Dynamic analysis and design of offshore structures
Chandrasekaran, Srinivasan
2015-01-01
This book attempts to provide readers with an overall idea of various types of offshore platform geometries. It covers the various environmental loads encountered by these structures, a detailed description of the fundamentals of structural dynamics in a class-room style, estimate of damping in offshore structures and their applications in the preliminary analysis and design. Basic concepts of structural dynamics are emphasized through simple illustrative examples and exercises. Design methodologies and guidelines, which are FORM based concepts are explained through a few applied example structures. Each chapter also has tutorials and exercises for self-learning. A dedicated chapter on stochastic dynamics will help the students to extend the basic concepts of structural dynamics to this advanced domain of research. Hydrodynamic response of offshore structures with perforated members is one of the recent research applications, which is found to be one of the effective manner of retrofitting offshore structur...
Dynamic Analysis of Structures Using Neural Networks
Directory of Open Access Journals (Sweden)
N. Ahmadi
2008-01-01
Full Text Available In the recent years, neural networks are considered as the best candidate for fast approximation with arbitrary accuracy in the time consuming problems. Dynamic analysis of structures against earthquake has the time consuming process. We employed two kinds of neural networks: Generalized Regression neural network (GR and Back-Propagation Wavenet neural network (BPW, for approximating of dynamic time history response of frame structures. GR is a traditional radial basis function neural network while BPW categorized as a wavelet neural network. In BPW, sigmoid activation functions of hidden layer neurons are substituted with wavelets and weights training are achieved using Scaled Conjugate Gradient (SCG algorithm. Comparison the results of BPW with those of GR in the dynamic analysis of eight story steel frame indicates that accuracy of the properly trained BPW was better than that of GR and therefore, BPW can be efficiently used for approximate dynamic analysis of structures.
Structural Dynamics and Data Analysis
Luthman, Briana L.
2013-01-01
This project consists of two parts, the first will be the post-flight analysis of data from a Delta IV launch vehicle, and the second will be a Finite Element Analysis of a CubeSat. Shock and vibration data was collected on WGS-5 (Wideband Global SATCOM- 5) which was launched on a Delta IV launch vehicle. Using CAM (CAlculation with Matrices) software, the data is to be plotted into Time History, Shock Response Spectrum, and SPL (Sound Pressure Level) curves. In this format the data is to be reviewed and compared to flight instrumentation data from previous flights of the same launch vehicle. This is done to ensure the current mission environments, such as shock, random vibration, and acoustics, are not out of family with existing flight experience. In family means the peaks on the SRS curve for WGS-5 are similar to the peaks from the previous flights and there are no major outliers. The curves from the data will then be compiled into a useful format so that is can be peer reviewed then presented before an engineering review board if required. Also, the reviewed data will be uploaded to the Engineering Review Board Information System (ERBIS) to archive. The second part of this project is conducting Finite Element Analysis of a CubeSat. In 2010, Merritt Island High School partnered with NASA to design, build and launch a CubeSat. The team is now called StangSat in honor of their mascot, the mustang. Over the past few years, the StangSat team has built a satellite and has now been manifested for flight on a SpaceX Falcon 9 launch in 2014. To prepare for the final launch, a test flight was conducted in Mojave, California. StangSat was launched on a Prospector 18D, a high altitude rocket made by Garvey Spacecraft Corporation, along with their sister satellite CP9 built by California Polytechnic University. However, StangSat was damaged during an off nominal landing and this project will give beneficial insights into what loads the CubeSat experienced during the crash
A Dynamic Model for Energy Structure Analysis
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
Energy structure is a complicated system concerning economic development, natural resources, technological innovation, ecological balance, social progress and many other elements. It is not easy to explain clearly the developmental mechanism of an energy system and the mutual relations between the energy system and its related environments by the traditional methods. It is necessary to develop a suitable dynamic model, which can reflect the dynamic characteristics and the mutual relations of the energy system and its related environments. In this paper, the historical development of China's energy structure was analyzed. A new quantitative analysis model was developed based on system dynamics principles through analysis of energy resources, and the production and consumption of energy in China and comparison with the world. Finally, this model was used to predict China's future energy structures under different conditions.
Finite Element Vibration and Dynamic Response Analysis of Engineering Structures
Directory of Open Access Journals (Sweden)
Jaroslav Mackerle
2000-01-01
Full Text Available This bibliography lists references to papers, conference proceedings, and theses/dissertations dealing with finite element vibration and dynamic response analysis of engineering structures that were published from 1994 to 1998. It contains 539 citations. The following types of structures are included: basic structural systems; ground structures; ocean and coastal structures; mobile structures; and containment structures.
Modal analysis application for dynamic characterization of simple structures
International Nuclear Information System (INIS)
The knowledge of the dynamic characteristics of a structure helps to foresee the vibrating behaviour under operating conditions. The modal analysis techniques offer a method to perform the dynamic characterization of a studied structure from the vibration modes of such structure. A hammer provided with a loaded cell to excite a wide frequency band and accelerometer and, on the basis of a measurement of the transfer function at different points, various simple structures were given with a dynamic structures analysis (of the type of Fourier's rapidly transformation) and the results were compared with those obtained by other methods. Different fields where these techniques are applied, are also enumerated. (Author)
Pseudo-dynamic method for structural analysis of automobile seats
J. O. Carneiro; Melo, F. J. Q. de; Pereira, J. T.; Teixeira, V.
2005-01-01
This work describes the application of a pseudo-dynamic (PsD) method to the dynamic analysis of passenger seats for the automotive industry. The project of such components involves a structural test considering the action of dynamic forces arising from a crash scenario. The laboratory certification of these automotive components consists essentially on the inspection of the propagation and extension of plastic deformations zones in metallic members of the seat structure as cons...
Stochastic Dynamic Analysis of Offshore Bottom-Fixed Structures
Horn, Jan-Tore Haugan
2015-01-01
Paper 1 The first part of this master thesis presented in paper one, is evaluating several methods to estimate dynamic amplification of drag dominated structures. This is done primarily by 3 hour time-domain analysis in the computer program USFOS with linear wave theory, Wheeler stretching and the Morison load equation in irregular, extreme seas. The dynamic amplification in irregular seas is estimated by performing dynamic and quasi-static analysis in the exact same conditions. Then,...
Structural dynamics in fast reactor accident analysis
International Nuclear Information System (INIS)
Analyses and codes are under development combining the hydrodynamics and solid mechanics (and more recently the bubble dynamics) phenomena to gage the stresses, strains, and deformations of important primary components, as well as the overall adequacy of primary and secondary containments. An arbitrary partition of the structural components treated evolves into (1) a core mechanics effort; and (2) a primary system and containment program. The primary system and containment program treats the structural response of components beyond the core, starting with the core barrel. Combined hydrodynamics-solid mechanics codes provide transient stresses and strains and final deformations for components such as the reactor vessel, reactor cover, cover holddown bolts, as well as the pulses for which the primary piping system is to be analyzed. Both, Lagrangian and Eulerian two-dimensional codes are under development, which provide greater accuracy and longer durations for the treatment of HCDA. The codes are being augmented with bubble migration capability pertaining to the latter stages of the HCDA, after slug impact. Recent developments involve the adaptation of the 2-D Eulerian primary system code to the 2-D elastic-plastic treatment of primary piping. Pulses are provided at the vessel-primary piping interfaces of the inlet and outlet nozzles, calculation includes the elbows and pressure drops along the components of the primary piping system. Recent improvements to the primary containment codes include introduction of bending strength in materials, Langrangian mesh regularization techniques, and treatment of energy absorbing materials for the slug impact. Another development involves the combination of a 2-D finite element code for the reactor cover with the hydrodynamic containment code
Sanaz Mahmoudpour; Reza Attarnejad; Cambyse Behnia
2011-01-01
Analysis and design of structures subjected to arbitrary dynamic loadings especially earthquakes have been studied during past decades. In practice, the effects of soil-structure interaction on the dynamic response of structures are usually neglected. In this study, the effect of soil-structure interaction on the dynamic response of structures has been examined. The substructure method using dynamic stiffness of soil is used to analyze soil-structure system. A coupled model based on finite el...
Dynamic Analysis of Composite Structural System for Looms Industry
Directory of Open Access Journals (Sweden)
Jigar K. Sevalia
2014-02-01
Full Text Available All the structures subjected to any kind of loads or displacement tends to behave dynamically. Thus the structures are always under continuous loading. The industrial buildings have to support the machineries in motion which are under high degree of vibrations. And so the design of base and the foundations of such structures under vibrations are very important and need to be stable. Problems of dynamics of bases and foundations are to be studied carefully, so as to understand the response characteristics of the power loom industry structure. This is very important from the economic point of view as well as to secure the stability and safety of the structure; dynamic analysis was carried out for Ground + One storey industry load bearing structure using STAAD.Pro software. In this paper, an attempt has been made to study the dynamic analysis of the structure under vibrations caused by reciprocating type machines. This paper makes attempt to study the effects of various structural parameters like Beam Size, Column Size and Storey Height and Wall Thickness variation on Frequency and Displacement of the industrial building which in future will serve as guidelines to the structural engineers and the industry people.
Factor analysis of dynamic structures in nuclear medicine
International Nuclear Information System (INIS)
In the field of data processing in nuclear medicine, we applied the principal component analysis to the data acquired by the method of dynamic data acquisition. The radioisotope, taken in the body, shows inherent dynamic structures at the region of internal organ. We make some inherent patterns (Physiological Components) from T. A. C. (Time Activity Curve), and we represent dynamic structures of inherent patterns as functional image by the operation between inherent pattern and acquired data. This approach is called a Factor Analysis. In this paper, we introduce 1) The principle of factor analysis and its application to nuclear medicine, 2) the clinical application of factor analysis on SCINTIPAC-2400, and 3) the examinations and the comparison with other clinical application. (author)
Structural dynamic analysis of a ball joint
Hwang, Seok-Cheol; Lee, Kwon-Hee
2012-11-01
Ball joint is a rotating and swiveling element that is typically installed at the interface between two parts. In an automobile, the ball joint is the component that connects the control arms to the steering knuckle. The ball joint can also be installed in linkage systems for motion control applications. This paper describes the simulation strategy for a ball joint analysis, considering manufacturing process. Its manufacturing process can be divided into plugging and spinning. Then, the interested responses is selected as the stress distribution generated between its ball and bearing. In this paper, a commercial code of NX DAFUL using an implicit integration method is introduced to calculate the response. In addition, the gap analysis is performed to investigate the fitness, focusing on the response of the displacement of a ball stud. Also, the optimum design is suggested through case studies.
Nonlinear dynamic analysis of quasi-symmetric anisotropic structures
Noor, Ahmed K.; Peters, Jeanne M.
1987-01-01
An efficient computational method for the nonlinear dynamic analysis of quasi-symmetric anisotropic structures is proposed. The application of mixed models simplifies the analytical development and improves the accuracy of the response predictions, and operator splitting allows the reduction of the analysis model of the quasi-symmetric structure to that of the corresponding symmetric structure. The preconditoned conjugate gradient provides a stable and effective technique for generating the unsymmetric response of the structure as the sum of a symmetrized response plus correction modes. The effectiveness of the strategy is demonstrated with the example of a laminated anisotropic shallow shell of quadrilateral planform subjected to uniform normal loading.
Processing of radionuclide cystography using factor analysis of dynamic structures
International Nuclear Information System (INIS)
Radionuclide cystography allows the detection of vesico-ureteral reflux. Numerical image processing using the region of interest (ROI) method can improve the sensitivity of the detection, but with some disadvantages, particularly, the lack of reproducibility. The use of factor analysis of dynamic structures can avoid this defects and enable vesico-ureteral reflux to be analysed automatically
Interactive computer code for dynamic and soil structure interaction analysis
Energy Technology Data Exchange (ETDEWEB)
Mulliken, J.S.
1995-12-01
A new interactive computer code is presented in this paper for dynamic and soil-structure interaction (SSI) analyses. The computer program FETA (Finite Element Transient Analysis) is a self contained interactive graphics environment for IBM-PC`s that is used for the development of structural and soil models as well as post-processing dynamic analysis output. Full 3-D isometric views of the soil-structure system, animation of displacements, frequency and time domain responses at nodes, and response spectra are all graphically available simply by pointing and clicking with a mouse. FETA`s finite element solver performs 2-D and 3-D frequency and time domain soil-structure interaction analyses. The solver can be directly accessed from the graphical interface on a PC, or run on a number of other computer platforms.
Dynamic analysis of large structures by modal synthesis techniques.
Hurty, W. C.; Hart, G. C.; Collins, J. D.
1971-01-01
Several criteria that may be used to evaluate the merits of some of the existing techniques for the dynamic analysis of large structures which involve division into substructures or components are examined. These techniques make use of component displacement modes to synthetize global systems of generalized coordinates and, for that reason, they have come to be known as modal synthesis or component mode methods. Two techniques have been found to be particularly useful - i.e., the modal synthesis method with fixed attachment modes, and the modal synthesis method with free attachment modes. These two methods are treated in detail, and general flow charts are presented for guidance in computer programming.
Structural dynamics: Probabilistic structural analysis methods. Program overview
Chamis, Christos C.; Hopkins, Dale A.
1991-01-01
A brief description is provided of the fundamental aspects of a quantification process. Progress since the last structural durability conference in 1989 is summarized. The methodology to date and that to be developed during the life of the program is presented. The uncertain factors are presented. The approach is outlined that is required to achieve component and/or system certification in the shortest possible time for affordable reliability risk. Two new elements appear in a block diagram: (1) uncertainties in human factor, and (2) uncertainties in the computer code. Research to quantify the uncertainties in the human factor was initiated and is discussed.
Nonlinear dynamic analysis of hydrodynamically-coupled stainless steel structures
International Nuclear Information System (INIS)
Spent nuclear fuel is usually stored temporarily on the site of nuclear power plants. The spent fuel storage racks are nuclear-safety-related stainless steel structures required to be analyzed for seismic loads. When the storage pool is subjected to three-dimensional (3-D) floor seismic excitations, rack modules, stored fuel bundles, adjacent racks and pool walls, and surrounding water are hydrodynamically coupled. Hydrodynamic coupling (HC) significantly affects the dynamic responses of the racks that are free-standing and submerged in water within the pool. A nonlinear time-history dynamic analysis is usually needed to describe the motion behavior of the racks that are both geometrically nonlinear and material nonlinear in nature. The nonlinearities include the friction resistance between the rack supporting legs and the pool floor, and various potential impacts of fuel-rack, rack-rack, and rack-pool wall. The HC induced should be included in the nonlinear dynamic analysis using the added-hydrodynamic-mass concept based on potential theory per the US Nuclear Regulatory Commission (USNRC) acceptance criteria. To this end, a finite element analysis constitutes a feasible and effective tool. However, most people perform somewhat simplified 1-D, or 2-D, or 3-D single rack and 2-D multiple rack analyses. These analyses are incomplete because a 3-D single rack model behaves quite differently from a 2-D mode. Furthermore, a 3-D whole pool multi-rack model behaves differently than a 3-D single rack model, especially when the strong HC effects are unsymmetrical. In this paper 3-D nonlinear dynamic time-history analyses were performed in a more quantitative manner using sophisticated finite element models developed for a single rack as well as all twelve racks in the whole-pool. Typical response results due to different HC effects are determined and discussed
Directory of Open Access Journals (Sweden)
Sanaz Mahmoudpour
2011-01-01
Full Text Available Analysis and design of structures subjected to arbitrary dynamic loadings especially earthquakes have been studied during past decades. In practice, the effects of soil-structure interaction on the dynamic response of structures are usually neglected. In this study, the effect of soil-structure interaction on the dynamic response of structures has been examined. The substructure method using dynamic stiffness of soil is used to analyze soil-structure system. A coupled model based on finite element method and scaled boundary finite element method is applied. Finite element method is used to analyze the structure, and scaled boundary finite element method is applied in the analysis of unbounded soil region. Due to analytical solution in the radial direction, the radiation condition is satisfied exactly. The material behavior of soil and structure is assumed to be linear. The soil region is considered as a homogeneous half-space. The analysis is performed in time domain. A computer program is prepared to analyze the soil-structure system. Comparing the results with those in literature shows the exactness and competency of the proposed method.
Dynamic analysis of magnetorheological elastomer configured sandwich structures
Choi, Won Jun
2009-01-01
The work presented in this thesis is concerned with the investigation of the dynamic behaviour of magnetorheological elastomers (MREs) and smart sandwich structures. An extensive review, covering existing smart materials and their applications, has highlighted that smart materials and structures can be applied to large scale structures. Comprehensive experimental tests have been carried out in order to gain knowledge and data on the dynamic shear properties and behaviour of sti...
Dynamic Analysis of Structural Columns Subjected to Impulsive Loading
Institute of Scientific and Technical Information of China (English)
GONG Shunfeng; LU Yong; GAO Feng; JIN Weiliang
2006-01-01
For a building structure subjected to impulsive loading,particularly shock and impact loading,the response of the critical columns is crucial to the behaviour of the entire system during and after the blast loading phase.Therefore,an appropriate evaluation of the column response and damage under short-duration impulsive loading is important in a comprehensive assessment of the performance of a building system.This paper reports a dynamic analysis approach for the response of RC columns subjected to impulsive loading.Considering that the dynamic response of a column in a frame structure can also be affected by the floor movement which relates to the global vibration of the frame system,a generic column-mass model is used,in which a concentrated mass is attached to the column top to simulate the effect of a global vibration.To take into account the high shear effect under impulsive load,the model is formulated using Timoshenko beam theory,and three main nonlinear mechanisms are considered.Two typical scenarios,one under a direct air blast loading,and another under a blast-induced ground excitation,are analyzed and the primary response features are highlighted.
Structural dynamic analysis with generalized damping models analysis
Adhikari , Sondipon
2013-01-01
Since Lord Rayleigh introduced the idea of viscous damping in his classic work ""The Theory of Sound"" in 1877, it has become standard practice to use this approach in dynamics, covering a wide range of applications from aerospace to civil engineering. However, in the majority of practical cases this approach is adopted more for mathematical convenience than for modeling the physics of vibration damping. Over the past decade, extensive research has been undertaken on more general ""non-viscous"" damping models and vibration of non-viscously damped systems. This book, along with a related book
Directory of Open Access Journals (Sweden)
Pan Dan-guang
2015-01-01
Full Text Available For realizing the variation of structural dynamic characteristics due to neighbor structure in buildings group, the surface structure is idealized as an equivalent single degree of freedom system with rigid base whose site consists of a single homogeneous layer. Based on the model, a equivalent method on the equivalent seismic excitation is proposed. Then, the differences of seismic response and equivalent seismic input between soil - structure interaction (SSI system and structure -soil-structure interaction (SSSI system are investigated by harmonic analysis. The numerical results show that dynamic responses would be underestimated in SSSI system when the forcing frequencies are close to the Natural frequency if the effects of neighborhood structure were ignored. Neighborhood structure would make the translational displacement increase and rocking vibration decrease. When establishing an effective seismic input, it is necessary to consider the impact of inertia interaction.
On the use of Stockwell transform in structural dynamic analysis
Indian Academy of Sciences (India)
H Serdar Kuyuk
2015-02-01
Time-frequency analysis of earthquake records using Fourier transform is a fundamental, reliable and useful tool in earthquake engineering and engineering seismology. It will be however no longer functional if the frequency variation is analysed in time domain. Short time Fourier transform is utilized for the same purpose but this has also its own limitations and restrictions. In this research, Stockwell transform (S-transform), is evaluated in investigating frequency content of signal in time domain. First, the effectiveness of S-transform was tested by a non-stationary synthetic signal series with a sum of various instantaneous time varying frequency functions. Then, transform was employed to three different earthquake waveforms of Iwate-Miyagi Nairiku earthquake (Mw 6.9, 2008); recorded in near, moderate and far sites. Finally, an application was demonstrated for determining dynamic response of three-story frame structure by using El Centro earthquake compiled with harmonic motion. Unlike widely used continuous wavelet transform, which provides temporal and spectral information simultaneously, S-transform is very straightforward and easy to manipulate for interpretations. All cases considered in this research showed that Stransform can be implemented for further research activities related with frequencydependent strong motion analysis by practitioners and engineers. S-transform can distinguish abrupt frequency changes in structures effectively and accurately.
The ABRAVIBE toolbox for teaching vibration analysis and structural dynamics
DEFF Research Database (Denmark)
Brandt, A.
2013-01-01
Vibration analysis is a subject where students often find it hard to comprehend the fundamental theory. The fact that we have, in general, almost no intuition for dynamic phenomena, means that students need to explore various dynamic phenomena in order to grasp the subject. For this reason, a...... functional limitations. The toolbox includes functionality for simulation of mechanical models as well as advanced analysis such as time series analysis, spectral analysis, frequency response and correlation function estimation, modal parameter extraction, and rotating machinery analysis (order tracking). In...
Ricles, James M.
1990-01-01
The development and preliminary assessment of a method for dynamic structural analysis based on load-dependent Ritz vectors are presented. The vector basis is orthogonalized with respect to the mass and structural stiffness in order that the equations of motion can be uncoupled and efficient analysis of large space structure performed. A series of computer programs was developed based on the algorithm for generating the orthogonal load-dependent Ritz vectors. Transient dynamic analysis performed on the Space Station Freedom using the software was found to provide solutions that require a smaller number of vectors than the modal analysis method. Error norm based on the participation of the mass distribution of the structure and spatial distribution of structural loading, respectively, were developed in order to provide an indication of vector truncation. These norms are computed before the transient analysis is performed. An assessment of these norms through a convergence study of the structural response was performed. The results from this assessment indicate that the error norms can provide a means of judging the quality of the vector basis and accuracy of the transient dynamic solution.
Fundamentals of structural dynamics
Craig, Roy R
2006-01-01
From theory and fundamentals to the latest advances in computational and experimental modal analysis, this is the definitive, updated reference on structural dynamics.This edition updates Professor Craig's classic introduction to structural dynamics, which has been an invaluable resource for practicing engineers and a textbook for undergraduate and graduate courses in vibrations and/or structural dynamics. Along with comprehensive coverage of structural dynamics fundamentals, finite-element-based computational methods, and dynamic testing methods, this Second Edition includes new and e
Zhu, X. -M.; Yin, L.; Hood, L; Ao, P.
2004-01-01
Based on our physical and biological studies we have recently developed a mathematical framework for the analysis of nonlnear dynamics. We call this framework the dynamical structure analysis. It has four dynamical elements: potential landscape, transverse matrix, descendant matrix, and stochastic drive. In particular, the importance and the existence of the potential landscape is emphasized. The dynamical structure analysis is illustrated in detail by the study of stability, robustness, and ...
Approximate analysis of dynamic soil-structure interaction
Lanzi, Armando
2011-01-01
This study focuses on the approximate analysis of soil- structure interaction problems, specifically on the application of classical modal analysis for coupled horizontal-rocking vibrations of plane structures resting on a linear elastic soil. Although the classical modal approach provides a non-rigorous solution, it is particularly meaningful as it offers physical insight into the nature of soil-structure interaction effects. After validating the numerical algorithm by comparison with earlie...
Nonlinear dynamic analysis of framed structures including soil-structure interaction effects
International Nuclear Information System (INIS)
The role of oil-structure interaction on seismic behavior of reinforced concrete structures is investigated in this paper. A finite element approach has been adopted to model the interaction system that consists of the reinforced concrete plane frame, soil deposit and interface which represents the frictional between foundation of the structure and subsoil. The analysis is based on the elasto-plastic behavior of the frame members (beams and columns) that is defined by the ultimate axial force-bending moment interaction curve, while the cap model is adopted to govern the elasto-plastic behavior of the soil material. Mohr-Coulomb failure law is used to determine the initiation of slippage at the interface, while the separation is assumed to determine the initiation of slippage at the interface, while the separation is assumed to occur when the stresses at the interface becomes tension stresses. New-Mark's Predictor-Corrector algorithm is adopted for nonlinear dynamic analysis. The main aim of present work is to evaluate the sensitivity of structures to different behavior of the soil and interface layer when subjected to an earthquake excitation. Predicted results of the dynamic analysis of the interaction system indicate that the soil-structure interaction problem can have beneficial effects on the structural behavior when different soil models (elastic and elasto-plastic) and interface conditions (perfect bond and permitted slip)are considered. (author)
Accuracy of Dynamic and Acoustic Analysis of Lightweight Panel Structures
DEFF Research Database (Denmark)
Kirkegaard, Poul Henning; Dickow, Kristoffer Ahrens; Andersen, Lars Vabbersgaard;
2012-01-01
buildings is important. In the lowfrequency range, prediction of sound and vibration in building structures may be achieved by finite-element analysis (FEA). The aim of this paper is to compare the two commercial codes ABAQUS and ANSYS for FEA of an acoustic-structural coupling in a timber lightweight panel...
DYNAMIC ANALYSIS OF UNDERGROUND COMPOSITE STRUCTURES UNDER EXPLOSION LOADING
Institute of Scientific and Technical Information of China (English)
赵晓兵; 薛大为; 赵玉祥
2004-01-01
In selecting rational types of underground structures resisting explosion, in order to improve stress states of the structural section and make full use of material strength of each part of the section, the research method of composite structures is presented. Adopting the analysis method of micro-section free body, equilibrium equations, constraint equations and deformation coordination equations are given. Making use of the concept of generalized work and directly introducing Lagrange multiplier specific in physical meaning, the validity of the constructed generalized functional is proved by using variation method. The rational rigidity matching relationship of composite structure section is presented through example calculations.
STRUCTURAL ANALYSIS AND MOLECULAR DYNAMICS STUDY OF PHB SYNTHASE
Directory of Open Access Journals (Sweden)
T. Femlin Blessia
2012-02-01
Full Text Available Polyhydroxybutyrate (PHB is a polyhydroxyalkanoate (PHA, a polymer belonging to polyesters class and is composed of hydroxy fatty acids. PHB is produced by microorganisms apparently in response to conditions of physiological stress. PHB synthases are the key enzymes of PHB biosynthesis. The PHB synthases obtained from Chromobacterium violaceum, belongs to the class I PHA synthases. Due to the limited structural information of PHB synthase, its functional properties including catalysis are unknown. Therefore, this study seeks to investigate the structural and functional properties of PHB synthase (phaC by predicting its three dimensional structure using bioinformatics methods. Present 15 ns molecular dynamics study provides an overall insight about some of the parameters such as energy, RMSD (Root Mean Square Deviation, SASA (Solvent Accessible Surface Area, hydrogen bonds, etc., Protein-protein docking reveals the binding mode of the protein in the active dimer state.
Strømmen, Einar N
2014-01-01
This book introduces to the theory of structural dynamics, with focus on civil engineering structures that may be described by line-like beam or beam-column type of systems, or by a system of rectangular plates. Throughout this book the mathematical presentation contains a classical analytical description as well as a description in a discrete finite element format, covering the mathematical development from basic assumptions to the final equations ready for practical dynamic response predictions. Solutions are presented in time domain as well as in frequency domain. Structural Dynamics starts off at a basic level and step by step brings the reader up to a level where the necessary safety considerations to wind or horizontal ground motion induced dynamic design problems can be performed. The special theory of the tuned mass damper has been given a comprehensive treatment, as this is a theory not fully covered elsewhere. For the same reason a chapter on the problem of moving loads on beams has been included.
Correlative Microscopy for 3D Structural Analysis of Dynamic Interactions
Jun, Sangmi; Zhao, Gongpu; Ning, Jiying; Gibson, Gregory A.; Watkins, Simon C.; Zhang, Peijun
2013-01-01
Cryo-electron tomography (cryoET) allows 3D visualization of cellular structures at molecular resolution in a close-to-physiological state1. However, direct visualization of individual viral complexes in their host cellular environment with cryoET is challenging2, due to the infrequent and dynamic nature of viral entry, particularly in the case of HIV-1. While time-lapse live-cell imaging has yielded a great deal of information about many aspects of the life cycle of HIV-13-7, the resolution ...
Analysis of Nonlinear Structural Dynamics and Resonance in Trees
Directory of Open Access Journals (Sweden)
H. Doumiri Ganji
2012-01-01
Full Text Available Wind and gravity both impact trees in storms, but wind loads greatly exceed gravity loads in most situations. Complex behavior of trees in windstorms is gradually turning into a controversial concern among ecological engineers. To better understand the effects of nonlinear behavior of trees, the dynamic forces on tree structures during periods of high winds have been examined as a mass-spring system. In fact, the simulated dynamic forces created by strong winds are studied in order to determine the responses of the trees to such dynamic loads. Many of such nonlinear differential equations are complicated to solve. Therefore, this paper focuses on an accurate and simple solution, Differential Transformation Method (DTM, to solve the derived equation. In this regard, the concept of differential transformation is briefly introduced. The approximate solution to this equation is calculated in the form of a series with easily computable terms. Then, the method has been employed to achieve an acceptable solution to the presented nonlinear differential equation. To verify the accuracy of the proposed method, the obtained results from DTM are compared with those from the numerical solution. The results reveal that this method gives successive approximations of high accuracy solution.
Structural Modeling and Analysis on Dynamic Characteristics of Antenna Pedestal in Airborne SAR
Directory of Open Access Journals (Sweden)
He Li-ping
2012-06-01
Full Text Available Finite element modeling and structural dynamic characteristics of antenna pedestal in airborne SAR were studied in this paper. The Finite element model of antenna pedestal in airborne SAR was set up on the basis of structural dynamic theory, then, the key technologies of dynamic simulation were pointed out, and the modal analysis and transient analysis were carried out. Simulation results show that the dynamic characteristics of antenna pedestal in airborne SAR can meet the requirements of servo bandwidth and structural strength. The fast finite element modeling and simulation method proposed in this paper are of great significance to the weight reducing design of antenna pedestal in airborne SAR.
Dynamic Error Analysis Method for Vibration Shape Reconstruction of Smart FBG Plate Structure
Directory of Open Access Journals (Sweden)
Hesheng Zhang
2016-01-01
Full Text Available Shape reconstruction of aerospace plate structure is an important issue for safe operation of aerospace vehicles. One way to achieve such reconstruction is by constructing smart fiber Bragg grating (FBG plate structure with discrete distributed FBG sensor arrays using reconstruction algorithms in which error analysis of reconstruction algorithm is a key link. Considering that traditional error analysis methods can only deal with static data, a new dynamic data error analysis method are proposed based on LMS algorithm for shape reconstruction of smart FBG plate structure. Firstly, smart FBG structure and orthogonal curved network based reconstruction method is introduced. Then, a dynamic error analysis model is proposed for dynamic reconstruction error analysis. Thirdly, the parameter identification is done for the proposed dynamic error analysis model based on least mean square (LMS algorithm. Finally, an experimental verification platform is constructed and experimental dynamic reconstruction analysis is done. Experimental results show that the dynamic characteristics of the reconstruction performance for plate structure can be obtained accurately based on the proposed dynamic error analysis method. The proposed method can also be used for other data acquisition systems and data processing systems as a general error analysis method.
Deuterium labeling for neutron structure-function-dynamics analysis.
Meilleur, Flora; Weiss, Kevin L; Myles, Dean A A
2009-01-01
Neutron scattering and diffraction provide detailed information on the structure and dynamics of biological materials across time and length scales that range from picoseconds to nanoseconds and from 1 to 10,000 A, respectively. The particular sensitivity of neutrons to the isotopes of hydrogen makes selective deuterium labeling of biological systems an essential tool for maximizing the return from neutron scattering experiments. In neutron protein crystallography, the use of fully deuterated protein crystals improves the signal-to-noise ratio of the data by an order of magnitude and enhances the visibi-lity of the molecular structure (Proc Natl Acad Sci U S A 97:3872-3877, 2000; Acta Crystallogr D Biol Crystallogr 61:1413-1417, 2005; Acta Crystallogr D Biol Crystallogr 61:539-544, 2005). In solution and surface scattering experiments, the incorporation of deuterium-labeled subunits or components into complex assemblies or structures makes it possible to deconvolute the scattering of the labeled and unlabeled subunits and to determine their relative dispositions within the complex (J Mol Biol 93:255-265, 1975). With multiple labeling patterns, it is also possible to reconstruct the locations of multiple subunits in ternary and higher-order complexes (Science 238:1403-1406, 1987; J Mol Biol 271:588-601, 1997; J Biol Chem 275:14432-14439, 2000; Biochemistry 42:7790-7800, 2003). In inelastic neutron scattering experiments, which probe hydrogen dynamics in biological materials, the application of site, residue, or region-specific hydrogen-deuterium-labeling patterns can be used to distinguish and highlight the specific dynamics within a system (Proc Natl Acad Sci U S A 95:4970-4975, 1998).Partial, selective, or fully deuterated proteins can be readily produced by endogenous expression of recombinant proteins in bacterial systems that are adapted to growth in D(2)O solution and using selectively deuterated carbon sources. Adaptation can be achieved either by gradual
Nonlinear analysis and dynamic structure in the energy market
Aghababa, Hajar
This research assesses the dynamic structure of the energy sector of the aggregate economy in the context of nonlinear mechanisms. Earlier studies have focused mainly on the price of the energy products when detecting nonlinearities in time series data of the energy market, and there is little mention of the production side of the market. Moreover, there is a lack of exploration about the implication of high dimensionality and time aggregation when analyzing the market's fundamentals. This research will address these gaps by including the quantity side of the market in addition to the price and by systematically incorporating various frequencies for sample sizes in three essays. The goal of this research is to provide an inclusive and exhaustive examination of the dynamics in the energy markets. The first essay begins with the application of statistical techniques, and it incorporates the most well-known univariate tests for nonlinearity with distinct power functions over alternatives and tests different null hypotheses. It utilizes the daily spot price observations on five major products in the energy market. The results suggest that the time series daily spot prices of the energy products are highly nonlinear in their nature. They demonstrate apparent evidence of general nonlinear serial dependence in each individual series, as well as nonlinearity in the first, second, and third moments of the series. The second essay examines the underlying mechanism of crude oil production and identifies the nonlinear structure of the production market by utilizing various monthly time series observations of crude oil production: the U.S. field, Organization of the Petroleum Exporting Countries (OPEC), non-OPEC, and the world production of crude oil. The finding implies that the time series data of the U.S. field, OPEC, and the world production of crude oil exhibit deep nonlinearity in their structure and are generated by nonlinear mechanisms. However, the dynamics of the non
Development and application of structural dynamics analysis capabilities
Heinemann, Klaus W.; Hozaki, Shig
1994-01-01
Extensive research activities were performed in the area of multidisciplinary modeling and simulation of aerospace vehicles that are relevant to NASA Dryden Flight Research Facility. The efforts involved theoretical development, computer coding, and debugging of the STARS code. New solution procedures were developed in such areas as structures, CFD, and graphics, among others. Furthermore, systems-oriented codes were developed for rendering the code truly multidisciplinary and rather automated in nature. Also, work was performed in pre- and post-processing of engineering analysis data.
DYNAMICS ANALYSIS OF SPECIAL STRUCTURE OF MILLING-HEAD MACHINE TOOL
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
The milling-bead machine tool is a sophisticated and high-quality machine tool of which the spindle system is made up of special multi-element structure. Two special mechanical configurations make the cutting performance of the machine tool decline. One is the milling head spindle supported on two sets of complex bearings. The mechanical dynamic rigidity of milling head structure is researched on designed digital prototype with finite element analysis(FEA) and modal synthesis analysis (MSA) for identifying the weak structures. The other is the ram structure hanging on milling head. The structure is researched to get dynamic performance on cutting at different ram extending positions. The analysis results on spindle and ram are used to improve the mechanical configurations and structure in design. The machine tool is built up with modified structure and gets better dynamic rigidity than it was before.
Mast-antenna survivability : structural dynamic design analysis by component mode synthesis
Petersen, Lynn James
1994-01-01
Approved for public release; distribution is unlimited The structural survivability of shipboard mast/antenna systems subjected to underwater explosion can be designed in, through the determination of the structural dynamics of the mast/antenna system. This thesis details the specialized application of accurate and efficient analytic methods for the structural dynamic design analysis of shipboard mast/antenna systems. Investigated herein are a class of substructuring methods, generally ref...
Application of finite discrete element method in dynamic analysis of masonry structures
NIKOLIĆ, Željana; Smoljanović, Hrvoje; Zivaljić, Nikolina
2015-01-01
This paper presents the application of the numerical models for dynamic analysis of dry stone masonry structures strengthened with clamps and bolts and confined masonry structures based on finite discrete element method (FDEM). The proposed models considers the effects of the behavior of masonry structures due to dynamic action, crack initiation and propagation, energy dissipation mechanisms due to nonlinear effects, inertial effects due to motion, contact impact and attaining state of the re...
Tene, Yair; Tene, Noam; Tene, G.
1993-08-01
An interactive data fusion methodology of video, audio, and nonlinear structural dynamic analysis for potential application in forensic engineering is presented. The methodology was developed and successfully demonstrated in the analysis of heavy transportable bridge collapse during preparation for testing. Multiple bridge elements failures were identified after the collapse, including fracture, cracks and rupture of high performance structural materials. Videotape recording by hand held camcorder was the only source of information about the collapse sequence. The interactive data fusion methodology resulted in extracting relevant information form the videotape and from dynamic nonlinear structural analysis, leading to full account of the sequence of events during the bridge collapse.
Pan Dan-guang; Yu Xin
2015-01-01
For realizing the variation of structural dynamic characteristics due to neighbor structure in buildings group, the surface structure is idealized as an equivalent single degree of freedom system with rigid base whose site consists of a single homogeneous layer. Based on the model, a equivalent method on the equivalent seismic excitation is proposed. Then, the differences of seismic response and equivalent seismic input between soil - structure interaction (SSI) system and structure -soil-str...
Ukrainian Firm-Level Export Dynamics: Structural Analysis
Yevgeniya Shevtsova
2010-01-01
The paper studies the dynamics of exporting activity at the extensive and intensive margins and its impact on the firm-level total factor productivity growth for Ukraine manufacturing and service sectors in 2000-2005. The estimation is performed for different types of export markets distinguishing between developed and developing countries; and for different types of export products, distinguishing between capital versus labour intensive products and raw materials. The main finding of the pap...
Structural parameter identifiability analysis for dynamic reaction networks
DEFF Research Database (Denmark)
Davidescu, Florin Paul; Jørgensen, Sten Bay
2008-01-01
A fundamental problem in model identification is to investigate whether unknown parameters in a given model structure potentially can be uniquely recovered from experimental data. This issue of global or structural identifiability is essential during nonlinear first principles model development...... where for a given set of measured variables it is desirable to investigate which parameters may be estimated prior to spending computational effort on the actual estimation. This contribution addresses the structural parameter identifiability problem for the typical case of reaction network models. The...
Bayesian Analysis of Dynamic Multivariate Models with Multiple Structural Breaks
Sugita, Katsuhiro
2006-01-01
This paper considers a vector autoregressive model or a vector error correction model with multiple structural breaks in any subset of parameters, using a Bayesian approach with Markov chain Monte Carlo simulation technique. The number of structural breaks is determined as a sort of model selection by the posterior odds. For a cointegrated model, cointegrating rank is also allowed to change with breaks. Bayesian approach by Strachan (Journal of Business and Economic Statistics 21 (2003) 185) ...
International Nuclear Information System (INIS)
Inspired by methods of remote sensing image analysis, we analyze structural variation in cluster molecular dynamics (MD) simulations through a unique application of the principal component analysis (PCA) and Pearson Correlation Coefficient (PCC). The PCA analysis characterizes the geometric shape of the cluster structure at each time step, yielding a detailed and quantitative measure of structural stability and variation at finite temperature. Our PCC analysis captures bond structure variation in MD, which can be used to both supplement the PCA analysis as well as compare bond patterns between different cluster sizes. Relying only on atomic position data, without requirement for a priori structural input, PCA and PCC can be used to analyze both classical and ab initio MD simulations for any cluster composition or electronic configuration. Taken together, these statistical tools represent powerful new techniques for quantitative structural characterization and isomer identification in cluster MD
Modified precise time step integration method of structural dynamic analysis
Institute of Scientific and Technical Information of China (English)
Wang Mengfu; Zhou Xiyuan
2005-01-01
The precise time step integration method proposed for linear time-invariant homogeneous dynamic systems can provide precise numerical results that approach an exact solution at the integration points. However, difficulty arises when the algorithm is used for non-homogeneous dynamic systems, due to the inverse matrix calculation and the simulation accuracy of the applied loading. By combining the Gaussian quadrature method and state space theory with the calculation technique of matrix exponential function in the precise time step integration method, a new modified precise time step integration method (e.g., an algorithm with an arbitrary order of accuracy) is proposed. In the new method, no inverse matrix calculation or simulation of the applied loading is needed, and the computing efficiency is improved. In particular, the proposed method is independent of the quality of the matrix H. If the matrix H is singular or nearly singular, the advantage of the method is remarkable. The numerical stability of the proposed algorithm is discussed and a numerical example is given to demonstrate the validity and efficiency of the algorithm.
Dynamic Analysis of Wind Turbines Including Soil-Structure Interaction
DEFF Research Database (Denmark)
Harte, M.; Basu, B.; Nielsen, Søren R.K.
2012-01-01
, developed using blade element momentum theory and the Kaimal spectrum, have been considered. Soil stiffness and damping properties acquired from DNV/Risø standards are used as a comparison. The soil-structure interaction is shown to affect the response of the wind turbine. This is examined in terms of the...
Model Reduction in Dynamic Finite Element Analysis of Lightweight Structures
DEFF Research Database (Denmark)
Flodén, Ola; Persson, Kent; Sjöström, Anders;
2012-01-01
The application of wood as a construction material when building multi-storey buildings has many advantages, e.g., light weight, sustainability and low energy consumption during the construction and lifecycle of the building. However, compared to heavy structures, it is a greater challenge to bui...
A rheonomic model for the dynamical analysis of the structure-soil interaction
International Nuclear Information System (INIS)
The dynamical analysis of the structure-soil interaction requires an adequate modeling of the geometrical radiation phenomenon (g.r.) i.e. the propagation of the vibrating energy of the structure in the infinite medium. Newton's law of motion is not including the g.r., considered in this paper like an irreversible phenomenon. To incorporate this, a new wave motion equation is proposed, according to a complete analysis of the structure-soil interactions with an adequate formulation of the g.r. By using a system of fundamental dynamical solutions, the rheonom constraint applied to the half-space is represented as a restriction to the displacement solutions. A dimensionless formulation of the problem and the variation of dynamical and energetical quantities in respect to the frequency, as according to the diagram of the characteristic curve of g.r. are presented numerically. Sample results showing the importance of radiation energy for several motions are also shown
DEFF Research Database (Denmark)
Nielsen, Søren R.K.
The present textbook has been written for a course on stochastic vibration theory that is being given on the 9th semester at Aalborg University for M.Sc. students in structural engineering.......The present textbook has been written for a course on stochastic vibration theory that is being given on the 9th semester at Aalborg University for M.Sc. students in structural engineering....
Faucher, Vincent
2003-01-01
This PhD thesis sets the principles of the usage of model reduction in the framework of domain decomposition for transient structural dynamics. Time integration is explicit, designed to handle fast phenomena. The implemented multi-domains approach allows to uncouple the time scales within each subdomain, thanks to a management of non-matching meshes and a multi-time step strategy. Reduction is introduced in a totally generic way, through the projection of the equilibrium on one given subdomai...
SAP-4, Static and Dynamic Linear System Stress Analysis for Various Structures
International Nuclear Information System (INIS)
1 - Description of problem or function: SAP4 is a structural analysis program for determining the static and dynamic response of linear systems. The structural systems to be analyzed may be composed of combinations of a number of different structural elements. Currently the program contains the following element types - (a) three-dimensional truss element, (b) three-dimensional beam element, (c) plane stress and plane strain element, (d) two-dimensional axisymmetric solid, (e) three-dimensional solid, (f) variable-number nodes thick shell and three-dimensional element, (g) thin-plate or thin-shell element, (h) boundary element, and (i) pipe element (tangent and bend). 2 - Method of solution: The formation of the structure matrices is carried out in the same way in a static or dynamic analysis. The static analysis is continued by solving the equations of equilibrium followed by the computation of element stresses. In a dynamic analysis the choice is between frequency calculations only, frequency calculations followed by response history analysis, frequency calculations followed by response spectrum analysis, or response history analysis by direct integration. To obtain the frequencies and vibration mode shapes, solution routines are used which calculate the required eigenvalues and eigenvectors directly without a transformation of the structure stiffness matrix and mass matrix to a reduced form. To perform the direct integration an unconditionally stable scheme is used, which also operates on the original structure stiffness matrix and mass matrix. In this manner the program operation and input data required for a dynamic analysis are simple extensions of those needed for a static analysis. 3 - Restrictions on the complexity of the problem: The capacity of the program depends mainly on the total number of nodal points in the system, the number of eigenvalues needed in the dynamic analysis, and the computer used. There is practically no restriction on the number of
Structural analysis of floating offshore wind turbine tower based on flexible multibody dynamics
Energy Technology Data Exchange (ETDEWEB)
Park, Kwang Phil; Jo, A Ra [Daewoo Shipbuilding and Marine Engineering, Co., Ltd., Seoul (Korea, Republic of); Cha, Ju Hwan [Mokpo Nat' l Univ., Muan (Korea, Republic of)
2012-12-15
In this study, we perform the structural analysis of a floating offshore wind turbine tower by considering the dynamic response of the floating platform. A multibody system consisting of three blades, a hub, a nacelle, the platform, and the tower is used to model the floating wind turbine. The blades and the tower are modeled as flexible bodies using three dimensional beam elements. The aerodynamic force on the blades is calculated by the Blade Element Momentum (BEM) theory with hub rotation. The hydrostatic, hydrodynamic, and mooring forces are considered for the platform. The structural dynamic responses of the tower are simulated by numerically solving the equations of motion. From the simulation results, the time history of the internal forces at the nodes, such as the bending moment and stress, are obtained. In conclusion, the internal forces are compared with those obtained from static analysis to assess the effects of wave loads on the structural stability of the tower.
