerial systems. For this purpose, the paper is devoted to the statistical study of the performance of a desktop 3D printer to understand how the process performs and which are the boundary limits of acceptance. Mechanical and geometrical properties of ABS (Acrylonitrile Butadiene Styrene) specimens, such as tensile strength and stiffness, have been evaluated. ASTM638 type specimens have been used. A capability analysis has been applied for both mechanical and dimensional performances. Statistically stable limits have been determined using experimentally collected data.

  20. The ecological structures as components of flood and erosion vulnerability analysis in costal landscapes

    Science.gov (United States)

    Valentini, E.; Taramelli, A.; Martina, M.; Persichillo, M. G.; Casarotti, C.; Meisina, C.

    2014-12-01

    The direct and the indirect changes of natural habitats for coastal development can affect the level of exposure to erosion and flooding (inundation). Although engineered structures are still preferred for coastal safety there is an increasing number of applications of ecosystem-based solutions worldwide as the building with nature approaches and the arising natural capital evaluation. A question to which we should respond, is the possibility of using the wide range of satellite data and the already available Earth Observation based products to make a synoptic structural and environmental vulnerability assessment. By answering to this, we could also understand, if and how many markers/signals can be identified in the landscape components, to define transitions to and from nonlinear processes - to and from scale invariant spatial distributions- characterizing the evolution of the environmental patch size mosaic, the landscape. The Wadden Sea, in example, is a productive estuarine area in the south-eastern coastal zone of the North Sea. It is characterized by extensive tidal mud flats, saltmarshes and by the tidal channel network between the mainland and the chain of islands along the North Sea side. The area has a UNESCO World Heritage Status and a Natura 2000 status. Here, we identified thresholds to distinguish spatial and temporal patterns controlled by changes in environmental variables. These patterns are represented by the cover percent and by the structural level of vegetation and sediment/soil in each identified patch. The environmental variables are those able to act on the patch size distribution as the forcing factors from the sea (wind and waves fields) or from the climate and the hydrology drivers. The Bayesian approach defines the dependencies of the spatial patch size distribution from the major flooding and erosion environmental variables. When the analysis is scaled up from the ecosystem units to the landscape level thanks to the satellite