Structural analysis of floating offshore wind turbine tower based on flexible multibody dynamics
International Nuclear Information System (INIS)
In this study, we perform the structural analysis of a floating offshore wind turbine tower by considering the dynamic response of the floating platform. A multibody system consisting of three blades, a hub, a nacelle, the platform, and the tower is used to model the floating wind turbine. The blades and the tower are modeled as flexible bodies using three dimensional beam elements. The aerodynamic force on the blades is calculated by the Blade Element Momentum (BEM) theory with hub rotation. The hydrostatic, hydrodynamic, and mooring forces are considered for the platform. The structural dynamic responses of the tower are simulated by numerically solving the equations of motion. From the simulation results, the time history of the internal forces at the nodes, such as the bending moment and stress, are obtained. In conclusion, the internal forces are compared with those obtained from static analysis to assess the effects of wave loads on the structural stability of the tower
International Nuclear Information System (INIS)
In view of thin walled large diameter shell structures with associated fluid effects, structural dynamics problems are very critical in a fast breeder reactor. Structural characteristics and consequent structural dynamics problems in typical pool type Fast Breeder Reactor are highlighted. A few important structural dynamics problems are pump induced as well as flow induced vibrations, seismic excitations, pressure transients in the intermediate heat exchangers and pipings due to a large sodium water reaction in the steam generator, and core disruptive accident loadings. The vibration problems which call for identification of excitation forces, formulation of special governing equations and detailed analysis with fluid structure interaction and sloshing effects, particularly for the components such as PSP, inner vessel, CP, CSRDM and TB are elaborated. Seismic design issues are presented in a comprehensive way. Other transient loadings which are specific to FBR, resulting from sodium-water reaction and core disruptive accident are highlighted. A few important results of theoretical as well as experimental works carried out for 500 MWe Prototype Fast Breeder Reactor (PFBR), in the domain of structural dynamics are presented. (author)
Factor analysis of dynamic structures (FADS) in the diagnosis of the renal disease
International Nuclear Information System (INIS)
Factor analysis of dynamic structures (FADS) has been used in the interpretation of dynamic scintigraphic studies since the technique was described by Bazin et al. (1980). This study was designed to analyse to what extent, if any, does physiological factor analysis of dynamic renal data really help the clinician and by how much the method improves the diagnostic accuracy when compared to deconvolution analysis and parenchymal transit time (PTT) measurements. One hundred and fifty patients who were clinically, biochemically and radiologically investigated for renal disease were included in the study. Fifty of these were found to have no clinical evidence of renal disease, 50 were diagnosed as having non obstructive kidney disease and 50 had evidence of renal obstruction. Data obtained from 99mTc-DTPA renography were processed using deconvolution (with PTTs) and physiological factor analysis and the results compared by ROC analysis. Clinically the information gained from factor analysis was superior to that obtained from deconvolution with PTT measurements in that a more accurate differentiation between an obstructive nephropathy and an obstructive uropathy was obtained. It is considered that physiological factor analysis enhances the clinical information obtained from renography, increases diagnostic accuracy and obviates the need for diuresis renography. (orig.)
Factor analysis of dynamic structures (FADS) in the diagnosis of the renal disease
Energy Technology Data Exchange (ETDEWEB)
Macleod, M.A.; Houston, A.S.
1989-09-01
Factor analysis of dynamic structures (FADS) has been used in the interpretation of dynamic scintigraphic studies since the technique was described by Bazin et al. (1980). This study was designed to analyse to what extent, if any, does physiological factor analysis of dynamic renal data really help the clinician and by how much the method improves the diagnostic accuracy when compared to deconvolution analysis and parenchymal transit time (PTT) measurements. One hundred and fifty patients who were clinically, biochemically and radiologically investigated for renal disease were included in the study. Fifty of these were found to have no clinical evidence of renal disease, 50 were diagnosed as having non obstructive kidney disease and 50 had evidence of renal obstruction. Data obtained from /sup 99m/Tc-DTPA renography were processed using deconvolution (with PTTs) and physiological factor analysis and the results compared by ROC analysis. Clinically the information gained from factor analysis was superior to that obtained from deconvolution with PTT measurements in that a more accurate differentiation between an obstructive nephropathy and an obstructive uropathy was obtained. It is considered that physiological factor analysis enhances the clinical information obtained from renography, increases diagnostic accuracy and obviates the need for diuresis renography. (orig.).
DEFF Research Database (Denmark)
Peters, Günther H.J.; Larsen, Niels Bent; Bjørnholm, T.;
1998-01-01
We report a detailed structural analysis of the phases of 1,2-sn-dipalmitoylglycerol Langmuir monolayers at room temperature. Pressure-induced transitions have been investigated by combination of molecular-dynamics simulations and grazing-incidence x-ray diffraction (XRD). The diglyceride film un...... indicate that in the simulated monolayer the finite size with periodic boundary conditions imposes a higher degree of order....
Non-linear dynamic analysis of ancient masonry structures by 3D rigid block models
Orduña, Agustin; Ayala, A. Gustavo
2015-12-01
This work presents a formulation for non-linear dynamic analysis of unreinforced masonry structures using rigid block models. This procedure is akin to the distinct element family of methods, nevertheless, we assume that small displacements occur and, therefore, the formulation does not involve the search for new contacts between blocks. This proposal is also related to the rigid element method, although, in this case we use full three-dimensional models and a more robust interface formulation.
Hastings, Whitney Allen
This dissertation combines rigid body motion kinematics and statistical analysis techniques to extract information from detailed dynamic simulations and large databases of biomolecular structures. This information is then used to quantify and elucidate structural patterns that could be used to design functional nano-structures or provide new targets for ligand-based drug design. In this regard, three particular classes of problems are examined. First, we propose new methods for estimating the stiffness of continuum filament models of helical nucleic acid structures. In this work, molecular dynamics is used to sample RNA helices consisting of several base-pairs fluctuating about an equilibrium position. At equilibrium, each base-pair has a tightly clustered probability distribution and so we can describe the rigid body motion of the helix as the convolution of highly concentrated probability densities on SE(3). Second, the structure and dynamics of a common RNA non-helical motif is classified. We examine several RNA bulges with varying sequences and helix curvature, and establish degrees of similarity (and dissimilarity) in the bulge motif according to the nucleic acid type of the bulge and surrounding base-pairs. Both the "static" X-ray-crystal and NMR structures and the dynamics generated from molecular dynamics simulations are used to quantify the flexibility and conservative aspects of the motif. The resulting classification scheme provides bulge motifs that could be included in a toolbox of "nanostructures" where one could pick the pieces to design a structure that has the needed shape and desired behavior. Finally, we analyze a large collection of adenosine binding sites, focusing on the functional region of the binding site. We provide a new analysis tool that finds spatial patterns in adenosine binding pockets by examining the relative pose (position and orientation) between the adenosine ligand and the amino acids at each binding site. The similarities of
CAVER 3.0: a tool for the analysis of transport pathways in dynamic protein structures.
Directory of Open Access Journals (Sweden)
Eva Chovancova
Full Text Available Tunnels and channels facilitate the transport of small molecules, ions and water solvent in a large variety of proteins. Characteristics of individual transport pathways, including their geometry, physico-chemical properties and dynamics are instrumental for understanding of structure-function relationships of these proteins, for the design of new inhibitors and construction of improved biocatalysts. CAVER is a software tool widely used for the identification and characterization of transport pathways in static macromolecular structures. Herein we present a new version of CAVER enabling automatic analysis of tunnels and channels in large ensembles of protein conformations. CAVER 3.0 implements new algorithms for the calculation and clustering of pathways. A trajectory from a molecular dynamics simulation serves as the typical input, while detailed characteristics and summary statistics of the time evolution of individual pathways are provided in the outputs. To illustrate the capabilities of CAVER 3.0, the tool was applied for the analysis of molecular dynamics simulation of the microbial enzyme haloalkane dehalogenase DhaA. CAVER 3.0 safely identified and reliably estimated the importance of all previously published DhaA tunnels, including the tunnels closed in DhaA crystal structures. Obtained results clearly demonstrate that analysis of molecular dynamics simulation is essential for the estimation of pathway characteristics and elucidation of the structural basis of the tunnel gating. CAVER 3.0 paves the way for the study of important biochemical phenomena in the area of molecular transport, molecular recognition and enzymatic catalysis. The software is freely available as a multiplatform command-line application at http://www.caver.cz.
Saether, Erik; Hochhalter, Jacob D.; Glaessgen, Edward H.; Mishin, Yuri
2014-01-01
A multiscale modeling methodology is developed for structurally-graded material microstructures. Molecular dynamic (MD) simulations are performed at the nanoscale to determine fundamental failure mechanisms and quantify material constitutive parameters. These parameters are used to calibrate material processes at the mesoscale using discrete dislocation dynamics (DD). Different grain boundary interactions with dislocations are analyzed using DD to predict grain-size dependent stress-strain behavior. These relationships are mapped into crystal plasticity (CP) parameters to develop a computationally efficient finite element-based DD/CP model for continuum-level simulations and complete the multiscale analysis by predicting the behavior of macroscopic physical specimens. The present analysis is focused on simulating the behavior of a graded microstructure in which grain sizes are on the order of nanometers in the exterior region and transition to larger, multi-micron size in the interior domain. This microstructural configuration has been shown to offer improved mechanical properties over homogeneous coarse-grained materials by increasing yield stress while maintaining ductility. Various mesoscopic polycrystal models of structurally-graded microstructures are generated, analyzed and used as a benchmark for comparison between multiscale DD/CP model and DD predictions. A final series of simulations utilize the DD/CP analysis method exclusively to study macroscopic models that cannot be analyzed by MD or DD methods alone due to the model size.
International Nuclear Information System (INIS)
In recent years, the use of computer codes to study the response of primary containment of large, liquid-metal fast breeder reactors (LMFBR) under postulated accident conditions has been adopted by most fast reactor projects. This paper gives a brief survey of the computational methods and codes available for LMFBR containment analysis. The various numerical methods commonly used in the computer codes are compared. It provides the reactor engineers up-to-date information on the development of structural dynamics in LMFBR containment analysis. It can also be used as a basis for the selection of the numerical method in the future code development. (Auth.)
Task 7a: Dynamic analysis of Paks NPP structures reactor building
International Nuclear Information System (INIS)
This report describes dynamic response calculation of the NPP Paks, reactor building to the full scale blast testing. All calculations described in this report have been elaborated within the scope of IAEA co-ordinated research - Benchmark Study for for seismic analysis/testing of NPPs type WWER - Task 7a - Dynamic Analysis of PAKS NPP structures, i.e. reactor building. The input in the form of time history of velocities or accelerations on the free field caused by blast testing was only available for the participants of the task No.7a. The aim of this task is to calculate the dynamic response to the blast load in the form of floor response spectra in selected nodes of the structure without knowing the measured data. The data measured by the full scale blast test are published and the results of different calculations compared. The following structures were taken into account: turbine hall, intermediate multi-storey building, lateral multi-storey building, reactor building, ventilation center and condenser towers
Sreekantamurthy, Tham; Gaspar, James L.; Mann, Troy; Behun, Vaughn; Pearson, James C., Jr.; Scarborough, Stephen
2007-01-01
Ultra-light weight and ultra-thin membrane inflatable antenna concepts are fast evolving to become the state-of-the-art antenna concepts for deep-space applications. NASA Langley Research Center has been involved in the structural dynamics research on antenna structures. One of the goals of the research is to develop structural analysis methodology for prediction of the static and dynamic response characteristics of the inflatable antenna concepts. This research is focused on the computational studies to use nonlinear large deformation finite element analysis to characterize the ultra-thin membrane responses of the antennas. Recently, structural analyses have been performed on a few parabolic reflector antennas of varying size and shape, which are referred in the paper as 0.3 meters subscale, 2 meters half-scale, and 4 meters full-scale antenna. The various aspects studied included nonlinear analysis methodology and solution techniques, ways to speed convergence in iterative methods, the sensitivities of responses with respect to structural loads, such as inflation pressure, gravity, and pretension loads in the ground and in-space conditions, and the ultra-thin membrane wrinkling characteristics. Several such intrinsic aspects studied have provided valuable insight into evaluation of structural characteristics of such antennas. While analyzing these structural characteristics, a quick study was also made to assess the applicability of dynamics scaling of the half-scale antenna. This paper presents the details of the nonlinear structural analysis results, and discusses the insight gained from the studies on the various intrinsic aspects of the analysis methodology. The predicted reflector surface characteristics of the three inflatable ultra-thin membrane parabolic reflector antenna concepts are presented as easily observable displacement fringe patterns with associated maximum values, and normal mode shapes and associated frequencies. Wrinkling patterns are
The effect of glycosylation on the transferrin structure: A molecular dynamic simulation analysis.
Ghanbari, Z; Housaindokht, M R; Bozorgmehr, M R; Izadyar, M
2016-09-01
Transferrins have been defined by the highly cooperative binding of iron and a carbonate anion to form a Fe-CO3-Tf ternary complex. As such, the layout of the binding site residues affects transferrin function significantly; In contrast to N-lobe, C-lobe binding site of the transferrin structure has been less characterized and little research which surveyed the interaction of carbonate with transferrin in the C-lobe binding site has been found. In the present work, molecular dynamic simulation was employed to gain access into the molecular level understanding of carbonate binding site and their interactions in each lobe. Residues responsible for carbonate binding of transferrin structure were pointed out. In addition, native human transferrin is a glycoprotein that two N-linked complex glycan chains located in the C-lobe. Usually, in the molecular dynamic simulation for simplifying, glycan is removed from the protein structure. Here, we explore the effect of glycosylation on the transferrin structure. Glycosylation appears to have an effect on the layout of the binding site residue and transferrin structure. On the other hand, sometimes the entire transferrin formed by separated lobes that it allows the results to be interpreted in a straightforward manner rather than more parameters required for full length protein. But, it should be noted that there are differences between the separated lobe and full length transferrin, hence, a comparative analysis by the molecular dynamic simulation was performed to investigate such structural variations. Results revealed that separation in C-lobe caused a significant structural variation in comparison to N-lobe. Consequently, the separated lobes and the full length one are different, showing the importance of the interlobe communication and the impact of the lobes on each other in the transferrin structure. PMID:27235585
Dynamics of High-speed Machining of Aerospace Structures using Finite-element Analysis
Directory of Open Access Journals (Sweden)
J. Kanchana
2002-10-01
Full Text Available "The study is aimed to investigate certain aspects of high-speed machining for improving the accuracy of thin-walled aerospace components. The approach used involved the development of finite-element model of the workpiece to be machined and its subsequent frequency response analysis. The response of the workpiece subjected to dynamic cutting force gives an indication of the best possible speeds from the point of view of accuracy. Based on the results of the analysis, it is possible to predict the range of spindle speeds at which the workpiece demonstrates very high dynamic rigidity. In addition, this study has established the superiority of high-speed machining to produce aerospace structures with high stiffness-to-weight ratio and also throws some light on the capability of high speed in machining of low rigidity sculptured-surface components. "
International Nuclear Information System (INIS)
The safe and reliable satisfaction of the world's increasing energy demand at affordable costs is one of the major challenges of our century. Nuclear fusion power plants following the magnetic confinement approach may play an essential role in solving this issue. The energy loss of the fusion plasma due to plasma turbulence reduces the efficiency and poses a threat to the first wall of a fusion reactor. Close to the wall, in the scrape-off layer, this transport is dominated by blobs or filaments: Localized structures of increased pressure, which transport energy and particles towards the wall by propagating radially outwards. Their contribution to the transport depends on their size, propagation velocity and generation rate. An analytical model for the evolution of blobs predicts their velocity and size, but not the generation rate. Experiments indicate that edge turbulence in the vicinity of the last closed flux surface (the boundary between the confined plasma and the scrape-off layer) is involved in the blob generation process and should influence the generation rate. The present thesis aims at answering two main questions: How well do the blob properties predicted from the simple model compare to experimental observations in more complex magnetic field configurations of actual fusion experiments and does the edge turbulence influence the blob properties during the generation process. A fast camera was used to measure blob properties in two devices, TJ-K and ASDEX Upgrade. In TJ-K, blob sizes and velocities were determined together with the generation rate. An overall agreement with the predictions from the simple model is found. For the first time a clear influence of the edge dynamics on the analyzed blob properties is demonstrated. These measurements include the first systematic comparison of the structure-size scaling inside and outside of the last closed flux surface. Furthermore, measurements with a multi-probe array are used to reconstruct the blob
Directory of Open Access Journals (Sweden)
Leandro Martínez
Full Text Available The analysis of structural mobility in molecular dynamics plays a key role in data interpretation, particularly in the simulation of biomolecules. The most common mobility measures computed from simulations are the Root Mean Square Deviation (RMSD and Root Mean Square Fluctuations (RMSF of the structures. These are computed after the alignment of atomic coordinates in each trajectory step to a reference structure. This rigid-body alignment is not robust, in the sense that if a small portion of the structure is highly mobile, the RMSD and RMSF increase for all atoms, resulting possibly in poor quantification of the structural fluctuations and, often, to overlooking important fluctuations associated to biological function. The motivation of this work is to provide a robust measure of structural mobility that is practical, and easy to interpret. We propose a Low-Order-Value-Optimization (LOVO strategy for the robust alignment of the least mobile substructures in a simulation. These substructures are automatically identified by the method. The algorithm consists of the iterative superposition of the fraction of structure displaying the smallest displacements. Therefore, the least mobile substructures are identified, providing a clearer picture of the overall structural fluctuations. Examples are given to illustrate the interpretative advantages of this strategy. The software for performing the alignments was named MDLovoFit and it is available as free-software at: http://leandro.iqm.unicamp.br/mdlovofit.
A hybrid analysis method for linear dynamic soil-structure interaction in time and frequency domain
Institute of Scientific and Technical Information of China (English)
丁海平; 廖振鹏
2001-01-01
A hybrid analysis method in time and frequency domains for linear soil-structure interaction is presented. First, the time domain solution of the system with Rayleigh damping excited by a short time impulse is obtained by the decoupling numerical simulation technique of near-field wave motion. Then, the corresponding frequency domain solution can be got by Fourier transform. According to the relationship between damping value and dynamic re-sponse of a system, the solution of the system with complex damping can be got by Taylor expansion. The hybrid method makes the best of decoupling and explicit algorithm in time domain, and increases the calculation efficien-cy for linear soil-structure interaction analysis.
Application of the Probabilistic Dynamic Synthesis Method to the Analysis of a Realistic Structure
Brown, Andrew M.; Ferri, Aldo A.
1998-01-01
The Probabilistic Dynamic Synthesis method is a new technique for obtaining the statistics of a desired response engineering quantity for a structure with non-deterministic parameters. The method uses measured data from modal testing of the structure as the input random variables, rather than more "primitive" quantities like geometry or material variation. This modal information is much more comprehensive and easily measured than the "primitive" information. The probabilistic analysis is carried out using either response surface reliability methods or Monte Carlo simulation. A previous work verified the feasibility of the PDS method on a simple seven degree-of-freedom spring-mass system. In this paper, extensive issues involved with applying the method to a realistic three-substructure system are examined, and free and forced response analyses are performed. The results from using the method are promising, especially when the lack of alternatives for obtaining quantitative output for probabilistic structures is considered.
Yen, N. V.; Hong, N. V.; Hung, P. K.; Huy, N. V.
2015-06-01
The structure and dynamics of liquid lead silicate (PbSiO3) are investigated by molecular dynamics simulation with the pair potentials. The models of PbSiO3 consisting of 5000 atoms (1000 Pb, 1000 Si, and 3000 O atoms) are constructed at 3200 K and in a 0-35 GPa pressure range. The local structure, polymorphism, and dynamics in liquid PbSiO3 are investigated through pair radial distribution function, coordination distribution, topology structure of basic structural units, and mean square displacement. Short-range order (SRO) and intermediate-range order (IRO) are clarified by visualization of simulated data. The local environment around Pb+2 and Si+4 ions, the network structure of SiOx (x = 4, 5, 6) and PbOn (n = 3 - 9) polyhedra, and the correlation between structure and dynamics, as well as their change under compression, are also discussed in detail.
THE ANALYSIS OF THE EFFECT OF DYNAMIC STRUCTURE OF INSTITUTIONS ON ECONOMIC GROWTH
Selim Yildirim
2010-01-01
Institutional structure, in its most general form expresses any kind of cognitive habit that regulates relationship among individuals. Institutions are not structure without change, as the economic politic and social relations change institutional structure changes as well. Although institutions play a significant role in interaction among individuals it is a dynamic structure affected by relations among individuals. The dynamic structure of institutions affects the performance of the economy...
Institute of Scientific and Technical Information of China (English)
HUANG Hu; ZHANG She-rong
2011-01-01
Tension leg platform(TLP)for offshore wind turbine support is a new type structure in wind energy utilization.The strong-interaction method is used in analyzing the coupled model,and the dynamic characteristics of the TLP for offshore wind turbine support are recognized.As shown by the calculated results:for the lower modes,the shapes are water's vibration,and the vibration of water induces the structure's swing;the mode shapes of the structure are complex,and can largely change among different members;the mode shapes of the platform are related to the tower's.The frequencies of the structure do not change much after adjusting the length of the tension cables and the depth of the platform;the TLP has good adaptability for the water depths and the environment loads.The change of the size and parameters of TLP can improve the dynamic characteristics,which can reduce the vibration of the TLP caused by the loads.Through the vibration analysis,the natural vibration frequencies of TLP can be distinguished from the frequencies of condition loads,and thus the resonance vibration can be avoided,therefore the offshore wind turbine can work normally in the complex conditions.
Brown, A. M.
1998-01-01
Accounting for the statistical geometric and material variability of structures in analysis has been a topic of considerable research for the last 30 years. The determination of quantifiable measures of statistical probability of a desired response variable, such as natural frequency, maximum displacement, or stress, to replace experience-based "safety factors" has been a primary goal of these studies. There are, however, several problems associated with their satisfactory application to realistic structures, such as bladed disks in turbomachinery. These include the accurate definition of the input random variables (rv's), the large size of the finite element models frequently used to simulate these structures, which makes even a single deterministic analysis expensive, and accurate generation of the cumulative distribution function (CDF) necessary to obtain the probability of the desired response variables. The research presented here applies a methodology called probabilistic dynamic synthesis (PDS) to solve these problems. The PDS method uses dynamic characteristics of substructures measured from modal test as the input rv's, rather than "primitive" rv's such as material or geometric uncertainties. These dynamic characteristics, which are the free-free eigenvalues, eigenvectors, and residual flexibility (RF), are readily measured and for many substructures, a reasonable sample set of these measurements can be obtained. The statistics for these rv's accurately account for the entire random character of the substructure. Using the RF method of component mode synthesis, these dynamic characteristics are used to generate reduced-size sample models of the substructures, which are then coupled to form system models. These sample models are used to obtain the CDF of the response variable by either applying Monte Carlo simulation or by generating data points for use in the response surface reliability method, which can perform the probabilistic analysis with an order of
Institute of Scientific and Technical Information of China (English)
MA Juan; CHEN Jian-jun; XU Ya-lan; JIANG Tao
2006-01-01
A new fuzzy stochastic finite element method based on the fuzzy factor method and random factor method is given and the analysis of structural dynamic characteristic for fuzzy stochastic truss structures is presented. Considering the fuzzy randomness of the structural physical parameters and geometric dimensions simultaneously, the structural stiffness and mass matrices are constructed based on the fuzzy factor method and random factor method; from the Rayleigh's quotient of structural vibration, the structural fuzzy random dynamic characteristic is obtained by means of the interval arithmetic;the fuzzy numeric characteristics of dynamic characteristic are then derived by using the random variable's moment function method and algebra synthesis method. Two examples are used to illustrate the validity and rationality of the method given. The advantage of this method is that the effect of the fuzzy randomness of one of the structural parameters on the fuzzy randomness of the dynamic characteristic can be reflected expediently and objectively.
DYNAMIC ANALYSIS OF FOLDED CANTILEVER SHEAR STRUCTURE AND BASE ISOLATED STRUCTURE
Wijaya, Ming Narto; Katayama, Takuro; Yamao, Toshitaka; ウィジャヤ, ミン ナルト; 片山, 拓朗; 山尾, 敏孝
2014-01-01
Seismic isolation is the most important in earthquake resistant structural design. Many isolation techniques have been developed to reduce the impact of earthquake. The seismic responses of eleven-storey models of folded cantilever shear structure as a proposed structure have been studied numerically. Folded cantilever shear structure (FCSS) consist of fixed-movable-fixed supported shear sub-frames and connection rigid sub-frame which connect their sub-frames at the top. The movable sub-frame...
Directory of Open Access Journals (Sweden)
James Lua
2004-01-01
Full Text Available Marine composite materials typically exhibit significant rate dependent response characteristics when subjected to extreme dynamic loading conditions. In this work, a strain-rate dependent continuum damage model is incorporated with multicontinuum technology (MCT to predict damage and failure progression for composite material structures. MCT treats the constituents of a woven fabric composite as separate but linked continua, thereby allowing a designer to extract constituent stress/strain information in a structural analysis. The MCT algorithm and material damage model are numerically implemented with the explicit finite element code LS-DYNA3D via a user-defined material model (umat. The effects of the strain-rate hardening model are demonstrated through both simple single element analyses for woven fabric composites and also structural level impact simulations of a composite panel subjected to various impact conditions. Progressive damage at the constituent level is monitored throughout the loading. The results qualitatively illustrate the value of rate dependent material models for marine composite materials under extreme dynamic loading conditions.
Nishiyama, Katsuhiko
2010-07-01
The binding of 10GLY to dynamic structures of papain was investigated by molecular dynamics and docking simulations. The binding free energies and sites were greatly fluctuated depending on the time and the binding was more stable and existed at the near site of active center when the structural changes in the highly flexible residues in papain were larger. Binding stability and sites would be significantly influenced by the highly flexible residues. Analysis of such residues would provide an important guideline for clarification of enzymatic activities and modification of structural dynamics of such residues would allow us to control enzymatic activities.
Dynamic analysis of the Green Bank Telescope structure and servo system
Ranka, Trupti; Garcia-Sanz, Mario; Symmes, Arthur; Ford, John M.; Weadon, Timothy
2016-01-01
The Green Bank Telescope is a 100-m aperture single-dish radio telescope. For high-frequency observations (above 100 GHz), it needs a tracking error below 1.5 arc sec rms. The present system has a tracking error of 1 arc sec rms for very low wind speeds of ≤1 m/s, which increases well above 1.5 arc sec for wind speeds above 4 m/s. Hence, improvements in the servo control system are needed to achieve pointing accuracy goals for high-frequency observations. As a first step toward this goal, it is necessary to evaluate the dynamic response of the present servo system and the telescope, which forms a large flexible structure. We derive the model of the telescope dynamics using finite element analysis data. This model is further tuned and validated using system identification experiments performed on the telescope. A reduced model is developed for controller design by using modes with the highest Hankel singular value for frequencies up to 2 Hz. We quantify the uncertainty in azimuth axis dynamics with a change in elevation angle by varying the zeros of the model. We discuss the effects of transient response, wind disturbances, and azimuth track joint disturbances on telescope tracking performance.
Dynamic soil-structure interaction analysis based on discretized Green function
International Nuclear Information System (INIS)
In the seismic design of massive and rigid structure such as a nuclear reactor building, it is important to evaluate the dynamic interaction effect between soil and structure. The authors developed an advanced and practical method to evaluate the interaction effect between the soil which is considered to be semi-infinite elastic medium, and the structure in which flexibility is considered. In this report, this method is applied to a seismic analysis of the full size BWR Mark I type reactor building. For horizontal input earthquake, the vibrational degrees of freedom shall be considered both horizontal and vertical as the rocking response occurs because of the overturning moment caused by the building's horizontal response. The results of earthquake response analysis show that the floors deform in-place and the response acceleration at the center of the floor is larger than that of at the side wall. The response spectra also differ each other even if on the same floor because of the in-place deformation of the floor slab. It means that in analytical modeling of the reactor building, multi-stick model considering deformation of floor slab is required instead of single-stick model. The ratio of the peak acceleration response of the roof floor to the input earthquake is about 2.5. (orig./HP)
Kandasamy, Ramkumar; Cui, Fangsen
2016-04-01
In the traditional layered piezoelectric structures, high stress concentrations could cause the structural failure in interlayer surfaces due to repeated strain reversals. To overcome the performance limitations of these structures, the concept of Functionally Graded Materials (FGMs) has been introduced to improve the lifetime, integrity, and reliability of these structures. In this paper, the free and forced vibration of radially polarized Functionally Graded Piezoelectric (FGP) cylinders under different sets of loading are studied. Material properties such as piezoelectric, elastic and permittivity are assumed to change along its thickness, based on a specific gradation function. Four-parameter power law distribution is used to grade the volume fraction of the constituents comprising of PZT-5A and PZT-5H. Material property is assumed to be temperature dependent for a few numerical studies. The present modeling approach is validated by comparing the free and forced vibration of radially polarized Functionally Graded Piezoelectric (FGP) cylinders with those reported in the literature. The effects of material composition, loading and boundary conditions on the dynamic behavior of FGP cylinder are described. Since the modeling of functionally graded piezoelectric systems is challenging, the present study can help in the design and analysis of FGP cylinders.
Anderson, James C
2012-01-01
A concise introduction to structural dynamics and earthquake engineering Basic Structural Dynamics serves as a fundamental introduction to the topic of structural dynamics. Covering single and multiple-degree-of-freedom systems while providing an introduction to earthquake engineering, the book keeps the coverage succinct and on topic at a level that is appropriate for undergraduate and graduate students. Through dozens of worked examples based on actual structures, it also introduces readers to MATLAB, a powerful software for solving both simple and complex structural d
Iungo, Giacomo Valerio; Lombardi, Edoardo
2011-01-01
Time–frequency analysis of the dynamics of different wake vorticity structures, generated from a triangular prism orientated with its apex edge against the incoming wind, is carried out. Time–frequency analysis of time-series obtained with hot-wire anemometry is performed through a procedure based on proper orthogonal decomposition and spectral components are extracted with a technique that provides an increased efficiency for fluid dynamic applications.
Computational Methods for Structural Mechanics and Dynamics
Stroud, W. Jefferson (Editor); Housner, Jerrold M. (Editor); Tanner, John A. (Editor); Hayduk, Robert J. (Editor)
1989-01-01
Topics addressed include: transient dynamics; transient finite element method; transient analysis in impact and crash dynamic studies; multibody computer codes; dynamic analysis of space structures; multibody mechanics and manipulators; spatial and coplanar linkage systems; flexible body simulation; multibody dynamics; dynamical systems; and nonlinear characteristics of joints.
DYNAPCON: a computer code for dynamic analysis of prestressed concrete structures. [LMFBR
Energy Technology Data Exchange (ETDEWEB)
Marchertas, A.H.
1982-09-01
A finite element computer code for the transient analysis of prestressed concrete reactor vessels (PCRVs) for LMFBR containment is described. The method assumes rotational symmetry of the structure. Time integration is by an explicit method. The quasistatic prestressing operation of the PCRV model is performed by a dynamic relaxation technique. The material model accounts for the crushing and tensile cracking in arbitrary direction in concrete and the elastic-plastic behavior of reinforcing steel. The variation of the concrete tensile cracking and compressive crushing limits with strain rate is taken into account. Relative slip is permitted between the concrete and tendons. Several example solutions are presented and compared with experimental results. These sample problems range from simply supported beams to small scale models of PCRV's. It is shown that the analytical methods correlate quite well with experimental results, although in the vicinity of the failure load the response of the models tend to be quite sensitive to input parameters.
DYNAPCON: a computer code for dynamic analysis of prestressed concrete structures
International Nuclear Information System (INIS)
A finite element computer code for the transient analysis of prestressed concrete reactor vessels (PCRVs) for LMFBR containment is described. The method assumes rotational symmetry of the structure. Time integration is by an explicit method. The quasistatic prestressing operation of the PCRV model is performed by a dynamic relaxation technique. The material model accounts for the crushing and tensile cracking in arbitrary direction in concrete and the elastic-plastic behavior of reinforcing steel. The variation of the concrete tensile cracking and compressive crushing limits with strain rate is taken into account. Relative slip is permitted between the concrete and tendons. Several example solutions are presented and compared with experimental results. These sample problems range from simply supported beams to small scale models of PCRV's. It is shown that the analytical methods correlate quite well with experimental results, although in the vicinity of the failure load the response of the models tend to be quite sensitive to input parameters
Dynamic Soil-Structure-Soil-Interaction Analysis of Structures in Dense Urban Environments
Jones, Katherine Carys
2013-01-01
Urban centers are increasingly becoming the locus of enterprise, innovation, and population. This pull toward the center of cities has steadily elevated the importance of these areas. Growth has necessarily spawned new construction. Consequently, modern buildings are often constructed alongside legacy structures, new deep basements are constructed alongside existing shallow foundations, and city blocks composed of a variety of building types result. The underlying soil, foundation, and super...
Nonlinear dynamics of structures
Oller, Sergio
2014-01-01
This book lays the foundation of knowledge that will allow a better understanding of nonlinear phenomena that occur in structural dynamics. This work is intended for graduate engineering students who want to expand their knowledge on the dynamic behavior of structures, specifically in the nonlinear field, by presenting the basis of dynamic balance in non‐linear behavior structures due to the material and kinematics mechanical effects. Particularly, this publication shows the solution of the equation of dynamic equilibrium for structure with nonlinear time‐independent materials (plasticity, damage and frequencies evolution), as well as those time dependent non‐linear behavior materials (viscoelasticity and viscoplasticity). The convergence conditions for the non‐linear dynamic structure solution are studied, and the theoretical concepts and its programming algorithms are presented.
A NASTRAN-based computer program for structural dynamic analysis of Horizontal Axis Wind Turbines
Lobitz, Don W.
1995-05-01
This paper describes a computer program developed for structural dynamic analysis of horizontal axis wind turbines (HAWT's). It is based on the finite element method through its reliance on NASTRAN for the development of mass, stiffness, and damping matrices of the tower end rotor, which are treated in NASTRAN as separate structures. The tower is modeled in a stationary frame and the rotor in one rotating at a constant angular velocity. The two structures are subsequently joined together (external to NASTRAN) using a time-dependent transformation consistent with the hub configuration. Aerodynamic loads are computed with an established flow model based on strip theory. Aeroelastic effects are included by incorporating the local velocity and twisting deformation of the blade in the load computation. The turbulent nature of the wind, both in space and time, is modeled by adding in stochastic wind increments. The resulting equations of motion are solved in the time domain using the implicit Newmark-Beta integrator. Preliminary comparisons with data from the Boeing/NASA MOD2 HAWT indicate that the code is capable of accurately and efficiently predicting the response of HAWT's driven by turbulent winds.
International Nuclear Information System (INIS)
Within the framework of project RS1197, analysis methods have been further developed and tested for the determination of the structural dynamic loading and the maximum load-bearing capacity of containment structures with a focus on the quantification of safety margins against failures due to loads resulting from selected internal and external hazards. The analyses comprised a model containment structure of prestressed reinforced concrete under internal pressure loading until reaching failure pressure, an outer containment structure made of reinforced concrete under local impact loads that may occur during a targeted aircraft crash, and a steel containment under local peak loads from internal pressure and temperature loads due to core melt scenarios with a local hydrogen combustion. GRS participated in the international ''Standard Problem Exercise 3'' on the issue ''Performance of Containment Vessel under Severe Accident Conditions''. Together with the cooperation partners, aspects of the global containment behaviour were considered based on the example of the Sandia 1:4 model containment of prestressed concrete, which was loaded by rising internal pressure until failure. Complex analysis models were developed, calculating the behaviour of the prestressing tendons under consideration of the frictional contact with the cladding tubes. Compared with corresponding measurement values, the analysis results show that the stresses near the tensioning device and the deformation of the inner surface can be realistically modelled as a function of the internal pressure. In the experiment, global structural failure of the containment model was caused by tendon rupture at about 3.64 times the design pressure. With the developed analysis models of a generic structure of an outer reinforced concrete containment, simulations were carried out for various aircraft crash scenarios as contact problems with explicit impactor simulation. For this
Sensitivity analysis of asphalt-pavement structure dynamic responses under heavy load
Directory of Open Access Journals (Sweden)
ZHANG Lijuan
2015-04-01
Full Text Available With the 3-Dimensional finite-element dynamic model,the influence of axis-load,axis-speed,and pavement structure parameters on dynamic performance of pavement structure is studied.The results show that with the increase in load,the dynamic response of pavement is nearly proportional to axis-load and increases noticeably;Axis-speed influences the dynamic response to some extent.With the increase of axis-speed,dynamic response of pavement structure increases firstly.With axis-speed further increasing,dynamic response of pavement structure then decreases gradually.For fatigue failure,the influence of heavy-load with common moving speed is much greater than that of static load.Among the pavement structure parameters,thickness of surface-layer has a significant effect on shear stress and the compression stress at road surface.Subgrade modulus has a significant effect on road surface deflection,tensile stress at the bottom of subbase,and compression-strain at the top of subgrade.
Directory of Open Access Journals (Sweden)
Yang Yang
2014-01-01
Full Text Available Based on the characteristics of the dynamic interaction between an underground powerhouse concrete structure and its surrounding rock in a hydropower plant, an algorithm of dynamic contact force was proposed. This algorithm enables the simulation of three states of contact surface under dynamic loads, namely, cohesive contact, sliding contact, and separation. It is suitable for the numerical analysis of the dynamic response of the large and complex contact system consisting of underground powerhouse concrete structure and the surrounding rock. This algorithm and a 3D plastic-damage model were implemented in a dynamic computing platform, SUCED, to analyze the dynamic characteristics of the underground powerhouse structure of Yingxiuwan Hydropower Plant. By comparing the numerical results and postearthquake investigations, it was concluded that the amplitude and duration of seismic waves were the external factors causing seismic damage of the underground powerhouse structure, and the spatial variations in structural properties were the internal factors. The existence of rock mass surrounding the underground powerhouse was vital to the seismic stability of the structure. This work provides the theoretical basis for the anti-seismic design of underground powerhouse structures.
Shan, Lu; Mathews, Irimpan I; Khosla, Chaitan
2005-03-01
Prolyl endopeptidases (PEPs) are a unique class of serine proteases with considerable therapeutic potential for the treatment of celiac sprue. The crystal structures of two didomain PEPs have been solved in alternative configurations, thereby providing insights into the mode of action of these enzymes. The structure of the Sphingomonas capsulata PEP, solved and refined to 1.8-A resolution, revealed an open configuration of the active site. In contrast, the inhibitor-bound PEP from Myxococcus xanthus was crystallized (1.5-A resolution) in a closed form. Comparative analysis of the two structures highlights a critical role for the domain interface in regulating interdomain dynamics and substrate specificity. Structure-based mutagenesis of the M. xanthus PEP confirms an important role for several interfacial residues. A salt bridge between Arg-572 and Asp-196/Glu-197 appears to act as a latch for opening or closing the didomain enzyme, and Arg-572 and Ile-575 may also help secure the incoming peptide substrate to the open form of the enzyme. Arg-618 and Asp-145 are responsible for anchoring the invariant proline residue in the active site of this postproline-cleaving enzyme. A model is proposed for the docking of a representative substrate PQPQLPYPQPQLP in the active site, where the N-terminal substrate residues interact extensively with the catalytic domain, and the C-terminal residues stretch into the propeller domain. Given the promise of the M. xanthus PEP as an oral therapeutic enzyme for treating celiac sprue, our results provide a strong foundation for further optimization of the PEP's clinically useful features. PMID:15738423
General Dynamics Convair Division approach to structural analysis of large superconducting coils
International Nuclear Information System (INIS)
Most of the procedures and techniques described were developed over the past three years. Starting in late 1976, development began on high-accuracy computer codes for electromagnetic field and force analysis. This effort resulted in completion of a family of computer programs called MAGIC (MAGnetic Integration Calcaultion). Included in this group of programs is a post-processor called POSTMAGIC that links MAGIC to GDSAP (General Dynamics Structural Analysis Program) by automatically transferring force data. Integrating these computer programs afforded us the capability to readily analyze several different conditions that are anticipated to occur during tokamak operation. During 1977 we initiated the development of the CONVERT program that effectively links our THERMAL ANALYZER program to GDSAP by automatically transferring temperature data. The CONVERT program allowed us the capability to readily predict thermal stresses at several different time phases during the computer-simulated cooldown and warmup cycle. This feature aided us in determining the most crucial time phases and to adjust recommended operating procedure to minimize risk
Dynamic analysis of offshore structures with non-zero initial conditions in the frequency domain
Liu, Fushun; Lu, Hongchao; Li, Huajun
2016-03-01
The state of non-zero conditions is typically treated as fact when considering the dynamic analysis of offshore structures. This article extends a newly proposed method [1] to manage the non-zero initial conditions of offshore structures in the frequency domain, including new studies on original environmental loads reconstruction, response comparisons with the commercial software ANSYS, and a demonstration using an experimental cantilever beam. The original environmental loads, such as waves, currents, and winds, that act on a structure are decomposed into multiple complex exponential components are represented by a series of poles and corresponding residues. Counter to the traditional frequency-domain method, the non-zero initial conditions of offshore structures could be solved in the frequency domain. Compared with reference [1], an improvement reported in this article is that practical issues, including the choice of model order and central-processing-unit (CPU) time consumption, are further studied when applying this new method to offshore structures. To investigate the feasibility of the representation of initial environmental loads by their poles and corresponding residues, a measured random wave force collected from a column experiment at the Lab of Ocean University of China is used, decomposed, reconstructed and then compared with the original wave force; then, a numerical offshore platform is used to study the performance of the proposed method in detail. The numerical results of this study indicate that (1) a short duration of environmental loads are required to obtain their constitutive poles and residues, which implies good computational efficiency; and (2) the proposed method has a similar computational efficiency to traditional methods due to the use of the inverse Fourier transform technique. To better understand the performance, of time consumption and accuracy of the proposed method, the commercial software ANSYS is used to determine responses
Energy Technology Data Exchange (ETDEWEB)
Ahn, Chang Kee; Shim, Joo Sup [Shinwa Technology Information, Seoul (Korea)
2001-04-01
The objective of this study is to deduce the dynamic correlation between the fuel assembly and the reactor structure. Dynamic characteristics analyses for reactor structure related with vibration of HANARO fuel assembly have been performed For the dynamic characteristic analysis, the in-air models of the round and hexagonal flow tubes, 18-element and 36-element fuel assemblies, and reactor structure were developed. By calculating the hydrodynamic mass and distributing it on the in-air models, the in-water models of the flow tubes, the fuel assemblies, and the reactor structure were developed. Then, modal analyses for developed in-air and in-water models have been performed. Especially, two 18-element fuel assemblies and three 36-element fuel assemblies were included in the in-water reactor models. For the verification of the modal analysis results, the natural frequencies and the mode shapes of the fuel assembly were compared with those obtained from the experiment. Finally the analysis results of the reactor structure were compared with them performed by AECL Based on the reactor model without PCS piping, the in-water reactor model including the fuel assemblies was developed, and its modal analysis was performed. The analysis results demonstrate that there are no resonance between the fuel assembly and the reactor structures. 26 refs., 419 figs., 85 tabs. (Author)
Market Structure and Innovation: A Dynamic Analysis of the Global Automobile Industry
Johannes Van Biesebroeck; Aamir Hashmi
2007-01-01
We study the relationship between market structure and innovation in the global automobile industry from 1982 to 2004 using the dynamic industry framework of Ericson and Pakes (1995). Firms optimally choose a continuous level of innovation in a strategic and forward-looking manner, while anticipating the possibility of future mergers. We show that our estimated model predicts the data well and that changes in the modeling assumptions have a predictable effect on the key dynamic parameter -- t...
Perino, Scott; Bayandor, Javid; Siddens, Aaron
2012-01-01
The anticipated NASA Mars Sample Return Mission (MSR) requires a simple and reliable method in which to return collected Martian samples back to earth for scientific analysis. The Multi-Mission Earth Entry Vehicle (MMEEV) is NASA's proposed solution to this MSR requirement. Key aspects of the MMEEV are its reliable and passive operation, energy absorbing foam-composite structure, and modular impact sphere (IS) design. To aid in the development of an EEV design that can be modified for various missions requirements, two fully parametric finite element models were developed. The first model was developed in an explicit finite element code and was designed to evaluate the impact response of the vehicle and payload during the final stage of the vehicle's return to earth. The second model was developed in an explicit code and was designed to evaluate the static and dynamic structural response of the vehicle during launch and reentry. In contrast to most other FE models, built through a Graphical User Interface (GUI) pre-processor, the current model was developed using a coding technique that allows the analyst to quickly change nearly all aspects of the model including: geometric dimensions, material properties, load and boundary conditions, mesh properties, and analysis controls. Using the developed design tool, a full range of proposed designs can quickly be analyzed numerically and thus the design trade space for the EEV can be fully understood. An engineer can then quickly reach the best design for a specific mission and also adapt and optimize the general design for different missions.
Structural Modeling and Analysis of a Wave Energy Converter Applying Dynamical Substructuring Method
DEFF Research Database (Denmark)
Zurkinden, Andrew Stephen; Damkilde, Lars; Gao, Zhen; Moan, Torgeir
2013-01-01
This paper deals with structural modeling and analysis of a wave energy converter. The device, called Wavestar, is a bottom fixed structure, located in a shallow water environment at the Danish Northwest coast. The analysis is concentrated on a single float and its structural arm which connects the...... WEC to a jackup structure. The wave energy converter is characterized by having an operational and survival mode. The survival mode drastically reduces the exposure to waves and therfore to the wave loads. Structural response analysis of the Wavestar arm is carried out in this study. Due to the...... relative stiff behavior of the arm the calculation can be reduced to a quasi-static analysis. The hydrodynamic and the structural analyses are thus performed separately. In order to reduce the computational time of the finite element calculation the main structure is modeled as a superelement. The...
Structural dynamic modification using additive damping
Indian Academy of Sciences (India)
B C Nakra
2000-06-01
In order to control dynamic response in structures and machines, modofications using additive viscoelastic damping materials are highlighted. The techniques described for analysis include analytical methods for structural elements, FEM and perturbation methods for reanalysis or structural dynamic modifications for complex structures. Optimisation techniques are used for damping effectiveness include multi-parameter optimisatoin techniques and a technique using dynamic sensitivity analysis and structural dynamic modification. These have been applied for optimum dynamic design of structures incorporating viscoelastic damping. Some current trends for vibraton control are also discussed.
Wind Turbine Structural Dynamics
Miller, D. R. (Editor)
1978-01-01
A workshop on wind turbine structural dynamics was held to review and document current United States work on the dynamic behavior of large wind turbines, primarily of the horizontal-axis type, and to identify and discuss other wind turbine configurations that may have lower cost and weight. Information was exchanged on the following topics: (1) Methods for calculating dynamic loads; (2) Aeroelasticity stability (3) Wind loads, both steady and transient; (4) Critical design conditions; (5) Drive train dynamics; and (6) Behavior of operating wind turbines.
Sub-modeling approach for obtaining structural stress histories during dynamic analysis
Directory of Open Access Journals (Sweden)
T. T. Rantalainen
2013-02-01
Full Text Available Modern machine structures are often fabricated by welding. From a fatigue point of view, the structural details and especially, the welded details are the most prone to fatigue damage and failure. Design against fatigue requires information on the fatigue resistance of a structure's critical details and the stress loads that act on each detail. Even though, dynamic simulation of flexible bodies is already current method for analyzing structures, obtaining the stress history of a structural detail during dynamic simulation is a challenging task; especially when the detail has a complex geometry. In particular, analyzing the stress history of every structural detail within a single finite element model can be overwhelming since the amount of nodal degrees of freedom needed in the model may require an impractical amount of computational effort. The purpose of computer simulation is to reduce amount of prototypes and speed up the product development process. Also, to take operator influence into account, real time models, i.e. simplified and computationally efficient models are required. This in turn, requires stress computation to be efficient if it will be performed during dynamic simulation. The research looks back at the theoretical background of multibody simulation and finite element method to find suitable parts to form a new approach for efficient stress calculation. This study proposes that, the problem of stress calculation during dynamic simulation can be greatly simplified by using a combination of Floating Frame of Reference Formulation with modal superposition and a sub-modeling approach. In practice, the proposed approach can be used to efficiently generate the relevant fatigue assessment stress history for a structural detail during or after dynamic simulation. Proposed approach is demonstrated in practice using one numerical example. Even though, examples are simplified the results show that approach is applicable and can be used as
Structural dynamics in LMFBR containment analysis. A brief survey of computational methods and codes
International Nuclear Information System (INIS)
This paper gives a brief survey of the computational methods and codes available for LMFBR containment analysis. The various numerical methods commonly used in the computer codes are compared. It provides the reactor engineers to up-to-date information on the development of structural dynamics in LMFBR containment analysis. It can also be used as a basis for the selection of the numerical method in the future code development. First, the commonly used finite-difference expressions in the Lagrangian codes will be compared. Sample calculations will be used as a basis for discussing and comparing the accuracy of the various finite-difference representations. The distortion of the meshes will also be compared; the techniques used for eliminating the numerical instabilities will be discussed and compared using examples. Next, the numerical methods used in the Eulerian formulation will be compared, first among themselves and then with the Lagrangian formulations. Special emphasis is placed on the effect of mass diffusion of the Eulerian calculation on the propagation of discontinuities. Implicit and explicit numerical integrations will be discussed and results obtained from these two techniques will be compared. Then, the finite-element methods are compared with the finite-difference methods. The advantages and disadvantages of the two methods will be discussed in detail, together with the versatility and ease of application of the method to containment analysis having complex geometries. It will also be shown that the finite-element equations for a constant-pressure fluid element is identical to the finite-difference equations using contour integrations. Finally, conclusions based on this study will be given
Senkel, Luise
2016-01-01
This edited book aims at presenting current research activities in the field of robust variable-structure systems. The scope equally comprises highlighting novel methodological aspects as well as presenting the use of variable-structure techniques in industrial applications including their efficient implementation on hardware for real-time control. The target audience primarily comprises research experts in the field of control theory and nonlinear dynamics but the book may also be beneficial for graduate students.
Arvidsson, Therese; Li, Jiajia
2011-01-01
With the development of high-speed railroads the dynamic behaviour of railroad bridges is increasingly important to explore. Deeper knowledge about the influence of different factors and what should be included in a model is essential if the designer shall be able to make reliable estimates of responses in existing and new structures. One factor is the soil-structure interaction (SSI), describing how the foundation of the bridge and the soil properties affect the behavior of the bridge under ...
DEFF Research Database (Denmark)
Andreasen, Martin Møller; Meldrum, Andrew
This paper studies whether dynamic term structure models for US nominal bond yields should enforce the zero lower bound by a quadratic policy rate or a shadow rate specification. We address the question by estimating quadratic term structure models (QTSMs) and shadow rate models with at most four...
Tang, Z. B.; Deng, Y. D.; Su, C. Q.; Yuan, X. H.
2015-06-01
In this study, a numerical model has been employed to analyze the internal flow field distribution in a heat exchanger applied for an automotive thermoelectric generator based on computational fluid dynamics. The model simulates the influence of factors relevant to the heat exchanger, including the automotive waste heat mass flow velocity, temperature, internal fins, and back pressure. The result is in good agreement with experimental test data. Sensitivity analysis of the inlet parameters shows that increase of the exhaust velocity, compared with the inlet temperature, makes little contribution (0.1 versus 0.19) to the heat transfer but results in a detrimental back pressure increase (0.69 versus 0.21). A configuration equipped with internal fins is proved to offer better thermal performance compared with that without fins. Finally, based on an attempt to improve the internal flow field, a more rational structure is obtained, offering a more homogeneous temperature distribution, higher average heat transfer coefficient, and lower back pressure.
Sahoo, Bikash R; Maharana, Jitendra; Bhoi, Gopal K; Lenka, Santosh K; Patra, Mahesh C; Dikhit, Manas R; Dubey, Praveen K; Pradhan, Sukanta K; Behera, Bijay K
2014-05-01
Scrutinizing various nucleotide-binding oligomerization domain (NOD)-like receptor (NLR) genes in higher eukaryotes is very important for understanding the intriguing mechanism of the host defense against pathogens. The nucleotide-binding domain (NACHT), leucine-rich repeat (LRR), and pyrin domains (PYD)-containing protein 3 (Nalp3), is an intracellular innate immune receptor and is associated with several immune system related disorders. Despite Nalp3's protective role during a pathogenic invasion, the molecular features and structural organization of this crucial protein is poorly understood. Using comparative modeling and molecular dynamics simulations, we have studied the structural architecture of Nalp3 domains, and characterized the dynamic and energetic parameters of adenosine triphosphate (ATP) binding in NACHT, and pathogen-derived ligands muramyl dipeptide (MDP) and imidazoquinoline with LRR domains. The results suggested that walker A, B and extended walker B motifs were the key ATP binding regions in NACHT that mediate self-oligomerization. The analysis of the binding sites of MDP and imidazoquinoline revealed LRR 7-9 to be the most energetically favored site for imidazoquinoline interaction. However, the binding free energy calculations using the Molecular Mechanics/Poisson-Boltzmann Surface Area (MM/PBSA) method indicated that MDP is incompatible for activating the Nalp3 molecule in its monomeric form, and suggest its complex interaction with NOD2 or other NLRs accounts for MDP recognition. The high binding affinity of ATP with NACHT was correlated to the experimental data for human NLRs. Our binding site prediction for imidazoquinoline in LRR warrants further investigation via in vivo models. This is the first study that provides ligand recognition in mouse Nalp3 and its spatial structural arrangements. PMID:24595807
Relation of Structure and Dynamics in Complex Systems: Consequences for Graph-Theoretical Analysis
Czech Academy of Sciences Publication Activity Database
Hlinka, Jaroslav; Hartman, David; Vejmelka, Martin; Paluš, Milan
Oldenburg : ICBM, 2011. s. 184-185. [Dynamics Days Europe 2011 /31./. 12.09.2011-16.09.2011, Oldenburg] R&D Projects: GA ČR GCP103/11/J068 Institutional research plan: CEZ:AV0Z10300504 Keywords : complex systems * complex networks * graph theory * structure and function small world networks Subject RIV: BB - Applied Statistics, Operational Research
Analysis of structural dynamic data from Skylab. Volume 1: Technical discussion
Demchak, L.; Harcrow, H.
1976-01-01
The results of a study to analyze data and document dynamic program highlights of the Skylab Program are presented. Included are structural model sources, illustration of the analytical models, utilization of models and the resultant derived data, data supplied to organization and subsequent utilization, and specifications of model cycles.
Institute of Scientific and Technical Information of China (English)
2011-01-01
By using the dynamic shift-share analysis, the industrial structure and competitive strength of 31 provincial districts except Taiwan, Hong Kong and Macau are studied by taking the GDP of the three industries as the research entrance and the whole nation as the reference district. The industrial structure and competitive strength of each provincial district is measured. Through the analysis of pertinence, the correlation degree of industrial structure and industrial competitive strength to economic growth is analyzed. The results show that the industrial competitive strength is closely related to the economic growth of the 31 provincial districts, but the contribution made by the industrial structure to economic growth is insufficient and the effect of industrial structure does not match with that of industrial competitive strength. According to industrial competitiveness and industrial structure effect, 31 provincial districts of the whole nation are divided into 4 types and the relevant countermeasures of the four types are put forward.
Structures in entanglement dynamics
International Nuclear Information System (INIS)
Understanding the dynamics of entanglement that is exhibited by a quantum system constitutes a major step in the venture to harvest this quantum effect in potential applications, and to elaborate the role that entanglement plays in real world settings. Interesting dynamics include collective coherent driving and general decoherence processes. Without resorting to the phenomenological treatment of specific examples, we present general features of the structure underlying the dynamics of entanglement. Starting from low dimensional systems where algebraic properties of some entanglement monotones allow for an ''entanglement equation of motion'' we continue, using topological and measure theoretic approaches, to typical behaviour exhibited in the thermodynamic limit
DEFF Research Database (Denmark)
Tsakalidis, Konstantinos
We study dynamic data structures for diﬀerent variants of orthogonal range reporting query problems. In particular, we consider (1) the planar orthogonal 3-sided range reporting problem: given a set of points in the plane, report the points that lie within a given 3-sided rectangle with one....... Dynamic problems like the above arise in various applications of network optimization, VLSI layout design, computer graphics and distributed computing. For the ﬁrst problem, we present dynamic data structures for internal and external memory that support planar orthogonal 3-sided range reporting queries......, and insertions and deletions of points eﬃciently over an average case sequence of update operations. The external memory data structures ﬁnd applications in constraint and temporal databases. In particular, we assume that the coordinates of the points are drawn from diﬀerent probabilistic distributions...
Paultre, Patrick
2013-01-01
This book covers structural dynamics from a theoretical and algorithmic approach. It covers systems with both single and multiple degrees-of-freedom. Numerous case studies are given to provide the reader with a deeper insight into the practicalities of the area, and the solutions to these case studies are given in terms of real-time and frequency in both geometric and modal spaces. Emphasis is also given to the subject of seismic loading. The text is based on many lectures on the subject of structural dynamics given at numerous institutions and thus will be an accessible and practical aid to
Structural Monitoring of a Weapons Test Unit Using Imaging Methods for Dynamic Signature Analysis
International Nuclear Information System (INIS)
A methodology to identify structural changes in weapons systems during environmental tests is being developed at Lawrence Livermore National Laboratory. The method is coherence based and relies on comparing the ''dynamic signature'' response of the test article before and after an environmental test or test series. Physical changes in the test article result in changes in the dynamic signature and are mapped to an image matrix where a color scale represents changes in sensor-to-sensor coherence. This methodology is convenient because it allows an image to represent large amounts of information in a very compact form, where even subtle system changes may be easily and quickly identified. Furthermore, comparison of the dynamic signature response data before and after any test event can be made on a quasi-real-time basis. This approach is particularly useful on large and/or complex test articles where many sensors are present, and large volumes of data are generated
International Nuclear Information System (INIS)
We present an investigation on the structural and dynamical properties of a 'human protein signalling network' (HPSN). This biological network is composed of nodes that correspond to proteins and directed edges that represent signal flows. In order to gain insight into the organization of cell information processing this network is analysed taking into account explicitly the edge directions. We explore the topological properties of the HPSN at the global and the local scale, further applying the generating function formalism to provide a suitable comparative model. The relationship between the node degrees and the distribution of signals through the network is characterized using degree correlation profiles. Finally, we analyse the dynamical properties of small sub-graphs showing high correlation between their occurrence and dynamic stability
Factor analysis of dynamic scintigraphy structures. Application to kinetics of hepatobiliary tracers
International Nuclear Information System (INIS)
The objective of the analysis method is to extract the spatial and dynamic components in a sequence of images. The factor extracted by the analysis represent all the significant information contained in the experimental data. The factor analysis results in the different groups studied present a good stability, rendering it most often possible to propose a satisfying physiological interpretation. In comparison to the method of regions of interest, the factor analysis method presents several advantages. It is an automatic method which can be used once the dynamic acquisition is achieved. This assures a gain in time and the assurance that acquisition was performed under good conditions. Factor analysis takes all the information in the gamma-camera field of view into account. Last but not the least, factor analysis leads to a remarkable result: it enables the components representing vascular, hepatic and biliary activities to be extracted, even if they are superposed. Factor analysis increases diagnostic security for problems normally resolved by hepatobiliary scintigraphy
Development of intensity compatible time-histories for dynamic analysis of structures
Klügel, Jens-Uwe; Akcay Stäuble, Sunay
2016-04-01
The assessment of the functionality of critical infrastructures and lifelines after an earthquake strongly depends on an accurate assessment of the degree of damage exhibited during the earthquake. Usual engineering parameters like linear-elastic response spectra or linear-elastic uniform hazard spectra in terms of spectral accelerations are not suitable for predicting damage because the process of damaging is a non-linear process. The only seismological parameter that implicitly contains the required information on the damaging impact of earthquakes is intensity. This parameter in different scales (EMS-98, MSK-64, MMI) is directly linked to physical observations including the damage of buildings. Additionally, intensity information directly captures spatial variation of ground motions related to the same or similar degree damage by construction of isoseismal lines. Therefore intensities are very suitable for predicting possible impacts of earthquakes on critical infrastructures or lifelines. For engineering applications intensity relevant information has to be converted into engineering characteristics. Because dynamic analyses (time-history analysis, frequently even nonlinear ones) became a standard approach for the design and for the validation of safety of critical infrastructures and lifelines it is reasonable to develop intensity-compatible time-histories for engineering application as an alternative to standard methods. In the paper an approach how to develop intensity-compatible time-histories from recorded time-histories is presented. Based on published international data a set of intensity compatible time-histories covering the site intensity range between intensity V and VIII (EMS scale) is developed. The time-histories developed are compared with typical time-histories derived from spectral matching of a uniform hazard spectrum from a large scale PSHA corresponding to approximately the same intensity class. For this comparison in-structure floor
Directory of Open Access Journals (Sweden)
Zghal S.
2014-01-01
Full Text Available The present paper deals with the analysis of the dynamic behavior of viscoelastic sandwich structures with localized nonlinearities. The Golla-Hughes Mac Tavish (GHM viscoelastic model is used and the finite elements procedure is established to derive both linear and non-linear equations of motion. This model increase the order of the differential equations of motion through the addition of dissipative coordinates, which complicate further the numerical resolution with the addition of local nonlinearities in the junctions of the assembled structures. Hence, a reduced-order model is proposed to enhance the control of the dynamic behavior of such structures incorporating viscoelastic materials especially for structures with large finite element model.
Chung, Doug Jin; Steenburgh, Thomas; Sudhir, K.
2013-01-01
We estimate a dynamic structural model of sales force response to a bonus based compensation plan. Substantively, the paper sheds insights on how different elements of the compensation plan enhance productivity. We find evidence that: (1) bonuses enhance productivity across all segments; (2) overachievement commissions help sustain the high productivity of the best performers even after attaining quotas; and (3) quarterly bonuses help improve performance of the weak performers by serving as p...
International Nuclear Information System (INIS)
The aim of this study was to identify malignant thyroid nodules using iodine-123 and thallium-201 simultaneous dynamic acquisition. The image sequences acquired were processed by factor analysis of spectral and dynamic structures (FASDS). Some 49 patients were investigated, and their diagnoses were confirmed by histological examination. Data processing enables the estimation of the spectra of the two isotopes and the evaluation of the kinetics and spatial structures related to each tracer. The superimposition of thallium and iodide sum images allowed us to delineate the nodule accurately. Two groups were defined: 21 patients who had 201Tl uptake in the nodule, and 28 who had none. In the first group, 5 nodules were carcinomas, whereas all nodules in the second group were benign. The results of the 201Tl dynamic study improved the diagnosis of carcinoma as the number of false-positive cases decreased. FASDS succeeds in extracting spectral and kinetic information, proving its usefulness in clinical diagnosis. (orig.)
DEFF Research Database (Denmark)
Kejlberg-Rasmussen, Casper
statements about our data structure, which are based on the structure of the underlying problem, that we are trying to solve. We can rely on the properties of the invariants when performing queries, and in return we need to ensure that the invariants remain true after we perform updates. When designing data......In this thesis I will address three dynamic data structure problems using the concept of invariants. The first problem is maintaining a dynamically changing set of keys – a dictionary – where the queries we can ask are: does it contain a given key? and what is the preceding (or succeeding) key...... to a given key? The updates we can do are: inserting a new key or deleting a given key. Our dictionary has the working set property, which means that the running time of a query depends on the query distribution. Specifically the time to search for a key depends on when we last searched for it. Our data...
McGhee, David S.; Peck, Jeff A.; McDonald, Emmett J.
2012-01-01
This paper examines Probabilistic Sensitivity Analysis (PSA) methods and tools in an effort to understand their utility in vehicle loads and dynamic analysis. Specifically, this study addresses how these methods may be used to establish limits on payload mass and cg location and requirements on adaptor stiffnesses while maintaining vehicle loads and frequencies within established bounds. To this end, PSA methods and tools are applied to a realistic, but manageable, integrated launch vehicle analysis where payload and payload adaptor parameters are modeled as random variables. This analysis is used to study both Regional Response PSA (RRPSA) and Global Response PSA (GRPSA) methods, with a primary focus on sampling based techniques. For contrast, some MPP based approaches are also examined.
Dynamic structural analysis of a head assembly for a large loop-type LMFBR
International Nuclear Information System (INIS)
An investigation is presented on the dynamic structural response of the primary vessel's head closure to slug impact loadings generated from a 1000 MJ source term. The reference reactor considered was designed in a loop configuration. The head structure consisted of a deck and a triple rotatable plug assembly. Two designs were considered for the deck structure: a reference design and an alternate design. The reference deck was designed as a single flat annular plate. For the alternate design, the deck plate was reinforced by adding an extender cylinder with a flange and flanged webs between the deck-plate and cylinder. The investigation showed that the reference design cannot maintain containment integrity when subjected to slug loading generated by a 1000 MJ source term. It was determined that the head deformed excessively
Kawahara, Kazuaki; Shirasawa, Tetsuroh; Lin, Chun-Liang; Nagao, Ryo; Tsukahara, Noriyuki; Takahashi, Toshio; Arafune, Ryuichi; Kawai, Maki; Takagi, Noriaki
2016-09-01
We have investigated the atomic structure of the "multilayer silicene" grown on the Ag(111) single crystal surface by using low energy electron diffraction (LEED) and scanning tunneling microscopy (STM). We measured the intensity of the LEED spot as a function of the incident electron energy (I-V curve) and analyzed the I-V curve using a dynamical LEED theory. We have found that the Si(111)(√{ 3} ×√{ 3})-Ag model well reproduces the I-V curve whereas the models consisting of the honeycomb structure of Si do not. The bias dependence of the STM image of multilayer silicene agrees with that of the Si(111)(√{ 3} ×√{ 3})-Ag reconstructed surface. Consequently, we have concluded that the multilayer silicene grown on Ag(111) is identical to the Si(111)(√{ 3} ×√{ 3})-Ag reconstructed structure.
International Nuclear Information System (INIS)
A slave manipulator which handles a payload in highly hazardous hot cell, is designed to have 6-DOF motions such as pitching and rolling motion of a shoulder joint, a elbow joint, and a wrist joint. Structural dynamic analysis of the slave manipulator needs to be investigated for safe manipulation. In this report, we developed analysis models based on flexible multi-bodies dynamics and performed simulations for some operation cases with predefined tracking trajectories in order to obtain dynamic stress of structures, joint reaction torques, and tensions of cables. The main results are as follows: (1) joint reaction torques, the maximum stress of structures, and cable tensions at dynamic movement are much larger than those of static ones due to the inertia force of payloads which are accelerated to 3g. (2) we could reduce the reaction torques significantly through adjustment of the direction of the inertia force during operation. The results obtained in this study will help the safe manipulation of the slave manipulator, and will be applied to the re-design of the slave manipulator
Wright, Aidan G. C.; Beltz, Adriene M.; Gates, Kathleen M.; Molenaar, Peter C. M.; Simms, Leonard J.
2015-01-01
Psychiatric diagnostic covariation suggests that the underlying structure of psychopathology is not one of circumscribed disorders. Quantitative modeling of individual differences in diagnostic patterns has uncovered several broad domains of mental disorder liability, of which the Internalizing and Externalizing spectra have garnered the greatest support. These dimensions have generally been estimated from lifetime or past-year comorbidity patters, which are distal from the covariation of symptoms and maladaptive behavior that ebb and flow in daily life. In this study, structural models are applied to daily diary data (Median = 94 days) of maladaptive behaviors collected from a sample (N = 101) of individuals diagnosed with personality disorders (PDs). Using multilevel and unified structural equation modeling, between-person, within-person, and person-specific structures were estimated from 16 behaviors that are encompassed by the Internalizing and Externalizing spectra. At the between-person level (i.e., individual differences in average endorsement across days) we found support for a two-factor Internalizing–Externalizing model, which exhibits significant associations with corresponding diagnostic spectra. At the within-person level (i.e., dynamic covariation among daily behavior pooled across individuals) we found support for a more differentiated, four-factor, Negative Affect-Detachment-Hostility-Disinhibition structure. Finally, we demonstrate that the person-specific structures of associations between these four domains are highly idiosyncratic. PMID:26732546
Directory of Open Access Journals (Sweden)
Aidan G.C. Wright
2015-12-01
Full Text Available Psychiatric diagnostic covariation suggests that the underlying structure of psychopathology is not one of circumscribed disorders. Quantitative modeling of individual differences in diagnostic patterns has uncovered several broad domains of mental disorder liability, of which the Internalizing and Externalizing spectra have garnered the greatest support. These dimensions have generally been estimated from lifetime or past-year comorbidity patters, which are distal from the covariation of symptoms and maladaptive behavior that ebb and flow in daily life. In this study, structural models are applied to daily diary data (Median = 94 days of maladaptive behaviors collected from a sample (N = 101 of individuals diagnosed with personality disorders. Using multilevel and unified structural equation modeling, between-person, within-person, and person-specific structures were estimated from 16 behaviors that are encompassed by the Internalizing and Externalizing spectra. At the between-person level (i.e., individual differences in average endorsement across days we found support for a two-factor Internalizing-Externalizing model, which exhibits significant associations with corresponding diagnostic spectra. At the within-person level (i.e., dynamic covariation among daily behavior pooled across individuals we found support for a more differentiated, four-factor, Negative Affect-Detachment-Hostility-Impulsivity structure. Finally, we demonstrate that the person-specific structures of associations between these four domains are highly idiosyncratic.
Finite element analysis of dynamic stability of skeletal structures under periodic loading
Institute of Scientific and Technical Information of China (English)
THANA Hemantha Kumar; AMEEN Mohammed
2007-01-01
This paper addresses the dynamic stability problem of columns and frames subjected to axially applied periodic loads. Such a structure can become unstable under certain combinations of amplitudes and frequencies of the imposed load acting on its columns/beams. These are usually shown in the form of plots which describe regions of instability. The finite element method (FEM) is used in this work to analyse dynamic stability problems of columns. Two-noded beam elements are used for this purpose.The periodic loading is decomposed into various harmonics using Fourier series expansion. Computer codes in C++ using object oriented concepts are developed to determine the stability regions of columns subjected to periodic loading. A number of numerical examples are presented to illustrate the working of the program. The direct integration of the equations of motions of the discretised system is carried out using Newmark's method to verify the results.
Complex dynamics analysis of impulsively coupled Duffing oscillators with ring structure
International Nuclear Information System (INIS)
Impulsively coupled systems are high-dimensional non-smooth systems that can exhibit rich and complex dynamics. This paper studies the complex dynamics of a non-smooth system which is unidirectionally impulsively coupled by three Duffing oscillators in a ring structure. By constructing a proper Poincaré map of the non-smooth system, an analytical expression of the Jacobian matrix of Poincaré map is given. Two-parameter Hopf bifurcation sets are obtained by combining the shooting method and the Runge–Kutta method. When the period is fixed and the coupling strength changes, the system undergoes stable, periodic, quasi-periodic, and hyper-chaotic solutions, etc. Floquet theory is used to study the stability of the periodic solutions of the system and their bifurcations. (paper)
A Dynamic Analysis of Capital Structure Determinants. Empirical Results for Romanian Capital Market
Directory of Open Access Journals (Sweden)
Mihaela Dragota
2008-04-01
Full Text Available The analysis of capital structure and its determinants represents an useful approach for the Romanian and foreign investors and for the companies, at the same time. The main conclusion for capital structure analysis was that Romanian listed companies sustained their assets, in this order, on equity, commercial debt and, finally, on financial debt. The four variables used in the regression model are significant. The pecking order theory seemed to be more appropriate for the Romanian capital market, but the signalling theory was not entirely rejected.
Boscolo, M.; Banerjee, J. R.
2012-01-01
The dynamic stiffness method for composite plate elements based on the first order shear deformation theory is implemented in a program called DySAP to compute exact natural frequencies and mode shapes of composite structures. After extensive validation of results using published literature, DySAP is subsequently used to carry out exact free vibration analysis of composite stringer panels. For each example, a finite element solution using NASTRAN is provided and commented on. It is concluded ...
Effects of Structural Damage on Dynamic Behavior at Sandwich Composite Beams – Part II- FEM Analysis
Directory of Open Access Journals (Sweden)
Marius Tufoi
2014-07-01
Full Text Available This paper presents results obtained by modal analysis on composite beam like structures in healthy and damaged state. The aim is to obtain damage “signatures” for all possible damage scenarios and to use these data to assess transversal cracks based on vibration techniques, by involving natural frequency shifts. The analysis was performed in SolidWorks software for a five-layer composite, 20 vibration modes being obtained by numerical simulation.
Structural system identification: Structural dynamics model validation
Energy Technology Data Exchange (ETDEWEB)
Red-Horse, J.R.
1997-04-01
Structural system identification is concerned with the development of systematic procedures and tools for developing predictive analytical models based on a physical structure`s dynamic response characteristics. It is a multidisciplinary process that involves the ability (1) to define high fidelity physics-based analysis models, (2) to acquire accurate test-derived information for physical specimens using diagnostic experiments, (3) to validate the numerical simulation model by reconciling differences that inevitably exist between the analysis model and the experimental data, and (4) to quantify uncertainties in the final system models and subsequent numerical simulations. The goal of this project was to develop structural system identification techniques and software suitable for both research and production applications in code and model validation.
Institute of Scientific and Technical Information of China (English)
XIA Dongdong; ZHAO Chunzhang; ZHANG Xiwen; BAI Jing
2006-01-01
The flow fields in the blood pump were analyzed three-dimensionally using computational fluid dynamics (CFD).Hemolysis of the pump was calculated based on the changes in shear stress and related exposure times along the particle trace lines using a forward Euler approach. In this way, how different impeller structures and rotational speeds affect the hemolysis was particularly acquired. As a result, impeller with long-short alternant vanes behaved best in hemolysis property and can be utilized to axial blood pumps' development and design.
Institute of Scientific and Technical Information of China (English)
Panos C. Tsopelas; Panayiotis C. Roussis; Michael C. Constantinou
2009-01-01
The complexity of modern seismically isolated structures requires the analysis of the structural system and the isolation system in its entirety and the ability to capture potential discontinuous phenomena such as isolator uplift and their effects on the superstructures and the isolation hardware. In this paper, an analytical model is developed and a computational algorithm is formulated to analyze complex seismically isolated superstructures even when undergoing highly-nonlinear phenomena such as uplift. The computational model has the capability of modeling various types of isolation devices with strong nonlinearities, analyzing multiple superstructures (up to five separate superstructures) on multiple bases (up to five bases), and capturing the effects of lateral loads on bearing axial forces, including bearing uplift. The model developed herein has been utilized to form the software platform 3D-BASIS-ME-MB, which provides the practicing engineering community with a versatile tool for analysis and design of complex structures with modem isolation systems.
Structural dynamic modification
Indian Academy of Sciences (India)
A Sestieri
2000-06-01
Vibration and acoustic requirements are becoming increasingly important in the design of mechanical structures, but they are not usually of primary concern in the design process. So the need to vary the structural behaviour to solve noise and vibration problems often occurs at the prototype stage, giving rise to the so-called structural modification problem. In this paper, the direct problem of determing the new response of a system, after some modifications are introduced into the sestem, is analysed using two different databases: the modal database and the frequency response function database. The limitaions of the modal database are discussed. Structural modifications that can be accounted for are lumped masses, springs, dampers and dynamic absorbers.
Analysis of dynamic testing performed on structural clay tile infilled frames
Energy Technology Data Exchange (ETDEWEB)
Fowler, J.J.
1994-12-18
The behavior of two structural clay tile infilled frames subjected to dynamic loading is investigated. The testing was performed by USACERL using a biaxial shake table machine on which two framed infills were spaced nine feet apart and connected by steel trusses and an eight inch concrete roof slab. The infills were composed of structural clay tile block which were laid with the cores horizontal. The specimen was loaded in both the out-of-plane and in-plane directions using a site specific time history record. The testing focused on determining frame and panel load-deflection behavior, acceleration amplification, and frequency degradation characteristics. The out-of-plane tests resulted in little degradation of frequency which means there was little loss of stiffness. There was no evidence of the infill {open_quotes}walking-out{close_quotes} of the steel frame; in fact the infill still had substantial stability after completion of the out-of-plane tests. As a result of the gradual increase in ground motion in the in-plane testing, the stiffness of the specimen gradually decreased. Strength and stiffness characteristics obtained from the dynamic testing were comparable to results and behavior seen in static tests. Degradation in the panel was much more rapid under the stronger ground motions which were produced during the sine sweep tests.
Dynamic analysis of steel-concrete structure of TVO power plant containment building
International Nuclear Information System (INIS)
The report presents results from a study concerning the ability of the containment to withstand the loads caused by steams explosions which are possible during a severe accident at TVO plant (BWR). In the first phase, the suitability of the engineering mechanics code (FLAC) for modelling the dynamic response of damaging steel-concrete structures was tested by post-calculating a small scale test. As a result, a new dynamic material model taking account the fracture orientation was developed. In containment calculations both the developed and the best generally accepted material model were used. The loads against the containment were obtained from a simple model for steam explosions, which allowed the impulse of the pressure load to be fixed by tuning a few parameters. The ability of the containment to withstand the pressure pulses was analysed with loads of 5, 1 0, 20, 40, 60, and 80 kPa s impulse. As a results, the area and magnitude of permanent damage together with time histories of displacement and stress at critical points are presented. The estimations on the consequences of the observed structural damages as far as the containment leak tightness and stability are concerned and presented as conclusions. (9 refs.)
Structural dynamic modification of vibrating systems
Naď M.
2007-01-01
Vibration and acoustic requirements are becoming increasingly important in the design of mechanical structures. The need to vary the structural behaviour to solve noise and vibration problems occurs at design or prototype stage, giving rise to the so-called structural modification problem. Structural dynamic modification(SDM) as an application of modal analysis is a technique to study the effect of physical and geometrical parameter changes of a structural system on its dynamic properties whi...
Dynamic structural analysis of a head assembly for a large loop-type LMFBR
International Nuclear Information System (INIS)
An investigation is presented here on the dynamic structural response of the primary vessel's head closure to slug impact loadings generated from a 1000 MJ source term. The reference reactor considered was designed in a loop configuration. The head structure consisted of a deck and a triple rotatable plug assembly. Two designs were considered for the deck structure: a reference design and an alternate design. The reference deck was designed as a single flat annular plate. For the alternate design, the deck plate was reinforced by adding an extender cylinder with a flange and flanged webs between the deck-plate and cylinder. This investigation showed that the reference design cannot maintain containment integrity when subjected to slug loading generated by a 1000 MJ source term. It was determined that the head deformed excessively. The excessive deformation would, at least, permanently disengage the HCDA seals. More importantly, however, it appears that the entire TRP assembly would be disengaged from the deck creating a large opening for sodium expulsion. With regard to the alternate design, the computations indicated that the deck deformations were acceptable and that no sodium expulsion would occur at the deck-plug juncture
Czech Academy of Sciences Publication Activity Database
Hlinka, Jaroslav; Hartman, David; Vejmelka, Martin; Paluš, Milan
Vienna: Löcker Verlag, 2011 - (Thurner, S.; Szell, M.). s. 156 ISBN 978-3-85409-613-9. [ECCS '11. European Conference on Complex Systems. 12.09.2011-16.09.2011, Vienna] R&D Projects: GA ČR GCP103/11/J068 Institutional research plan: CEZ:AV0Z10300504 Keywords : complex systems * structural connectivity * functional connectivity * graph theoretical analysis * Pearson correlation * small-world * multivariate linear process Subject RIV: BB - Applied Statistics, Operational Research
Wang, Guorong; Zhong, Lin; He, Xia; Lei, Zhongqing; Hu, Gang; Li, Rong; Wang, Yunhai
2015-01-01
The influence of spring stiffness and valve quality on the motion behaviors of reciprocating plunger pump discharge valves was investigated by fluid structure interaction (FSI) simulation and experimental analysis. The mathematical model of the discharge valve motion of a 2000-fracturing pump was developed and the discrete differential equations were solved according to FSI and results obtained by ANDINA software. Results indicate that spring stiffness influences the maximum lift, the opening...
Static and dynamic analysis of isotropic shell structures by the spectral finite element method
International Nuclear Information System (INIS)
The paper deals with certain problems related to static and modal analysis of isotropic shell structures by the use of the approach known in the literature as the time-domain spectral finite element method. Although recently this spectral approach has been widely reported as a very powerful numerical tool used to solve various wave propagation problems, its properties make it very well suited to solve static and modal problems. The robustness and effectiveness of the spectral approach has been successfully demonstrated by the authors in the case of a thin-walled spherical shell structure representing a pressure vessel. Static and modal responses of the structure have been investigated by the use of transversally deformable shell-type spectral finite elements and the results of this investigation have been compared to known analytical solutions as well as those obtained by the use of commercially available software for the finite element method.
Shock structure in continuum models of gas dynamics: stability and bifurcation analysis
International Nuclear Information System (INIS)
The problem of shock structure in gas dynamics is analysed through a comparative study of two continuum models: the parabolic Navier–Stokes–Fourier model and the hyperbolic system of 13 moments equations modeling viscous, heat-conducting monatomic gases within the context of extended thermodynamics. When dissipative phenomena are neglected these models both reduce to classical Euler's equations of gas dynamics. The shock profile solution, assumed in the form of a planar travelling wave, reduces the problem to a system of ordinary differential equations, and equilibrium states appear to be stationary points of the system. It is shown that in both models an upstream equilibrium state suffers an exchange of stability when the shock speed crosses the critical value which coincides with the highest characteristic speed of the Euler's system. At the same time a downstream equilibrium state could be seen as a steady bifurcating solution, while the shock profile represents a heteroclinic orbit connecting the two stationary points. Using centre manifold reduction it is demonstrated that both models, although mathematically different, obey the same transcritical bifurcation pattern in the neighbourhood of the bifurcation point corresponding to the critical value of shock speed, the speed of sound
SHOCK, Nonlinear Dynamic Structure Analysis, Spring and Mass Model, Runge-Kutta-Gill Method
International Nuclear Information System (INIS)
1 - Description of problem or function: SHOCK calculates the dynamic response of a structure modeled as a spring-mass system having one or two degrees of freedom for each mass when subjected to specified environments. The code determines the behavior of each lumped mass (displacement, velocity, and acceleration for each degree of freedom) and the behavior of each spring or coupling (force, shear, moment, and displacement) as a function of time. Two types of models, axial, having one degree of freedom, and lateral, having two degrees of freedom at each mass can be processed. Damping can be included in all models and shock spectrums of responses can be obtained. 2 - Method of solution: Two methods of numerical integration of the second-order dynamic equations are provided: the Runge-Kutta-Gill method with variable step-size is recommended for highly nonlinear problems, and a variation of the Newmark-Beta method is available for use with large linear problems. 3 - Restrictions on the complexity of the problem: Maxima of: 100 masses, 200 springs or couplings. Complex arrangements of nonlinear options must be carefully checked by the user
The Structure and Dynamics of Co-Citation Clusters: A Multiple-Perspective Co-Citation Analysis
Chen, Chaomei; Hou, Jianhua
2010-01-01
A multiple-perspective co-citation analysis method is introduced for characterizing and interpreting the structure and dynamics of co-citation clusters. The method facilitates analytic and sense making tasks by integrating network visualization, spectral clustering, automatic cluster labeling, and text summarization. Co-citation networks are decomposed into co-citation clusters. The interpretation of these clusters is augmented by automatic cluster labeling and summarization. The method focuses on the interrelations between a co-citation cluster's members and their citers. The generic method is applied to a three-part analysis of the field of Information Science as defined by 12 journals published between 1996 and 2008: 1) a comparative author co-citation analysis (ACA), 2) a progressive ACA of a time series of co-citation networks, and 3) a progressive document co-citation analysis (DCA). Results show that the multiple-perspective method increases the interpretability and accountability of both ACA and DCA n...
International Nuclear Information System (INIS)
Of great interest in Performance-Based Earthquake Engineering (PBEE) is the accurate estimation of the seismic performance of structures. A performance prediction and evaluation procedure is based on nonlinear dynamics and reliability theory. In this method, a full integration over the three key stochastic models is as follow: ground motion hazard curve, nonlinear dynamic displacement demand, and displacement capacity. Further, both epistemic and aleatory uncertainties are evaluated and carried through the analysis.In this paper, jacket and soil-pile system have been modeled using Finite Element program (OpenSees) and the incremental dynamic analysis (IDA) are performed to investigate nonlinear behavior of offshore platforms. The system demand is determined by performing time history response analyses of the jacket under a suite of FEMA/SAC uniform hazard ground motions. The system capacity in terms of the drift ratio against incipient collapse is generally difficult to predict since the structural response goes into nonlinear range before collapse. All the analyses are performed in two directions and the results are compared with each others. The confidence level of a jacket in each direction for a given hazard level is calculated using the procedure described
Asgarian, Behrouz; Shokrgozar, Hamed R.; Talarposhti, Ali Shakeri
2008-07-01
Of great interest in Performance-Based Earthquake Engineering (PBEE) is the accurate estimation of the seismic performance of structures. A performance prediction and evaluation procedure is based on nonlinear dynamics and reliability theory. In this method, a full integration over the three key stochastic models is as follow: ground motion hazard curve, nonlinear dynamic displacement demand, and displacement capacity. Further, both epistemic and aleatory uncertainties are evaluated and carried through the analysis. In this paper, jacket and soil-pile system have been modeled using Finite Element program (OpenSees) and the incremental dynamic analysis (IDA) are performed to investigate nonlinear behavior of offshore platforms. The system demand is determined by performing time history response analyses of the jacket under a suite of FEMA/SAC uniform hazard ground motions. The system capacity in terms of the drift ratio against incipient collapse is generally difficult to predict since the structural response goes into nonlinear range before collapse. All the analyses are performed in two directions and the results are compared with each others. The confidence level of a jacket in each direction for a given hazard level is calculated using the procedure described.
Kobayashi, Fumiharu; Kanada-En'yo, Yoshiko
2016-02-01
We extend the method of antisymmetrized molecular dynamics (AMD) to investigate dineutron correlation. We regard the total system as the core plus two valence neutrons in the AMD framework and treat the valence neutron wave functions by multirange Gaussians with the d -constraint method, in which the distance between the core and the center of mass of the two neutrons is constrained, to describe the size changing effect and the motion of two neutrons. We apply this method to the ground state of 10Be as an example and investigate the motion of two neutrons around a largely deformed 8Be core by analyzing the two-neutron overlap function around the core. Comparing the results including the different 8Be core structures, we show that the core structure plays an important role in dineutron formation and expansion from the core. The radial fluctuation in the core leads to the expansion of the core potential to the farther region and, as a result, two valence neutrons can be expanded far from the core to form a dineutron. Differently, when the core is less deformed, the dineutron is dissociated by the spin-orbit potential at the surface of the core. We can investigate the dineutron correlation clearly by using the present framework and conclude that the framework is effective for the studies of dineutron correlation.
Energy Technology Data Exchange (ETDEWEB)
Monteiro, Nuno Miguel Barroso, E-mail: nuno.barroso.monteiro@gmail.com; Silva, Miguel Pedro Tavares da, E-mail: MiguelSilva@ist.utl.pt; Folgado, Joao Orlando Marques Gameiro, E-mail: jfolgado@dem.ist.utl.pt [Technical University of Lisbon, IDMEC/IST-Instituto Superior Tecnico (Portugal); Melancia, Joao Pedro Levy, E-mail: levymelancia@netcabo.pt [University of Lisbon, FML-Faculdade de Medicina de Lisboa (Portugal)
2011-02-15
This work describes a methodology for the dynamic and structural analysis of complex (bio)mechanical systems that joins both multibody dynamics and finite element domains, in a synergetic way, through a cosimulation procedure that takes benefit of the advantages of each numerical formulation. To accomplish this goal, a cosimulation module is developed based on the gluing algorithm X-X, which is the key element responsible for the management of the information flux between the two software packages (each using its own mathematical formulation and code). The X-X algorithm uses for each cosimulated structure multiple pairs of reference points whose kinematics are solved by the multibody module and prescribed, as initial data, to the finite element counterpart. The finite element module, by its turn, solves the structural problem imposed by the prescribed kinematics, calculates the resulting generalized loads applied over the reference points and return these loads back to the multibody module that uses them to solve the dynamic problem and to calculate new reference kinematics to prescribe to the finite element module in the next time step. The proposed method is applied to study the cervical spine dynamics in a pathologic situation in which an intersomatic fusion is simulated to confirm its potential advantages. Taking into account the proposed simulation scenario, a cervical spine multibody model that includes the rigid vertebrae, the facet joints' and spinous processes' contacts, ligaments and the finite element models of the intervertebral discs, and their surrogates is developed. The proposed model is simulated for extension in a forward dynamics perspective.
International Nuclear Information System (INIS)
This work describes a methodology for the dynamic and structural analysis of complex (bio)mechanical systems that joins both multibody dynamics and finite element domains, in a synergetic way, through a cosimulation procedure that takes benefit of the advantages of each numerical formulation. To accomplish this goal, a cosimulation module is developed based on the gluing algorithm X-X, which is the key element responsible for the management of the information flux between the two software packages (each using its own mathematical formulation and code). The X-X algorithm uses for each cosimulated structure multiple pairs of reference points whose kinematics are solved by the multibody module and prescribed, as initial data, to the finite element counterpart. The finite element module, by its turn, solves the structural problem imposed by the prescribed kinematics, calculates the resulting generalized loads applied over the reference points and return these loads back to the multibody module that uses them to solve the dynamic problem and to calculate new reference kinematics to prescribe to the finite element module in the next time step. The proposed method is applied to study the cervical spine dynamics in a pathologic situation in which an intersomatic fusion is simulated to confirm its potential advantages. Taking into account the proposed simulation scenario, a cervical spine multibody model that includes the rigid vertebrae, the facet joints’ and spinous processes’ contacts, ligaments and the finite element models of the intervertebral discs, and their surrogates is developed. The proposed model is simulated for extension in a forward dynamics perspective.
Structural dynamic modifications via models
Indian Academy of Sciences (India)
T K Kundra
2000-06-01
Structural dynamic modification techniques attempt to reduce dynamic design time and can be implemented beginning with spatial models of structures, dynamic test data or updated models. The models assumed in this discussion are mathematical models, namely mass, stiffness, and damping matrices of the equations of motion of a structure. These models are identified/extracted from dynamic test data viz. frequency response functions (FRFs). Alternatively these models could have been obtained by adjusting or updating the finite element model of the structure in the light of the test data. The methods of structural modification for getting desired dynamic characteristics by using modifiers namely mass, beams and tuned absorbers are discussed.
Structural dynamics teaching example: A linear test analysis case using open software
DEFF Research Database (Denmark)
Sturesson, P. O.; Brandt, A.; Ristinmaa, M.
2013-01-01
approximations, and knowledge about their limitations. Equally important is for students to have knowledge of the experimental verification of the obtained models. This paper describes a teaching example where a simple plate structure is modeled by shell elements, followed by a model calibration using...... experimental modal analysis data. By using open software, based on MATLAB®1 as a basis for the example, the applied numerical methods are made transparent to the student. The example is built on a combination of the free CALFEM®2 and ABRAVIBE toolboxes, and thus all code used in this paper is publically...
International Nuclear Information System (INIS)
In the framework of the activities concerning the safety of nuclear power plants (NPP) in Middle- and East Europe among others the behaviour of the reactor cavity bottom ceiling of a NPP of type WWER-1000 impinged by impact loads due to the postulated failure of the lower head of the reactor pressure vessel (RPV-LH) caused by an assumed core melt accident has been investigated. For the investigations of the structure dynamical behaviour of the reactor cavity ceiling the AUTODYN-Code was used. This code is using an explicit solver and is suitable particularly for the simulation of impact problems. For the investigations on the load bearing capacity of the cavity ceiling an axisymmetric Finite Element (FE) model of both the RPV-LH made of steel and the reactor cavity ceiling with detailed consideration of the reinforcement in the concrete was generated. The effects of the rebars were simulated by shell elements with adequate cross-sections based on the number of rebars. To represent the load and temperature dependent deformation of the heated RPV-LH during the impact phase the FE-model has steel layers of different temperature dependent material properties representing the assumed temperature distribution over the wall thickness at postulated failure. The assumed molten core material located above the inner surface of the RPV-LH is taken into account by adjusting the density of the lower head. In the dynamic calculations the internal pressure conditions at the time of failure and consequently the impact velocity were varied. The calculations show the damage of the concrete and the strains in the reinforcement were assessed by adequate failure criteria. (authors)
Comet C/2011 J2 (LINEAR) nucleus splitting: Dynamical and structural analysis
Manzini, Federico; Oldani, Virginio; Hirabayashi, Masatoshi; Behrend, Raoul; Crippa, Roberto; Ochner, Paolo; Pina, José Pablo Navarro; Haver, Roberto; Baransky, Alexander; Bryssinck, Eric; Dan, Andras; De Queiroz, Josè; Frappa, Eric; Lavayssiere, Maylis
2016-07-01
After the discovery of the breakup event of comet C/2011 J2 in August 2014, we followed the primary body and the main fragment B for about 120 days in the context of a wide international collaboration. From the analysis of all published magnitude estimates we calculated the comet's absolute magnitude H=10.4, and its photometric index n=1.7. We also calculated a water production of only 110 kg/s at the perihelion. These values are typical of a low-activity, long-period or new comet. Analysis of the motion of fragment B over the observation period showed that the first breakout event likely occurred between 12 July and 30 July 2014. Nucleus B remained persistently visible throughout the 4-month observation period. The projected separation velocity of nucleus B from the parent body was 4.22 m/s at the time of the breakup and 12.7 m/s at the end of the observation period, suggesting that nucleus B was subjected to a constant deceleration a = 6.87 • 10-7 m / s2 . The spin period of the main nucleus was estimated as 4.56 h±0.05 h by photometric analysis. The structural analysis of the comet showed a cohesive strength of the nucleus greater than ~0.9 kPa; assuming a bulk density of 500 kg/m3, with a rotation period of 4.56 h the cometary nucleus might have failed structurally, especially if the body was elongated. These results suggest that the nucleus of comet C/2011 J2 has an elongated shape, with a ratio of the semi-minor axis to the semi-major axis β event in comet C/2011 J2.
Dynamic Soil-Structure-Interaction
DEFF Research Database (Denmark)
Kellezi, Lindita
1998-01-01
The aim of this thesis is to investigate and develop alternative methods of analyzing problems in dynamic soil-structure-interaction. The main focus is the major difficulty posed by such an analysis - the phenomenon of waves which radiate outward from the excited structures towards infinity. In...... numerical calculations, only a finite region of the foundation metium is analyzed and something is done to prevent the outgoing radiating waves to reflect from the regions's boundary. The prosent work concerns itself with the study of such effects, using the finite element method, and artificial...... transmitting boundary at the edges of the computational mesh. To start with, an investigation of the main effects of the interaction phenomena is carried out employing a widely used model, considering dynamic stiffness of the unbounded soil as frequency independent. Then a complete description, with the...
International Nuclear Information System (INIS)
This article focuses on the study of the mesoscopic structure in neutron irradiated EPDM both from experimental and theoretical points of view. In this work we reveal completely the modification of the mesostructure of the EPDM due to neutron irradiation, resolving volume fraction, size and distribution of the crystalline zones as a function of the irradiation dose. Positron annihilation spectroscopy and dynamic mechanical analysis techniques are applied and the results are discussed by means of new theoretical results for describing the interaction process between the crystals and amorphous zones in EPDM.
Liberdová, I.
2015-01-01
This article is focused on the dynamic drawing analysis. It deals with temporal segmentation methods for hand-drawn pictures. The automatic vectorization of segmentation results is considered as well. Dynamic drawing analysis may significantly improves tracing drawing test utilization in the clinical physiology trials.
Analysis of the Nonlinear Static and Dynamic Behavior of Offshore Structures
Alfosail, Feras
2015-07-01
Understanding static and dynamic nonlinear behavior of pipes and risers is crucial for the design aspects in offshore engineering fields. In this work, we examine two nonlinear problems in offshore engineering field: vortex Induced vibration of straight horizontal pipes, and boundary layer static solution of inclined risers. In the first study, we analyze the effect of the internal velocity of straight horizontal pipe and obtain the vortex induced vibration forces via coupling the pipe equation of motion with the recently modified Van Der Pol oscillator governing the lift coefficient. Our numerical results are obtained for two different pipe configurations: hinged-hinged, and clamped- clamped. The results show that the internal velocity reduces the vibration and the oscillation amplitudes. Also, it is shown that the clamped-clamped pipe configuration offers a wider range of internal velocities before buckling instability occurs. The results also demonstrate the effect of the end condition on the amplitudes of vibration. In the second study, we develop a boundary layer perturbation static solution to govern and simulate the static behavior of inclined risers. In the boundary layer analysis, we take in consideration the effects of the axial stretch, applied tension, and internal velocity. Our numerical simulation results show good agreement with the exact solutions for special cases. In addition, our developed method overcomes the mathematical and numerical limitations of the previous methods used before.
Dynamic Responses Analysis of a Building Structure Subjected to Ground Shock from a Tunnel Explosion
Institute of Scientific and Technical Information of China (English)
TIAN Li; LI Zhongxian; HAO Hong
2006-01-01
Dynamic responses of a multi-storey building without or with a sliding base-isolation device for ground shock induced by an in-tunnel explosion are numerically analyzed.The effect of an adjacent tunnel in between the building and the explosion tunnel,which affects ground shock propagation,is considered in the analysis.Different modeling methods,such as the eight-node equal-parametric finite element and mass-lumped system,are used to establish the coupling model consisting of the two adjacent tunnels,the surrounding soil medium with the Lysmer viscous boundary condition,and the multi-storey building with or without the sliding base-isolation device.In numerical calculations,a continuous friction model,which is different from the traditional Coulomb friction model,is adopted to improve the computational efficiency and reduce the accumulated errors.Some example analyses are subsequently performed to study the response characteristics of the building and the sliding base-isolation device to ground shock.The effect of the adjacent tunnel in between the building and the explosion tunnel on the ground shock wave propagation is also investigated.The final conclusions based on the numerical results will provide some guidance in engineering practice.
Energy Technology Data Exchange (ETDEWEB)
Schmid, G.; Wang, S.; Chouw, N.
1991-04-01
SSI-FEBEM is a computer program for dynamic soil-structure (or structure-soil-structure) interaction analysis in the frequency domain. The program SAP IV (FEM) and the program SSI 2D/3D (BEM) have been integrated into a new program, which allows a coupling of finite and boundary elements. It is applicable to two- and three-dimensional problems. In this manual, the theoretical concept for both FEM and BEM, as used in the program, are briefly introduced. Details of the coupling of FE and BE, are also discussed. However, emphasis is directed towards the use of the computer program concerning data input and output. Finally, several examples on soil-structure interaction (SSI) and structure-soil-structure interaction (SSSI), together with their data are presented. (orig.). [Deutsch] SSI-FEBEM ist ein Programm zur Berechnung der dynamischen Antwort eines Systems Bauwerk-Boden (oder Bauwerk-Boden-Bauwerk) im Frequenzbereich. Das Programm besteht aus dem Programm SAP IV (FEM) und dem Programm SSI 2D/3D (BEM) und koppelt Finite Elemente und Randelemente. Zwei- und dreidimensionale Probleme koennen damit behandelt werden. In dem vorliegenden Bericht werden die theoretischen Grundlagen der angewendeten Methode der Finiten Elemente und der Randelemente kurz vorgestellt und deren Kopplung beschrieben. Der Bericht ist als Benutzerhandbuch anzusehen. Er beinhaltet auch Beispiele der Wechselwirkung zwischen Bauwerk und Baugrund (SSI) und zwischen Bauwerk-Boden-Bauwerk (SSSI). (orig.).
Directory of Open Access Journals (Sweden)
Charles R. Steele
1995-01-01
Full Text Available Shell structures are indispensable in virtually every industry. However, in the design, analysis, fabrication, and maintenance of such structures, there are many pitfalls leading to various forms of disaster. The experience gained by engineers over some 200 years of disasters and brushes with disaster is expressed in the extensive archival literature, national codes, and procedural documentation found in larger companies. However, the advantage of the richness in the behavior of shells is that the way is always open for innovation. In this survey, we present a broad overview of the dynamic response of shell structures. The intention is to provide an understanding of the basic themes behind the detailed codes and stimulate, not restrict, positive innovation. Such understanding is also crucial for the correct computation of shell structures by any computer code. The physics dictates that the thin shell structure offers a challenge for analysis and computation. Shell response can be generally categorized by states of extension, inextensional bending, edge bending, and edge transverse shear. Simple estimates for the magnitudes of stress, deformation, and resonance in the extensional and inextensional states are provided by ring response. Several shell examples demonstrate the different states and combinations. For excitation frequency above the extensional resonance, such as in impact and acoustic excitation, a fine mesh is needed over the entire shell surface. For this range, modal and implicit methods are of limited value. The example of a sphere impacting a rigid surface shows that plastic unloading occurs continuously. Thus, there are no short cuts; the complete material behavior must be included.
Sierra Structural Dynamics Theory Manual
Energy Technology Data Exchange (ETDEWEB)
Reese, Garth M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2015-10-19
Sierra/SD provides a massively parallel implementation of structural dynamics finite element analysis, required for high fidelity, validated models used in modal, vibration, static and shock analysis of structural systems. This manual describes the theory behind many of the constructs in Sierra/SD. For a more detailed description of how to use Sierra/SD , we refer the reader to Sierra/SD, User's Notes . Many of the constructs in Sierra/SD are pulled directly from published material. Where possible, these materials are referenced herein. However, certain functions in Sierra/SD are specific to our implementation. We try to be far more complete in those areas. The theory manual was developed from several sources including general notes, a programmer notes manual, the user's notes and of course the material in the open literature. This page intentionally left blank.
Directory of Open Access Journals (Sweden)
Swati Kaushik
Full Text Available Prolyl oligopeptidase (POP is considered as an important pharmaceutical target for the treatment of numerous diseases. Despite enormous studies on various aspects of POPs structure and function still some of the questions are intriguing like conformational dynamics of the protein and interplay between ligand entry/egress. Here, we have used molecular modeling and docking based approaches to unravel questions like differences in ligand binding affinities in three POP species (porcine, human and A. thaliana. Despite high sequence and structural similarity, they possess different affinities for the ligands. Interestingly, human POP was found to be more specific, selective and incapable of binding to a few planar ligands which showed extrapolation of porcine POP in human context is more complicated. Possible routes for substrate entry and product egress were also investigated by detailed analyses of molecular dynamics (MD simulations for the three proteins. Trajectory analysis of bound and unbound forms of three species showed differences in conformational dynamics, especially variations in β-propeller pore size, which was found to be hidden by five lysine residues present on blades one and seven. During simulation, β-propeller pore size was increased by ∼2 Å in porcine ligand-bound form which might act as a passage for smaller product movement as free energy barrier was reduced, while there were no significant changes in human and A. thaliana POPs. We also suggest that these differences in pore size could lead to fundamental differences in mode of product egress among three species. This analysis also showed some functionally important residues which can be used further for in vitro mutagenesis and inhibitor design. This study can help us in better understanding of the etiology of POPs in several neurodegenerative diseases.
Rigid Finite Element Method in Analysis of Dynamics of Offshore Structures
Wittbrodt, Edmund; Maczyński, Andrzej; Wojciech, Stanisław
2013-01-01
This book describes new methods developed for modelling dynamics of machines commonly used in the offshore industry. These methods are based both on the rigid finite element method, used for the description of link deformations, and on homogeneous transformations and joint coordinates, which is applied to the modelling of multibody system dynamics. In this monograph, the bases of the rigid finite element method and homogeneous transformations are introduced. Selected models for modelling dynamics of offshore devices are then verified both by using commercial software, based on the finite element method, as well as by using additional methods. Examples of mathematical models of offshore machines, such as a gantry crane for Blowout-Preventer (BOP) valve block transportation, a pedestal crane with shock absorber, and pipe laying machinery are presented. Selected problems of control in offshore machinery as well as dynamic optimization in device control are also discussed. Additionally, numerical simulations of...
Rigid finite element method in analysis of dynamics of offshore structures
Energy Technology Data Exchange (ETDEWEB)
Wittbrodt, Edmund [Gdansk Univ. of Technology (Poland); Szczotka, Marek; Maczynski, Andrzej; Wojciech, Stanislaw [Bielsko-Biala Univ. (Poland)
2013-07-01
This book describes new methods developed for modelling dynamics of machines commonly used in the offshore industry. These methods are based both on the rigid finite element method, used for the description of link deformations, and on homogeneous transformations and joint coordinates, which is applied to the modelling of multibody system dynamics. In this monograph, the bases of the rigid finite element method and homogeneous transformations are introduced. Selected models for modelling dynamics of offshore devices are then verified both by using commercial software, based on the finite element method, as well as by using additional methods. Examples of mathematical models of offshore machines, such as a gantry crane for Blowout-Preventer (BOP) valve block transportation, a pedestal crane with shock absorber, and pipe laying machinery are presented. Selected problems of control in offshore machinery as well as dynamic optimization in device control are also discussed. Additionally, numerical simulations of pipe-laying operations taking active reel drive into account are shown.
Mass Spectrometry-Based Proteomics for the Analysis of Chromatin Structure and Dynamics
Directory of Open Access Journals (Sweden)
Monica Soldi
2013-03-01
Full Text Available Chromatin is a highly structured nucleoprotein complex made of histone proteins and DNA that controls nearly all DNA-dependent processes. Chromatin plasticity is regulated by different associated proteins, post-translational modifications on histones (hPTMs and DNA methylation, which act in a concerted manner to enforce a specific “chromatin landscape”, with a regulatory effect on gene expression. Mass Spectrometry (MS has emerged as a powerful analytical strategy to detect histone PTMs, revealing interplays between neighbouring PTMs and enabling screens for their readers in a comprehensive and quantitative fashion. Here we provide an overview of the recent achievements of state-of-the-art mass spectrometry-based proteomics for the detailed qualitative and quantitative characterization of histone post-translational modifications, histone variants, and global interactomes at specific chromatin regions. This synopsis emphasizes how the advances in high resolution MS, from “Bottom Up” to “Top Down” analysis, together with the uptake of quantitative proteomics methods by chromatin biologists, have made MS a well-established method in the epigenetics field, enabling the acquisition of original information, highly complementary to that offered by more conventional, antibody-based, assays.
Wang, Guorong; Zhong, Lin; He, Xia; Lei, Zhongqing; Hu, Gang; Li, Rong; Wang, Yunhai
2015-01-01
The influence of spring stiffness and valve quality on the motion behaviors of reciprocating plunger pump discharge valves was investigated by fluid structure interaction (FSI) simulation and experimental analysis. The mathematical model of the discharge valve motion of a 2000-fracturing pump was developed and the discrete differential equations were solved according to FSI and results obtained by ANDINA software. Results indicate that spring stiffness influences the maximum lift, the opening resistance and shut-off lag angle, as well as the fluid velocity of the clearance, the impact stress and the volume efficiency of the pump valve in relation to the valve quality. An optimal spring stiffness parameter of 14.6 N/mm was obtained, and the volumetric efficiency of the pumping valve increased by 4‰ in comparison to results obtained with the original spring stiffness of 10.09N/mm. The experimental results indicated that the mathematical model and FSI method could provide an effective approach for the subsequent improvement of valve reliability, volumetric efficiency and lifespan. PMID:26488290
Directory of Open Access Journals (Sweden)
Guorong Wang
Full Text Available The influence of spring stiffness and valve quality on the motion behaviors of reciprocating plunger pump discharge valves was investigated by fluid structure interaction (FSI simulation and experimental analysis. The mathematical model of the discharge valve motion of a 2000-fracturing pump was developed and the discrete differential equations were solved according to FSI and results obtained by ANDINA software. Results indicate that spring stiffness influences the maximum lift, the opening resistance and shut-off lag angle, as well as the fluid velocity of the clearance, the impact stress and the volume efficiency of the pump valve in relation to the valve quality. An optimal spring stiffness parameter of 14.6 N/mm was obtained, and the volumetric efficiency of the pumping valve increased by 4‰ in comparison to results obtained with the original spring stiffness of 10.09N/mm. The experimental results indicated that the mathematical model and FSI method could provide an effective approach for the subsequent improvement of valve reliability, volumetric efficiency and lifespan.
Wang, Guorong; Zhong, Lin; He, Xia; Lei, Zhongqing; Hu, Gang; Li, Rong; Wang, Yunhai
2015-01-01
The influence of spring stiffness and valve quality on the motion behaviors of reciprocating plunger pump discharge valves was investigated by fluid structure interaction (FSI) simulation and experimental analysis. The mathematical model of the discharge valve motion of a 2000-fracturing pump was developed and the discrete differential equations were solved according to FSI and results obtained by ANDINA software. Results indicate that spring stiffness influences the maximum lift, the opening resistance and shut-off lag angle, as well as the fluid velocity of the clearance, the impact stress and the volume efficiency of the pump valve in relation to the valve quality. An optimal spring stiffness parameter of 14.6 N/mm was obtained, and the volumetric efficiency of the pumping valve increased by 4‰ in comparison to results obtained with the original spring stiffness of 10.09N/mm. The experimental results indicated that the mathematical model and FSI method could provide an effective approach for the subsequent improvement of valve reliability, volumetric efficiency and lifespan. PMID:26488290
Nonlinear Dynamic Analysis of Isolated and Fixed-Base Reinforced Concrete Structures
Komur, Mehmet A; Karabork, Turan; Deneme, Ibrahim O
2011-01-01
Earthquakes are a major threat to human lives and to the integrity of the infrastructures in seismic regions. Structures are the worst hit with the phenomenal damages due to ground motions resulting from earthquakes. Recent research and studies have led to new techniques to reduce the damages caused by earthquakes on structures and these techniques are applied for innovative structural design. One of the techniques is the base isolation method, which is used to design structures against earth...
FE-analysis of dynamic creep-damage in thin-walled structures
Morachkovsky, Oleg; Breslavsky, Dmitry; Burlayenko, Vyacheslav
2002-01-01
The models for description of creep-damage behaviour in materials and thin shallow shells and plates deforming in conditions of joint action of static and fast cyclic load are given. The properties of the proposed material model were established by comparison of experimental and numerical data. The method for numerical simulation by in-house code of a dynamic creep and long-term strength of shallow shells and plates is created on the basis of the FEM. New laws of dynamic creep influence on st...
Nonlinear dynamic analysis of a structure with a friction-based seismic base isolation system
Suy, H.M.R.; Fey, R.H.B.; Galanti, F.M.B.; Nijmeijer, H.
2007-01-01
Many dynamical systems are subject to some form of non-smooth or discontinuous nonlinearity. One eminent example of such a nonlinearity is friction. This is caused by the fact that friction always opposes the direction of movement, thus changing sign when the sliding velocity changes sign. In this p
Modeling of Network Dynamics: From Dynamic Nodes to Dynamic Structure
Czech Academy of Sciences Publication Activity Database
Kulhavý, Rudolf
Albany, NY : The System Dynamics Society, 2008, s. 1-29. ISBN 978-1-935056-01-0. [International Conference of the System Dynamics Society /26./. Athens (GR), 20.07.2008-24.07.2008] R&D Projects: GA AV ČR IAA700750701 Institutional research plan: CEZ:AV0Z10750506 Keywords : system dynamics * Markov random fields * Bayesian inference Subject RIV: BB - Applied Statistics, Operational Research http://library.utia.cas.cz/separaty/2008/AS/kulhavy-modeling%20of%20network%20dynamics%20from%20dynamic%20nodes%20to%20dynamic%20structure.pdf
Sequence-Structure Alignment Using a Statistical Analysis of Core Models and Dynamic Programming
Brunnert, Marcus; Fischer, Paul; Urfer, Wolfgang
2002-01-01
The expanding availability of protein data enforces the application of empirical methods necessary to recognize protein structures. In this paper a sequence-structure alignment method is described and applied to various Ubiquitin-like folded Ras-binding domains. On the basis of two probability functions that evaluate similarities between the occurrence of amino-acids in the primary and secondary protein structure, different versions of simple scoring functions are proposed. The application of...
Zhang, Zi-Long; Chen, Xing-Peng; Yang, Jing; Xue, Bing; Li, Yong-Jin
2010-02-01
Based on the ideology of macro environmental economics, a function of environmental pressure represented by pollutant emission was built, and the relative importance of the driving factors in the dynamic changes of the relationships between economic growth and environmental pressure in Gansu Province in 1990 - 2005 was analyzed by using structural decomposition analysis (SDA) model combining with 'refined Laspeyres' method. In the study period, the environmental pressure in the Province was mainly caused by the emission of waste gases and solids in the process of economic growth, and showed a rapid increasing trend at the late stage of the period. Population factor had less impact on the increase of this environmental pressure, while economic growth factor had obvious impact on it. Technological progress did mitigate, but could not offset the impact of economic growth factor, and the impacts of economic growth and technological factors on the environmental pressure differed with the kinds of pollutants. PMID:20462016
International Nuclear Information System (INIS)
This paper presents the researching activities, in which the nonlinear dynamic analysis, optimization of the cables' tension distribution, real 50 meters model experiment are discussed. The long cable structure has been utilized in new generation large radio telescope with the diameter of 500 meters. In design, there are six high concrete towers form which are six computer controlled long cables about 250 meters long met at a cabin, which is a hemisphere with 6 meters diameter. The cabin can be moved three dimensional to track the target. Within the cabin, there is a stable platform. The positioning precision for the platform and cabin are 4mm and 50cm respectively. By which means, the poisoning accuracy can be received becomes a sensible and important problem. For the sake of this, study on vibration of cable with respect to random wind, such as nonlinear response, vortex and galloping, is investigated in this paper. Desirable design is that the tension forces among the six long cables are the same, at least as even as possible. This will be benefit to the control of the system, so that the higher dynamic positioning precision is easy to be obtained. To meet this kind of requirement, the optimal distribution of the cable tensions among cables is discussed and pretty good result is received. Before the real 500 meters diameters antenna is built, an experiment model with 50 meters diameter was built in Xidian University of China, shown in figure 2. The dynamic analysis on vibration (random wind response, vortex and galloping), optimization of the cable tensions' distribution is made with good result. Lots of 50-meter-model site experiments are carried out with useful and valuable results, form which the theory and simulation model has been improved repeatedly until both the model simulation and experiment results are very closed so that the difference can be accepted from the viewpoint of thoroughly, systematically and deeply in the paper. The conclusion
The structure and dynamics of health centres in the Netherlands: an institutional analysis.
Batenburg, R.; Eyck, A.
2011-01-01
Context: Health centres are seen as a preferred organization of the modernized and integrated primary care. they are expected to facilitate an accessible contact point for medical care as close to people’s homes. Also, health centres are expected to deliver care in an efficient and effective way, minimizing the referring of patients to care and cure institutions. Methods: The population of health centres in the Netherlands is described by analysing the dynamics of (currently nearly 200) membe...
Mahmoudi, S.; Trivaudey, F.; Bouhaddi, N.
2015-07-01
The aim of this study is the prediction of the dynamic response of damaged laminated composite structures in the context of component mode synthesis. Hence, a method of damage localization of complex structures is proposed. The dynamic behavior of transversely isotropic layers is expressed through elasticity coupled with damage based on an existing macro model for cracked structures. The damage is located only in some regions of the whole structure, which is decomposed on substructures. The incremental linear dynamic governing equations are obtained by using the classical linear Kirchhoff-Love theory of plates. Then, considering the damage-induced nonlinearity, the obtained nonlinear dynamic equations are solved in time domain. However, a detailed finite element modelling of such structure on the scale of localized damage would generate very high computational costs. To reduce this cost, Component Mode Synthesis method (CMS) is used for modelling a nonlinear fine-scale substructure damaged, connected to linear dynamic models of the remaining substructures, which can be condensed and not updated at each iteration. Numerical results show that the mechanical properties of the structure highly change when damage is taken into account. Under an impact load, damage increases and reaches its highest value with the maximum of the applied load and then remains unchanged. Besides, the eigenfrequencies of the damaged structure decrease comparing with those of an undamaged one. This methodology can be used for monitoring strategies and lifetime estimations of hybrid complex structures due to the damage state is known in space and time.
Shan, Lu; Mathews, Irimpan I.; Khosla, Chaitan
2005-01-01
Prolyl endopeptidases (PEPs) are a unique class of serine proteases with considerable therapeutic potential for the treatment of celiac sprue. The crystal structures of two didomain PEPs have been solved in alternative configurations, thereby providing insights into the mode of action of these enzymes. The structure of the Sphingomonas capsulata PEP, solved and refined to 1.8-Å resolution, revealed an open configuration of the active site. In contrast, the inhibitor-bound PEP from Myxococcus ...
Essentials of applied dynamic analysis
Jia, Junbo
2014-01-01
This book presents up-to-date knowledge of dynamic analysis in engineering world. To facilitate the understanding of the topics by readers with various backgrounds, general principles are linked to their applications from different angles. Special interesting topics such as statistics of motions and loading, damping modeling and measurement, nonlinear dynamics, fatigue assessment, vibration and buckling under axial loading, structural health monitoring, human body vibrations, and vehicle-structure interactions etc., are also presented. The target readers include industry professionals in civil, marine and mechanical engineering, as well as researchers and students in this area.
International Nuclear Information System (INIS)
A combined multibody and finite element approach is given to solve the dynamic interaction of a Shinkansen train (high-speed train in Japan) and the railway structure including post-derailment during an earthquake effectively. The motion of the train is expressed in multibody dynamics. Efficient mechanical models to express interactions between wheel and track structure including post-derailment are given. Rail and track elements expressed in multibody dynamics and FEM are given to solve contact problems between wheel and long railway components effectively. The motion of a railway structure is modeled with various finite elements and rail and track elements. The computer program has been developed for the dynamic interaction analysis of a Shinkansen train and railway structure including post derailment during an earthquake. Numerical examples are demonstrated.
Structural Dynamics of Electronic Systems
Suhir, E.
2013-03-01
The published work on analytical ("mathematical") and computer-aided, primarily finite-element-analysis (FEA) based, predictive modeling of the dynamic response of electronic systems to shocks and vibrations is reviewed. While understanding the physics of and the ability to predict the response of an electronic structure to dynamic loading has been always of significant importance in military, avionic, aeronautic, automotive and maritime electronics, during the last decade this problem has become especially important also in commercial, and, particularly, in portable electronics in connection with accelerated testing of various surface mount technology (SMT) systems on the board level. The emphasis of the review is on the nonlinear shock-excited vibrations of flexible printed circuit boards (PCBs) experiencing shock loading applied to their support contours during drop tests. At the end of the review we provide, as a suitable and useful illustration, the exact solution to a highly nonlinear problem of the dynamic response of a "flexible-and-heavy" PCB to an impact load applied to its support contour during drop testing.
Meier, D L
1999-01-01
A new field of numerical astrophysics is introduced which addresses the solution of large, multidimensional structural or slowly-evolving problems (rotating stars, interacting binaries, thick advective accretion disks, four dimensional spacetimes, etc.). The technique employed is the Finite Element Method (FEM), commonly used to solve engineering structural problems. The approach developed herein has the following key features: 1. The computational mesh can extend into the time dimension, as well as space, perhaps only a few cells, or throughout spacetime. 2. Virtually all equations describing the astrophysics of continuous media, including the field equations, can be written in a compact form similar to that routinely solved by most engineering finite element codes. 3. The transformations that occur naturally in the four-dimensional FEM possess both coordinate and boost features, such that (a) although the computational mesh may have a complex, non-analytic, curvilinear structure, the physical equations stil...
On the Accuracy of Dynamic and Acoustic Analysis of Lightweight Panel Structures
DEFF Research Database (Denmark)
Kirkegaard, Poul Henning; Andersen, Lars Vabbersgaard; Dickow, Kristoffer Ahrens
2012-01-01
During the last couple of years, there has been an increasing focus on the vibro-acoustic performance of built environments due to increasing requirements in building codes regarding impact and airborne sound transmission. Hence, development of efficient and accurate methods for prediction of sou......, lightweight panel structure. For this purpose, modal analyses are carried out employing a fully coupled model of sound waves within an acoustic medium and vibrations in the structural part. The study concerns the frequency range 50–250 Hz....
International Nuclear Information System (INIS)
The heat transport systems of MONJU are three main heat transport loops, each loop consist of the primary, the secondary loop and the water-steam system, in addition, the auxiliary cooling system. These systems are under the influence one another on plant transient. So it is important to evaluate the flow and heat characteristics of the heat transport systems on calculating plant transient. We made the plant dynamic analysis codes of MONJU to calculate the plant transient analysis and evaluate the plant characteristics by the disturbance on the on-power operation and the performance of the plant control systems. In this paper, one of the main plant dynamic simulation code of MONJU, the calculation conditions on analysis, the plant safety analysis, the plant stability analysis and the plant thermal transient analysis are discribed. (author)
Mass Spectrometry-Based Proteomics for the Analysis of Chromatin Structure and Dynamics
Monica Soldi; Alessandro Cuomo; Michael Bremang; Tiziana Bonaldi
2013-01-01
Chromatin is a highly structured nucleoprotein complex made of histone proteins and DNA that controls nearly all DNA-dependent processes. Chromatin plasticity is regulated by different associated proteins, post-translational modifications on histones (hPTMs) and DNA methylation, which act in a concerted manner to enforce a specific “chromatin landscape”, with a regulatory effect on gene expression. Mass Spectrometry (MS) has emerged as a powerful analytical strategy to detect histone PTMs, re...
Estrada, Ernesto
2016-01-01
We propose a new model to account for the main structural characteristics of rock fracture networks (RFNs). The model is based on a generalization of the random neighborhood graphs to consider fractures embedded into rectangular spaces. We study a series of 29 real-world RFNs and find the best fit with the random rectangular neighborhood graphs (RRNGs) proposed here. We show that this model captures most of the structural characteristics of the RFNs and allows a distinction between small and more spherical rocks and large and more elongated ones. We use a diffusion equation on the graphs in order to model diffusive processes taking place through the channels of the RFNs. We find a small set of structural parameters that highly correlates with the average diffusion time in the RFNs. In particular, the second smallest eigenvalue of the Laplacian matrix is a good predictor of the average diffusion time on RFNs, showing a Pearson correlation coefficient larger than $0.99$ with the average diffusion time on RFNs. ...
PRONTO3D users` instructions: A transient dynamic code for nonlinear structural analysis
Energy Technology Data Exchange (ETDEWEB)
Attaway, S.W.; Mello, F.J.; Heinstein, M.W.; Swegle, J.W.; Ratner, J.A. [Sandia National Labs., Albuquerque, NM (United States); Zadoks, R.I. [Univ. of Texas, El Paso, TX (United States)
1998-06-01
This report provides an updated set of users` instructions for PRONTO3D. PRONTO3D is a three-dimensional, transient, solid dynamics code for analyzing large deformations of highly nonlinear materials subjected to extremely high strain rates. This Lagrangian finite element program uses an explicit time integration operator to integrate the equations of motion. Eight-node, uniform strain, hexahedral elements and four-node, quadrilateral, uniform strain shells are used in the finite element formulation. An adaptive time step control algorithm is used to improve stability and performance in plasticity problems. Hourglass distortions can be eliminated without disturbing the finite element solution using either the Flanagan-Belytschko hourglass control scheme or an assumed strain hourglass control scheme. All constitutive models in PRONTO3D are cast in an unrotated configuration defined using the rotation determined from the polar decomposition of the deformation gradient. A robust contact algorithm allows for the impact and interaction of deforming contact surfaces of quite general geometry. The Smooth Particle Hydrodynamics method has been embedded into PRONTO3D using the contact algorithm to couple it with the finite element method.
Dynamic response of structures constructed from smart materials
Caughey, T. K.
1995-01-01
The dynamic analysis of structures constructed of homogeneous smart materials is greatly simplified by the observation that the eigenfunctions of such structures are identical to those of the same structures constructed entirely of purely elastic materials. The dynamic analysis of such structures is thus reduced to the analysis of the temporal behaviour of the eigenmodes of the structure. The theory is illustrated for both continuous and discrete structures using the generalization of 'positi...
31st IMAC Conference on Structural Dynamics
Adams, Douglas; Carrella, Alex; Mayes, Randy; Rixen, Daniel; Allen, Matt; Cunha, Alvaro; Catbas, Fikret; Pakzad, Shamim; Racic, Vitomir; Pavic, Aleksandar; Reynolds, Paul; Simmermacher, Todd; Cogan, Scott; Moaveni, Babak; Papadimitriou, Costas; Allemang, Randall; Clerck, James; Niezrecki, Christopher; Wicks, Alfred
2013-01-01
Topics in Nonlinear Dynamics, Volume 1: Proceedings of the 31st IMAC, A Conference and Exposition on Structural Dynamics, 2013, the first volume of seven from the Conference, brings together contributions to this important area of research and engineering. The collection presents early findings and case studies on fundamental and applied aspects of Structural Dynamics, including papers on: Nonlinear Oscillations Nonlinearities In Practice Nonlinear System Identification: Methods Nonlinear System Identification: Friction & Contact Nonlinear Modal Analysis Nonlinear Modeling & Simulation Nonlinear Vibration Absorbers Constructive Utilization of Nonlinearity.
Structural dynamics in LMFBR containment analysis: a brief survey of computational methods and codes
Energy Technology Data Exchange (ETDEWEB)
Chang, Y.W.; Gvildys, J.
1977-01-01
In recent years, the use of computer codes to study the response of primary containment of large, liquid-metal fast breeder reactors (LMFBR) under postulated accident conditions has been adopted by most fast reactor projects. Since the first introduction of REXCO-H containment code in 1969, a number of containment codes have evolved and been reported in the literature. The paper briefly summarizes the various numerical methods commonly used in containment analysis in computer programs. They are compared on the basis of truncation errors resulting in the numerical approximation, the method of integration, the resolution of the computed results, and the ease of programming in computer codes. The aim of the paper is to provide enough information to an analyst so that he can suitably define his choice of method, and hence his choice of programs.
Fluid structure interaction dynamic analysis of a mixed-flow waterjet pump
International Nuclear Information System (INIS)
In order to avoid resonance of a mixed-flow waterjet pump at run time and calculate the stress and deformation of the pump rotor in the flow field, a one-way fluid structure interaction method was applied to simulate the pump rotor using ANSYS CFX and ANSYS Workbench software. The natural frequencies and mode shapes of the pump rotor in the air and in the flow field were analyzed, and the stress and deformation of the impeller were obtained at different flow rates. The obtained numerical results indicated that the mode shapes were similar both in the air and in the flow field, but the pump rotor's natural frequency in the flow field was slightly smaller than that in the air; the difference of the pump rotor's natural frequency varied lightly at different flow rates, and all frequencies at different flow rates were higher than the safe frequency, the pump rotor under the effect of prestress rate did not occur resonance; The maximum stress was on the blade near the hub and the maximum deformation on the blade tip at different flow rates
Fluid structure interaction dynamic analysis of a mixed-flow waterjet pump
Pan, X. W.; Y Pan, Z.; Huang, D.; Shen, Z. H.
2013-12-01
In order to avoid resonance of a mixed-flow waterjet pump at run time and calculate the stress and deformation of the pump rotor in the flow field, a one-way fluid structure interaction method was applied to simulate the pump rotor using ANSYS CFX and ANSYS Workbench software. The natural frequencies and mode shapes of the pump rotor in the air and in the flow field were analyzed, and the stress and deformation of the impeller were obtained at different flow rates. The obtained numerical results indicated that the mode shapes were similar both in the air and in the flow field, but the pump rotor's natural frequency in the flow field was slightly smaller than that in the air; the difference of the pump rotor's natural frequency varied lightly at different flow rates, and all frequencies at different flow rates were higher than the safe frequency, the pump rotor under the effect of prestress rate did not occur resonance; The maximum stress was on the blade near the hub and the maximum deformation on the blade tip at different flow rates.
DEFF Research Database (Denmark)
Nielsen, Søren R.K.
The present textbook has been written for a course on stochastic vibration theory that is being given on the 9th semester at Aalborg University for M.Sc. students in structural engineering.......The present textbook has been written for a course on stochastic vibration theory that is being given on the 9th semester at Aalborg University for M.Sc. students in structural engineering....
Brown, Andrew M.
2014-01-01
Numerical and Analytical methods developed to determine damage accumulation in specific engine components when speed variation included. Dither Life Ratio shown to be well over factor of 2 for specific example. Steady-State assumption shown to be accurate for most turbopump cases, allowing rapid calculation of DLR. If hot-fire speed data unknown, Monte Carlo method developed that uses speed statistics for similar engines. Application of techniques allow analyst to reduce both uncertainty and excess conservatism. High values of DLR could allow previously unacceptable part to pass HCF criteria without redesign. Given benefit and ease of implementation, recommend that any finite life turbomachine component analysis adopt these techniques. Probability Values calculated, compared, and evaluated for several industry-proposed methods for combining random and harmonic loads. Two new excel macros written to calculate combined load for any specific probability level. Closed form Curve fits generated for widely used 3(sigma) and 2(sigma) probability levels. For design of lightweight aerospace components, obtaining accurate, reproducible, statistically meaningful answer critical.
Karunanayaka, Prasanna; Eslinger, Paul J; Wang, Jian-Li; Weitekamp, Christopher W; Molitoris, Sarah; Gates, Kathleen M; Molenaar, Peter C M; Yang, Qing X
2014-05-01
The study of human olfaction is complicated by the myriad of processing demands in conscious perceptual and emotional experiences of odors. Combining functional magnetic resonance imaging with convergent multivariate network analyses, we examined the spatiotemporal behavior of olfactory-generated blood-oxygenated-level-dependent signal in healthy adults. The experimental functional magnetic resonance imaging (fMRI) paradigm was found to offset the limitations of olfactory habituation effects and permitted the identification of five functional networks. Analysis delineated separable neuronal circuits that were spatially centered in the primary olfactory cortex, striatum, dorsolateral prefrontal cortex, rostral prefrontal cortex/anterior cingulate, and parietal-occipital junction. We hypothesize that these functional networks subserve primary perceptual, affective/motivational, and higher order olfactory-related cognitive processes. Results provided direct evidence for the existence of parallel networks with top-down modulation for olfactory processing and clearly distinguished brain activations that were sniffing-related versus odor-related. A comprehensive neurocognitive model for olfaction is presented that may be applied to broader translational studies of olfactory function, aging, and neurological disease. PMID:23818133
Energy Technology Data Exchange (ETDEWEB)
Halbritter, A.L.; Krutzik, N.J. [Siemens AG Unternehmensbereich KWU, Offenbach am Main (Germany); Boyadjiev, Z. [Kozloduy Nuclear Power Plant, Kozloduy (Bulgaria); Katona, T. [Paks Nuclear Power Plant Ltd, PAKS (Hungary)
1998-05-01
The dynamic response of structures due to seismic loadings is conventionally analyzed in the time domain using substructure methods (decoupled system models). This procedure uses frequency-independent impedances to represent capabilities of the soil underneath the structure. The soil parameters are tuned to the fundamental frequencies of the soil-structure system. This is a common procedure widely used in the preliminary design of power plant structures which provides conservative results. However, parallel to the rapid progress being made in upgrading the capability of data processing systems, methods and software tools have become available which work also in the frequency domain using complex models (for the soil and the structure) or models in which the soil is represented by frequency-dependent impedances. This procedure (coupled system models) also allows realistic treatment of kinematic interaction effects and especially consideration of the embedment parameters of the building structure. The main goal of the study presented here was to demonstrate the effects of different procedures for consideration of soil-structure interaction on the dynamic response of the structures mentioned above. The analyses were based on appropriate mathematical models of the coupled vibrating structures (reactor building, turbine hall, intermediate building structures of a VVER 440/213 as well as the main building of the VVER 1000) and the layered soil. On the basis of this study, it can be concluded that substructure methods using frequency-independent impedances (equivalent dashpots) and cut-off of modal damping usually provide conservative results. (orig.) 7 refs.
International Nuclear Information System (INIS)
The dynamic response of structures due to seismic loadings is conventionally analyzed in the time domain using substructure methods (decoupled system models). This procedure uses frequency-independent impedances to represent capabilities of the soil underneath the structure. The soil parameters are tuned to the fundamental frequencies of the soil-structure system. This is a common procedure widely used in the preliminary design of power plant structures which provides conservative results. However, parallel to the rapid progress being made in upgrading the capability of data processing systems, methods and software tools have become available which work also in the frequency domain using complex models (for the soil and the structure) or models in which the soil is represented by frequency-dependent impedances. This procedure (coupled system models) also allows realistic treatment of kinematic interaction effects and especially consideration of the embedment parameters of the building structure. The main goal of the study presented here was to demonstrate the effects of different procedures for consideration of soil-structure interaction on the dynamic response of the structures mentioned above. The analyses were based on appropriate mathematical models of the coupled vibrating structures (reactor building, turbine hall, intermediate building structures of a VVER 440/213 as well as the main building of the VVER 1000) and the layered soil. On the basis of this study, it can be concluded that substructure methods using frequency-independent impedances (equivalent dashpots) and cut-off of modal damping usually provide conservative results. (orig.)
Dynamical analysis of highly excited molecular spectra
Energy Technology Data Exchange (ETDEWEB)
Kellman, M.E. [Univ. of Oregon, Eugene (United States)
1993-12-01
The goal of this program is new methods for analysis of spectra and dynamics of highly excited vibrational states of molecules. In these systems, strong mode coupling and anharmonicity give rise to complicated classical dynamics, and make the simple normal modes analysis unsatisfactory. New methods of spectral analysis, pattern recognition, and assignment are sought using techniques of nonlinear dynamics including bifurcation theory, phase space classification, and quantization of phase space structures. The emphasis is chaotic systems and systems with many degrees of freedom.
Dynamically variable negative stiffness structures
Churchill, Christopher B.; Shahan, David W.; Smith, Sloan P.; Keefe, Andrew C.; McKnight, Geoffrey P.
2016-01-01
Variable stiffness structures that enable a wide range of efficient load-bearing and dexterous activity are ubiquitous in mammalian musculoskeletal systems but are rare in engineered systems because of their complexity, power, and cost. We present a new negative stiffness–based load-bearing structure with dynamically tunable stiffness. Negative stiffness, traditionally used to achieve novel response from passive structures, is a powerful tool to achieve dynamic stiffness changes when configured with an active component. Using relatively simple hardware and low-power, low-frequency actuation, we show an assembly capable of fast (100×) dynamic stiffness control. This approach mitigates limitations of conventional tunable stiffness structures that exhibit either small (humanoid robotic limbs and lightweight adaptive vibration isolators. PMID:26989771
30th IMAC, A Conference on Structural Dynamics
Catbas, FN; Mayes, R; Rixen, D; Griffith, DT; Allemang, R; Clerck, J; Klerk, D; Simmermacher, T; Cogan, S; Chauhan, S; Cunha, A; Racic, V; Reynolds, P; Salyards, K; Adams, D; Kerschen, G; Carrella, A; Voormeeren, SN; Allen, MS; Horta, LG; Barthorpe, R; Niezrecki, C; Blough, JR; Vol.1 Topics on the Dynamics of Civil Structures; Vol.2 Topics in Experimental Dynamics Substructuring and Wind Turbine Dynamics; Vol.3 Topics in Nonlinear Dynamics; Vol.4 Topics in Model Validation and Uncertainty Quantification; Vol.5 Topics in Modal Analysis I; Vol.6 Topics in Modal Analysis II
2012-01-01
Topics on the Dynamics of Civil Structures, Volume 1, Proceedings of the 30th IMAC, A Conference and Exposition on Structural Dynamics, 2012, the first volume of six from the Conference, brings together 45 contributions to this important area of research and engineering. The collection presents early findings and case studies on fundamental and applied aspects of Structural Dynamics, including papers on: Human Induced Vibrations Bridge Dynamics Operational Modal Analysis Experimental Techniques and Modeling for Civil Structures System Identification for Civil Structures Method and Technologies for Bridge Monitoring Damage Detection for Civil Structures Structural Modeling Vibration Control Method and Approaches for Civil Structures Modal Testing of Civil Structures.
Directory of Open Access Journals (Sweden)
DuBois Debra C
2010-10-01
Full Text Available Abstract Background Comprehensively understanding corticosteroid pharmacogenomic effects is an essential step towards an insight into the underlying molecular mechanisms for both beneficial and detrimental clinical effects. Nevertheless, even in a single tissue different methods of corticosteroid administration can induce different patterns of expression and regulatory control structures. Therefore, rich in vivo datasets of pharmacological time-series with two dosing regimens sampled from rat liver are examined for temporal patterns of changes in gene expression and their regulatory commonalities. Results The study addresses two issues, including (1 identifying significant transcriptional modules coupled with dynamic expression patterns and (2 predicting relevant common transcriptional controls to better understand the underlying mechanisms of corticosteroid adverse effects. Following the orientation of meta-analysis, an extended computational approach that explores the concept of agreement matrix from consensus clustering has been proposed with the aims of identifying gene clusters that share common expression patterns across multiple dosing regimens as well as handling challenges in the analysis of microarray data from heterogeneous sources, e.g. different platforms and time-grids in this study. Six significant transcriptional modules coupled with typical patterns of expression have been identified. Functional analysis reveals that virtually all enriched functions (gene ontologies, pathways in these modules are shown to be related to metabolic processes, implying the importance of these modules in adverse effects under the administration of corticosteroids. Relevant putative transcriptional regulators (e.g. RXRF, FKHD, SP1F are also predicted to provide another source of information towards better understanding the complexities of expression patterns and the underlying regulatory mechanisms of those modules. Conclusions We have proposed a
Dynamic Contingency Analysis Tool
Energy Technology Data Exchange (ETDEWEB)
2016-01-14
The Dynamic Contingency Analysis Tool (DCAT) is an open-platform and publicly available methodology to help develop applications that aim to improve the capabilities of power system planning engineers to assess the impact and likelihood of extreme contingencies and potential cascading events across their systems and interconnections. Outputs from the DCAT will help find mitigation solutions to reduce the risk of cascading outages in technically sound and effective ways. The current prototype DCAT implementation has been developed as a Python code that accesses the simulation functions of the Siemens PSS�E planning tool (PSS/E). It has the following features: It uses a hybrid dynamic and steady-state approach to simulating the cascading outage sequences that includes fast dynamic and slower steady-state events. It integrates dynamic models with protection scheme models for generation, transmission, and load. It models special protection systems (SPSs)/remedial action schemes (RASs) and automatic and manual corrective actions. Overall, the DCAT attempts to bridge multiple gaps in cascading-outage analysis in a single, unique prototype tool capable of automatically simulating and analyzing cascading sequences in real systems using multiprocessor computers.While the DCAT has been implemented using PSS/E in Phase I of the study, other commercial software packages with similar capabilities can be used within the DCAT framework.
Namazi, Hamidreza; Kulish, Vladimir V.; Akrami, Amin
2016-05-01
One of the major challenges in vision research is to analyze the effect of visual stimuli on human vision. However, no relationship has been yet discovered between the structure of the visual stimulus, and the structure of fixational eye movements. This study reveals the plasticity of human fixational eye movements in relation to the ‘complex’ visual stimulus. We demonstrated that the fractal temporal structure of visual dynamics shifts towards the fractal dynamics of the visual stimulus (image). The results showed that images with higher complexity (higher fractality) cause fixational eye movements with lower fractality. Considering the brain, as the main part of nervous system that is engaged in eye movements, we analyzed the governed Electroencephalogram (EEG) signal during fixation. We have found out that there is a coupling between fractality of image, EEG and fixational eye movements. The capability observed in this research can be further investigated and applied for treatment of different vision disorders.
From structure to function, via dynamics
Stetter, O.; Soriano, J.; Geisel, T.; Battaglia, D.
2013-01-01
Neurons in the brain are wired into a synaptic network that spans multiple scales, from local circuits within cortical columns to fiber tracts interconnecting distant areas. However, brain function require the dynamic control of inter-circuit interactions on time-scales faster than synaptic changes. In particular, strength and direction of causal influences between neural populations (described by the so-called directed functional connectivity) must be reconfigurable even when the underlying structural connectivity is fixed. Such directed functional influences can be quantified resorting to causal analysis of time-series based on tools like Granger Causality or Transfer Entropy. The ability to quickly reorganize inter-areal interactions is a chief requirement for performance in a changing natural environment. But how can manifold functional networks stem "on demand" from an essentially fixed structure? We explore the hypothesis that the self-organization of neuronal synchronous activity underlies the control of brain functional connectivity. Based on simulated and real recordings of critical neuronal cultures in vitro, as well as on mean-field and spiking network models of interacting brain areas, we have found that "function follows dynamics", rather than structure. Different dynamic states of a same structural network, characterized by different synchronization properties, are indeed associated to different functional digraphs (functional multiplicity). We also highlight the crucial role of dynamics in establishing a structure-to-function link, by showing that whenever different structural topologies lead to similar dynamical states, than the associated functional connectivities are also very similar (structural degeneracy).
International Nuclear Information System (INIS)
Using set theory, it is shown that the apex-seeking algorithm for determining the oblique transformation used in FADS will be valid only under conditions which are rarely met in nuclear medicine. An alternative approach using cluster analysis is suggested. It is shown using these methods that the problem of dependent factors may be reduced to one of constraint finding. Using the example of an abnormal gated cardiac study, it is shown that a more realistic solution is found using the new methodology and a background constraint. The problem of non-homogeneity, present in cardiac studies and contrary to the theory of FADS, remains. (Auth.)
Band structure and nuclear dynamics
International Nuclear Information System (INIS)
The relation between the Variable Moment of Inertia model and the Interacting Boson Model are discussed from a phenomenological viewpoint. New results on ground state mean-square radii in nuclei far from stability are reported, and a discussion of band structure extending to high angular momentum states and methods of extracting information on the underlying dynamics is given
Kobayashi, Kazuya; Liang, Yunfeng; Amano, Ken-Ichi; Murata, Sumihiko; Matsuoka, Toshifumi; Takahashi, Satoru; Nishi, Naoya; Sakka, Tetsuo
2016-04-19
With the development of atomic force microscopy (AFM), it is now possible to detect the buried liquid-solid interfacial structure in three dimensions at the atomic scale. One of the model surfaces used for AFM is the muscovite surface because it is atomically flat after cleavage along the basal plane. Although it is considered that force profiles obtained by AFM reflect the interfacial structures (e.g., muscovite surface and water structure), the force profiles are not straightforward because of the lack of a quantitative relationship between the force and the interfacial structure. In the present study, molecular dynamics simulations were performed to investigate the relationship between the muscovite-water interfacial structure and the measured AFM force using a capped carbon nanotube (CNT) AFM tip. We provide divided force profiles, where the force contributions from each water layer at the interface are shown. They reveal that the first hydration layer is dominant in the total force from water even after destruction of the layer. Moreover, the lateral structure of the first hydration layer transcribes the muscovite surface structure. It resembles the experimentally resolved surface structure of muscovite in previous AFM studies. The local density profile of water between the tip and the surface provides further insight into the relationship between the water structure and the detected force structure. The detected force structure reflects the basic features of the atomic structure for the local hydration layers. However, details including the peak-peak distance in the force profile (force-distance curve) differ from those in the density profile (density-distance curve) because of disturbance by the tip. PMID:27018633
Particular Approaches about Symmetrical Structures Dynamics
Directory of Open Access Journals (Sweden)
Aurora Potirniche
2013-09-01
Full Text Available The paper presents some aspects about dynamic behaviour of a rigid structure building insulated on anti-seismic elastic devices. The structure presents symmetries in terms of the geometrical and insulation configurations, and this allows decoupling of the eigenmodes. Thereby, is simpler to evaluate the impact of the dynamic forces transmitted through the terrain-structure path during the earthquake. Based on the vibration isolation theory, it can be evaluated the isolation degree for the considered structure. It has considered as an excitation factor the complex signal of an earthquake defined through the ground motion acceleration. The analysis that was made in the paper reveals the need to identification and evaluation requirements for the functional correlations between the reference parameters of the considered structure and the characteristics of the isolating and insulating devices.
Distributed Dynamic Condition Response Structures
DEFF Research Database (Denmark)
Hildebrandt, Thomas; Mukkamala, Raghava Rao
repeated, possibly infinite behavior, 2) finitely specify fine-grained acceptance conditions for (possibly infinite) runs based on the notion of responses and 3) distribute events via roles. We give a graphical notation inspired by related work by van der Aalst et al and formalize the execution semantics......We present distributed dynamic condition response structures as a declarative process model inspired by the workflow language employed by our industrial partner and conservatively generalizing labelled event structures. The model adds to event structures the possibility to 1) finitely specify...
Goldgruber, Markus; Shahriari, Shervin; Zenz, Gerald
2015-11-01
To reduce the natural hazard risks—due to, e.g., earthquake excitation—seismic safety assessments are carried out. Especially under severe loading, due to maximum credible or the so-called safety evaluation earthquake, critical infrastructure, as these are high dams, must not fail. However, under high loading local failure might be allowed as long as the entire structure does not collapse. Hence, for a dam, the loss of sliding stability during a short time period might be acceptable if the cumulative displacements after an event are below an acceptable value. This performance is not only valid for gravity dams but also for rock blocks as sliding is even more imminent in zones with higher seismic activity. Sliding modes cannot only occur in the dam-foundation contact, but also in sliding planes formed due to geological conditions. This work compares the qualitative possible and critical displacements for two methods, the well-known Newmark's sliding block analysis and a Fluid-Foundation-Structure Interaction simulation with the finite elements method. The results comparison of the maximum displacements at the end of the seismic event of the two methods depicts that for high friction angles, they are fairly close. For low friction angles, the results are differing more. The conclusion is that the commonly used Newmark's sliding block analysis and the finite elements simulation are only comparable for high friction angles, where this factor dominates the behaviour of the structure. Worth to mention is that the proposed simulation methods are also applicable to dynamic rock wedge problems and not only to dams.
Schindler, Tanja; Kröner, Dietmar; Steinhauser, Martin O
2016-09-01
We present a molecular dynamics simulation study of the self-assembly of coarse-grained lipid molecules from unbiased random initial configurations. Our lipid model is based on a well-tried CG polymer model with an additional potential that mimics the hydrophobic properties of lipid tails. We find that several stages of self-organization of lipid clusters are involved in the dynamics of bilayer formation and that the resulting equilibrium structures sensitively depend on the strength of hydrophobic interactions hc of the lipid tails and on temperature T. The obtained stable lipid membranes are quantitatively analyzed with respect to their local structure and their degree of order. At equilibrium, we obtain self-stabilizing bilayer membrane structures that exhibit a bending stiffness κB and compression modulus KC comparable to experimental measurements under physiological conditions. We present a phase diagram of our lipid model which covers a sol-gel transition, a liquid (or gel-like) phase including stable bilayer structures and vesicle formation, as well as a quasi-crystalline phase. We also determine the exact conditions for temperature T and degree of hydrophobicity hc for stable bilayer formation including closed vesicles. PMID:27216316
Cau, Ylenia; Fiorillo, Annarita; Mori, Mattia; Ilari, Andrea; Botta, Maurizo; Lalle, Marco
2015-12-28
Giardiasis is a gastrointestinal diarrheal illness caused by the protozoan parasite Giardia duodenalis, which affects annually over 200 million people worldwide. The limited antigiardial drug arsenal and the emergence of clinical cases refractory to standard treatments dictate the need for new chemotherapeutics. The 14-3-3 family of regulatory proteins, extensively involved in protein-protein interactions (PPIs) with pSer/pThr clients, represents a highly promising target. Despite homology with human counterparts, the single 14-3-3 of G. duodenalis (g14-3-3) is characterized by a constitutive phosphorylation in a region critical for target binding, thus affecting the function and the conformation of g14-3-3/clients interaction. However, to approach the design of specific small molecule modulators of g14-3-3 PPIs, structural elucidations are required. Here, we present a detailed computational and crystallographic study exploring the implications of g14-3-3 phosphorylation on protein structure and target binding. Self-Guided Langevin Dynamics and classical molecular dynamics simulations show that phosphorylation affects locally and globally g14-3-3 conformation, inducing a structural rearrangement more suitable for target binding. Profitable features for g14-3-3/clients interaction were highlighted using a hydrophobicity-based descriptor to characterize g14-3-3 client peptides. Finally, the X-ray structure of g14-3-3 in complex with a mode-1 prototype phosphopeptide was solved and combined with structure-based simulations to identify molecular features relevant for clients binding to g14-3-3. The data presented herein provide a further and structural understanding of g14-3-3 features and set the basis for drug design studies. PMID:26551337
DEFF Research Database (Denmark)
Poulsen, Mikael Zebbelin
2002-01-01
Differential algebraic equations (DAEs) constitute a fundamental model class for many modelling purposes in engineering and other sciences, especially for dynamical simulation of component based systems. This thesis describes a practical methodology and approach for analysing general DAE. The...... underlying ODE for finding consistent initial values and solve the initial value problem for the original DAE. As a methodology for integrating the augmented underlying ODE, the dummy derivative method is investigated. The methodology avoids the traditional stability and drift-of problems of using the...... structural index analysis of DAE is original in the sense that it is based on a new matrix representation of the structural information of a general DAE system instead of a graph oriented representation. Also the presentation of the theory is found to be more complete compared to other presentations, since...
Kim, Byoung Wan; Sung, Hong Gun; Kim, Jin Ha; Hong, Sa Young
2013-10-01
This paper compares the dynamic coupled behavior of floating structure and mooring system in time domain using two numerical methods for the mooring lines such as the linear spring method and the nonlinear FEM (Finite Element Method). In the linear spring method, hydrodynamic coefficients and forces on the floating body are calculated using BEM (Boundary Element Method) and the time domain equation is derived using convolution. The coupled solution is obtained by simply adding the pre-determined spring constants of the mooring lines into the floating body equation. In FEM, the minimum energy principle is applied to formulate the nonlinear dynamic equation of the mooring system with a discrete numerical model. The ground contact model and Morison formula for drag forces are also included in the formulation. The coupled solution is obtained by iteratively solving the floating body equation and the FEM equation of the mooring system. Two example structures such as weathervane ship and semi-submersible structure are analyzed using linear spring and nonlinear FEM methods and the difference of those two methods are presented. By analyzing the cases with or without surge-pitch or sway-roll coupling stiffness of mooring lines in the linear spring method, the effect of coupling stiffness of the mooring system is also discussed.
Rahneshin, Vahid; Chierichetti, Maria
2016-09-01
In this paper, a combined numerical and experimental method, called Extended Load Confluence Algorithm, is presented to accurately predict the dynamic response of non-periodic structures when little or no information about the applied loads is available. This approach, which falls into the category of Shape Sensing methods, inputs limited experimental information acquired from sensors to a mapping algorithm that predicts the response at unmeasured locations. The proposed algorithm consists of three major cores: an experimental core for data acquisition, a numerical core based on Finite Element Method for modeling the structure, and a mapping algorithm that improves the numerical model based on a modal approach in the frequency domain. The robustness and precision of the proposed algorithm are verified through numerical and experimental examples. The results of this paper demonstrate that without a precise knowledge of the loads acting on the structure, the dynamic behavior of the system can be predicted in an effective and precise manner after just a few iterations.
Guidelines for dynamic data acquisition and analysis
Piersol, Allan G.
1992-10-01
The recommendations concerning pyroshock data presented in the final draft of a proposed military handbook on Guidelines for Dynamic Data Acquisition and Analysis are reviewed. The structural responses produced by pyroshocks are considered to be one of the most difficult types of dynamic data to accurately measure and analyze.
International Nuclear Information System (INIS)
The purpose of this work is the development of a method to analyze on impact load structural systems whose topologically variable system arrangements are dependent on temporarily varying deformation conditions impact loads. This method serves to examine the prototype of a dynamically excited burst protection system for a nuclear power plant. Evidence is given that in case of hypothetical failure of the prestressed reactor pressure vessel the maximum load capacity of the reactor core is not exceeded, which in turn guarantees safe shutdown of the reactor. (orig./HP)
Institute of Scientific and Technical Information of China (English)
WANG; Xiaoguang; JIANG; Tingting; LI; Xiaoyu
2010-01-01
Co-word networks are constructed with author-provided keywords in academic publications and their relations of co-occurrence.As special form of scientific knowledge networks,they represent the cognitive structure of scientific literature.This paper analyzes the complex structure of a co-word network based on 8,190 author-provided keywords extracted from 3,651 papers in five Chinese core journals in the field of management science.Small-world and scale-free phenomena are found in this network.A large-scale co-word network graph,which consists of one major giant component and many small isolated components,has been generated with the GUESS software.The dynamic growth of keywords and keyword co-occurrence relationships are described with four new informetrics measures.The results indicate that existing concepts always serve as the intellectual base of new ideas as represented by keywords.
Czech Academy of Sciences Publication Activity Database
Hračov, Stanislav
Ústí nad Labem: Fakulta výrobních technologií a managementu, Univerzita J.E. Purkyně v Ústí nad Labem, 2013 - (Petrenko, A.; Svoboda, M.) ISBN 978-80-7414-607-7. [Dynamics of rigid and deformable bodies /11./. Ústí nad Labem (CZ), 09.10.2013-11.10.2013] R&D Projects: GA ČR(CZ) GP13-41574P; GA ČR(CZ) GA103/09/0094; GA AV ČR(CZ) IAA200710902 Institutional support: RVO:68378297 Keywords : soil-structure interaction * tuned mass damper * tall slender structures Subject RIV: JM - Building Engineering http://www.itam.cas.cz/?pid=5
Blacklock, Kristin; Verkhivker, Gennady M
2013-11-25
A fundamental role of the Hsp90 chaperone system in mediating maturation of protein clients is essential for the integrity of signaling pathways involved in cell cycle control and organism development. Molecular characterization of Hsp90 interactions with client proteins is fundamental to understanding the activity of many tumor-inducing signaling proteins and presents an active area of structural and biochemical studies. In this work, we have probed mechanistic aspects of allosteric regulation of Hsp90 by client proteins via a detailed computational study of Hsp90 interactions with the tumor suppressor protein p53. Experimentally guided protein docking and molecular dynamics structural refinement have reconstructed the recognition-competent states of the Hsp90-p53 complexes that are consistent with the NMR studies. Protein structure network analysis has identified critical interacting networks and specific residues responsible for structural integrity and stability of the Hsp90-p53 complexes. Coarse-grained modeling was used to characterize the global dynamics of the regulatory complexes and map p53-induced changes in the conformational equilibrium of Hsp90. The variations in the functional dynamics profiles of the Hsp90-p53 complexes are consistent with the NMR studies and could explain differences in the functional role of the alternative binding sites. Despite the overall similarity of the collective movements and the same global interaction footprint, p53 binding at the C-terminal interaction site of Hsp90 may have a more significant impact on the chaperone dynamics, which is consistent with the stronger allosteric effect of these interactions revealed by the experimental studies. The results suggest that p53-induced modulation of the global dynamics and structurally stable interaction networks can target the regulatory hinge regions and facilitate stabilization of the closed Hsp90 dimer that underlies the fundamental stimulatory effect of the p53 client. PMID
Dynamic analysis for shuttle design verification
Fralich, R. W.; Green, C. E.; Rheinfurth, M. H.
1972-01-01
Two approaches that are used for determining the modes and frequencies of space shuttle structures are discussed. The first method, direct numerical analysis, involves finite element mathematical modeling of the space shuttle structure in order to use computer programs for dynamic structural analysis. The second method utilizes modal-coupling techniques of experimental verification made by vibrating only spacecraft components and by deducing modes and frequencies of the complete vehicle from results obtained in the component tests.
Comparative analysis of the quasi-similar structures on the dynamic spectra of the Sun and Jupiter
Litvinenko, G.; Konovalenko, A.; Zakharenko, V.; Vinogradov, V.; Dorovsky, V.; Melnik, V.; Brazhenko, A.; Shaposhnikov, V.; Rucker, H. O.; Zarka, Ph.
2014-04-01
In many literary sources planet Jupiter called the Sun, which is not fully developed. It should be partially confirmed by the experimental fact that the quasisimilar in shape features appear in the dynamic spectra both in the Sun and the Jovian radio emission. The comparative analysis of the similar properties in the emission spectra of Jupiter and the Sun and analogy between the plasma processes in the solar corona and magnetosphere of Jupiter can allow also define the similar features in the radiation mechanisms of these cosmic objects. One of the promising approaches to investigating features of the Jovian DAM emission and the decameter solar radiation is application of novel experimental techniques with a further detailed analysis of the obtained data.
International Nuclear Information System (INIS)
Highlights: → We propose a method to compute the polarization for a multi-dimensional random distribution. → We apply the method to the eigenemodes of the Dirac operator in pure glue QCD. → We compute the chiral polarization for these modes and study its scale dependence. → We find that in a finite volume there is a scale where the polarization tendency changes. → We study the continuum limit of this chiral polarization scale. - Abstract: We propose a framework for quantitative evaluation of dynamical tendency for polarization in an arbitrary random variable that can be decomposed into a pair of orthogonal subspaces. The method uses measures based on comparisons of given dynamics to its counterpart with statistically independent components. The formalism of previously considered X-distributions is used to express the aforementioned comparisons, in effect putting the former approach on solid footing. Our analysis leads to the definition of a suitable correlation coefficient with clear statistical meaning. We apply the method to the dynamics induced by pure-glue lattice QCD in local left-right components of overlap Dirac eigenmodes. It is found that, in finite physical volume, there exists a non-zero physical scale in the spectrum of eigenvalues such that eigenmodes at smaller (fixed) eigenvalues exhibit convex X-distribution (positive correlation), while at larger eigenvalues the distribution is concave (negative correlation). This chiral polarization scale thus separates a regime where dynamics enhances chirality relative to statistical independence from a regime where it suppresses it, and gives an objective definition to the notion of 'low' and 'high' Dirac eigenmode. We propose to investigate whether the polarization scale remains non-zero in the infinite volume limit, in which case it would represent a new kind of low energy scale in QCD.
Separdar, L; Davatolhagh, S
2013-02-01
We investigate the static structure and diffusive dynamics of binary Lennard-Jones mixture upon supercooling in the presence of gold nanoparticle within the framework of the mode-coupling theory of the dynamic glass transition in the direct space by means of constant-NVT molecular dynamics simulations. It is found that the presence of gold nanoparticle causes the energy per particle and the pressure of this system to decrease with respect to the bulk binary Lennard-Jones mixture. Furthermore, the presence of nanoparticle has a direct effect on the liquid structure and causes the peaks of the radial distribution functions to become shorter with respect to the bulk binary Lennard-Jones liquid. The dynamics of the liquid at a given density is found to be consistent with the mode-coupling theory (MCT) predictions in a certain range at low temperatures. In accordance with the idealized MCT, the diffusion constants D(T) show a power-law behavior at low temperatures for both types of binary Lennard-Jones (BLJ) particles as well as the gold atoms comprising the nanoparticle. The mode-coupling crossover temperature T(c) is the same for all particle types; however, T(c)=0.4 is reduced with respect to that of the bulk BLJ liquid, and the γ exponent is found to depend on the particle type. The existence of the nanoparticle causes the short-time β-relaxation regime to shorten and the range of validity of the MCT shrinks with respect to the bulk BLJ. It is also found that at intermediate and low temperatures the curves of the mean-squared displacements (MSDs) versus tD(T) fall onto a master curve. The MSDs follow the master curve in an identical time range with the long-time α-relaxation regime of the mode-coupling theory. By obtaining the viscosity, it is observed that the Stokes-Einstein relation remains valid at high and intermediate temperatures but breaks down as the temperatures approach T(c) as a result of the cooperative motion or activated processes. PMID:23496514
Separdar, L.; Davatolhagh, S.
2013-02-01
We investigate the static structure and diffusive dynamics of binary Lennard-Jones mixture upon supercooling in the presence of gold nanoparticle within the framework of the mode-coupling theory of the dynamic glass transition in the direct space by means of constant-NVT molecular dynamics simulations. It is found that the presence of gold nanoparticle causes the energy per particle and the pressure of this system to decrease with respect to the bulk binary Lennard-Jones mixture. Furthermore, the presence of nanoparticle has a direct effect on the liquid structure and causes the peaks of the radial distribution functions to become shorter with respect to the bulk binary Lennard-Jones liquid. The dynamics of the liquid at a given density is found to be consistent with the mode-coupling theory (MCT) predictions in a certain range at low temperatures. In accordance with the idealized MCT, the diffusion constants D(T) show a power-law behavior at low temperatures for both types of binary Lennard-Jones (BLJ) particles as well as the gold atoms comprising the nanoparticle. The mode-coupling crossover temperature Tc is the same for all particle types; however, Tc=0.4 is reduced with respect to that of the bulk BLJ liquid, and the γ exponent is found to depend on the particle type. The existence of the nanoparticle causes the short-time β-relaxation regime to shorten and the range of validity of the MCT shrinks with respect to the bulk BLJ. It is also found that at intermediate and low temperatures the curves of the mean-squared displacements (MSDs) versus tD(T) fall onto a master curve. The MSDs follow the master curve in an identical time range with the long-time α-relaxation regime of the mode-coupling theory. By obtaining the viscosity, it is observed that the Stokes-Einstein relation remains valid at high and intermediate temperatures but breaks down as the temperatures approach Tc as a result of the cooperative motion or activated processes.
International Nuclear Information System (INIS)
The goal of the present report is to provide for a comprehensive users' manual describing the capabilities of the computer code EURDYN-1D. It includes information and examples about the type of problems which can be solved with the code and explanation on how to prepare input data and, how to interpret output results. The field of applications of EURDYN-1D is the one dimensional dynamic analysis of general structural systems and the code is particularly suited for fast transient events involving propagation of longitudinal mechanical waves (subsonic) in structures. Both geometrical and physical non-linearities can be taken into account. Typical examples are impact problems, fast dynamic loading due the explosions or sudden release for initial loads due to failures, etc. To these classes belong many problems encountered in the reactor safety field as well as in more common and general technological applications
Global Analysis of Nonlinear Dynamics
Luo, Albert
2012-01-01
Global Analysis of Nonlinear Dynamics collects chapters on recent developments in global analysis of non-linear dynamical systems with a particular emphasis on cell mapping methods developed by Professor C.S. Hsu of the University of California, Berkeley. This collection of contributions prepared by a diverse group of internationally recognized researchers is intended to stimulate interests in global analysis of complex and high-dimensional nonlinear dynamical systems, whose global properties are largely unexplored at this time. This book also: Presents recent developments in global analysis of non-linear dynamical systems Provides in-depth considerations and extensions of cell mapping methods Adopts an inclusive style accessible to non-specialists and graduate students Global Analysis of Nonlinear Dynamics is an ideal reference for the community of nonlinear dynamics in different disciplines including engineering, applied mathematics, meteorology, life science, computational science, and medicine.
Dynamic Response Analysis of Motorized Spindle System
Institute of Scientific and Technical Information of China (English)
ZHANG Li; LUO Yi-chao; XU Juan; XIAO Ru-feng; LI Xian-hui
2013-01-01
As to motorized spindle system, this paper builds a simplified 3D model of spindle and bearing, performs structure modal analysis, reveals its dynamic characteristics under the free model;furthermore, modifies bearing radial stiffness and number of model, and studies the change of modal parameters. On this basis, through the harmonic response analysis of the finite element model, dy-namic response characteristic caused by imbalance of monitored spindle system and law of vibration response to different amount of unbalance is analyzed.
International Nuclear Information System (INIS)
The EURDYN computer codes are mainly designed for the simulation of nonlinear dynamic response of fast-reactor compoments submitted to impulse loading due to abnormal working conditions. Two releases of the structural computer codes EURDYN 01 (2-D beams and triangles and axisymmetric conical shells and triangular tores), 02 (axisymmetric and 2-D quadratic isoparametric elements) and 03 (triangular plate elements) have already been produced. They include material (elasto-plasticity using the classical flow theory approach) and geometrical (large displacements and rotations treated by a corotational technique) nonlinearities. The new features of Release 3 roughly consist in: full large strain capability for 9-node isoparametric elements, generalized array dimensions, introduction of the radial return algorithm for elasto-plastic material modelling, extension of the energy check facility to the case of prescribed displacements, and, possible interface to a post-processing package including time plot facilities
Structure and dynamics of solutions
Ohtaki, H
2013-01-01
Recent advances in the study of structural and dynamic properties of solutions have provided a molecular picture of solute-solvent interactions. Although the study of thermodynamic as well as electronic properties of solutions have played a role in the development of research on the rate and mechanism of chemical reactions, such macroscopic and microscopic properties are insufficient for a deeper understanding of fast chemical and biological reactions. In order to fill the gap between the two extremes, it is necessary to know how molecules are arranged in solution and how they change their pos
Dynamic active earth pressure on retaining structures
Indian Academy of Sciences (India)
Deepankar Choudhury; Santiram Chatterjee
2006-12-01
Earth-retaining structures constitute an important topic of research in civil engineering, more so under earthquake conditions. For the analysis and design of retaining walls in earthquake-prone zones, accurate estimation of dynamic earth pressures is very important. Conventional methods either use pseudo-static approaches of analysis even for dynamic cases or a simple single-degree of freedom model for the retaining wall–soil system. In this paper, a simpliﬁed two-degree of freedom mass–spring–dashpot (2-DOF) dynamic model has been proposed to estimate the active earth pressure at the back of the retaining walls for translation modes of wall movement under seismic conditions. The horizontal zone of inﬂuence on dynamic earth force on the wall is estimated. Results in terms of displacement, velocity and acceleration-time history are presented for some typical cases, which show the ﬁnal movement of the wall in terms of wall height, which is required for the design. The non-dimensional design chart proposed in the present study can be used to compute the total dynamic earth force on the wall under different input ground motion and backﬁll conditions. Finally, the results obtained have been compared with those of the available Scott model and the merits of the present results have been discussed.
Structural dynamics of turbo-machines
Rangwala, AS
2009-01-01
The book presents a detailed and comprehensive treatment of structural vibration evaluation of turbo-machines. Starting with the fundamentals of the theory of vibration as related to various aspects of rotating machines, the dynamic analysis procedures of a broad spectrum of turbo-machines is covered. An in-depth procedure for analyzing the torsional and flexural oscillations of the components and of the rotor-bearing system is presented. The latest trends in design and analysis are presented, chief among them: Blade and coupled disk-blade mod
Dynamics and structure of stretched flames
Energy Technology Data Exchange (ETDEWEB)
Law, C.K. [Princeton Univ., NJ (United States)
1993-12-01
This program aims to gain fundamental understanding on the structure, geometry, and dynamics of laminar premixed flames, and relate these understanding to the practical issues of flame extinction and stabilization. The underlying fundamental interest here is the recent recognition that the response of premixed flames can be profoundly affected by flame stretch, as manifested by flow nonuniformity, flame curvature, and flame/flow unsteadiness. As such, many of the existing understanding on the behavior of premixed flames need to be qualitatively revised. The research program consists of three major thrusts: (1) detailed experimental and computational mapping of the structure of aerodynamically-strained planar flames, with emphasis on the effects of heat loss, nonequidiffusion, and finite residence time on the flame thickness, extent of incomplete reaction, and the state of extinction. (2) Analytical study of the geometry and dynamics of stretch-affected wrinkled flame sheets in simple configurations, as exemplified by the Bunsen flame and the spatially-periodic flame, with emphasis on the effects of nonlinear stretch, the phenomena of flame cusping, smoothing, and tip opening, and their implications on the structure and burning rate of turbulent flames. (3) Stabilization and blowoff of two-dimensional inverted premixed and stabilization and determining the criteria governing flame blowoff. The research is synergistically conducted through the use of laser-based diagnostics, computational simulation of the flame structure with detailed chemistry and transport, and mathematical analysis of the flame dynamics.
Structural analysis system THANKS
International Nuclear Information System (INIS)
The analytical codes THANKS (Three Dimensional Analysis of NIPPON KOKAN Systems) V-1, THANKS V-2, and THANKS V-3 were developed to analyze the structures having complicated configuration, to simulate the actual phenomena including elastoplastic property, creep, large deformation and dynamic behavior, and to analyze thermal and hydraulic characteristics. These codes are supported with the development of pre-processor PRE-THANKS and post-processor POST-THANKS. The special features of this code system are as follows: 1) it is possible to analyze the strength of three dimensional structures having any complex configuration and to calculate the large scale problems with 160,000 freedom, 2) it is possible to treat the broad range of linear and nonlinear problems of both static and dynamic and thermal conduction, 3) the calculating time is shortened, 4) the program consists of modules, therefore the partial improvement is simple, and the addition of new functions is easy, 5) the graphic display utilizing cathode ray tubes (CRT) is available, and 6) the high efficiency and the reduction of labor are planned. The hardwares of THANKS system consist of a computer IBM S370/168, a card reader, magnetic discs, a printer, a graphic display and a plotter, and PRE-THANKS, THANKS V-1 THANKS V-2 THANKS V-3 and POST-THANKS are included in this computer system. PRE-THANKS has the functions such as the input of two and three dimensional mesh configurations, the production of mesh files, and the display with a CRT. POST-THANKS has the function displaying stress contours, stress distribution, change of stress in course of time and deformation on CRT or drawing them utilizing a plotter. (Nakai, Y.)
International Nuclear Information System (INIS)
This paper deals with static and dynamic analysis of thin-walled structures with integrated piezoelectric layers as sensors and actuators in the geometrically nonlinear range of deformations. A variational formulation is derived by using the Reissner–Mindlin first-order shear deformation (FOSD) hypothesis and full geometrically nonlinear strain-displacement relations accounting for finite rotations. The finite rotations are treated by Rodriguez parameterization. In order to enhance the accuracy of a four-node shell element, a combination of an assumed natural strain (ANS) method for the shear strains, an enhanced assumed strain (EAS) method for the membrane strains and an enhanced assumed gradient (EAG) method for the electric field are employed. The present shell element has five mechanical degrees of freedom (DOFs) and three electrical DOFs per node. The Newton–Raphson method for static analysis and the Newmark method for dynamic analysis are used to perform linear and nonlinear simulations. In comparison to the results obtained by simplified nonlinear models reported in the existing literature, the finite-element simulations performed in this paper show the importance of the present model, precisely for structures undergoing finite deformations and rotations. (paper)
Operational Dynamic Configuration Analysis
Lai, Chok Fung; Zelinski, Shannon
2010-01-01
Sectors may combine or split within areas of specialization in response to changing traffic patterns. This method of managing capacity and controller workload could be made more flexible by dynamically modifying sector boundaries. Much work has been done on methods for dynamically creating new sector boundaries [1-5]. Many assessments of dynamic configuration methods assume the current day baseline configuration remains fixed [6-7]. A challenging question is how to select a dynamic configuration baseline to assess potential benefits of proposed dynamic configuration concepts. Bloem used operational sector reconfigurations as a baseline [8]. The main difficulty is that operational reconfiguration data is noisy. Reconfigurations often occur frequently to accommodate staff training or breaks, or to complete a more complicated reconfiguration through a rapid sequence of simpler reconfigurations. Gupta quantified a few aspects of airspace boundary changes from this data [9]. Most of these metrics are unique to sector combining operations and not applicable to more flexible dynamic configuration concepts. To better understand what sort of reconfigurations are acceptable or beneficial, more configuration change metrics should be developed and their distribution in current practice should be computed. This paper proposes a method to select a simple sequence of configurations among operational configurations to serve as a dynamic configuration baseline for future dynamic configuration concept assessments. New configuration change metrics are applied to the operational data to establish current day thresholds for these metrics. These thresholds are then corroborated, refined, or dismissed based on airspace practitioner feedback. The dynamic configuration baseline selection method uses a k-means clustering algorithm to select the sequence of configurations and trigger times from a given day of operational sector combination data. The clustering algorithm selects a simplified
On Dynamics of Spinning Structures
Gupta, K. K.; Ibrahim, A.
2012-01-01
This paper provides details of developments pertaining to vibration analysis of gyroscopic systems, that involves a finite element structural discretization followed by the solution of the resulting matrix eigenvalue problem by a progressive, accelerated simultaneous iteration technique. Thus Coriolis, centrifugal and geometrical stiffness matrices are derived for shell and line elements, followed by the eigensolution details as well as solution of representative problems that demonstrates the efficacy of the currently developed numerical procedures and tools.
The Structure and Dynamics of Sodium Disilicate
Horbach, Jurgen; Kob, Walter
1999-01-01
We investigate the structure and dynamics of sodium disilicate by means of molecular dynamics computer simulation. We show that the structure is described by a partially destroyed tetrahedral SiO_4 network and a spherical super structure formed by the silicon and sodium atoms. The static structure factor of our simulation is in very good agreement with one from a neutron scattering experiment. For 1008 particles we find strong finite size effects in the dynamics which are due to the missing o...
International Nuclear Information System (INIS)
The influence of Fluid-Structure interaction phenomena on seismically or LOCA excited reactor internals is becoming increasingly important for an accurate behavior and nuclear safety considerations. The internals by virtue of their location are exposed to mass of surrounding fluid and excited in motion by severe transients such as LOCA or an earthquake. The response of reactor internals, including fuel assemblies, core mass, upper and lower grid assemblies, core support frame, plenum-assembly, control-rod drive system and thermal-shield, is related to the operational requirements of each subcomponent in assessing their integrity. These subcomponents, submerged in an excited fluid-mass, constitute intrinsically an overall vibrating system with individual and combined eigen frequencies. Each individual subcomponent is subjected to fluid-elastic interaction, which affects their vibrating characteristics. Numerical results have been obtained for PWR internals and fuel-assemblies in water of a typical 950 MWe plant. In order to completely assess the adequacy of each subcomponent, the overall effects of both seismic and LOCA conditions are evaluated and superimposed directly. Various effects of local non-linearities due to gaps, coulomb friction, impacting and sliding are taken into account. An overall dynamic response due to seismic and LOCA effects, has shown that maximum displacements and stress-resultants are well below the specified critical limits. (orig./GL)
Institute of Scientific and Technical Information of China (English)
WU Cai-qin; HUA Cheng; YANG Lin; DAI Pei-dong; ZHANG Tian-yu; WANG Ke-qiang
2011-01-01
The semicircular canals,composed of lateral,anterior and posterior canals in the inner ear,are the sensors of equilibrium during head rotation movements in the three-dimensional space.Semicircular canals are filled with endolymph confined by the cupula.The study of the relationship between endolymph flow and cupular deformation is important in revealing the semicircular canals biomechanical behavior.To date,there are few studies focusing on the transient endolymph flow and cupular deformation in response to a head rotation motion.The lateral semicircular canal is mainly responsible for the sense of the horizontal rotation movement.In order to figure out the intricate dynamics in the lateral semicircular canal during the head rotation motion,the time evolutions of both endolymph flow and cupular deformation are analyzed in this article by using a fully coupled fluid-structure interaction model.It is shown that the cupular deformation provides cues for understanding the physiology of sensing the head rotation.
Navarro-Zafra, J.; Curiel-Sosa, J. L.; Serna Moreno, M. C.
2016-04-01
A three-dimensional structural integrity analysis using the eXtended Finite Element Method (XFEM) is considered for simulating the crack behaviour of a chopped fibre-glass-reinforced polyester (CGRP) cruciform specimen subjected to a quasi-static tensile biaxial loading. This is the first time this problem is accomplished for computing the stress intensity factors (SIFs) produced in the biaxially loaded area of the cruciform specimen. A static crack analysis for the calculation of the mixed-mode SIFs is carried out. SIFs are calculated for infinite plates under biaxial loading as well as for the CGRP cruciform specimens in order to review the possible edge effects. A ratio relating the side of the central zone of the cruciform and the crack length is proposed. Additionally, the initiation and evolution of a three-dimensional crack are successfully simulated. Specific challenges such as the 3D crack initiation, based on a principal stress criterion, and its front propagation, in perpendicular to the principal stress direction, are conveniently addressed. No initial crack location is pre-defined and an unique crack is developed. Finally, computational outputs are compared with theoretical and experimental results validating the analysis.
Structural Dynamics and Control Interaction of Flexible Structures
Ryan, Robert S. (Editor); Scofield, Harold N. (Editor)
1987-01-01
A workshop on structural dynamics and control interaction of flexible structures was held to promote technical exchange between the structural dynamics and control disciplines, foster joint technology, and provide a forum for discussing and focusing critical issues in the separate and combined areas. Issues and areas of emphasis were identified in structure-control interaction for the next generation of flexible systems.
Handbook on dynamics of jointed structures.
Energy Technology Data Exchange (ETDEWEB)
Ames, Nicoli M.; Lauffer, James P.; Jew, Michael D.; Segalman, Daniel Joseph; Gregory, Danny Lynn; Starr, Michael James; Resor, Brian Ray
2009-07-01
The problem of understanding and modeling the complicated physics underlying the action and response of the interfaces in typical structures under dynamic loading conditions has occupied researchers for many decades. This handbook presents an integrated approach to the goal of dynamic modeling of typical jointed structures, beginning with a mathematical assessment of experimental or simulation data, development of constitutive models to account for load histories to deformation, establishment of kinematic models coupling to the continuum models, and application of finite element analysis leading to dynamic structural simulation. In addition, formulations are discussed to mitigate the very short simulation time steps that appear to be required in numerical simulation for problems such as this. This handbook satisfies the commitment to DOE that Sandia will develop the technical content and write a Joints Handbook. The content will include: (1) Methods for characterizing the nonlinear stiffness and energy dissipation for typical joints used in mechanical systems and components. (2) The methodology will include practical guidance on experiments, and reduced order models that can be used to characterize joint behavior. (3) Examples for typical bolted and screw joints will be provided.
Dynamics of Correlation Structure in Stock Market
Directory of Open Access Journals (Sweden)
Maman Abdurachman Djauhari
2014-01-01
Full Text Available In this paper a correction factor for Jennrich’s statistic is introduced in order to be able not only to test the stability of correlation structure, but also to identify the time windows where the instability occurs. If Jennrich’s statistic is only to test the stability of correlation structure along predetermined non-overlapping time windows, the corrected statistic provides us with the history of correlation structure dynamics from time window to time window. A graphical representation will be provided to visualize that history. This information is necessary to make further analysis about, for example, the change of topological properties of minimal spanning tree. An example using NYSE data will illustrate its advantages.
Directory of Open Access Journals (Sweden)
Yonghui Xie
2014-01-01
Full Text Available A three-dimensional fluid-thermal-structural coupled analysis for a radial inflow micro gas turbine is conducted. First, a fluid-thermal coupled analysis of the flow and temperature fields of the nozzle passage and the blade passage is performed by using computational fluid dynamics (CFD. The flow and heat transfer characteristics of different sections are analyzed in detail. The thermal load and the aerodynamic load are then obtained from the temperature field and the pressure distribution. The stress distributions of the blade are finally studied by using computational solid mechanics (CSM considering three cases of loads: thermal load, aerodynamics load combined with centrifugal load, and all the three types of loads. The detailed parameters of the flow, temperature, and the stress are obtained and analyzed. The numerical results obtained provide a useful knowledge base for further exploration of radial gas turbine design.
International Nuclear Information System (INIS)
Resonant nuclear reaction analysis, using the 1H(15N, αγ)12C reaction at 6.4 MeV, has been successfully applied to the investigation of hydrogen incorporation and radiation induced migration in metal-oxide-silicon structures. A preliminary study of the influence of processing parameters on the H content of thermal oxides, with and without gate material present, has been performed. It is found that the dominant source of hydrogen in Al gate devices and dry oxides is often contamination, likely in the form of adsorbed water vapor, formed upon exposure to room air after removal from the oxidation furnace. Concentrations of hydrogen in the bulk oxide as high as 3 1020 cm-3 (Al gate), and as low as 1 1018 cm-3 (poly Si-gate) have been observed. Hydrogen accumulation at the Si-SiO2 interface has been reproducibly demonstrated for as-oxidized samples, as well as for oxides exposed to H2 containing atmospheres during subsequent thermal processing. The migration of hydrogen, from the bulk oxide to the silicon-oxide interface during NRA, has been observed and intensively investigated. A direct correlation between the hydrogen content of the bulk oxide and the radiation generated oxide charges and interface states is presented. These data provide strong support for the important role of hydrogen in determining the radiation sensitivity of electronic devices. (orig.)
Dynamic Probabilistic Instability of Composite Structures
Chamis, Christos C.
2009-01-01
A computationally effective method is described to evaluate the non-deterministic dynamic instability (probabilistic dynamic buckling) of thin composite shells. The method is a judicious combination of available computer codes for finite element, composite mechanics and probabilistic structural analysis. The solution method is incrementally updated Lagrangian. It is illustrated by applying it to thin composite cylindrical shell subjected to dynamic loads. Both deterministic and probabilistic buckling loads are evaluated to demonstrate the effectiveness of the method. A universal plot is obtained for the specific shell that can be used to approximate buckling loads for different load rates and different probability levels. Results from this plot show that the faster the rate, the higher the buckling load and the shorter the time. The lower the probability, the lower is the buckling load for a specific time. Probabilistic sensitivity results show that the ply thickness, the fiber volume ratio and the fiber longitudinal modulus, dynamic load and loading rate are the dominant uncertainties in that order.
Error Location in Structural Dynamic Model of a Rocket Structure
Sundararajan, T.; Sam, C.
2012-06-01
Structural dynamic characteristics of the aerospace structures are essential to obtain the structural responses due to dynamic loads during its mission. The structural dynamic parameters of the aerospace structures are frequencies, associated mode shape and damping. Usually finite element (FE) model of the aerospace structures are generated to estimate the frequencies and the associated mode shape. These FE models are validated by modal survey/ground resonance tests to ensure its completeness and correctness. The modeling deficiencies, if any, in these FE models have to be corrected. This paper describes the method to locate the FE modeling errors using residual force method.
Dynamic stimulated Brillouin scattering analysis
DEFF Research Database (Denmark)
Djupsöbacka, A.; Jacobsen, Gunnar; Tromborg, Bjarne
2000-01-01
We present a new simple analysis - including the effect of spontaneous emission - of the (dynamic) influence of SBS on the detected receiver eye diagram. It applies in principle for general types of modulation formats such as the digital formats of ASK, FSK, and PSK. The analysis is formulated fo...
Dynamic analysis of process reactors
Energy Technology Data Exchange (ETDEWEB)
Shadle, L.J.; Lawson, L.O.; Noel, S.D.
1995-06-01
The approach and methodology of conducting a dynamic analysis is presented in this poster session in order to describe how this type of analysis can be used to evaluate the operation and control of process reactors. Dynamic analysis of the PyGas{trademark} gasification process is used to illustrate the utility of this approach. PyGas{trademark} is the gasifier being developed for the Gasification Product Improvement Facility (GPIF) by Jacobs-Siffine Engineering and Riley Stoker. In the first step of the analysis, process models are used to calculate the steady-state conditions and associated sensitivities for the process. For the PyGas{trademark} gasifier, the process models are non-linear mechanistic models of the jetting fluidized-bed pyrolyzer and the fixed-bed gasifier. These process sensitivities are key input, in the form of gain parameters or transfer functions, to the dynamic engineering models.
Structural and dynamical properties of Yukawa balls
International Nuclear Information System (INIS)
To study the structural and dynamical properties of finite 3D dust clouds (Yukawa balls) new diagnostic tools have been developed. This contribution describes the progress towards 3D diagnostics for measuring the particle positions. It is shown that these diagnostics are capable of investigating the structural and dynamical properties of Yukawa balls and gaining insight into their basic construction principles
Flexible rotor dynamics analysis
Shen, F. A.
1973-01-01
A digital computer program was developed to analyze the general nonaxisymmetric and nonsynchronous transient and steady-state rotor dynamic performance of a bending- and shear-wise flexible rotor-bearing system under various operating conditions. The effects of rotor material mechanical hysteresis, rotor torsion flexibility, transverse effects of rotor axial and torsional loading and the anisotropic, in-phase and out-of-phase bearing stiffness and damping force and moment coefficients were included in the program to broaden its capability. An optimum solution method was found and incorporated in the computer program. Computer simulation of experimental data was made and qualitative agreements observed. The mathematical formulations, computer program verification, test data simulation, and user instruction was presented and discussed.
The effects of bolted joints on dynamic response of structures
International Nuclear Information System (INIS)
Joint is an universal fastening technology for structural members; in particular bolted joints are extensively used in mechanical structures due to their simple maintenance and low cost. However, the components of bolted joints are imperative because failure could be catastrophic and endanger lives. Hence, in this study, the effects of bolted joints on vibrating structures are investigated by determining the structural dynamic properties, such as mode shapes, damping ratios and natural frequencies, and these are compared with the monolithic structures (welding). Two approaches of experimental rigs are developed: a beam and a frame where both are subjected to dynamic loading. The analysis reveals the importance of bolted joints in increasing the damping properties and minimizing the vibration magnitude of structures, this indicates the significant influence of bolted joints on the dynamic behaviour of assembled structures. The outcome of this study provides a good model for predicting the experimental variable response in different types of structural joints
Directory of Open Access Journals (Sweden)
Yung-Chi Lu
2014-01-01
Full Text Available This work presents a digital image processing approach with a unique hive triangle pattern by integrating subpixel analysis for noncontact measurement of structural dynamic response data. Feasibility of proposed approach is demonstrated based on numerical simulation of a photography experiment. According to those results, the measured time-history displacement of simulated image correlates well with the numerical solution. A small three-story frame is then mounted on a small shaker table, and a linear variation differential transformation (LVDT is set on the second floor. Experimental results indicate that the relative error between data from LVDT and analyzed data from digital image correlation is below 0.007%, 0.0205 in terms of frequency and displacement, respectively. Additionally, the appropriate image block affects the estimation accuracy of the measurement system. Importantly, the proposed approach for evaluating pattern center and size is highly promising for use in assigning the adaptive block for a digital image correlation method.
Esmaili, Elham; Shahlaei, Mohsen
2015-04-01
The precise mode of the antimicrobial activity of Magainin (Mag)-an antimicrobial peptide (AMP)-is still unclear. In this study, the conformation of Mag was characterized in water, and in a methanol and lipid bilayer [palmitoyl-oleoylphosphatidylcholine (POPC)] using a molecular dynamics (MD) simulation technique. To describe the role conformation plays in Mag function, the global conformational differences within three systems were studied. Through analysis of the resulting configuration ensembles, the differences in the three systems, such as overall flexibility and average secondary structure, were studied. It is suggested that these differences may be important enough to influence interactions with lipid biomembranes, thereby influencing key properties such as penetration into cell membrane and stability. PMID:25750019
Adaptive dynamics for physiologically structured population models.
Durinx, Michel; Metz, J A J Hans; Meszéna, Géza
2008-05-01
We develop a systematic toolbox for analyzing the adaptive dynamics of multidimensional traits in physiologically structured population models with point equilibria (sensu Dieckmann et al. in Theor. Popul. Biol. 63:309-338, 2003). Firstly, we show how the canonical equation of adaptive dynamics (Dieckmann and Law in J. Math. Biol. 34:579-612, 1996), an approximation for the rate of evolutionary change in characters under directional selection, can be extended so as to apply to general physiologically structured population models with multiple birth states. Secondly, we show that the invasion fitness function (up to and including second order terms, in the distances of the trait vectors to the singularity) for a community of N coexisting types near an evolutionarily singular point has a rational form, which is model-independent in the following sense: the form depends on the strategies of the residents and the invader, and on the second order partial derivatives of the one-resident fitness function at the singular point. This normal form holds for Lotka-Volterra models as well as for physiologically structured population models with multiple birth states, in discrete as well as continuous time and can thus be considered universal for the evolutionary dynamics in the neighbourhood of singular points. Only in the case of one-dimensional trait spaces or when N = 1 can the normal form be reduced to a Taylor polynomial. Lastly we show, in the form of a stylized recipe, how these results can be combined into a systematic approach for the analysis of the (large) class of evolutionary models that satisfy the above restrictions. PMID:17943289
Predicting protein dynamics from structural ensembles
Copperman, J
2015-01-01
The biological properties of proteins are uniquely determined by their structure and dynamics. A protein in solution populates a structural ensemble of metastable configurations around the global fold. From overall rotation to local fluctuations, the dynamics of proteins can cover several orders of magnitude in time scales. We propose a simulation-free coarse-grained approach which utilizes knowledge of the important metastable folded states of the protein to predict the protein dynamics. This approach is based upon the Langevin Equation for Protein Dynamics (LE4PD), a Langevin formalism in the coordinates of the protein backbone. The linear modes of this Langevin formalism organize the fluctuations of the protein, so that more extended dynamical cooperativity relates to increasing energy barriers to mode diffusion. The accuracy of the LE4PD is verified by analyzing the predicted dynamics across a set of seven different proteins for which both relaxation data and NMR solution structures are available. Using e...
Structural analysis for Diagnosis
DEFF Research Database (Denmark)
Izadi-Zamanabadi, Roozbeh; Blanke, M.
2001-01-01
Aiming at design of algorithms for fault diagnosis, structural analysis of systems offers concise yet easy overall analysis. Graph-based matching, which is the essential technique to obtain redundant information for diagnosis, is re-considered in this paper. Matching is re-formulated as a problem...
Structural analysis for diagnosis
DEFF Research Database (Denmark)
Izadi-Zamanabadi, Roozbeh; Blanke, M.
2002-01-01
Aiming at design of algorithms for fault diagnosis, structural analysis of systems offers concise yet easy overall analysis. Graph-based matching, which is the essential tech-nique to obtain redundant information for diagnosis, is reconsidered in this paper. Matching is reformulated as a problem of...
Dynamical symmetries in nuclear structure
International Nuclear Information System (INIS)
In recent years the concept of dynamical symmetries in nuclei has witnessed a renaissance of interest and activity. Much of this work has been developed in the context of the Interacting Boson Approximation (or IBA) model. The appearance and properties of dynamical symmetries in nuclei will be reviewed, with emphasis on their characteristic signatures and on the role of the proton-neutron interaction in their formation, systematics and evolution. 36 refs., 20 figs
Gradient-based optimization in nonlinear structural dynamics
DEFF Research Database (Denmark)
Dou, Suguang
optimization of nonlinear structural dynamics. In the modelling, nonlinear finite elements are used. In the analysis, nonlinear frequency response and nonlinear normal modes are calculated based on a harmonic balance method with higher-order harmonics. In the characterization, nonlinear modal coupling...... coefficients are calculated directly from a nonlinear finite element model. Based on the analysis and the characterization, a new class of optimization problems is studied. In the optimization, design sensitivity analysis is performed by using the adjoint method which is suitable for large-scale structural......The intrinsic nonlinearity of mechanical structures can give rise to rich nonlinear dynamics. Recently, nonlinear dynamics of micro-mechanical structures have contributed to developing new Micro-Electro-Mechanical Systems (MEMS), for example, atomic force microscope, passive frequency divider...
Structural concerns in dynamic drop loads on transfer lock mechanisms
International Nuclear Information System (INIS)
Drop loads are usually low probability events that can generate substantial loading to the impacted structures. When the impacted structure contains slender elements, the concern about dynamic buckling must be addressed. The problem of interest here is a structure is also under significant preload, which must be taken into account in the transient analysis. For complex structures, numerical simulations are the only viable option for assessing the transient response to short duration impactive loads. this paper addresses several analysis issues of preloaded structures with slender members subjected to drop loads. A three-dimensional beam element is validated for use in dynamic buckling analysis. the numerical algorithm used to solve the transient response of preloaded structures is discussed. The methodology is applied to an inter-compartment lock that is under significant preloads, and subjected to a drop load
Structurally dynamic spin market networks
Horváth, D
2007-01-01
The agent-based model of price dynamics on a directed evolving complex network is suggested and studied by direct simulation. The resulting stationary regime is maintained as a result of the balance between the extremal dynamics, adaptivity of strategic variables and reconnection rules. For some properly selected parametric combination the network displays small-world phenomenon with high mean clustering coefficient and power-law node degree distribution. The mechanism of repeated random walk through network combined with a fitness recognition is proposed and tested to generate modular multi-leader market. The simulations suggest that dynamics of fitness is the slowest process that manifests itself in the volatility clustering of the log-price returns.
Structural Dynamics of Filament-Wound Booster Rockets
Bugg, F. M.
1987-01-01
Report summarizes program of measurements and calculations of vibrations in filament-wound composite models of Space Shuttle solid-rocket boosters. Vibrational behavior predicted by finite-element computer model of structural dynamics correlates well with data from tests on full- and quarter-scale models. Computer model developed with NASTRAN general-purpose structural-analysis computer code.
Fluorescence relaxation spectroscopy: light on dynamical structures of flavoproteins.
Burten-Bastiaens, P.I.H.
1992-01-01
Refinements in technique and data analysis have opened new avenues for a detailed interpretation of protein fluorescence. What is more, by combining new insights in protein structure and dynamics with improved knowledge of photophysics of biological chromophores, the coupling between structure-funct
Limitations and corrections in measuring dynamic characteristics of structural systems
International Nuclear Information System (INIS)
The work deals with limitations encountered in measuring the dynamic characteristics of structural systems. Structural loading and response are measured by transducers possessing multiple resonant frequencies in their transfer function. In transient environments, the resultant signals from these transducers are shown to be analytically unpredictable in amplitude level and frequency content. Data recorded during nuclear effects simulation testing on structures are analyzed. Results of analysis can be generalized to any structure which encounters dynamic loading. Methods to improve the recorded data are described which can be implemented on a frequency selective basis during the measurement process. These improvements minimize data distortion attributable to the transfer characteristics of the measuring transducers
Directory of Open Access Journals (Sweden)
Shan Wang
Full Text Available CYP82E4, a cytochrome P450 monooxygenase, has nicotine N-demethylase (NND activity, which mediates the bioconversion of nicotine into nornicotine in senescing tobacco leaves. Nornicotine is a precursor of the carcinogen, tobacco-specific nitrosamine. CYP82E3 is an ortholog of CYP82E4 with 95% sequence identity, but it lacks NND activity. A recent site-directed mutagenesis study revealed that a single amino acid substitution, i.e., cysteine to tryptophan at the 330 position in the middle of protein, restores the NND activity of CYP82E3 entirely. However, the same amino acid change caused the loss of the NND activity of CYP82E4. To determine the mechanism of the functional turnover of the two molecules, four 3D structures, i.e., the two molecules and their corresponding cys-trp mutants were modeled. The resulting structures exhibited that the mutation site is far from the active site, which suggests that no direct interaction occurs between the two sites. Simulation studies in different biological scenarios revealed that the mutation introduces a conformation drift with the largest change at the F-G loop. The dynamics trajectories analysis using principal component analysis and covariance analysis suggests that the single amino acid change causes the opening and closing of the transfer channels of the substrates, products, and water by altering the motion of the F-G and B-C loops. The motion of helix I is also correlated with the motion of both the F-G loop and the B-C loop and; the single amino acid mutation resulted in the curvature of helix I. These results suggest that the single amino acid mutation outside the active site region may have indirectly mediated the flexibility of the F-G and B-C loops through helix I, causing a functional turnover of the P450 monooxygenase.
Simultaneous determination of protein structure and dynamics
DEFF Research Database (Denmark)
Lindorff-Larsen, Kresten; Best, Robert B.; DePristo, M. A.;
2005-01-01
We present a protocol for the experimental determination of ensembles of protein conformations that represent simultaneously the native structure and its associated dynamics. The procedure combines the strengths of nuclear magnetic resonance spectroscopy-for obtaining experimental information at...
Miller, G.; Heimann, Paula J.; Scheiman, Daniel A.; Duffy, Kirsten P.; Johnston, J. Chris; Roberts, Gary D.
2013-01-01
Vibration mitigation in composite structures has been demonstrated through widely varying methods which include both active and passive damping. Recently, nanomaterials have been investigated as a viable approach to composite vibration damping due to the large surface available to generate energy dissipation through friction. This work evaluates the influence of dispersed nanoparticles on the damping ratio of an epoxy matrix. Limited benefit was observed through dispersion methods, however nanoparticle application as a coating resulting in up to a three-fold increase in damping.
Alvarez-Lacalle, E.; Dorow, B.; Eckmann, J. -P.; Moses, E
2005-01-01
Understanding texts requires memory: the reader has to keep in mind enough words to create meaning. This calls for a relation between the memory of the reader and the structure of the text. To investigate this interaction, we first identify a connectivity matrix defined by co-occurrence of words in the text. A vector space of words characterizing the text is spanned by the principal directions of this matrix. It is useful to think of these weighted combinations of words as representing ``conc...
NEW TYPE OF VIBRATION STRUCTURE OF VERTICAL DYNAMIC BALANCING MACHINE
Institute of Scientific and Technical Information of China (English)
Li Dinggen; Cao Jiguang; Chen Chuanyao; Wang Junwen
2004-01-01
A new type of vibration structure of vertical dynamic balancing machine is designed, which is based on the analysis for swing frame of a traditional vertical dynamic balancing machine. The static unbalance and couple unbalance can be separated effectively by using the new machine with the new swing frame. By building the dynamics model, the advantages of the new structure are discussed in detail. The modal and harmonic response are analyzed by using the ANSYS7.0. By comparing the finite element modal analysis with the experimental modal analysis, the natural frequencies and vibration modes are found out. There are many spring boards in the new swing frame. Their stiffness is different and assort with each other. Furthermore, there are three sensors on the measurement points. Therefore, the new dynamic balancing machine can measure the static unbalance and couple unbalance directly, and the influence between them is faint. The new structure has the function of belt-strain compensation to improve the measurement precision. The practical result indicates that the new vertical dynamic balancing machine is suitable for inertial measurement of flying objects, and can overcome the shortcomings of traditional double-plane vertical dynamic balancing machines. The vertical dynamic balancing machine with the new vibration structure can be widely used in the future applications. The modeling and analysis of the new vibration structure provide theoretic instruction and practical experience for designing new type of vertical dynamic balancing machines. Based on the design principles such as stiffness-matching, frequency-adjacence and strain-compensation and so on, various new type of vibration structures can be designed.
Ebrahimi, Ali
2010-01-01
The objective of this thesis is to identify, which hazards and failures in operation process will affect Reliability, Availability, Maintainability and Safety of floating offshore structures. The focus is on Dynamic Positioning (DP) system that has the responsibility of keeping the offshore structure in the upright position operation. DP system is one of the most critical subsystems on these types of structures in terms of safety of operation and failure risk costs. Reliability of the system ...
The fundamental structures of dynamic social networks
Sekara, Vedran; Stopczynski, Arkadiusz; Lehmann, Sune
2015-01-01
Networks provide a powerful mathematical framework for analyzing the structure and dynamics of complex systems (1-3). The study of group behavior has deep roots in the social science literature (4,5) and community detection is a central part of modern network science. Network communities have been found to be highly overlapping and organized in a hierarchical structure (6-9). Recent technological advances have provided a toolset for measuring the detailed social dynamics at scale (10,11). In ...
Dynamic Neighborhood Structures in Parallel Evolution Strategies
Mehnen, Jörn; Rudolph, Günter; Weinert, Klaus
2001-01-01
Parallelizing is a straightforward approach to reduce the total computation time of evolutionary algorithms. Finding an appropriate communication network within spatially structured populations for improving convergence speed and convergence probability is a difficult task. A new method that uses a dynamic communication scheme in an evolution strategy will be compared with conventional static and dynamic approaches. The communication structure is based on a socalled diffusion model approach. ...
Analysis of Dynamic Flight Loads
Jansson, Natascha
2012-01-01
This thesis deals with the determination of loads on an aircraft struc- ture during flight. The focus is on flight conditions where the loads are significantly time-dependent. Analysis of flight loads is primarily motivated to ensure that structural failure is avoided. The ability to ac- curately determine the resulting structural loads which can occur during operation allows for a reduction of the safety margins in the structural design. Consequently it is then possible to decrease the aircr...
Structural Dynamic Behavior of Wind Turbines
Thresher, Robert W.; Mirandy, Louis P.; Carne, Thomas G.; Lobitz, Donald W.; James, George H. III
2009-01-01
The structural dynamicist s areas of responsibility require interaction with most other members of the wind turbine project team. These responsibilities are to predict structural loads and deflections that will occur over the lifetime of the machine, ensure favorable dynamic responses through appropriate design and operational procedures, evaluate potential design improvements for their impact on dynamic loads and stability, and correlate load and control test data with design predictions. Load prediction has been a major concern in wind turbine designs to date, and it is perhaps the single most important task faced by the structural dynamics engineer. However, even if we were able to predict all loads perfectly, this in itself would not lead to an economic system. Reduction of dynamic loads, not merely a "design to loads" policy, is required to achieve a cost-effective design. The two processes of load prediction and structural design are highly interactive: loads and deflections must be known before designers and stress analysts can perform structural sizing, which in turn influences the loads through changes in stiffness and mass. Structural design identifies "hot spots" (local areas of high stress) that would benefit most from dynamic load alleviation. Convergence of this cycle leads to a turbine structure that is neither under-designed (which may result in structural failure), nor over-designed (which will lead to excessive weight and cost).
Dynamic Analysis of Esfahan Metro Tunnels
Bagherzadeh, A.; Ferdowsi, B.
2009-01-01
This study discusses the modeling of Esfahan metro tunnels subjected to earthquake and interaction of tunnels. In critical structures like subway tunnels, performing a time history dynamic analysis is the only acceptable method for determining the seismic-induced forces. For sites with no recorded earthquake ground motion, artificially generated accelerograms to represent the real earthquake records has been suggested by many experts. This study addressed the modeling of metro tunnels s...
Structure, dynamics, and function of biomolecules
Energy Technology Data Exchange (ETDEWEB)
Frauenfelder, H.; Berendzen, J.R.; Garcia, A.; Gupta, G.; Olah, G.A.; Terwilliger, T.C.; Trewhella, J.; Wood, C.C.; Woodruff, W.H.
1998-11-01
This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The authors enhanced Los Alamos' core competency in Bioscience and Biotechnology by building on present strengths in experimental techniques, theory, high-performance computing, modeling, and simulation applied to biomolecular structure, dynamics, and function. Specifically, the authors strengthened their capabilities in neutron/x-ray scattering, x-ray crystallography, NMR, laser, and optical spectroscopies. Initially they focused on supporting the Los alamos Neutron Science Center (LANSCE) in the design and implementation of new neutron scattering instrumentation, they developed new methods for analysis of scattering data, and they developed new projects to study the structures of biomolecular complexes. The authors have also worked to strengthen interactions between theory and experiment, and between the biological and physical sciences. They sponsored regular meetings of members from all interested LANL technical divisions, and supported two lecture series: ''Biology for Physicists'' and ''Issues in Modern Biology''. They also supported the formation of interdisciplinary/inter-divisional teams to develop projects in science-based bioremediation and an integrated structural biology resource. Finally, they successfully worked with a multidisciplinary team to put forward the Laboratory's Genome and Beyond tactical goal.
Structure, dynamics, and function of biomolecules
International Nuclear Information System (INIS)
This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The authors enhanced Los Alamos' core competency in Bioscience and Biotechnology by building on present strengths in experimental techniques, theory, high-performance computing, modeling, and simulation applied to biomolecular structure, dynamics, and function. Specifically, the authors strengthened their capabilities in neutron/x-ray scattering, x-ray crystallography, NMR, laser, and optical spectroscopies. Initially they focused on supporting the Los alamos Neutron Science Center (LANSCE) in the design and implementation of new neutron scattering instrumentation, they developed new methods for analysis of scattering data, and they developed new projects to study the structures of biomolecular complexes. The authors have also worked to strengthen interactions between theory and experiment, and between the biological and physical sciences. They sponsored regular meetings of members from all interested LANL technical divisions, and supported two lecture series: ''Biology for Physicists'' and ''Issues in Modern Biology''. They also supported the formation of interdisciplinary/inter-divisional teams to develop projects in science-based bioremediation and an integrated structural biology resource. Finally, they successfully worked with a multidisciplinary team to put forward the Laboratory's Genome and Beyond tactical goal
Selective {sup 2}H and {sup 13}C labeling in NMR analysis of solution protein structure and dynamics
Energy Technology Data Exchange (ETDEWEB)
LeMaster, D.M. [Northwestern Univ., Evanston, IL (United States)
1994-12-01
Preparation of samples bearing combined isotope enrichment patterns has played a central role in the recent advances in NMR analysis of proteins in solution. In particular, uniform {sup 13}C, {sup 15}N enrichment has made it possible to apply heteronuclear multidimensional correlation experiments for the mainchain assignments of proteins larger than 30 KDa. In contrast, selective labeling approaches can offer advantages in terms of the directedness of the information provided, such as chirality and residue type assignments, as well as through enhancements in resolution and sensitivity that result from editing the spectral complexity, the relaxation pathways and the scalar coupling networks. In addition, the combination of selective {sup 13}C and {sup 2}H enrichment can greatly facilitate the determination of heteronuclear relaxation behavior.
Dynamical structure of fluid mercury: Molecular-dynamics simulations
Hoshino, Kozo; Tanaka, Shunichiro; Shimojo, Fuyuki
2007-01-01
We have carried out molecular-dynamics simulations for nonmetallic fluid mercury in liquid and vapor phases using a Lennard-Jones type effective potential and shown that the structure factors S(Q) and the dynamic structure factors S(Q, omega) of nonmetallic fluid mercury obtained by our MD simulations are in good agreement with recent X-ray diffraction and inelastic X-ray scattering experiments. We conclude from these results that, though the fluid mercury which shows a metal-nonmetal transit...
Computational Methods for Structural Mechanics and Dynamics, part 1
Stroud, W. Jefferson (Editor); Housner, Jerrold M. (Editor); Tanner, John A. (Editor); Hayduk, Robert J. (Editor)
1989-01-01
The structural analysis methods research has several goals. One goal is to develop analysis methods that are general. This goal of generality leads naturally to finite-element methods, but the research will also include other structural analysis methods. Another goal is that the methods be amenable to error analysis; that is, given a physical problem and a mathematical model of that problem, an analyst would like to know the probable error in predicting a given response quantity. The ultimate objective is to specify the error tolerances and to use automated logic to adjust the mathematical model or solution strategy to obtain that accuracy. A third goal is to develop structural analysis methods that can exploit parallel processing computers. The structural analysis methods research will focus initially on three types of problems: local/global nonlinear stress analysis, nonlinear transient dynamics, and tire modeling.
Theoretical and software considerations for nonlinear dynamic analysis
Schmidt, R. J.; Dodds, R. H., Jr.
1983-01-01
In the finite element method for structural analysis, it is generally necessary to discretize the structural model into a very large number of elements to accurately evaluate displacements, strains, and stresses. As the complexity of the model increases, the number of degrees of freedom can easily exceed the capacity of present-day software system. Improvements of structural analysis software including more efficient use of existing hardware and improved structural modeling techniques are discussed. One modeling technique that is used successfully in static linear and nonlinear analysis is multilevel substructuring. This research extends the use of multilevel substructure modeling to include dynamic analysis and defines the requirements for a general purpose software system capable of efficient nonlinear dynamic analysis. The multilevel substructuring technique is presented, the analytical formulations and computational procedures for dynamic analysis and nonlinear mechanics are reviewed, and an approach to the design and implementation of a general purpose structural software system is presented.
Structural Analysis of a Tracked Vehicle Hull .
Directory of Open Access Journals (Sweden)
M. Mala
1997-04-01
Full Text Available The hull of a tracked military vehicle is complex in geometry and loading pattern. Analytical studies were carried out using numerically integrated elements for system analysis (NISA, a general finite element programme developed by the Engineering Mechanics Research Corporation (EMRC, USA. Structural changes in the initial design were made to bring deflection within acceptable limits. Dynamic stress levels for the hull structure, were determined from strain gauge measurements. The resultant stresses were obtained adding the static and dynamic values. Finite element analysis was found to be very useful to check the rigidity of the structure at design stage and to suggest suitable design stage and to suggest suitable modifications.
EXPERIMENTAL RESEARCH ON EVALUATING STRUCTURE DAMAGE WITH PIEZOELECTRIC DYNAMIC IMPEDANCE
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
A dynamic impedance-based structural health monitoring technique is introduced. According to the direct and the converse piezoelectric property of piezoelectric materials, the piezoceramic ( PZT ) can be used as an actuator and a sensor synchronously. If damages like cracks, holes, debonding or loose connections are presented in the structure, the physical variations of the structure will cause the mechanical impedance modified. On the basis of introducing the principle and the theory, the experiment and the analysis on some damages of the structure are studied by means of the dynamic impedance technique. On the view of experiment, kinds of structural damages are evaluated by the information of dynamic impedance in order to validate the feasibility of the method.
Firm ownership structures: dynamic development
Czech Academy of Sciences Publication Activity Database
Kočenda, Evžen; Valachy, Juraj
2002-01-01
Roč. 11, č. 3 (2002), s. 255-268. ISSN 1210-0455 R&D Projects: GA AV ČR KSK9058117 Institutional research plan: CEZ:AV0Z7085904 Keywords : ownership structure * privatized firms * industry sector Subject RIV: AH - Economics
Dynamic Analysis of a Pendulum Dynamic Automatic Balancer
Directory of Open Access Journals (Sweden)
Jin-Seung Sohn
2007-01-01
Full Text Available The automatic dynamic balancer is a device to reduce the vibration from unbalanced mass of rotors. Instead of considering prevailing ball automatic dynamic balancer, pendulum automatic dynamic balancer is analyzed. For the analysis of dynamic stability and behavior, the nonlinear equations of motion for a system are derived with respect to polar coordinates by the Lagrange's equations. The perturbation method is applied to investigate the dynamic behavior of the system around the equilibrium position. Based on the linearized equations, the dynamic stability of the system around the equilibrium positions is investigated by the eigenvalue analysis.
Lattice Dynamics of the Hexagonal Close-Packed Structure
International Nuclear Information System (INIS)
Lattice dynamics of hexagonal close-packed (hcp) structures, using the Born-von Kármán approach and assuming interactions with any number of interacting neighbours, were calculated. The general properties of a dynamical matrix, coming from the symmetry of hcp structure, have been established. Using the operations of a point group of the symmetry group of hcp structure, the families of equivalent, equidistant lattice points and their force matrices have been evaluated. This permitted the calculation of the elements of the Fourier transform of the dynamical matrix. Using the long waves procedure, the general formulas for elastic constants expressed by elements of a dynamical matrix have been obtained. The phonon dispersion relations have also been evaluated, by a factorization of a secular equation of a problem. In the course of the work a nomenclature convenient for further analysis of formulas obtained has been used. (author)
Dynamic response of composite structures underwater
Russell, Jacob E.
2013-01-01
Approved for public release; distribution is unlimited This paper presents a comparison of the dynamic response of composite structures that are subjected to low velocity impacts while being suspended both in air, and submerged in water. As the U.S. Navy continues to use larger composite components in the construction of their ships, an understanding of the effect of submergence in water (i.e., fluid-structure interaction) on various locations of the structures can be instrumental in the d...
Modelling of Spectroscopic and Structural Properties using Molecular Dynamics
Francesco Muniz Miranda
2013-01-01
The following dissertation is about the study that I performed at the Chemistry Department of the University of Florence and at the European Laboratory for Non- Linear Spectroscopy (LENS) to recover and elucidate structural, dynamical, and spectroscopic molecular features adopting computer simulations. In particular, here ab initio molecular dynamics simulations and time-frequency analysis are the most employed “tools”, in order to have a better understanding of the origins ...
International Nuclear Information System (INIS)
This paper presents the structural analysis developed during the TBR-2 tokamak project studies. Starting with electromagnetic interaction forces on each, toroidal and poloidal coils many structural calculations have been carried out using locally developed usual E.M. interaction codes and a finite element method stress code. Following the analysis it has been determined that there is radially inward force of 1235 kN and overturning torque of 243 kNm acting on toroidal coils. This stress and displacements due to in plane loads have been calculated using a finite element code which show that the maximum stress of 240 MPa and displacement of 0.21 mm can be present at the inner part of the toroidal field coil. (Author)
DEFF Research Database (Denmark)
Kumpf, C.; Müller, A.; Weigand, W.;
2003-01-01
The atomic structure and lattice dynamics of epitaxial BeTe(001) thin films are derived from surface x-ray diffraction and Raman spectroscopy. On the Te-rich BeTe(001) surface [1 (1) over bar0]-oriented Te dimers are identified. They cause a (2 X 1) superstructure and induce a pronounced buckling...
Institute of Scientific and Technical Information of China (English)
刘毅; 薛素铎; 李雄彦; 王国鑫
2015-01-01
Based on the foundation dynamic impedance calculation formulas suggested by different scholars,the S-R (swing-rocking)model was modified by combining with the integral finite element method and starting from the view point of engineering application.The practical simplified calculation method suitable for the soil-structure dynamic interaction analysis of long-span spatial structures was proposed.Then,the model of soil-grid structure interaction was established according to the modified S-R model,and the three-dimensional finite element model verified was also established for a comparative analysis.The study showed that the natural vibration properties and seismic response of the soil-grid structure interaction model based on the modified S-R model reveal same regularities and agree well with those of the 3-D FE model,the rationality of the modified S-R model is verified;the nodal maximum displacement error and peak acceleration error of the soil-grid structure interaction system established with the foundation dynamic impedance calculation formulas proposed by Gazetas are less than 8.0%,and the maximum stress error of members is less than 10%compared with those obtained with the 3-D FE model under different seismic waves;thus the foundation dynamic impedance calculation formulas proposed by Gazetas are more suitable for the analysis of soil-large span spatial structure interaction and have a higher precision.%根据不同学者有关地基动力阻抗的计算公式，结合整体有限元法，从工程应用出发对 S-R（Swing-Rock-ing）模型进行修正，提出适用于分析土－结构动力相互作用下大跨空间结构的简化计算方法。基于修正的 S-R 模型建立土－网架结构动力相互作用的计算模型，与已验证的三维整体有限元（3－D）模型进行对比分析。研究表明，根据修正S-R模型计算所得土－网架结构相互作用体系的自振特性和地震响应与已验证的3－D 模型结果呈
Consistent time histories in transient dynamic analysis of reactors
International Nuclear Information System (INIS)
The paper includes the results of the comparison of consistent acceleration time histories corresponding to various selected earthquake records. The results of the transient dynamic seismic analysis of the TREAT Upgrade reactor support structure are also presented. (orig./HP)
Structure and dynamics of glycosphingolipid micelles
International Nuclear Information System (INIS)
Disialoganglioside (GD1a) is one of the functional lipids involved in various surface events on biological cells. In order to clarify a relation between the structural feature and dynamics of the GD1a micelle depending on temperature elevation, we have carried out neutron spin echo (NSE) and synchrotron radiation small-angle X-ray scattering (SR-SAXS) measurements. We have found that the change of the dynamics of the micelle is coupled with the dehydration of ganglioside headgroups. (author)
Spin Dynamics in Confined Magnetic Structures III
Hillebrands, Burkard
2006-01-01
This third volume of Spin Dynamics in Confined Magnetic Structures addresses central aspects of spin-dynamic phenomena, including recent new developments, on a tutorial level. Researchers will find a comprehensive compilation of the current work in the field. Introductory chapters help newcomers to understand the basic concepts. The more advanced chapters give the current state of the art of spin dynamic issues ranging from the femtosecond to the microsecond regime. This volume concentrates on new experimental techniques such as ferromagnetic-resonance-force microscopy and two-photon photoemission, as well as on aspects of precessional switching, spin-wave excitation, vortex dynamics, spin relaxation, domain-wall dynamics in nanowires and their applications to magnetic logic devices. An important chapter is devoted to the presently very hot subject of the spin-transfer torque, combining the physics of electronic transport and micromagnetics. The comprehensive presentation of these developments makes this volu...
Substitution dynamical systems spectral analysis
Queffélec, Martine
2010-01-01
This volume mainly deals with the dynamics of finitely valued sequences, and more specifically, of sequences generated by substitutions and automata. Those sequences demonstrate fairly simple combinatorical and arithmetical properties and naturally appear in various domains. As the title suggests, the aim of the initial version of this book was the spectral study of the associated dynamical systems: the first chapters consisted in a detailed introduction to the mathematical notions involved, and the description of the spectral invariants followed in the closing chapters. This approach, combined with new material added to the new edition, results in a nearly self-contained book on the subject. New tools - which have also proven helpful in other contexts - had to be developed for this study. Moreover, its findings can be concretely applied, the method providing an algorithm to exhibit the spectral measures and the spectral multiplicity, as is demonstrated in several examples. Beyond this advanced analysis, many...
Dynamic analysis of reactor auxiliary buildings
International Nuclear Information System (INIS)
A review of structural methods of generalized use in the dynamic analysis of Auxiliary Buildings and similar structures of Nuclear Power Plants is presented. Emphasis is placed on the structural response to blast and seismic loading studied from a global view point. Alternative models for the representation of both element and global stiffnesses are discussed. The assumption of rigid floor behaviour for lateral force excitation is studied. Advantages of using multi-stick models are referred and illustrated. The occurrence of torsional motions on the response is examined. The study evidences the importance of the low aspect ratio of these structures and shows its influence on parameters currently used in design of conventional buildings. (Author)
Origin and Structure of Dynamic Cooperative Networks
Wardil, Lucas; Hauert, Christoph
2014-07-01
Societies are built on social interactions among individuals. Cooperation represents the simplest form of a social interaction: one individual provides a benefit to another one at a cost to itself. Social networks represent a dynamical abstraction of social interactions in a society. The behaviour of an individual towards others and of others towards the individual shape the individual's neighbourhood and hence the local structure of the social network. Here we propose a simple theoretical framework to model dynamic social networks by focussing on each individual's actions instead of interactions between individuals. This eliminates the traditional dichotomy between the strategy of individuals and the structure of the population and easily complements empirical studies. As a consequence, altruists, egoists and fair types are naturally determined by the local social structures, while globally egalitarian networks or stratified structures arise. Cooperative interactions drive the emergence and shape the structure of social networks.
Matrix of transmission in structural dynamics
International Nuclear Information System (INIS)
Within the last few years numerous papers have been published on the subject of matrix method in elasto-mechanics. 'Matrix of Transmission' is one of the methods in this field which has gained considerable attention in recent years. The basic philosophy adopted in this method is based on the idea of breaking up a complicated system into component parts with simple elastic and dynamic properties which can be readily expressed in matrix form. These component matrices are considered as building blocks, which are fitted together according to a set of predetermined rules which then provide the static and dynamic properties of the entire system. A common type of system occuring in engineering practice consists of a number of elements linked together end to end in the form of a chain. The 'Transfer Matrix' is ideally suited for such a system, because only successive multiplication is necessary to connect these elements together. The number of degrees of freedom and intermediate conditions present no difficulty. Although the 'Transfer Matrix' method is suitable for the treatment of branched and coupled systems its application to systems which do not have predominant chain topology is not effective. Apart from the requirement that the system be linearely elastic, no other restrictions are made. In this paper, it is intended to give a general outline and theoretical formulation of 'Transfer Matrix' and then its application to actual problems in structural dynamics related to seismic analysis. The natural frequencies of a freely vibrating elastic system can be found by applying proper end conditions. The end conditions will yield the frequency determinate to zero. By using a suitable numerical method, the natural frequencies and mode shapes are determined by making a frequency sweep within the range of interest. Results of an analysis of a typical nuclear building by this method show very close agreement with the results obtained by using ASKA and SAP IV program. Therefore
Strength of concrete structures under dynamic loading
International Nuclear Information System (INIS)
The use of elastic supports is one the efficient methods of decreasing the dynamic loading. The paper describes the influence of elastic supports on the stress-strain state of steel concrete structures exposed to one-time dynamic loading resulting in failure. Oblique bending beams on elastic supports and their elastic, elastoplastic, and elastoplastic consolidation behavior are considered in this paper. For numerical calculations the developed computer program is used based on the finite element method. Research findings prove high efficiency of elastic supports under dynamic loading conditions. The most effective behavior of elastic supports is demonstrated at the elastoplastic stage. A good agreement is observed between the theoretical and experimental results
Strength of concrete structures under dynamic loading
Energy Technology Data Exchange (ETDEWEB)
Kumpyak, O. G., E-mail: ogkumpyak@yandex.ru; Galyautdinov, Z. R., E-mail: gazr@yandex.ru; Kokorin, D. N., E-mail: kokorindenn@yandex.ru [Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation)
2016-01-15
The use of elastic supports is one the efficient methods of decreasing the dynamic loading. The paper describes the influence of elastic supports on the stress-strain state of steel concrete structures exposed to one-time dynamic loading resulting in failure. Oblique bending beams on elastic supports and their elastic, elastoplastic, and elastoplastic consolidation behavior are considered in this paper. For numerical calculations the developed computer program is used based on the finite element method. Research findings prove high efficiency of elastic supports under dynamic loading conditions. The most effective behavior of elastic supports is demonstrated at the elastoplastic stage. A good agreement is observed between the theoretical and experimental results.
Dynamics and structure of energetic displacement cascades
International Nuclear Information System (INIS)
This paper summarizes recent progress in the understanding of energetic displacement cascades and the primary state of damage in metals. On the theoretical side, the availability of supercomputers has greatly enhanced our ability to simulate cascades by molecular dynamics. Recent application of this simulation technique to Cu and Ni provides new insight into the dynamics of cascade processes. On the experimental side, new data on ion beam mixing and in situ electron microscopy studies of ion damage at low temperatures reveal the role of the thermodynamic properties of the material on cascade dynamics and structure. 38 refs., 9 figs
Analysis of DCC domain structure
International Nuclear Information System (INIS)
Wavelet-type methods are employed for the analysis of pion field configurations that have been obtained by dynamical simulations in idealized scenarios relevant to the formation of disoriented chiral condensates. It is illustrated how the measurement of the isospin domain structure depends on the ability to zoom in on limited parts of the phase space, due to the interplay between the pion correlation length and the effective source geometry. The need for advanced analysis methods is underscored by the fact that the extracted neutral-fraction distribution would differ significantly from the ideal form, even under perfect experimental conditions, and, moreover, by the circumstance that thermal sources with suitably adjusted temperatures can lead to distributions that may be practically indistinguishable from those arising from DCC-type nonequilibrium evolutions. copyright 1997 The American Physical Society
Mid-frequency Band Dynamics of Large Space Structures
Coppolino, Robert N.; Adams, Douglas S.
2004-01-01
High and low intensity dynamic environments experienced by a spacecraft during launch and on-orbit operations, respectively, induce structural loads and motions, which are difficult to reliably predict. Structural dynamics in low- and mid-frequency bands are sensitive to component interface uncertainty and non-linearity as evidenced in laboratory testing and flight operations. Analytical tools for prediction of linear system response are not necessarily adequate for reliable prediction of mid-frequency band dynamics and analysis of measured laboratory and flight data. A new MATLAB toolbox, designed to address the key challenges of mid-frequency band dynamics, is introduced in this paper. Finite-element models of major subassemblies are defined following rational frequency-wavelength guidelines. For computational efficiency, these subassemblies are described as linear, component mode models. The complete structural system model is composed of component mode subassemblies and linear or non-linear joint descriptions. Computation and display of structural dynamic responses are accomplished employing well-established, stable numerical methods, modern signal processing procedures and descriptive graphical tools. Parametric sensitivity and Monte-Carlo based system identification tools are used to reconcile models with experimental data and investigate the effects of uncertainties. Models and dynamic responses are exported for employment in applications, such as detailed structural integrity and mechanical-optical-control performance analyses.
Structural dynamics of electronic and photonic systems
Suhir, Ephraim; Steinberg, David S
2011-01-01
The proposed book will offer comprehensive and versatile methodologies and recommendations on how to determine dynamic characteristics of typical micro- and opto-electronic structural elements (printed circuit boards, solder joints, heavy devices, etc.) and how to design a viable and reliable structure that would be able to withstand high-level dynamic loading. Particular attention will be given to portable devices and systems designed for operation in harsh environments (such as automotive, aerospace, military, etc.) In-depth discussion from a mechanical engineer's viewpoint will be conducte
Dynamical analysis of anisotropic inflation
Karčiauskas, Mindaugas
2016-06-01
The inflaton coupling to a vector field via the f(φ)2F μνFμν term is used in several contexts in the literature, such as to generate primordial magnetic fields, to produce statistically anisotropic curvature perturbation, to support anisotropic inflation, and to circumvent the η-problem. In this work, I perform dynamical analysis of this system allowing for the most general Bianchi I initial conditions. I also confirm the stability of attractor fixed points along phase-space directions that had not been investigated before.
Dynamic Analysis of Engine Bearings
Directory of Open Access Journals (Sweden)
H. Hirani
1999-01-01
Full Text Available This paper presents a simple methodology to evaluate the stiffness and damping coefficients of an engine bearing over a load cycle. A rapid technique is used to determine the shaft ‘limit cycle’ under engine dynamic loads. The proposed theoretical model is based on short and long bearing approximations. The results obtained by present approximation are compared with those obtained by numerical method. The influence of thermal effects on the stiffness and damping coefficients is predicted by using a simplified thermal analysis. In order to illustrate the application of the proposed scheme, one engine main bearing and a connecting rod bearing are analysed.
Chemical structure and dynamics: Annual report 1993
Energy Technology Data Exchange (ETDEWEB)
Colson, S.D.
1994-07-01
The Chemical Structure and Dynamics program responds to the need for a fundamental, molecular-level understanding of chemistry at the wide variety of environmentally-important interfaces. The research program is built around the established relationship between structure, thermodynamics, and kinetics. This research effort continues to evolve into a program of rigorous studies of fundamental molecular processes in model systems (e.g., well-characterized surfaces, single-component solutions, clusters, and biological molecules), and studies of complex systems found in the environment. Experimental studies of molecular and supramolecular structures and thermodynamics are key to understanding the nature of matter, and lead to direct comparison with computational results. Kinetic and mechanistic measurements, combined with real-time dynamics measurements of atomic and molecular motions during chemical reactions, provide for a molecular-level description of chemical reactions. The anticipated results of this work are the achievement of a quantitative understanding of chemical processes at complex interfaces, the development of new techniques for the detection and measurement of species at such interfaces, and the interpretation and extrapolation of the observations in terms of models of interfacial chemistry. The Chemical Structure and Dynamics research program includes five areas described in detail in this report: Reaction mechanisms at solid interfaces; Solution and solution interfaces; Structure and dynamics of biological systems; Analytical methods development; and atmospheric chemistry. Extended abstracts are presented for 23 studies.
Multiscale structure in eco-evolutionary dynamics
Stacey, Blake C.
In a complex system, the individual components are neither so tightly coupled or correlated that they can all be treated as a single unit, nor so uncorrelated that they can be approximated as independent entities. Instead, patterns of interdependency lead to structure at multiple scales of organization. Evolution excels at producing such complex structures. In turn, the existence of these complex interrelationships within a biological system affects the evolutionary dynamics of that system. I present a mathematical formalism for multiscale structure, grounded in information theory, which makes these intuitions quantitative, and I show how dynamics defined in terms of population genetics or evolutionary game theory can lead to multiscale organization. For complex systems, "more is different," and I address this from several perspectives. Spatial host--consumer models demonstrate the importance of the structures which can arise due to dynamical pattern formation. Evolutionary game theory reveals the novel effects which can result from multiplayer games, nonlinear payoffs and ecological stochasticity. Replicator dynamics in an environment with mesoscale structure relates to generalized conditionalization rules in probability theory. The idea of natural selection "acting at multiple levels" has been mathematized in a variety of ways, not all of which are equivalent. We will face down the confusion, using the experience developed over the course of this thesis to clarify the situation.
Ergodic Theory, Open Dynamics, and Coherent Structures
Bose, Christopher; Froyland, Gary
2014-01-01
This book is comprised of selected research articles developed from a workshop on Ergodic Theory, Probabilistic Methods and Applications, held in April 2012 at the Banff International Research Station. It contains contributions from world leading experts in ergodic theory, dynamical systems, numerical analysis, fluid dynamics, and networks. The volume will serve as a valuable reference for mathematicians, physicists, engineers, physical oceanographers, atmospheric scientists, biologists, and climate scientists, who currently use, or wish to learn how to use, probabilistic techniques to cope with dynamical models that display open, coherent, or non-equilibrium behavior.
34th IMAC, A Conference and Exposition on Structural Dynamics
Brandt, Anders; Singhal, Raj
2016-01-01
Nonlinear Dynamics, Volume 1. Proceedings of the 34th IMAC, A Conference and Exposition on Dynamics of Multiphysical Systems: From Active Materials to Vibroacoustics, 2016, the fi rst volume of ten from the Conference, brings together contributions to this important area of research and engineering. Th e collection presents early fi ndings and case studies on fundamental and applied aspects of Structural Dynamics, including papers on: • Nonlinear Oscillations • Nonlinear Modal Analysis • Nonlinear System Identifi cation • Nonlinear Modeling & Simulation • Nonlinearity in Practice • Nonlinearity in Multi-Physics Systems • Nonlinear Modes and Modal Interactions.
Energy Technology Data Exchange (ETDEWEB)
Sievers, Juergen; Bahr, Ludwig; Arndt, Jens; Heckoetter, Christian; Grebner, Hans
2014-11-15
Within the framework of project RS1197, analysis methods have been further developed and tested for the determination of the structural dynamic loading and the maximum load-bearing capacity of containment structures with a focus on the quantification of safety margins against failures due to loads resulting from selected internal and external hazards. The analyses comprised a model containment structure of prestressed reinforced concrete under internal pressure loading until reaching failure pressure, an outer containment structure made of reinforced concrete under local impact loads that may occur during a targeted aircraft crash, and a steel containment under local peak loads from internal pressure and temperature loads due to core melt scenarios with a local hydrogen combustion. GRS participated in the international ''Standard Problem Exercise 3'' on the issue ''Performance of Containment Vessel under Severe Accident Conditions''. Together with the cooperation partners, aspects of the global containment behaviour were considered based on the example of the Sandia 1:4 model containment of prestressed concrete, which was loaded by rising internal pressure until failure. Complex analysis models were developed, calculating the behaviour of the prestressing tendons under consideration of the frictional contact with the cladding tubes. Compared with corresponding measurement values, the analysis results show that the stresses near the tensioning device and the deformation of the inner surface can be realistically modelled as a function of the internal pressure. In the experiment, global structural failure of the containment model was caused by tendon rupture at about 3.64 times the design pressure. With the developed analysis models of a generic structure of an outer reinforced concrete containment, simulations were carried out for various aircraft crash scenarios as contact problems with explicit impactor simulation. For this
Capital structure dynamics in private business groups
Dewaelheyns, Nico; Van Hulle, Cynthia
2010-01-01
Dynamic models of capital structure assume that companies trade-off the advantages of a leverage adjustment to its costs. Private companies are expected to have more restricted access to capital markets and are therefore likely to adjust their capital structure less frequently than public ones. However, private companies that are part of a business group have access to both internal and external capital markets and may face lower adjustment costs. We find significant differences in the levera...
Benchmarking dynamic Bayesian network structure learning algorithms
Trabelsi, Ghada; Leray, Philippe; Ben Ayed, Mounir; Alimi, Adel
2012-01-01
Dynamic Bayesian Networks (DBNs) are probabilistic graphical models dedicated to modeling multivariate time series. Two-time slice BNs (2-TBNs) are the most current type of these models. Static BN structure learning is a well-studied domain. Many approaches have been proposed and the quality of these algorithms has been studied over a range of di erent standard networks and methods of evaluation. To the best of our knowledge, all studies about DBN structure learning use their own benchmarks a...
32nd IMAC Conference and Exposition on Structural Dynamics
Mayes, Randy; Rixen, Daniel; Catbas, Fikret; Atamturktur, H; Moaveni, Babak; Papadimitriou, Costas; Schoenherr, Tyler; Foss, Gary; Niezrecki, Christopher; Allemang, Randall; Kerschen, Gaetan
2014-01-01
This critical collection examines a range of topics in modal analysis, from experimental techniques to acoustics to biodynamics, as presented in early findings and case studies from the Proceedings of the 32nd IMAC, A Conference and Exposition on Structural Dynamics, 2014. The collection includes papers in the following general technical research areas: Experimental Techniques, Processing Modal Data, Rotating Machinery, Acoustics, Adaptive Structures, Biodynamics, Damping
Dynamic energy absorption characteristics of hollow microlattice structures
Energy Technology Data Exchange (ETDEWEB)
Liu, YL; Schaedler, TA; Chen, X
2014-10-01
Hollow microlattice structures are promising candidates for advanced energy absorption and their characteristics under dynamic crushing are explored. The energy absorption can be significantly enhanced by inertial stabilization, shock wave effect and strain rate hardening effect. In this paper we combine theoretical analysis and comprehensive finite element method simulation to decouple the three effects, and then obtain a simple model to predict the overall dynamic effects of hollow microlattice structures. Inertial stabilization originates from the suppression of sudden crushing of the microlattice and its contribution scales with the crushing speed, v. Shock wave effect comes from the discontinuity across the plastic shock wave front during dynamic loading and its contribution scales with e. The strain rate effect increases the effective yield strength upon dynamic deformation and increases the energy absorption density. A mechanism map is established that illustrates the dominance of these three dynamic effects at a range of crushing speeds. Compared with quasi-static loading, the energy absorption capacity a dynamic loading of 250 m/s can be enhanced by an order of magnitude. The study may shed useful insight on designing and optimizing the energy absorption performance of hollow microlattice structures under various dynamic loads. (C) 2014 Elsevier Ltd. All rights reserved.
Experimental research on structural dynamics and control
Montgomery, R. C.; Horner, G. C.; Cole, S. R.
1981-01-01
This report describes an apparatus at the NASA Langley Research Center for conducting research on dynamics and control of structural dynamics systems. The apparatus consists of a 3.66 m (12 ft.) long flexible beam to which are attached four electromagnetic actuators, nine noncontacting sensors to measure deflection of beam at various locations, and four strain gage type load cells one at each actuator attachment point. The important feature of the apparatus is that the actuators can be controlled and deflection and load sensor data can be processed in real time using the research centers CDC Cyber 175 computer system - thereby allowing research to be conducted on structural dynamics systems using advanced control laws. The facility is described in the report along with a detailed discussion of the actuators used.
Identifying Community Structures in Dynamic Networks
Alvari, Hamidreza; Sukthankar, Gita; Lakkaraju, Kiran
2016-01-01
Most real-world social networks are inherently dynamic, composed of communities that are constantly changing in membership. To track these evolving communities, we need dynamic community detection techniques. This article evaluates the performance of a set of game theoretic approaches for identifying communities in dynamic networks. Our method, D-GT (Dynamic Game Theoretic community detection), models each network node as a rational agent who periodically plays a community membership game with its neighbors. During game play, nodes seek to maximize their local utility by joining or leaving the communities of network neighbors. The community structure emerges after the game reaches a Nash equilibrium. Compared to the benchmark community detection methods, D-GT more accurately predicts the number of communities and finds community assignments with a higher normalized mutual information, while retaining a good modularity.
Modified Newtonian Dynamics of Large Scale Structure
Nusser, Adi
2001-01-01
We examine the implications of Modified Newtonian Dynamics (MOND) on the large scale structure in a Friedmann-Robertson-Walker universe. We employ a ``Jeans swindle'' to write a MOND-type relationship between the fluctuations in the density and the gravitational force, $\\vg$. In linear Newtonian theory, $|\\vg|$ decreases with time and eventually becomes $
Natural Poisson structures of nonlinear plasma dynamics
International Nuclear Information System (INIS)
Hamiltonian field theories, for models of nonlinear plasma dynamics, require a Poisson bracket structure for functionals of the field variables. These are presented, applied, and derived for several sets of field variables: coherent waves, incoherent waves, particle distributions, and multifluid electrodynamics. Parametric coupling of waves and plasma yields concise expressions for ponderomotive effects (in kinetic and fluid models) and for induced scattering
Simplified Dynamic Analysis of Grinders Spindle Node
Demec, Peter
2014-12-01
The contribution deals with the simplified dynamic analysis of surface grinding machine spindle node. Dynamic analysis is based on the use of the transfer matrix method, which is essentially a matrix form of method of initial parameters. The advantage of the described method, despite the seemingly complex mathematical apparatus, is primarily, that it does not require for solve the problem of costly commercial software using finite element method. All calculations can be made for example in MS Excel, which is advantageous especially in the initial stages of constructing of spindle node for the rapid assessment of the suitability its design. After detailing the entire structure of spindle node is then also necessary to perform the refined dynamic analysis in the environment of FEM, which it requires the necessary skills and experience and it is therefore economically difficult. This work was developed within grant project KEGA No. 023TUKE-4/2012 Creation of a comprehensive educational - teaching material for the article Production technique using a combination of traditional and modern information technology and e-learning.
The dynamic measurement of the full scale containment structure
International Nuclear Information System (INIS)
The containment of Qin Shan Nuclear Power Station in China is a prestressed concrete. The containment is composited of a cylindrical shell and a shallow spherical shell. The environmental random vibration is employed in the dynamic measurement of the full scale containment structure. V401CR servo accelerometer is used for measuring acceleration. First, second and torsion frequencies, damping ratios, mode shapes are obtained. Dynamic finite element method is applied to analyze vibration of the containment and results of analysis is presented. Experimental data and results of analysis are close. (J.P.N.)
Dynamic soil-structure interactions on embedded buildings
International Nuclear Information System (INIS)
The dynamic soil-structure interaction on the horizontal seismic excitation is investigated on two typical embedded auxiliary buildings of a nuclear power plant. The structure and the soil are modelled by various analytical and numerical methods. Under the condition of the linear viscoelastic theory, i.e. soil characteristic constant in time and independent of strain, the interaction influences between a homogenous soil layer and a structure are analysied for the following parameters: 4) mathematical soil modells; 4) mathematical structure modells; 4) shear wave velocities; 3) embedment conditions; 4) earthquake time histories. (orig.)
Proteins with Novel Structure, Function and Dynamics
Pohorille, Andrew
2014-01-01
Recently, a small enzyme that ligates two RNA fragments with the rate of 10(exp 6) above background was evolved in vitro (Seelig and Szostak, Nature 448:828-831, 2007). This enzyme does not resemble any contemporary protein (Chao et al., Nature Chem. Biol. 9:81-83, 2013). It consists of a dynamic, catalytic loop, a small, rigid core containing two zinc ions coordinated by neighboring amino acids, and two highly flexible tails that might be unimportant for protein function. In contrast to other proteins, this enzyme does not contain ordered secondary structure elements, such as alpha-helix or beta-sheet. The loop is kept together by just two interactions of a charged residue and a histidine with a zinc ion, which they coordinate on the opposite side of the loop. Such structure appears to be very fragile. Surprisingly, computer simulations indicate otherwise. As the coordinating, charged residue is mutated to alanine, another, nearby charged residue takes its place, thus keeping the structure nearly intact. If this residue is also substituted by alanine a salt bridge involving two other, charged residues on the opposite sides of the loop keeps the loop in place. These adjustments are facilitated by high flexibility of the protein. Computational predictions have been confirmed experimentally, as both mutants retain full activity and overall structure. These results challenge our notions about what is required for protein activity and about the relationship between protein dynamics, stability and robustness. We hypothesize that small, highly dynamic proteins could be both active and fault tolerant in ways that many other proteins are not, i.e. they can adjust to retain their structure and activity even if subjected to mutations in structurally critical regions. This opens the doors for designing proteins with novel functions, structures and dynamics that have not been yet considered.
Sierra Structural Dynamics User's Notes
Energy Technology Data Exchange (ETDEWEB)
Reese, Garth M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2015-10-19
Sierra/SD provides a massively parallel implementation of structural dynamics finite element analysis, required for high fidelity, validated models used in modal, vibration, static and shock analysis of weapons systems. This document provides a users guide to the input for Sierra/SD. Details of input specifications for the different solution types, output options, element types and parameters are included. The appendices contain detailed examples, and instructions for running the software on parallel platforms.
Theories and models of structural dynamics: an ‘ideal’ general framework ?
Schilirò, Daniele
2007-01-01
This contribution concerns models and theories of structural economic dynamics. The theories and models analyzed in the paper follow two different approaches, circular and vertical, in the analysis of structural dynamics. The content of this contribution is essentially methodological. This work also aims at identifying a possible ‘ideal’ general framework for the analysis of structural economic dynamics, by singling out a core set of fundamental methodological and analytical principles that s...
Control of complex networks requires both structure and dynamics
Gates, Alexander J.; Rocha, Luis M.
2016-01-01
The study of network structure has uncovered signatures of the organization of complex systems. However, there is also a need to understand how to control them; for example, identifying strategies to revert a diseased cell to a healthy state, or a mature cell to a pluripotent state. Two recent methodologies suggest that the controllability of complex systems can be predicted solely from the graph of interactions between variables, without considering their dynamics: structural controllability and minimum dominating sets. We demonstrate that such structure-only methods fail to characterize controllability when dynamics are introduced. We study Boolean network ensembles of network motifs as well as three models of biochemical regulation: the segment polarity network in Drosophila melanogaster, the cell cycle of budding yeast Saccharomyces cerevisiae, and the floral organ arrangement in Arabidopsis thaliana. We demonstrate that structure-only methods both undershoot and overshoot the number and which sets of critical variables best control the dynamics of these models, highlighting the importance of the actual system dynamics in determining control. Our analysis further shows that the logic of automata transition functions, namely how canalizing they are, plays an important role in the extent to which structure predicts dynamics. PMID:27087469
Control of complex networks requires both structure and dynamics.
Gates, Alexander J; Rocha, Luis M
2016-01-01
The study of network structure has uncovered signatures of the organization of complex systems. However, there is also a need to understand how to control them; for example, identifying strategies to revert a diseased cell to a healthy state, or a mature cell to a pluripotent state. Two recent methodologies suggest that the controllability of complex systems can be predicted solely from the graph of interactions between variables, without considering their dynamics: structural controllability and minimum dominating sets. We demonstrate that such structure-only methods fail to characterize controllability when dynamics are introduced. We study Boolean network ensembles of network motifs as well as three models of biochemical regulation: the segment polarity network in Drosophila melanogaster, the cell cycle of budding yeast Saccharomyces cerevisiae, and the floral organ arrangement in Arabidopsis thaliana. We demonstrate that structure-only methods both undershoot and overshoot the number and which sets of critical variables best control the dynamics of these models, highlighting the importance of the actual system dynamics in determining control. Our analysis further shows that the logic of automata transition functions, namely how canalizing they are, plays an important role in the extent to which structure predicts dynamics. PMID:27087469
Information Diversity in Structure and Dynamics of Simulated Neuronal Networks
Directory of Open Access Journals (Sweden)
Tuomo eMäki-Marttunen
2011-06-01
Full Text Available Neuronal networks exhibit a wide diversity of structures, which contributes to the diversity of the dynamics therein. The presented work applies an information theoretic framework to simultaneously analyze structure and dynamics in neuronal networks. Information diversity within the structure and dynamics of a neuronal network is studied using the normalized compression distance (NCD. To describe the structure, a scheme for generating distance-dependent networks with identical in-degree distribution but variable strength of dependence on distance is presented. The resulting network structure classes possess diﬀering path length and clustering coeﬃcient distributions. In parallel, comparable realistic neuronal networks are generated with NETMORPH simulator and similar analysis is done on them. To describe the dynamics, network spike trains are simulated using diﬀerent network structures and their bursting behaviours are analyzed. For the simulation of the network activity the Izhikevich model of spiking neurons is used together with the Tsodyks model of dynamical synapses.We show that the structure of the simulated neuronal networks aﬀects the spontaneous bursting activity when measured with bursting frequency and a set of intraburst measures: the more locally connected networks produce more and longer bursts than the more random networks. The information diversity of the structure of a network is greatest in the most locally connected networks, smallest in random networks, and somewhere in between in the networks between order and disorder. As for the dynamics, the most locally connected networks and some of the in-between networks produce the most complex intraburst spike trains. The same result also holds for sparser of the two considered network densities in the case of full spike trains.
Exploiting Dynamically Propositional Logic Structures in SAT
Chen, Jingchao
2011-01-01
The 32-bit hwb (hwb-n32 for short) problem is from equivalence checking that arises in combining two circuits computing the hidden weighted bit function. Since 2002, it remains still unsolvable in every SAT competition. This paper focuses on solving problems such as hwb-n32. Generally speaking, modern solvers can detect only XOR, AND, OR and ITE gates. Other non-clausal formulas (propositional logic structures) cannot be detected. To solve the hwb-n32 problem, we extract dynamically some special propositional logic structures, and then use a variant of DPLL-based solvers to solve the subproblem simplified by the extracted structure information. Using the dynamic extraction technique, we solved efficiently the hwb-n32 problem, even some of which were solved within 3000 seconds.
Correlation Measure Equivalence in Dynamic Causal Structures
Gyongyosi, Laszlo
2016-01-01
We prove an equivalence transformation between the correlation measure functions of the causally-unbiased quantum gravity space and the causally-biased standard space. The theory of quantum gravity fuses the dynamic (nonfixed) causal structure of general relativity and the quantum uncertainty of quantum mechanics. In a quantum gravity space, the events are causally nonseparable and all time bias vanishes, which makes it no possible to use the standard causally-biased entropy and the correlation measure functions. Since a corrected causally-unbiased entropy function leads to an undefined, obscure mathematical structure, in our approach the correction is made in the data representation of the causally-unbiased space. We prove that the standard causally-biased entropy function with a data correction can be used to identify correlations in dynamic causal structures. As a corollary, all mathematical properties of the causally-biased correlation measure functions are preserved in the causally-unbiased space. The eq...
The fundamental structures of dynamic social networks
Sekara, Vedran; Lehmann, Sune
2015-01-01
Networks provide a powerful mathematical framework for analyzing the structure and dynamics of complex systems (1-3). The study of group behavior has deep roots in the social science literature (4,5) and community detection is a central part of modern network science. Network communities have been found to be highly overlapping and organized in a hierarchical structure (6-9). Recent technological advances have provided a toolset for measuring the detailed social dynamics at scale (10,11). In spite of great progress, a quantitative description of the complex temporal behavior of social groups-with dynamics spanning from minute-by-minute changes to patterns expressed on the timescale of years-is still absent. Here we uncover a class of fundamental structures embedded within highly dynamic social networks. On the shortest time-scale, we find that social gatherings are fluid, with members coming and going, but organized via a stable core of individuals. We show that cores represent social contexts (9), with recur...
Dynamic structural disorder in supported nanoscale catalysts.
Rehr, J J; Vila, F D
2014-04-01
We investigate the origin and physical effects of "dynamic structural disorder" (DSD) in supported nano-scale catalysts. DSD refers to the intrinsic fluctuating, inhomogeneous structure of such nano-scale systems. In contrast to bulk materials, nano-scale systems exhibit substantial fluctuations in structure, charge, temperature, and other quantities, as well as large surface effects. The DSD is driven largely by the stochastic librational motion of the center of mass and fluxional bonding at the nanoparticle surface due to thermal coupling with the substrate. Our approach for calculating and understanding DSD is based on a combination of real-time density functional theory/molecular dynamics simulations, transient coupled-oscillator models, and statistical mechanics. This approach treats thermal and dynamic effects over multiple time-scales, and includes bond-stretching and -bending vibrations, and transient tethering to the substrate at longer ps time-scales. Potential effects on the catalytic properties of these clusters are briefly explored. Model calculations of molecule-cluster interactions and molecular dissociation reaction paths are presented in which the reactant molecules are adsorbed on the surface of dynamically sampled clusters. This model suggests that DSD can affect both the prefactors and distribution of energy barriers in reaction rates, and thus can significantly affect catalytic activity at the nano-scale. PMID:24712802
Dynamic structural disorder in supported nanoscale catalysts
International Nuclear Information System (INIS)
We investigate the origin and physical effects of “dynamic structural disorder” (DSD) in supported nano-scale catalysts. DSD refers to the intrinsic fluctuating, inhomogeneous structure of such nano-scale systems. In contrast to bulk materials, nano-scale systems exhibit substantial fluctuations in structure, charge, temperature, and other quantities, as well as large surface effects. The DSD is driven largely by the stochastic librational motion of the center of mass and fluxional bonding at the nanoparticle surface due to thermal coupling with the substrate. Our approach for calculating and understanding DSD is based on a combination of real-time density functional theory/molecular dynamics simulations, transient coupled-oscillator models, and statistical mechanics. This approach treats thermal and dynamic effects over multiple time-scales, and includes bond-stretching and -bending vibrations, and transient tethering to the substrate at longer ps time-scales. Potential effects on the catalytic properties of these clusters are briefly explored. Model calculations of molecule-cluster interactions and molecular dissociation reaction paths are presented in which the reactant molecules are adsorbed on the surface of dynamically sampled clusters. This model suggests that DSD can affect both the prefactors and distribution of energy barriers in reaction rates, and thus can significantly affect catalytic activity at the nano-scale
Structure and dynamics of glycosphingolipid micelles
Energy Technology Data Exchange (ETDEWEB)
Hirai, Mitsuhiro; Iwase, Hiroki; Hayakawa, Tomohiro [Department of Physics, Gunma University, Maebashi, Gunma (Japan)
2001-03-01
Disialoganglioside (G{sub D1a}) is one of the functional lipids involved in various surface events on biological cells. In order to clarify a relation between the structural feature and dynamics of the G{sub D1a} micelle depending on temperature elevation, we have carried out neutron spin echo (NSE) and synchrotron radiation small-angle X-ray scattering (SR-SAXS) measurements. We have found that the change of the dynamics of the micelle is coupled with the dehydration of ganglioside headgroups. (author)
Structural Dynamics and Control Interaction of Flexible Structures
Ryan, Robert S. (Editor); Scofield, Harold N. (Editor)
1987-01-01
A Workshop was held to promote technical exchange between the structural dynamic and control disciplines, foster joint technology, and provide a forum for discussing and focusing critical issues in the separate and combined areas. The workshop was closed by a panel meeting. Panel members' viewpoints and their responses to questions are included.
AGENT based structural static and dynamic collaborative optimization
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
A static and dynamic collaborative optimization mode for complex machine system and itsontology project relationship are put forward, on which an agent-based structural static and dynamiccollaborative optimization system is constructed as two agent colonies: optimization agent colony andfinite element analysis colony. And a two-level solving strategy as well as the necessity and possibilityfor handing with finite element analysis model in multi-level mode is discussed. Furthermore, the coop-eration of all FEA agents for optimal design of complicated structural is studied in detail. Structural stat-ic and dynamic collaborative optimization of hydraulic excavator working equimpent is taken as an ex-ample to show that the system is reliable.
Solid Launcher Dynamical Analysis and Autopilot Design
Directory of Open Access Journals (Sweden)
Ping Sun
2011-02-01
Full Text Available The dynamics of a small solid launch vehicle has been investigated. This launcher consists of a liquid upper stage and three fundamental solid rocket boosters aligned in series. During the ascent flight phase, lateral jets and grid fins are adopted by the flight control system to stable the attitude of the launcher. The launcher is a slender and aerodynamically unstable vehicle with sloshing tanks. A complete set of six-degrees-of-freedom dynamic models of the launcher, incorporation its rigid body, aerodynamics, gravity, sloshing, mass change, actuator, and elastic body, is developed. Dynamic analysis results of the structural modes and the bifurcation locus are calculated on the basis of the presented models. This complete set of dynamic models is used in flight control system design. A methodology for employing numerical optimization to develop the attitude filters is presented. The design objectives include attitude tracking accuracy and robust stability with respect to rigid body dynamics, propellant slosh, and flex. Later a control approach is presented for flight control system of the launcher using both State Dependent Riccati Equation (SDRE method and Fast Output Sampling (FOS technique. The dynamics and kinematics for attitude stable problem are of typical nonlinear character. SDRE technique has been well applied to this kind of highly nonlinear control problems. But in practice the system states needed in the SDRE method are sometimes difficult to obtain. FOS method, which makes use of only the output samples, is combined with SDRE to accommodate the incomplete system state information. Thus, the control approach is more practical and easy to implement. The resulting autopilot can provide stable control systems for the vehicle.
Principal component analysis within nuclear structure
Al-Sayed, A
2015-01-01
The principal component analysis (PCA) of different parameters affecting collectivity of nuclei predicted to be candidate of the interacting boson model dynamical symmetries are performed. The results show that, the use of PCA within nuclear structure can give us a simple way to identify collectivity together with the parameters simultaneously affecting it.
Energy Technology Data Exchange (ETDEWEB)
Buffarini, Giacomo; Clemente, Paolo; Rinaldis, Dario [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dipt. Ambiente
1997-07-01
The research work leading to this report is the result of a joint effort between the National Agency for New Technologies and the Environments and the Emilia Romagna regional council, that involved the Environmental Department of the National Agency for New Technologies and the Environments in the experimental analysis of the dynamic structural behaviour of the Hospital of Pievepelago (Modena). A strengthening design has been performed on behalf of the Pievepelago town council, and the Emilia Romagna regional council asked the National Agency for New Technologies and the Environments to study the effectiveness of the intervention by carrying out the analysis of the dynamic behaviour of the structure both before and after the works. The results of the first phase are shown in a previous report. This report is relative to the experimental study on the strengthened building.
Analysis of the dynamic hysteresis characteristic of finger seal
Institute of Scientific and Technical Information of China (English)
LEI Yanni; CHEN Guoding
2007-01-01
The research about hysteresis characteristic of finger seal (FS), which was carried out based on the model with static loads, could not reflect the dynamics behavior of FS system when the rotor runs at high speed. To solve this problem, the relations between the dynamics parameters, structure parameters as well as working parameters in the system were given out through the analysis of finite element analysis result. A mass-spring-damper dynamics model of FS system was proposed and the hysteresis characteristic of the FS system was analyzed. This work shows that the dynamics characteristic analysis of the FS is necessary and the dynamics model proposed in this paper is valid. This dynamics model is the basis for the optimization design of FS system.
Chemical structure and dynamics: Annual report 1996
Energy Technology Data Exchange (ETDEWEB)
Colson, S.D.; McDowell, R.S.
1997-03-01
The Chemical Structure and Dynamics (CS&D) program is a major component of the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL) developed by Pacific Northwest National Laboratory (PNNL) to provide a state-of-the-art collaborative facility for studies of chemical structure and dynamics. We respond to the need for a fundamental, molecular-level understanding of chemistry at a wide variety of environmentally important interfaces by (1) extending the experimental characterization and theoretical description of chemical reactions to encompass the effects of condensed media and interfaces; (2) developing a multidisciplinary capability for describing interfacial chemical processes within which the new knowledge generated can be brought to bear on complex phenomena in environmental chemistry and in nuclear waste processing and storage; and (3) developing state-of-the-art analytical methods for characterizing waste tanks and pollutant distributions, and for detecting and monitoring trace atmospheric species.
Chemical structure and dynamics: Annual report 1996
International Nuclear Information System (INIS)
The Chemical Structure and Dynamics (CS ampersand D) program is a major component of the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL) developed by Pacific Northwest National Laboratory (PNNL) to provide a state-of-the-art collaborative facility for studies of chemical structure and dynamics. We respond to the need for a fundamental, molecular-level understanding of chemistry at a wide variety of environmentally important interfaces by (1) extending the experimental characterization and theoretical description of chemical reactions to encompass the effects of condensed media and interfaces; (2) developing a multidisciplinary capability for describing interfacial chemical processes within which the new knowledge generated can be brought to bear on complex phenomena in environmental chemistry and in nuclear waste processing and storage; and (3) developing state-of-the-art analytical methods for characterizing waste tanks and pollutant distributions, and for detecting and monitoring trace atmospheric species
Time Collocation Method for Structural Dynamic Problems
Institute of Scientific and Technical Information of China (English)
TANG Chen; LUO Tao; YAN Haiqing; GU Xiaohui
2005-01-01
In order to achieve highly accurate and efficient numerical calculations of structural dynamics, time collocation method is presented. For a given time interval, the numerical solution of the method is approximated by a polynomial. The polynomial coefficients are evaluated by solving algebraic equation. Once the polynomial coefficients are evaluated, the numerical solutions at any time in the interval can be easily calculated. New formulae are derived for the polynomial coefficients,which are more practical and succinct than those previously given. Two structural dynamic equations are calculated by the proposed method. The numerical solutions are compared with the traditional fourth-order Runge-Kutta method. The results show that the method proposed is highly accurate and computationally efficient. In addition, an important advantage of the method is the simplicity in software programming.
Chemical structure and dynamics. Annual report 1995
Energy Technology Data Exchange (ETDEWEB)
Colson, S.D.; McDowell, R.S.
1996-05-01
The Chemical Structure and Dynamics program is a major component of Pacific Northwest National Laboratory`s Environmental Molecular Sciences Laboratory (EMSL), providing a state-of-the-art collaborative facility for studies of chemical structure and dynamics. We respond to the need for a fundamental, molecular-level understanding of chemistry at a wide variety of environmentally important interfaces by (1) extending the experimental characterization and theoretical description of chemical reactions to encompass the effects of condensed media and interfaces; (2) developing a multidisciplinary capability for describing interfacial chemical processes within which the new knowledge generated can be brought to bear on complex phenomena in environmental chemistry and in nuclear waste processing and storage; and (3) developing state-of-the-art analytical methods for the characterization of waste tanks and pollutant distributions, and for detection and monitoring of trace atmospheric species.
Annual Report 2000. Chemical Structure and Dynamics
Energy Technology Data Exchange (ETDEWEB)
Colson, Steven D.; McDowell, Robin S.
2001-04-15
This annual report describes the research and accomplishments of the Chemical Structure and Dynamics Program in the year 2000, one of six research programs at the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL) - a multidisciplinary, national scientific user facility and research organization. The Chemical Structure and Dynamics (CS&D) program is meeting the need for a fundamental, molecular-level understanding by 1) extending the experimental characterization and theoretical description of chemical reactions to encompass the effects of condensed media and interfaces; 2) developing a multidisciplinary capability for describing interfacial chemical processes relevant to environmental chemistry; and 3) developing state-of-the-art research and analytical methods for characterizing complex materials of the types found in natural and contaminated systems.
Hemispheric asymmetries in thermospheric structure and dynamics
Rees,David/Fuller-Rowell,Timothy J.
1987-01-01
Hemispheric differences in the structure and dynamics of the polar regions of the thermosphere and ionosphere are caused by seasonal/latitudinal asymmetries of solar insolation acting in addition to the effects of the distinctive asymmetries of the main geomagnetic field. Viewing the earth from a satellite, the longitudinal and universal time variations of the thermosphere and ionosphere are far more spectacular in the southern polar thermosphere and ionosphere than in the northern polar regi...
Space structure (dynamics and control) theme development
Russell, Richard A.; Gates, Richard M.
1988-01-01
A study was made to define the long-range technical objectives and goals for the Space Structure (Dynamics and Control) theme area. The approach was to evaluate ongoing and proposed technology activities such that the technology gaps and voids could be identified. After the technology needs were identified, a set of recommended experimental activities was defined including the technical objectives of each and their relationship.
Feature Extraction for Structural Dynamics Model Validation
Energy Technology Data Exchange (ETDEWEB)
Farrar, Charles [Los Alamos National Laboratory; Nishio, Mayuko [Yokohama University; Hemez, Francois [Los Alamos National Laboratory; Stull, Chris [Los Alamos National Laboratory; Park, Gyuhae [Chonnam Univesity; Cornwell, Phil [Rose-Hulman Institute of Technology; Figueiredo, Eloi [Universidade Lusófona; Luscher, D. J. [Los Alamos National Laboratory; Worden, Keith [University of Sheffield
2016-01-13
As structural dynamics becomes increasingly non-modal, stochastic and nonlinear, finite element model-updating technology must adopt the broader notions of model validation and uncertainty quantification. For example, particular re-sampling procedures must be implemented to propagate uncertainty through a forward calculation, and non-modal features must be defined to analyze nonlinear data sets. The latter topic is the focus of this report, but first, some more general comments regarding the concept of model validation will be discussed.
Dynamic Deployment Simulations of Inflatable Space Structures
Wang, John T.
2005-01-01
The feasibility of using Control Volume (CV) method and the Arbitrary Lagrangian Eulerian (ALE) method in LSDYNA to simulate the dynamic deployment of inflatable space structures is investigated. The CV and ALE methods were used to predict the inflation deployments of three folded tube configurations. The CV method was found to be a simple and computationally efficient method that may be adequate for modeling slow inflation deployment sine the inertia of the inflation gas can be neglected. The ALE method was found to be very computationally intensive since it involves the solving of three conservative equations of fluid as well as dealing with complex fluid structure interactions.
Dynamics of overlapping structures in modular networks.
Almendral, J A; Leyva, I; Li, D; Sendiña-Nadal, I; Havlin, S; Boccaletti, S
2010-07-01
Modularity is a fundamental feature of real networks, being intimately bounded to their functionality, i.e., to their capability of performing parallel tasks in a coordinated way. Although the modular structure of real graphs has been intensively studied, very little is known on the interactions between functional modules of a graph. Here, we present a general method based on synchronization of networking oscillators, that is able to detect overlapping structures in multimodular environments. We furthermore report the full analytical and theoretical description on the relationship between the overlapping dynamics and the underlying network topology. The method is illustrated by means of a series of applications. PMID:20866697
Directory of Open Access Journals (Sweden)
Hung-Cuong Trinh
Full Text Available It has been a challenge in systems biology to unravel relationships between structural properties and dynamic behaviors of biological networks. A Cytoscape plugin named NetDS was recently proposed to analyze the robustness-related dynamics and feed-forward/feedback loop structures of biological networks. Despite such a useful function, limitations on the network size that can be analyzed exist due to high computational costs. In addition, the plugin cannot verify an intrinsic property which can be induced by an observed result because it has no function to simulate the observation on a large number of random networks. To overcome these limitations, we have developed a novel software tool, PANET. First, the time-consuming parts of NetDS were redesigned to be processed in parallel using the OpenCL library. This approach utilizes the full computing power of multi-core central processing units and graphics processing units. Eventually, this made it possible to investigate a large-scale network such as a human signaling network with 1,609 nodes and 5,063 links. We also developed a new function to perform a batch-mode simulation where it generates a lot of random networks and conducts robustness calculations and feed-forward/feedback loop examinations of them. This helps us to determine if the findings in real biological networks are valid in arbitrary random networks or not. We tested our plugin in two case studies based on two large-scale signaling networks and found interesting results regarding relationships between coherently coupled feed-forward/feedback loops and robustness. In addition, we verified whether or not those findings are consistently conserved in random networks through batch-mode simulations. Taken together, our plugin is expected to effectively investigate various relationships between dynamics and structural properties in large-scale networks. Our software tool, user manual and example datasets are freely available at http://panet-csc.sourceforge.net/.
Nonlinear and stochastic dynamics of coherent structures
DEFF Research Database (Denmark)
Rasmussen, Kim
1997-01-01
This Thesis deals with nonlinear and stochastic dynamics in systems which can be described by nonlinear Schrödinger models. Basically three different models are investigated. The first is the continuum nonlinear Schröndinger model in one and two dimensions generalized by a tunable degree of...... continuum mod el is concluded by an investigation of the dynamics of localized states in the vici nity of an impurity. Studying the discrete nonlinear Schrödinger model, we first analyze the intrinsically localized excitations supported by this model in one dimension . This analysis is accomplished using....... Existence and dynamics of the intrinsically localized excitations in the two-dimensional discr ete model are also studied. It is found that in two dimensions a bistability phenomenon of the localized states appears. The bistability expresses itself by allowing localized states of various width to have equal...
Feature extraction for structural dynamics model validation
Energy Technology Data Exchange (ETDEWEB)
Hemez, Francois [Los Alamos National Laboratory; Farrar, Charles [Los Alamos National Laboratory; Park, Gyuhae [Los Alamos National Laboratory; Nishio, Mayuko [UNIV OF TOKYO; Worden, Keith [UNIV OF SHEFFIELD; Takeda, Nobuo [UNIV OF TOKYO
2010-11-08
This study focuses on defining and comparing response features that can be used for structural dynamics model validation studies. Features extracted from dynamic responses obtained analytically or experimentally, such as basic signal statistics, frequency spectra, and estimated time-series models, can be used to compare characteristics of structural system dynamics. By comparing those response features extracted from experimental data and numerical outputs, validation and uncertainty quantification of numerical model containing uncertain parameters can be realized. In this study, the applicability of some response features to model validation is first discussed using measured data from a simple test-bed structure and the associated numerical simulations of these experiments. issues that must be considered were sensitivity, dimensionality, type of response, and presence or absence of measurement noise in the response. Furthermore, we illustrate a comparison method of multivariate feature vectors for statistical model validation. Results show that the outlier detection technique using the Mahalanobis distance metric can be used as an effective and quantifiable technique for selecting appropriate model parameters. However, in this process, one must not only consider the sensitivity of the features being used, but also correlation of the parameters being compared.
International Nuclear Information System (INIS)
A stress and strain analysis was made of a scale model of a Prestressed Concrete Pressure Vessel for a Boiling Water Reactor. The aim of this work was to obtain an experimental verification of the calculation method actually used at IPEN. The 1/10 scale model was built and tested at the Instituto Sperimentale Modelli e Structture, ISMES, Italy. The dynamic relaxation program PV2-A and the finite element programs , FEAST-1 have been used. A comparative analysis of the final results was made. A preliminary analysis was made for a simplified monocavity model now under development at IPEN with the object of confirming the data and the calculation method used. (author)
International Nuclear Information System (INIS)
The paper describes the on-site dynamic tests carried out on the PEC fast reactor building, using various excitation methods (two eccentric back-rotating-mass mechanical vibrator, blasting in bore-hole, hydraulic actuators at the building foundations). It points out the purposes of the four tests campaigns performed at various construction stages and reports the main experimental results. These results concern both the design safety margins and the data for the validation of the three-dimensional numerical model of the reactor building, including soil-structure interaction phenomena. (author)
Dynamics and structure of turbulent premixed flames
Bilger, R. W.; Swaminathan, N.; Ruetsch, G. R.; Smith, N. S. A.
1995-01-01
In earlier work (Mantel & Bilger, 1994) the structure of the turbulent premixed flame was investigated using statistics based on conditional averaging with the reaction progress variable as the conditioning variable. The DNS data base of Trouve and Poinsot (1994) was used in this investigation. Attention was focused on the conditional dissipation and conditional axial velocity in the flame with a view to modeling these quantities for use in the conditional moment closure (CMC) approach to analysis of kinetics in premixed flames (Bilger, 1993). Two remarkable findings were made: there was almost no acceleration of the axial velocity in the flame front itself; and the conditional scalar dissipation remained as high, or higher, than that found in laminar premixed flames. The first finding was surprising since in laminar flames all the fluid acceleration occurs through the flame front, and this could be expected also for turbulent premixed flames at the flamelet limit. The finding gave hope of inventing a new approach to the dynamics of turbulent premixed flames through use of rapid distortion theory or an unsteady Bernoulli equation. This could lead to a new second order closure for turbulent premixed flames. The second finding was contrary to our measurements with laser diagnostics in lean hydrocarbon flames where it is found that conditional scalar dissipation drops dramatically below that for laminar flamelets when the turbulence intensity becomes high. Such behavior was not explainable with a one-step kinetic model, even at non-unity Lewis number. It could be due to depletion of H2 from the reaction zone by preferential diffusion. The capacity of the flame to generate radicals is critically dependent on the levels of H2 present (Bilger, et al., 1991). It seemed that a DNS computation with a multistep reduced mechanism would be worthwhile if a way could be found to make this feasible. Truly innovative approaches to complex problems often come only when there is the
International Nuclear Information System (INIS)
To determine the effect of F ions on the structure of the molten alkali silicate systems, quenched Na2O-SiO2-NaF systems were investigated by Raman spectroscopy and molecular dynamics simulation. The systematic increase of 1100cm-1 band intensity in the Raman spectra of the silicate melts accompanying the replacement of O by F provides the evidence for concomitant polymerization of melts. From the molecular dynamics simulation, it was confirmed that most of substituted F was mainly coordinated to Na+ ions but not Si4+ ions at least up to 12.5 mol% of F ion content. A small amount of F was found to be coordinated to Si as a non-bridging ion from the molecular dynamics simulation, although there was no recognizable evidence from Raman Spectroscopy. These results were consistent with the mechanism in which F associated with otherwise network-modifying Na rather than with network-forming Si. Since F was associated to Na+ ions, the replace of O ion by two F ions promote the polymerization of silicate melts. (author)
An analysis of dynamic bankruptcy problems
Turhan, Bertan
2009-01-01
In this paper, we analyse Pareto optimal and strategy-proof allocation rules on the dynamic bankruptcy domain. We first develop a model in which dynamic bankruptcy problems are defined. We then redefine the well-known axioms of the classical bankruptcy literature for the dynamic case. In our analysis, for simplicity, two agents and two periods are considered. We first characterize Pareto optimal allocations on the dynamic bankruptcy domain. The main result of the paper characterizes the Paret...
Dynamic Failure of Composite and Sandwich Structures
Abrate, Serge; Rajapakse, Yapa D S
2013-01-01
This book presents a broad view of the current state of the art regarding the dynamic response of composite and sandwich structures subjected to impacts and explosions. Each chapter combines a thorough assessment of the literature with original contributions made by the authors. The first section deals with fluid-structure interactions in marine structures. The first chapter focuses on hull slamming and particularly cases in which the deformation of the structure affects the motion of the fluid during the water entry of flexible hulls. Chapter 2 presents an extensive series of tests underwater and in the air to determine the effects of explosions on composite and sandwich structures. Full-scale structures were subjected to significant explosive charges, and such results are extremely rare in the open literature. Chapter 3 describes a simple geometrical theory of diffraction for describing the interaction of an underwater blast wave with submerged structures. The second section addresses the problem of...
Symplectic structures and dynamical symmetry groups
International Nuclear Information System (INIS)
Apart from the total energy, the two-dimensional isotropic harmonic oscillator possesses three independent constants of motion which, with the standard symplectic structure, generates a dynamical symmetry group isomorphic to SU (2). We show that, by suitably redefining the symplectic structure, any of these three constants of motion can be used as a Hamiltonian, and that the remaining two, together with the total energy, generate a dynamical symmetry group isomorphic to SU (1,1). We also show that the standard energy levels of the quantum two-dimensional isotropic harmonic oscillator and their degeneracies are obtained making use of the appropriate representations of SU(1,1), provided that the canonical commutation relations are modified according to the new symplectic structure. Whereas in classical mechanics the different symplectic structures lead to equivalent formulations of the equations of motion, in quantum mechanics the modifications of the commutation relations should be accompanied by modifications in the interpretation of the formalism in order to obtain results equivalent to those found with the common relations. (Author) 12 refs
Hybrid Dynamic Network Data Envelopment Analysis
Directory of Open Access Journals (Sweden)
Ling Li
2015-01-01
Full Text Available Conventional DEA models make no hypothesis concerning the internal operations in a static situation. To open the “black box” and work with dynamic assessment issues synchronously, we put forward a hybrid model for evaluating the relative efficiencies of a set of DMUs over an observed time period with a composite of network DEA and dynamic DEA. We vertically deal with intermediate products between divisions with assignable inputs in the network structure and, horizontally, we extend network structure by means of a dynamic pattern with unrelated activities between two succeeding periods. The hybrid dynamic network DEA model proposed in this paper enables us to (i pry into the internal operations of DEA by another network structure, (ii obtain dynamic change of period efficiency, and (iii gain the overall dynamic efficiency of DMUs over the entire observed periods. We finally illustrate the calculation procedure of the proposed approach by a numerical example.
Dynamic Hurricane Data Analysis Tool
Knosp, Brian W.; Li, Peggy; Vu, Quoc A.
2009-01-01
A dynamic hurricane data analysis tool allows users of the JPL Tropical Cyclone Information System (TCIS) to analyze data over a Web medium. The TCIS software is described in the previous article, Tropical Cyclone Information System (TCIS) (NPO-45748). This tool interfaces with the TCIS database to pull in data from several different atmospheric and oceanic data sets, both observed by instruments. Users can use this information to generate histograms, maps, and profile plots for specific storms. The tool also displays statistical values for the user-selected parameter for the mean, standard deviation, median, minimum, and maximum values. There is little wait time, allowing for fast data plots over date and spatial ranges. Users may also zoom-in for a closer look at a particular spatial range. This is version 1 of the software. Researchers will use the data and tools on the TCIS to understand hurricane processes, improve hurricane forecast models and identify what types of measurements the next generation of instruments will need to collect.
Systems-Dynamic Analysis for Neighborhood Study
Systems-dynamic analysis (or system dynamics (SD)) helps planners identify interrelated impacts of transportation and land-use policies on neighborhood-scale economic outcomes for households and businesses, among other applications. This form of analysis can show benefits and tr...
Structural optimization for nonlinear dynamic response
DEFF Research Database (Denmark)
Dou, Suguang; Strachan, B. Scott; Shaw, Steven W.;
2015-01-01
single vibrating mode, or by a pair of internally resonant modes. The approach combines techniques from nonlinear dynamics, computational mechanics and optimization, and it allows one to relate the geometric and material properties of structural elements to terms in the normal form for a given resonance......Much is known about the nonlinear resonant response of mechanical systems, but methods for the systematic design of structures that optimize aspects of these responses have received little attention. Progress in this area is particularly important in the area of micro-systems, where nonlinear...... resonant behaviour is being used for a variety of applications in sensing and signal conditioning. In this work, we describe a computational method that provides a systematic means for manipulating and optimizing features of nonlinear resonant responses of mechanical structures that are described by a...
Community structure and dynamics in social systems
Wilkinson, Dennis M.
This thesis presents applications of statistical physics to the study of the structure and dynamics of social systems, that is, systems whose interactions are based on information exchange. Social systems typically possess a community structure arising from the self organization of groups of interacting components into tightly-knit clusters. An automated method of identifying communities within a network of interactions is first presented. The method includes a statistical component crucial to obtaining accurate results in large, complex systems. It is applied to two real-world social networks, a network of email interactions and a network of related articles in the biomedical literature. The clusters it identifies within these networks are shown to correspond to communities of interrelated components. Next, the dynamics of cooperative problem solving processes on social systems are studied. A simple stochastic model is proposed which captures key aspects of the dynamics which have been empirically observed. Most important among these are the increase in average time to solution and in likelihood of long delays as the system size increases, as well as the log-normal distribution of times to solution. It is shown that a community structure both reduces the average time to solution and decreases the probability of delay. In cases where a system of cooperative efforts does not possess an inherent community structure, the effect of imposing communities is examined. The factor which most affects the dynamics when communities are imposed is shown to be the degree to which individuals neglect information from outside their own communities. The theory of stochastic vector processes is central to the dynamics of social systems and a mathematical study of this subject is presented. Expressions describing the evolution of the moments in the neighborhood of fixed points are obtained for arbitrary systems. Approximation techniques are applied in the small and large noise limits
Dynamic sign structures in visual art and music
DEFF Research Database (Denmark)
Zeller, Jörg
2006-01-01
Seemingly static meaning carriers in visual art are considered as aspects of holistic dynamical sign structures.......Seemingly static meaning carriers in visual art are considered as aspects of holistic dynamical sign structures....
Fundamental structures of dynamic social networks.
Sekara, Vedran; Stopczynski, Arkadiusz; Lehmann, Sune
2016-09-01
Social systems are in a constant state of flux, with dynamics spanning from minute-by-minute changes to patterns present on the timescale of years. Accurate models of social dynamics are important for understanding the spreading of influence or diseases, formation of friendships, and the productivity of teams. Although there has been much progress on understanding complex networks over the past decade, little is known about the regularities governing the microdynamics of social networks. Here, we explore the dynamic social network of a densely-connected population of ∼1,000 individuals and their interactions in the network of real-world person-to-person proximity measured via Bluetooth, as well as their telecommunication networks, online social media contacts, geolocation, and demographic data. These high-resolution data allow us to observe social groups directly, rendering community detection unnecessary. Starting from 5-min time slices, we uncover dynamic social structures expressed on multiple timescales. On the hourly timescale, we find that gatherings are fluid, with members coming and going, but organized via a stable core of individuals. Each core represents a social context. Cores exhibit a pattern of recurring meetings across weeks and months, each with varying degrees of regularity. Taken together, these findings provide a powerful simplification of the social network, where cores represent fundamental structures expressed with strong temporal and spatial regularity. Using this framework, we explore the complex interplay between social and geospatial behavior, documenting how the formation of cores is preceded by coordination behavior in the communication networks and demonstrating that social behavior can be predicted with high precision. PMID:27555584
NAPS: Network Analysis of Protein Structures.
Chakrabarty, Broto; Parekh, Nita
2016-07-01
Traditionally, protein structures have been analysed by the secondary structure architecture and fold arrangement. An alternative approach that has shown promise is modelling proteins as a network of non-covalent interactions between amino acid residues. The network representation of proteins provide a systems approach to topological analysis of complex three-dimensional structures irrespective of secondary structure and fold type and provide insights into structure-function relationship. We have developed a web server for network based analysis of protein structures, NAPS, that facilitates quantitative and qualitative (visual) analysis of residue-residue interactions in: single chains, protein complex, modelled protein structures and trajectories (e.g. from molecular dynamics simulations). The user can specify atom type for network construction, distance range (in Å) and minimal amino acid separation along the sequence. NAPS provides users selection of node(s) and its neighbourhood based on centrality measures, physicochemical properties of amino acids or cluster of well-connected residues (k-cliques) for further analysis. Visual analysis of interacting domains and protein chains, and shortest path lengths between pair of residues are additional features that aid in functional analysis. NAPS support various analyses and visualization views for identifying functional residues, provide insight into mechanisms of protein folding, domain-domain and protein-protein interactions for understanding communication within and between proteins. URL:http://bioinf.iiit.ac.in/NAPS/. PMID:27151201
The Hierarchical Structure and Dynamics of Voids
Aragon-Calvo, M A
2012-01-01
Contrary to the common view voids have very complex internal structure and dynamics. Here we show how the hierarchy of structures in the density field inside voids is reflected by a similar hierarchy of structures in the velocity field. Voids defined by dense filaments and clusters can de described as simple expanding domains with coherent flows everywhere except at their boundaries. At scales smaller that the void radius the velocity field breaks into expanding sub-domains corresponding to sub- voids. These sub-domains break into even smaller sub-sub domains at smaller scales resulting in a nesting hierarchy of locally expanding domains. The ratio between the magnitude of the velocity field responsible for the expansion of the void and the velocity field defining the sub voids is approximately one order of magnitude. The small-scale components of the velocity field play a minor role in the shaping of the voids but they define the local dynamics directly affecting the processes of galaxy formation and evoluti...
The chemical bond structure and dynamics
Zewail, Ahmed
1992-01-01
This inspired book by some of the most influential scientists of our time--including six Nobel laureates--chronicles our emerging understanding of the chemical bond through the last nine decades and into the future. From Pauling's early structural work using x-ray and electron diffraction to Zewail's femtosecond lasers that probe molecular dynamics in real time; from Crick's molecular biology to Rich's molecular recognition, this book explores a rich tradition of scientific heritage and accomplishment. The perspectives given by Pauling, Perutz, Rich, Crick, Porter, Polanyi, Herschbach, Zewail,
Jellyfish modulate bacterial dynamic and community structure.
Directory of Open Access Journals (Sweden)
Tinkara Tinta
Full Text Available Jellyfish blooms have increased in coastal areas around the world and the outbreaks have become longer and more frequent over the past few decades. The Mediterranean Sea is among the heavily affected regions and the common bloom-forming taxa are scyphozoans Aurelia aurita s.l., Pelagia noctiluca, and Rhizostoma pulmo. Jellyfish have few natural predators, therefore their carcasses at the termination of a bloom represent an organic-rich substrate that supports rapid bacterial growth, and may have a large impact on the surrounding environment. The focus of this study was to explore whether jellyfish substrate have an impact on bacterial community phylotype selection. We conducted in situ jellyfish-enrichment experiment with three different jellyfish species. Bacterial dynamic together with nutrients were monitored to assess decaying jellyfish-bacteria dynamics. Our results show that jellyfish biomass is characterized by protein rich organic matter, which is highly bioavailable to 'jellyfish-associated' and 'free-living' bacteria, and triggers rapid shifts in bacterial population dynamics and composition. Based on 16S rRNA clone libraries and denaturing gradient gel electrophoresis (DGGE analysis, we observed a rapid shift in community composition from unculturable Alphaproteobacteria to culturable species of Gammaproteobacteria and Flavobacteria. The results of sequence analyses of bacterial isolates and of total bacterial community determined by culture independent genetic analysis showed the dominance of the Pseudoalteromonadaceae and the Vibrionaceae families. Elevated levels of dissolved proteins, dissolved organic and inorganic nutrient release, bacterial abundance and carbon production as well as ammonium concentrations characterized the degradation process. The biochemical composition of jellyfish species may influence changes in the amount of accumulated dissolved organic and inorganic nutrients. Our results can contribute insights into
Membrane proteins structure and dynamics by nuclear magnetic resonance.
Maltsev, Sergey; Lorigan, Gary A
2011-10-01
Membrane proteins represent a challenging class of biological systems to study. They are extremely difficult to crystallize and in most cases they retain their structure and functions only in membrane environments. Therefore, commonly used diffraction methods fail to give detailed molecular structure and other approaches have to be utilized to obtain biologically relevant information. Nuclear magnetic resonance (NMR) spectroscopy, however, can provide powerful structural and dynamical constraints on these complicated systems. Solution- and solid-state NMR are powerful methods for investigating membrane proteins studies. In this work, we briefly review both solution and solid-state NMR techniques for membrane protein studies and illustrate the applications of these methods to elucidate proteins structure, conformation, topology, dynamics, and function. Recent advances in electronics, biological sample preparation, and spectral processing provided opportunities for complex biological systems, such as membrane proteins inside lipid vesicles, to be studied faster and with outstanding quality. New analysis methods therefore have emerged, that benefit from the combination of sample preparation and corresponding specific high-end NMR techniques, which give access to more structural and dynamic information. PMID:23733702
Statistical analysis of Sequence-Structure Alignment Scores
Brunnert, Marcus; Thiele, Ralf; Mevissen, Heinz-Theodor; Urfer, Wolfgang
2002-01-01
The structural analysis of proteins is fundamental to the analysis of protein functions. In this context, sequence-structure alignment methods are important among the different empirical methods. In order to assess the quality of sequence-structure alignments, a statistical method using a Bayesian approach proposed by Lathrop et al. (1998) will be presented. Finally, the results of a developed statistical analysis of scores of RDP(recursive dynamic programming)-sequence-structure alignments (...
Structure and dynamics of molten salts
International Nuclear Information System (INIS)
Modern techniques of liquid state physics have been successfully used over the last decade to probe the microscopic structure and dynamics of a variety of multicomponent liquids in which relative ordering of the species is present near freezing. The alkali halides are prototypes for this specific type of short range order in relation to the nature of bonding, but the systems in question include also other monovalent and polyvalent metal-ion halides, alkali-based intermetallic compounds, and chalcogen-based alloys. A viewpoint is taken in this review which gives attention to relations between liquid and solid phase properties across melting for compound systems at stoichiometric composition. In addition, large deviations from stoichiometry can be realized in the liquid phase, to display trends of evolution of structure, bonding and electronic states with composition. (author)
Fuchs, Maurice Bernard
2016-01-01
Addressing structures, this book presents a classic discipline in a modern setting by combining illustrated examples with insights into the solutions. It is the fruit of the author’s many years of teaching the subject and of just as many years of research into the design of optimal structures. Although intended for an advanced level of instruction it has an undergraduate course at its core. Further, the book was written with the advantage of having massive computer power in the background, an aspect which changes the entire approach to many engineering disciplines and in particular to structures. This paradigm shift has dislodged the force (flexibility) method from its former prominence and paved the way for the displacement (stiffness) method, despite the multitude of linear equations it spawns. In this book, however, both methods are taught: the force method offers a perfect vehicle for understanding structural behavior, bearing in mind that it is the displacement method which does the heavy number crunch...
Chemical Structure and Dynamics annual report 1997
International Nuclear Information System (INIS)
The Chemical Structure and Dynamics (CS and D) program is a major component of the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL), developed by Pacific Northwest National Laboratory (PNNL) to provide a state-of-the-art collaborative facility for studies of chemical structure and dynamics. The authors respond to the need for a fundamental, molecular level understanding of chemistry at a wide variety of environmentally important interfaces by: (1) extending the experimental characterization and theoretical description of chemical reactions to encompass the effects of condensed media and interfaces; (2) developing a multidisciplinary capability for describing interfacial chemical processes within which the new knowledge generated can be brought to bear on complex phenomena in environmental chemistry and in nuclear waste processing and storage; and (3) developing state-of-the-art analytical methods for characterizing complex materials of the types found in stored wastes and contaminated soils, and for detecting and monitoring trace atmospheric species. The focus of the research is defined primarily by DOE's environmental problems: fate and transport of contaminants in the subsurface environment, processing and storage of waste materials, cellular effects of chemical and radiological insult, and atmospheric chemistry as it relates to air quality and global change. Twenty-seven projects are described under the following topical sections: Reaction mechanisms at interfaces; High-energy processes at environmental interfaces; Cluster models of the condensed phase; and Miscellaneous
Chemical Structure and Dynamics annual report 1997
Energy Technology Data Exchange (ETDEWEB)
Colson, S.D.; McDowell, R.S.
1998-03-01
The Chemical Structure and Dynamics (CS and D) program is a major component of the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL), developed by Pacific Northwest National Laboratory (PNNL) to provide a state-of-the-art collaborative facility for studies of chemical structure and dynamics. The authors respond to the need for a fundamental, molecular level understanding of chemistry at a wide variety of environmentally important interfaces by: (1) extending the experimental characterization and theoretical description of chemical reactions to encompass the effects of condensed media and interfaces; (2) developing a multidisciplinary capability for describing interfacial chemical processes within which the new knowledge generated can be brought to bear on complex phenomena in environmental chemistry and in nuclear waste processing and storage; and (3) developing state-of-the-art analytical methods for characterizing complex materials of the types found in stored wastes and contaminated soils, and for detecting and monitoring trace atmospheric species. The focus of the research is defined primarily by DOE`s environmental problems: fate and transport of contaminants in the subsurface environment, processing and storage of waste materials, cellular effects of chemical and radiological insult, and atmospheric chemistry as it relates to air quality and global change. Twenty-seven projects are described under the following topical sections: Reaction mechanisms at interfaces; High-energy processes at environmental interfaces; Cluster models of the condensed phase; and Miscellaneous.
Local Dynamics of Offshore Wind Turbine Jacket Sub-structures
Kjetså, Anders; Saaghus, Lars Jørgen
2010-01-01
The scope of this thesis has been to investigate the existence of out-of-plane vibration of jacket sub-structures for offshore wind turbines. This is done by making the program code JAC (Jacket Analysis Code), which is capable of solving dynamic problems in both time and frequency domain. The code is also able to do damage analysis as it has been a major goal to quantify the change in damage caused by the out-of-plane vibrations and to see how this is influenced by dierent parameters.It is sh...
三杆张拉整体折展过程动力学分析%Dynamic analysis of the three-bar tensegrity deployable structure
Institute of Scientific and Technical Information of China (English)
罗阿妮; 李旭; 李全贺; 程建军; 刘贺平
2016-01-01
The string drive method is used to deploy the three⁃bar tensegrity structure. Based on the matrixes analy⁃sis, the mathematical model is built up with the generalized node coordinates and connectivity matrixes expressed positions and arrangements of members. The lengths of strings are adjusted with the bars'length constant to deploy the structure. Based on the flexible of the members, shortening the level strings to make the structure fold towards its'axis, it is analyzed that the dynamics of the structure. The simulation proved this deployable method is feasible. The changings of the lengths and inner forces of the members are given. The results show that adjusting the strings lengths could make the structure deployment. This method can be used in the three⁃bar tensegrity deployable struc⁃ture and other structures which build up with the three⁃bar basic units.%本文针对三杆张拉整体结构的折展问题，提出一种索驱动的方法。利用矩阵法分析，使用节点广义坐标和连接矩阵描述结构中各构件的位置和空间分布，建立结构数学模型；通过索构件长度协调变化，杆构件长度不变来分析结构的折展过程。在考虑构件弹性的情况下，对水平索为主动构件实现结构向轴线方向折叠的运动过程进行了动力学分析。通过仿真分析验证了此折叠方案的可行性。并对折展过程中构件的长度和内力的变化进行了分析，分析结果表明：张拉整体结构通过构件长度协调变化可实现折展功能，此方法可使用于三杆张拉整体单元以及以三杆张拉整体单元为基础的复杂张拉整体结构。
Structural Dynamics of the Vault Ribonucleoprotein Particle
Casañas, Arnau; Querol, Jordi; Fita, Ignasi; Verdaguer, Núria
Vaults are ubiquitous, highly conserved, 13 MDa ribonucleoprotein particles, involved in a diversity of cellular processes, including multidrug resistance, transport mechanisms and signal transmission. There are between 104 and 106 vault particles per mammalian cell and they do not trigger autoimmunity. The vault particle shows a hollow barrel-shaped structure organized in two identical moieties, each consisting of 39 copies of the major vault protein (MVP). Other data indicated that vault halves can dissociate at acidic pH. The high resolution, crystal structure of the of the seven N-terminal domains (R1-R7) of MVP, forming the central vault barrel, together with that of the native vault particle (solved at 8 Å resolution), revealed the interactions governing vault association and suggested a pH-dependent mechanism for a reversible dissociation induced by low pH. Vault particles posses many features making them very promising vehicles for the delivery of therapeutic agents including self-assembly, 100 nm size range, emerging atomic-level structural information, natural presence in humans ensuring biocompability, recombinant production system, existing features for targeting species to the large lumen and a dynamic structure that may be controlled for manipulation of drug release kinetics. All these attributes provide vaults with enormous potential as a drug/gene delivery platform.
Institute of Scientific and Technical Information of China (English)
戚蓝; 刘国威; 王海军
2012-01-01
In order to research the seismic dynamic response of the structure for ogshore wind turbine with bucket foundation, the sail-structure interaction(SSI) is considered with the equivalent linear dynamic constitutive model that can reflect the non-linearity and hysteresis of soil on the basis of the subroutine UMAT provided by ABAQUS, and then a finite element and infinite element coupling model for analysis on the rotor blade, tower, bucket foundation and soil is established for a domestic offshore wind power generation system; furthermore, the dynamic response analysis is made with the lime domain analysis based on i static analysis. The study shows that the natural frequency of the structure can be reduced by SSi eSect Lnder the seismic dynamic effect, the maximum horizontal acceleration response gf the tower structure of the wind turbine occurs near 1/3 height of it, while the vertical acceleration response keeps increasing all along the tower height and its amplification effect is stronger than that of the horizontal one.%为研究近海风电筒型基础风机结构的地震动力响应,基于ABAQUS软件的UMAT平台嵌入了能够反映土体非线性与滞后性的等效线性动本构模型,考虑土—结构相互作用( soil-structure interaction,SSI),针对国内某近海风力发电系统构建“桨叶—塔架—筒型基础—土体”的有限元—无限元耦合分析模型,在静力分析的基础上采用时域分析法对其进行动力响应分析.研究表明,SSI效应会降低结构的自振频率;在地震动作用下,该风机高塔结构水平向加速度响应在塔架2/3高度附近处最大,竖向加速度响应则沿塔架高程一直增大,且其放大效应强于水平向.
Structure and dynamics in Photosystem I
Jolley, Craig Charles
Photosystem I (PSI) is a transmembrane protein complex that uses incident light energy to drive an energetically unfavorable electron transfer reaction across a membrane in the early steps of oxygenic photosynthesis. This electron transfer reaction provides energy for the fixing of carbon dioxide and for the subsequent synthesis of nearly all biological material on Earth. Despite the morphological variety of oxygenic photosynthetic organisms---ranging from single-celled aquatic cyanobacteria to large, complex terrestrial plants---the structure and function of PSI are remarkably well-conserved across phyla. PSI has been the subject of extensive interdisciplinary research involving fields ranging from molecular genetics to condensed matter physics, and many aspects of its function still remain unclear. This study presents a variety of theoretical and experimental approaches to aspects of PSI structure and dynamics. An atomic-level structural model of higher plant PSI has been constructed based on recent protein crystal structures, and provides insight into the evolution of eukaryotic PSI. Time-resolved optical spectroscopic studies of PSI supercomplexes from the green freshwater alga Chlamydomonas reinhardtii illustrate how this organism adapts its photosynthetic apparatus to deal with changing environmental conditions and highlight the importance of structure-function relationships in light-harvesting systems. A novel computational approach using constrained geometric simulations has been used to model a portion of the PSI assembly process, shedding some light on how the heterodimeric PSI reaction center evolved from the more ancient homodimeric photosynthetic reaction centers found in green sulfur bacteria and heliobacteria. A new method is also demonstrated in which constrained geometric simulations are used to flexibly fit a high-resolution protein structure to a low-resolution density map obtained with cryo-electron microscopy (cryo-EM) or low-resolution x
Kinematics, Dynamics, and the Structure of Physical Theory
Curiel, Erik
2016-01-01
Every physical theory has (at least) two different forms of mathematical equations to represent its target systems: the dynamical (equations of motion) and the kinematical (kinematical constraints). Kinematical constraints are differentiated from equations of motion by the fact that their particular form is fixed once and for all, irrespective of the interactions the system enters into. By contrast, the particular form of a system's equations of motion depends essentially on the particular interaction the system enters into. All contemporary accounts of the structure and semantics of physical theory treat dynamics, i.e., the equations of motion, as the most important feature of a theory for the purposes of its philosophical analysis. I argue to the contrary that it is the kinematical constraints that determine the structure and empirical content of a physical theory in the most important ways: they function as necessary preconditions for the appropriate application of the theory; they differentiate types of p...
Analysis of the dynamics of reasoning using multiple representations
Jonker, C.M.; Treur, J.
2008-01-01
This paper presents a formalisation and analysis method for the dynamics of a reasoning process in which multiple representations play a role. Dynamics of reasoning processes are described by reasoning traces consisting of sequences of reasoning states over time. Reasoning states have a compositional structure; they are composed of different parts, for example, for different representations. Transitions between two reasoning states model reasoning steps. In relation to the compositional struc...
Static Analysis of Dynamic Languages
DEFF Research Database (Denmark)
Madsen, Magnus
Dynamic programming languages are highly popular and widely used. Java- Script is often called the lingua franca of the web and it is the de facto standard for client-side web programming. On the server-side the PHP, Python and Ruby languages are prevalent. What these languages have in common...... is an expressive power which is not easily captured by any static type system. These, and similar dynamic languages, are often praised for their ease-of-use and flexibility. Unfortunately, this dynamism comes at a great cost: The lack of a type system implies that most errors are not discovered until run......-time. Thus, in the worst-case, these bugs are not uncovered before they are encountered by real users of the system. A further cost is limited tool support: For instance, integrated development environments with code completion, code navigation and automatic refactorings are widely available for languages...
Dynamic testing of MFTF containment-vessel structural system
International Nuclear Information System (INIS)
Dynamic (modal) testing was performed on the Magnetic Fusion Test Facility (MFTF) containment vessel. The seismic design of this vessel was heavily dependent upon the value of structural damping used in the analysis. Typically for welded steel vessels, a value of 2 to 3% of critical is used. However, due to the large mass of the vessel and magnet supported inside, we felt that the interaction between the structure and its foundation would be enhanced. This would result in a larger value of damping because vibrational energy in the structure would be transferred through the foundation into the surrounding soil. The dynamic test performed on this structure (with the magnet in place) confirmed this later theory and resulted in damping values of approximately 4 to 5% for the whole body modes. This report presents a brief description of dynamic testing emphasizing the specific test procedure used on the MFTF-A system. It also presents an interpretation of the damping mechanisms observed (material and geometric) based upon the spatial characteristics of the modal parameters
Improving the Dynamic Characteristics of Body-in-White Structure Using Structural Optimization
Directory of Open Access Journals (Sweden)
Aizzat S. Yahaya Rashid
2014-01-01
Full Text Available The dynamic behavior of a body-in-white (BIW structure has significant influence on the noise, vibration, and harshness (NVH and crashworthiness of a car. Therefore, by improving the dynamic characteristics of BIW, problems and failures associated with resonance and fatigue can be prevented. The design objectives attempt to improve the existing torsion and bending modes by using structural optimization subjected to dynamic load without compromising other factors such as mass and stiffness of the structure. The natural frequency of the design was modified by identifying and reinforcing the structure at critical locations. These crucial points are first identified by topology optimization using mass and natural frequencies as the design variables. The individual components obtained from the analysis go through a size optimization step to find their target thickness of the structure. The thickness of affected regions of the components will be modified according to the analysis. The results of both optimization steps suggest several design modifications to achieve the target vibration specifications without compromising the stiffness of the structure. A method of combining both optimization approaches is proposed to improve the design modification process.
Dynamic testing of nuclear power plant structures: an evaluation
International Nuclear Information System (INIS)
Lawrence Livermore Laboratory (LLL) evaluated the applications of system identification techniques to the dynamic testing of nuclear power plant structures and subsystems. These experimental techniques involve exciting a structure and measuring, digitizing, and processing the time-history motions that result. The data can be compared to parameters calculated using finite element or other models of the test systems to validate the model and to verify the seismic analysis. This report summarizes work in three main areas: (1) analytical qualification of a set of computer programs developed at LLL to extract model parameters from the time histories; (2) examination of the feasibility of safely exciting nuclear power plant structures and accurately recording the resulting time-history motions; (3) study of how the model parameters that are extracted from the data be used best to evaluate structural integrity and analyze nuclear power plants
Structural Dynamics Experimental Activities in Ultra-Lightweight and Inflatable Space Structures
Pappa, Richard S.; Lassiter, John O.; Ross, Brian P.
2001-01-01
This paper reports recently completed structural dynamics experimental activities with new ultra-lightweight and inflatable space structures (a.k.a., "Gossamer" spacecraft) at NASA Langley Research Center, NASA Marshall Space Flight Center, and NASA Goddard Space Flight Center. Nine aspects of this work are covered: 1) inflated, rigidized tubes, 2) active control experiments, 3) photogrammetry, 4) laser vibrometry, 5) modal tests of inflatable structures, 6) in-vacuum modal tests, 7) tensioned membranes, 8) deployment tests, and 9) flight experiment support. Structural dynamics will play a major role in the design and eventually in-space deployment and performance of Gossamer spacecraft. Experimental research and development such as this is required to validate new analysis methods. The activities discussed in the paper are pathfinder accomplishments. conducted on unique components and prototypes of future spacecraft systems.
Spectral analysis of bedform dynamics
DEFF Research Database (Denmark)
Winter, Christian; Ernstsen, Verner Brandbyge; Noormets, Riko
single harmonic constituents is assumed to be uniform and stationary, bedform dynamics can be completely assessed by changes in amplitude and phase. Dune migration at several transects were analysed and quantified by taking into account the phase differences of individual harmonic constituents. An...
Automated Functional Analysis in Dynamic Medical Imaging
Czech Academy of Sciences Publication Activity Database
Tichý, Ondřej
Praha : Katedra matematiky, FSv ČVUT v Praze, 2012, s. 19-20. [Aplikovaná matematika – Rektorysova soutěž. Praha (CZ), 07.12.2012] Institutional support: RVO:67985556 Keywords : Factor Analysis * Dynamic Sequence * Scintigraphy Subject RIV: BB - Applied Statistics, Operational Research http://library.utia.cas.cz/separaty/2012/AS/tichy-automated functional analysis in dynamic medical imaging.pdf
The dynamic analysis of offshore mooring terminals
Langley, R.S.
1983-01-01
This Thesis investigates the methods which are currently avail- able for the dynamic analysis of Offshore Mooring Terminals, particular regard being paid to Single Point Mooring (SPM) Terminals. Various aspects of the problem are considered in turn, these being the random vibration of non-linear systems, the analysis of catenary mooring lines, buoy dynamics, ship motions, second order (or slow drift) forces and motions, and low frequency motions caused by instabilities. T...
String Analysis for Dynamic Field Access
DEFF Research Database (Denmark)
Madsen, Magnus; Andreasen, Esben
2014-01-01
In JavaScript, and scripting languages in general, dynamic field access is a commonly used feature. Unfortunately, current static analysis tools either completely ignore dynamic field access or use overly conservative approximations that lead to poor precision and scalability. We present new string...... with the Η domain gains significant precision resulting in an analysis speedup of more than 1.5x for 7 out of 10 benchmark programs....
Andlantis: Large-scale Android Dynamic Analysis
Bierma, Michael; Gustafson, Eric; Erickson, Jeremy; Fritz, David; Choe, Yung Ryn
2014-01-01
Analyzing Android applications for malicious behavior is an important area of research, and is made difficult, in part, by the increasingly large number of applications available for the platform. While techniques exist to perform static analysis on a large number of applications, dynamic analysis techniques are relatively limited in scale due to the computational resources required to emulate the full Android system to achieve accurate execution. We present Andlantis, a scalable dynamic anal...
Directory of Open Access Journals (Sweden)
Anastassia N. Rissanou
2015-02-01
Full Text Available Detailed atomistic (united atoms molecular dynamics simulations of several graphene based polymer (polyethylene, PE nanocomposite systems have been performed. Systems with graphene sheets of different sizes have been simulated at the same graphene concentration (~3%. In addition, a periodic graphene layer (“infinite sheet” has been studied. Results concerning structural and dynamical properties of PE chains are presented for the various systems and compared to data from a corresponding bulk system. The final properties of the material are the result of a complex effect of the graphene’s sheet size, mobility and fluctuations. A detailed investigation of density, structure and dynamics of the hybrid systems has been conducted. Particular emphasis has been given in spatial heterogeneities due to the PE/graphene interfaces, which were studied through a detailed analysis based on radial distances form the graphene’s center-of-mass. Chain segmental dynamics is found to be slower, compared to the bulk one, at the PE/graphene interface by a factor of 5 to 10. Furthermore, an analysis on the graphene sheets characteristics is presented in terms of conformational properties (i.e., wrinkling and mobility.
Lagrangian coherent structures and inertial particle dynamics
Sudharsan, M; Riley, James J
2015-01-01
In this work we investigate the dynamics of inertial particles using finite-time Lyapunov exponents (FTLE). In particular, we characterize the attractor and repeller structures underlying preferential concentration of inertial particles in terms of FTLE fields of the underlying carrier fluid. Inertial particles that are heavier than the ambient fluid (aerosols) attract onto ridges of the negative-time fluid FTLE. This negative-time FTLE ridge becomes a repeller for particles that are lighter than the carrier fluid (bubbles). We also examine the inertial FTLE (iFTLE) determined by the trajectories of inertial particles evolved using the Maxey-Riley equations with non-zero Stokes number and density ratio. Finally, we explore the low-pass filtering effect of Stokes number. These ideas are demonstrated on two-dimensional numerical simulations of the unsteady double gyre flow.
Institute of Scientific and Technical Information of China (English)
汪德江; 叶志明
2012-01-01
Based on the complex dynamic characteristics of new shell structure, a 3 -D nonlinear finite element model of interaction between large cylinder structure, soil and wave is established. The non-linear contact characteristics between shell structure and soil are simulated by setting contact element of zero thickness. The non-linear constitutive model of soil is used to simulate dynamic response analysis of the structure under the dynamic loads on waves. The distribution of stress in x- and y-directions, the changing law of stress with wave and buried depth are obtained. Finally the stress distribution function and reasonable size of cylinder structure are given.%针对新型的大圆筒薄壳结构的复杂动力特性,建立大圆筒结构-土-波浪相互作用的三维非线性有限元模型.通过设定无厚度的接触面单元,来模拟薄壳圆筒-土之间的非线性接触特性；采用土体的非线性本构模型,并同时计入波浪等动荷载的作用对结构进行动力响应分析,得到大圆筒上的x方向及y方向应力分布规律,以及应力随波浪力和埋深的变化规律；最终给出了圆筒结构的应力分布函数式及合理的壁厚尺度.
Chemical structure and dynamics. Annual report 1994
Energy Technology Data Exchange (ETDEWEB)
Colson, S.D.
1995-07-01
The Chemical Structure and Dynamics program was organized as a major component of Pacific Northwest Laboratory`s Environmental and Molecular Sciences Laboratory (EMSL), a state-of-the-art collaborative facility for studies of chemical structure and dynamics. Our program responds to the need for a fundamental, molecular-level understanding of chemistry at the wide variety of environmentally important interfaces by (1) extending the experimental characterization and theoretical description of chemical reactions to encompass the effects of condensed media and interfaces, and (2) developing a multidisciplinary capability for describing interfacial chemical processes within which the new knowledge generated can be brought to bear on complex phenomena in environmental chemistry and in nuclear waste processing and storage. This research effort was initiated in 1989 and will continue to evolve over the next few years into a program of rigorous studies of fundamental molecular processes in model systems, such as well-characterized surfaces, single-component solutions, clusters, and biological molecules; and studies of complex systems found in the environment (multispecies, multiphase solutions; solid/liquid, liquid/liquid, and gas/surface interfaces; colloidal dispersions; ultrafine aerosols; and functioning biological systems). The success of this program will result in the achievement of a quantitative understanding of chemical reactions at interfaces, and more generally in condensed media, that is comparable to that currently available for gas-phase reactions. This understanding will form the basis for the development of a priori theories for predictions of macroscopic chemical behavior in condensed and heterogeneous media, adding significantly to the value of field-scale environmental models, the prediction of short- and long-term nuclear waste storage stabilities, and other problems related to the primary missions of the DOE.
Annual Report 1998: Chemical Structure and Dynamics
Energy Technology Data Exchange (ETDEWEB)
SD Colson; RS McDowell
1999-05-10
The Chemical Structure and Dynamics (CS&D) program is a major component of the William R. Wiley Environmental Molecular Sciences Labo- ratory (EMSL), developed by Pacific Northwest National Laboratory (PNNL) to provide a state-of- the-art collaborative facility for studies of chemical structure and dynamics. We respond to the need for a fundamental, molecular-level understanding of chemistry at a wide variety of environmentally important interfaces by (1) extending the experimental characterization and theoretical description of chemical reactions to encompass the effects of condensed media and interfaces; (2) developing a multidisciplinary capability for describing interracial chemical processes within which the new knowledge generated can be brought to bear on complex phenomena in envi- ronmental chemistry and in nuclear waste proc- essing and storage; and (3) developing state-of- the-art analytical methods for characterizing com- plex materials of the types found in stored wastes and contaminated soils, and for detecting and monitoring trace atmospheric species. Our program aims at achieving a quantitative understanding of chemical reactions at interfaces and, more generally, in condensed media, compa- rable to that currently available for gas-phase reactions. This understanding will form the basis for the development of a priori theories for pre- dicting macroscopic chemical behavior in con- densed and heterogeneous media, which will add significantly to the value of field-scale envi- ronmental models, predictions of short- and long- term nuclear waste storage stabilities, and other areas related to the primary missions of the U.S. Department of Energy (DOE).
Analysis of dynamic multiplicity fluctuations at PHOBOS
Chai, Zhengwei; PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Chai, Z.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Holynski, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J. L.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wolfs, F. L. H.; Wosiek, B.; Wozniak, K.; Wuosmaa, A. H.; Wyslouch, B.
2005-01-01
This paper presents the analysis of the dynamic fluctuations in the inclusive charged particle multiplicity measured by PHOBOS for Au+Au collisions at surdsNN = 200GeV within the pseudo-rapidity range of -3 < η < 3. First the definition of the fluctuations observables used in this analysis is presented, together with the discussion of their physics meaning. Then the procedure for the extraction of dynamic fluctuations is described. Some preliminary results are included to illustrate the correlation features of the fluctuation observable. New dynamic fluctuations results will be available in a later publication.
Dynamic Analysis of a Military- Tracked Vehicle
Directory of Open Access Journals (Sweden)
V. Balamurugan
2000-04-01
Full Text Available 'The ride dynamic characteristics of a typical medium weight, high speed military-tracked vehicle for negotiating rough cross-counlry terrain have been studied. The vehicle is modelled using finiteelement simulation method with beam and shell elements. An eigenvalue analysis has been done to estimate natural modes ofNibration of the vehicle. The dynamic response of certain salient locations is obtained by carrying out a transient dynamic analysis using implicit Newmark beta method. A constant forwar vehicle speed and non-deformable sinusoidal terrain profile are assumed.
Development of an experimental space station model for structural dynamics research
Mcgowan, Paul E.; Edighoffer, Harold E.; Wallace, John W.
1990-01-01
Design, analysis, and testing of an experimental space station scale model is presented. The model contains hardware components with dynamic characteristics similar to those expected for other large space structures. Validation of analysis models is achieved through correlation with dynamic tests of hardware components and representative assembly configurations. A component mode synthesis analysis method is examined through comparisons with results from fully mated system models. Selection of input requirements for accurate component synthesis analysis predictions are assessed.
Dynamic Gust Load Analysis for Rotors
Directory of Open Access Journals (Sweden)
Yuting Dai
2016-01-01
Full Text Available Dynamic load of helicopter rotors due to gust directly affects the structural stress and flight performance for helicopters. Based on a large deflection beam theory, an aeroelastic model for isolated helicopter rotors in the time domain is constructed. The dynamic response and structural load for a rotor under the impulse gust and slope-shape gust are calculated, respectively. First, a nonlinear Euler beam model with 36 degrees-of-freedoms per element is applied to depict the structural dynamics for an isolated rotor. The generalized dynamic wake model and Leishman-Beddoes dynamic stall model are applied to calculate the nonlinear unsteady aerodynamic forces on rotors. Then, we transformed the differential aeroelastic governing equation to an algebraic one. Hence, the widely used Newton-Raphson iteration algorithm is employed to simulate the dynamic gust load. An isolated helicopter rotor with four blades is studied to validate the structural model and the aeroelastic model. The modal frequencies based on the Euler beam model agree well with published ones by CAMRAD. The flap deflection due to impulse gust with the speed of 2m/s increases twice to the one without gust. In this numerical example, results indicate that the bending moment at the blade root is alleviated due to elastic effect.
Lubov Zharova
2012-01-01
In the article the results of analysis of modern theoretical trends and practical examples in framework of nature management are represented. The series of propositions for formation structure-dynamic theory are formulated.
Physiological enhancement of factors in factor analysis of dynamic studies
International Nuclear Information System (INIS)
Factor analysis of dynamic radionuclide studies provides their decomposition into the images and time-activity curves corresponding to the underlying dynamic structures. The method is based on the analysis of study variance and on the subsequent differential imaging of its principal components into a simplified factor space. By changing the amount and the composition of the variance processed in the analysis it is possible to enhance the factors that are important for diagnosis while the less important factors can be suppressed. In our report, a short theoretical review of the problem is given and illustrated by the analysis of dynamic cholescintigraphy. It is shown that a suitable choice of region and/or the temporal interval of interest enables the differential evaluation of such intrahepatic compartments, which could not be observed without enhancement. (orig.)
ROLE OF UNDERGROUND STRUCTURE DEFORMATION VELOCITY IN THE ANALYSIS OF BLAST-RESISTANT STRUCTURES
Institute of Scientific and Technical Information of China (English)
赵晓兵; 方秦
2002-01-01
The structural deformation velocity plays a significant role in the dynamic calculation of underground blast-resistant structures. The motion differentiating equation of a structure system taking into account the role of deformation velocity of the structure will truthfully describe the actual situation of structural vibration. With the one-dimensional plane wave theory, the expression of load on the structural periphery is developed, and the generalized variation principle for the dynamic analysis of underground arched-bar structures is given. At the same time, the results of the numerical calculation are compared.
Nonlinear Analysis Of Rotor Dynamics
Day, William B.; Zalik, Richard
1988-01-01
Study explores analytical consequences of nonlinear Jeffcott equations of rotor dynamics. Section 1: Summary of previous studies. Section 2: Jeffcott Equations. Section 3: Proves two theorems that provide inequalities on coefficients of differential equations and magnitude of forcing function in absence of side force. Section 4: Numerical investigation of multiple-forcing-function problem by introducing both side force and mass imbalance. Section 5: Examples of numberical solutions of complex generalized Jeffcott equation with two forcing functions of different frequencies f1 and f2. Section 6: Boundedness and stability of solutions.Section 7: Concludes report reviewing analytical results and significance.
Stereological analysis of spatial structures
DEFF Research Database (Denmark)
Hansen, Linda Vadgård
The thesis deals with stereological analysis of spatial structures. One area of focus has been to improve the precision of well-known stereological estimators by including information that is available via automatic image analysis. Furthermore, the thesis presents a stochastic model for star...
Institute of Scientific and Technical Information of China (English)
Xu Long; Fei Ge; Lei Wang; Youshi Hong
2009-01-01
This paper investigates the effects of structure parameters on dynamic responses of submerged floating tunnel (SFT) under hydrodynamic loads. The structure parameters includes buoyancy-weight ratio (BWR), stiffness coefficients of the cable systems, tunnel net buoyancy and tunnel length. First, the importance of structural damp in relation to the dynamic responses of SFT is demonstrated and the mechanism of structural damp effect is discussed. Thereafter, the fundamental structure parameters are investi-gated through the analysis of SFT dynamic responses under hydrodynamic loads. The results indicate that the BWR of SFT is a key structure parameter. When BWR is 1.2, there is a remarkable trend change in the vertical dynamic response of SFT under hydrodynamic loads. The results also indicate that the ratio of the tunnel net buoyancy to the cable stiffness coefficient is not a characteristic factor affecting the dynamic responses of SFT under hydrodynamic loads.
Application of the Probabilistic Dynamic Synthesis Method to Realistic Structures
Brown, Andrew M.; Ferri, Aldo A.
1998-01-01
The Probabilistic Dynamic Synthesis method is a technique for obtaining the statistics of a desired response engineering quantity for a structure with non-deterministic parameters. The method uses measured data from modal testing of the structure as the input random variables, rather than more "primitive" quantities like geometry or material variation. This modal information is much more comprehensive and easily measured than the "primitive" information. The probabilistic analysis is carried out using either response surface reliability methods or Monte Carlo simulation. In previous work, the feasibility of the PDS method applied to a simple seven degree-of-freedom spring-mass system was verified. In this paper, extensive issues involved with applying the method to a realistic three-substructure system are examined, and free and forced response analyses are performed. The results from using the method are promising, especially when the lack of alternatives for obtaining quantitative output for probabilistic structures is considered.
Computational and theoretical aspects of biomolecular structure and dynamics
Energy Technology Data Exchange (ETDEWEB)
Garcia, A.E.; Berendzen, J.; Catasti, P., Chen, X. [and others
1996-09-01
This is the final report for a project that sought to evaluate and develop theoretical, and computational bases for designing, performing, and analyzing experimental studies in structural biology. Simulations of large biomolecular systems in solution, hydrophobic interactions, and quantum chemical calculations for large systems have been performed. We have developed a code that implements the Fast Multipole Algorithm (FMA) that scales linearly in the number of particles simulated in a large system. New methods have been developed for the analysis of multidimensional NMR data in order to obtain high resolution atomic structures. These methods have been applied to the study of DNA sequences in the human centromere, sequences linked to genetic diseases, and the dynamics and structure of myoglobin.
Static and dynamic structure analyses of polymer crystals
International Nuclear Information System (INIS)
Recent development in static and dynamic structure analyses of polymer crystals has been reviewed. Various methods were developed to enhance the reliability of static structure analysis. Usage of synchrotron high-energy X-ray beam allowed us to increase the total number of observed X-ray reflections by one order. Wide-angle neutron diffraction revealed the hydrogen atomic positions accurately, making it possible to evaluate the mechanical property of polymer crystals quantitatively. Time-resolved measurements of wide-angle and small-angle X-ray scatterings as well as infrared and Raman spectra have revealed the structural revolution processes as seen in the studies of isothermal crystallization and mechanical deformation processes. (author)
Structure-preserving integrators in nonlinear structural dynamics and flexible multibody dynamics
2016-01-01
This book focuses on structure-preserving numerical methods for flexible multibody dynamics, including nonlinear elastodynamics and geometrically exact models for beams and shells. It also deals with the newly emerging class of variational integrators as well as Lie-group integrators. It discusses two alternative approaches to the discretization in space of nonlinear beams and shells. Firstly, geometrically exact formulations, which are typically used in the finite element community and, secondly, the absolute nodal coordinate formulation, which is popular in the multibody dynamics community. Concerning the discretization in time, the energy-momentum method and its energy-decaying variants are discussed. It also addresses a number of issues that have arisen in the wake of the structure-preserving discretization in space. Among them are the parameterization of finite rotations, the incorporation of algebraic constraints and the computer implementation of the various numerical methods. The practical application...
Passivhaus: indoor comfort and energy dynamic analysis.
Guida, Antonella; Pagliuca, Antonello; Cardinale, Nicola; Rospi, Gianluca
2013-04-01
The research aims to verify the energy performance as well as the indoor comfort of an energy class A+ building, built so that the sum of the heat passive contributions of solar radiation, transmitted through the windows, and the heat generated inside the building, are adeguate to compensate for the envelope loss during the cold season. The building, located in Emilia Romagna (Italy), was built using a wooden structure, an envelope realized using a pinewood sandwich panels (transmittance U = 0.250 W/m2K) and, inside, a wool flax insulation layer and thermal window frame with low-emissivity glass (U = 0524 W/m2K). The building design and construction process has followed the guidelines set by "CasaClima". The building has been modeled in the code of dynamic calculation "Energy Plus" by the Design Builder application and divided it into homogenous thermal zones, characterized by winter indoor temperature set at 20 ° (+ / - 1 °) and summer indoor temperature set at 26 ° (+ / - 1 °). It has modeled: the envelope, as described above, the "free" heat contributions, the air conditioning system, the Mechanical Ventilation system as well as home automation solutions. The air conditioning system is an heat pump, able to guarantee an optimization of energy consumption (in fact, it uses the "free" heat offered by the external environment for conditioning indoor environment). As regards the air recirculation system, it has been used a mechanical ventilation system with internal heat cross-flow exchanger, with an efficiency equal to 50%. The domotic solutions, instead, regard a system for the control of windows external screening using reeds, adjustable as a function of incident solar radiation and a lighting management system adjusted automatically using a dimmer. A so realized building meets the requirement imposed from Italian standard UNI/TS 11300 1, UNI/TS 11300 2 and UNI/TS 11300 3. The analysis was performed according to two different configurations: in "spontaneous
Research of TREETOPS Structural Dynamics Controls Simulation Upgrade
Yates, Rose M.
1996-01-01
Under the provisions of contract number NAS8-40194, which was entitled 'TREETOPS Structural Dynamics and Controls Simulation System Upgrade', Oakwood College contracted to produce an upgrade to the existing TREETOPS suite of analysis tools. This suite includes the main simulation program, TREETOPS, two interactive preprocessors, TREESET and TREEFLX, an interactive post processor, TREEPLOT, and an adjunct program, TREESEL. A 'Software Design Document', which provides descriptions of the argument lists and internal variables for each subroutine in the TREETOPS suite, was established. Additionally, installation guides for both DOS and UNIX platforms were developed. Finally, updated User's Manuals, as well as a Theory Manual, were generated.
Bioinspired, dynamic, structured surfaces for biofilm prevention
Epstein, Alexander K.
Bacteria primarily exist in robust, surface-associated communities known as biofilms, ubiquitous in both natural and anthropogenic environments. Mature biofilms resist a wide range of biocidal treatments and pose persistent pathogenic threats. Treatment of adherent biofilm is difficult, costly, and, in medical systems such as catheters, frequently impossible. Adding to the challenge, we have discovered that biofilm can be both impenetrable to vapors and extremely nonwetting, repelling even low surface tension commercial antimicrobials. Our study shows multiple contributing factors, including biochemical components and multiscale reentrant topography. Reliant on surface chemistry, conventional strategies for preventing biofilm only transiently affect attachment and/or are environmentally toxic. In this work, we look to Nature's antifouling solutions, such as the dynamic spiny skin of the echinoderm, and we develop a versatile surface nanofabrication platform. Our benchtop approach unites soft lithography, electrodeposition, mold deformation, and material selection to enable many degrees of freedom—material, geometric, mechanical, dynamic—that can be programmed starting from a single master structure. The mechanical properties of the bio-inspired nanostructures, verified by AFM, are precisely and rationally tunable. We examine how synthetic dynamic nanostructured surfaces control the attachment of pathogenic biofilms. The parameters governing long-range patterning of bacteria on high-aspect-ratio (HAR) nanoarrays are combinatorially elucidated, and we discover that sufficiently low effective stiffness of these HAR arrays mechanoselectively inhibits ˜40% of Pseudomonas aeruginosa biofilm attachment. Inspired by the active echinoderm skin, we design and fabricate externally actuated dynamic elastomer surfaces with active surface microtopography. We extract from a large parameter space the critical topographic length scales and actuation time scales for achieving
Evaluation of dynamic testing of as-built civil engineering structures
International Nuclear Information System (INIS)
This paper summarizes an evaluation of dynamic tests performed on large as-built structures. The objectives and methods (excitation and data analysis) of tests are reviewed. The utility and limitations of dynamic testing in light of actual experience is discussed. Though low-level tests in themselves will not be useful for predicting structural response to strong ground motion, they are useful for verifying linear models and for clarifying physical phenomena related to soil-structure interaction
Dynamics and vibrations progress in nonlinear analysis
Kachapi, Seyed Habibollah Hashemi
2014-01-01
Dynamical and vibratory systems are basically an application of mathematics and applied sciences to the solution of real world problems. Before being able to solve real world problems, it is necessary to carefully study dynamical and vibratory systems and solve all available problems in case of linear and nonlinear equations using analytical and numerical methods. It is of great importance to study nonlinearity in dynamics and vibration; because almost all applied processes act nonlinearly, and on the other hand, nonlinear analysis of complex systems is one of the most important and complicated tasks, especially in engineering and applied sciences problems. There are probably a handful of books on nonlinear dynamics and vibrations analysis. Some of these books are written at a fundamental level that may not meet ambitious engineering program requirements. Others are specialized in certain fields of oscillatory systems, including modeling and simulations. In this book, we attempt to strike a balance between th...
Application of Finite Volume Method to Structural Stochastic Dynamics
Weidong Chen; Yanchun Yu; Ping Jia; Xiande Wu; Fengchao Zhang
2013-01-01
The stochastic dynamic problems were becoming more difficult after considering the influences of stochastic factors and the complexity of the dynamic problems. To this background, the finite volume method combined with Perturbation Method was proposed for the stochastic dynamic analysis. The equations of perturbation-finite volume method were derived; the explicit expressions between random response and basic random variables were given; the method of stochastic dynamic analysis was discussed...
Institute of Scientific and Technical Information of China (English)
WU Qiong; ZHANG Yidu; ZHANG Hongwei
2012-01-01
A cyclic symmetry analysis method is proposed for analyzing the dynamic characteristic problems of thin walled integral impeller.Reliability and feasibility of the present method are investigated by means of simulation and experiment.The fundamental cyclic symmetry equations and the solutions of these equations are derived for the cyclic symmetry structure.The computational efficiency analysis between whole and part is performed.Comparison of results obtained by the finite element analysis (FEA)and experiment shows that the local dynamic characteristic of integral impeller has consistency with the single cyclic symmetry blade.When the integral impeller is constrained and the thin walled blade becomes a concerned object in analysis,the dynamic characteristic of integral impeller can be replaced by the cyclic symmetry blade approximately.Hence,a cyclic symmetry analysis method is effectively used to improve efficiency and obtain more information of parameters for dynamic characteristic of integral impellers.
Optimizing Dynamical Network Structure for Pinning Control
Orouskhani, Yasin; Jalili, Mahdi; Yu, Xinghuo
2016-04-01
Controlling dynamics of a network from any initial state to a final desired state has many applications in different disciplines from engineering to biology and social sciences. In this work, we optimize the network structure for pinning control. The problem is formulated as four optimization tasks: i) optimizing the locations of driver nodes, ii) optimizing the feedback gains, iii) optimizing simultaneously the locations of driver nodes and feedback gains, and iv) optimizing the connection weights. A newly developed population-based optimization technique (cat swarm optimization) is used as the optimization method. In order to verify the methods, we use both real-world networks, and model scale-free and small-world networks. Extensive simulation results show that the optimal placement of driver nodes significantly outperforms heuristic methods including placing drivers based on various centrality measures (degree, betweenness, closeness and clustering coefficient). The pinning controllability is further improved by optimizing the feedback gains. We also show that one can significantly improve the controllability by optimizing the connection weights.
Flexible joints in structural and multibody dynamics
Directory of Open Access Journals (Sweden)
O. A. Bauchau
2013-02-01
Full Text Available Flexible joints, sometimes called bushing elements or force elements, are found in all structural and multibody dynamics codes. In their simplest form, flexible joints simply consist of sets of three linear and three torsional springs placed between two nodes of the model. For infinitesimal deformations, the selection of the lumped spring constants is an easy task, which can be based on a numerical simulation of the joint or on experimental measurements. If the joint undergoes finite deformations, identification of its stiffness characteristics is not so simple, specially if the joint is itself a complex system. When finite deformations occur, the definition of deformation measures becomes a critical issue. This paper proposes a family of tensorial deformation measures suitable for elastic bodies of finite dimension. These families are generated by two parameters that can be used to modify the constitutive behavior of the joint, while maintaining the tensorial nature of the deformation measures. Numerical results demonstrate the objectivity of the deformations measures, a feature that is not shared by the deformations measures presently used in the literature. The impact of the choice of the two parameters on the constitutive behavior of the flexible joint is also investigated.
Dynamic properties of high structural integrity auxetic open cell foam
Scarpa, F.; Ciffo, L. G.; Yates, J. R.
2004-02-01
This paper illustrates various dynamic characteristics of open cell compliant polyurethane foam with auxetic (negative Poisson's ratio) behaviour. The foam is obtained from off-the-shelf open cell polyurethane grey foam with a manufacturing process based on mechanical deformation on a mould in a temperature-controlled oven. The Poisson's ratio is measured with an image processing technique based on edge detection with wavelet methods. Foam samples have been tested in a viscoelastic analyser tensile test machine to determine the Young's modulus and loss factor for small dynamic strains. The same samples have also been tested in an acoustic impedance tube to measure acoustic absorption and specific acoustic resistance and reactance with a transmissibility technique. Another set of tests has been set up on a cam plastometer machine for constant strain rate dynamic crushing analysis. All the tests have been carried out on auxetic and normal foam samples to provide a comparison between the two types of cellular solids. The results from the experimental tests are discussed and interpreted using microstructure models for cellular materials existing in the literature. The negative Poisson's ratio foam presented in this paper shows an overall superiority regarding damping and acoustic properties compared to the original conventional foam. Its dynamic crushing performance is also significantly superior to the normal foam, suggesting a possible use in structural integrity compliant elements.
Knottin cyclization: impact on structure and dynamics
Directory of Open Access Journals (Sweden)
Gracy Jérôme
2008-12-01
Full Text Available Abstract Background Present in various species, the knottins (also referred to as inhibitor cystine knots constitute a group of extremely stable miniproteins with a plethora of biological activities. Owing to their small size and their high stability, knottins are considered as excellent leads or scaffolds in drug design. Two knottin families contain macrocyclic compounds, namely the cyclotides and the squash inhibitors. The cyclotide family nearly exclusively contains head-to-tail cyclized members. On the other hand, the squash family predominantly contains linear members. Head-to-tail cyclization is intuitively expected to improve bioactivities by increasing stability and lowering flexibility as well as sensitivity to proteolytic attack. Results In this paper, we report data on solution structure, thermal stability, and flexibility as inferred from NMR experiments and molecular dynamics simulations of a linear squash inhibitor EETI-II, a circular squash inhibitor MCoTI-II, and a linear analog lin-MCoTI. Strikingly, the head-to-tail linker in cyclic MCoTI-II is by far the most flexible region of all three compounds. Moreover, we show that cyclic and linear squash inhibitors do not display large differences in structure or flexibility in standard conditions, raising the question as to why few squash inhibitors have evolved into cyclic compounds. The simulations revealed however that the cyclization increases resistance to high temperatures by limiting structure unfolding. Conclusion In this work, we show that, in contrast to what could have been intuitively expected, cyclization of squash inhibitors does not provide clear stability or flexibility modification. Overall, our results suggest that, for squash inhibitors in standard conditions, the circularization impact might come from incorporation of an additional loop sequence, that can contribute to the miniprotein specificity and affinity, rather than from an increase in conformational rigidity
Carbon dioxide in an ionic liquid: Structural and rotational dynamics
Giammanco, Chiara H.; Kramer, Patrick L.; Yamada, Steven A.; Nishida, Jun; Tamimi, Amr; Fayer, Michael D.
2016-03-01
Ionic liquids (ILs), which have widely tunable structural motifs and intermolecular interactions with solutes, have been proposed as possible carbon capture media. To inform the choice of an optimal ionic liquid system, it can be useful to understand the details of dynamics and interactions on fundamental time scales (femtoseconds to picoseconds) of dissolved gases, particularly carbon dioxide (CO2), within the complex solvation structures present in these uniquely organized materials. The rotational and local structural fluctuation dynamics of CO2 in the room temperature ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EmimNTf2) were investigated by using ultrafast infrared spectroscopy to interrogate the CO2 asymmetric stretch. Polarization-selective pump probe measurements yielded the orientational correlation function of the CO2 vibrational transition dipole. It was found that reorientation of the carbon dioxide occurs on 3 time scales: 0.91 ± 0.03, 8.3 ± 0.1, 54 ± 1 ps. The initial two are attributed to restricted wobbling motions originating from a gating of CO2 motions by the IL cations and anions. The final (slowest) decay corresponds to complete orientational randomization. Two-dimensional infrared vibrational echo (2D IR) spectroscopy provided information on structural rearrangements, which cause spectral diffusion, through the time dependence of the 2D line shape. Analysis of the time-dependent 2D IR spectra yields the frequency-frequency correlation function (FFCF). Polarization-selective 2D IR experiments conducted on the CO2 asymmetric stretch in the parallel- and perpendicular-pumped geometries yield significantly different FFCFs due to a phenomenon known as reorientation-induced spectral diffusion (RISD), revealing strong vector interactions with the liquid structures that evolve slowly on the (independently measured) rotation time scales. To separate the RISD contribution to the FFCF from the structural spectral
Single-Molecule Analysis of Translational Dynamics
Petrov, Alexey; CHEN, JIN; O’Leary, Seán; Tsai, Albert; Puglisi, Joseph D.
2012-01-01
Decades of extensive biochemical and biophysical research have outlined the mechanism of translation. Rich structural studies have provided detailed snapshots of the translational machinery at all phases of the translation cycle. However, the relationship between structural dynamics, composition, and function remains unknown. The multistep nature of each stage of the translation cycle results in rapid desynchronization of individual ribosomes, thus hindering elucidation of the underlying mech...
Soklaski, Ryan
Central to the field of condensed matter physics is a decades old outstanding problem in the study of glasses -- namely explaining the extreme slowing of dynamics in a liquid as it is supercooled towards the so-called glass transition. Efforts to universally describe the stretched relaxation processes and heterogeneous dynamics that characteristically develop in supercooled liquids remain divided in both their approaches and successes. Towards this end, a consensus on the role that atomic and molecular structures play in the liquid is even more tenuous. However, mounting material science research efforts have culminated to reveal that the vast diversity of metallic glass species and their properties are rooted in an equally-broad set of structural archetypes. Herein lies the motivation of this dissertation: the detailed information available regarding the structure-property relationships of metallic glasses provides a new context in which one can study the evolution of a supercooled liquid by utilizing a structural motif that is known to dominate the glass. Cu64Zr36 is a binary alloy whose good glass-forming ability and simple composition makes it a canonical material to both empirical and numerical studies. Here, we perform classical molecular dynamics simulations and conduct a comprehensive analysis of the dynamical regimes of liquid Cu64Zr36, while focusing on the roles played by atomic icosahedral ordering -- a structural motif which ultimately percolates the glass' structure. Large data analysis techniques are leveraged to obtain uniquely detailed structural and dynamical information in this context. In doing so, we develop the first account of the origin of icosahedral order in this alloy, revealing deep connections between this incipient structural ordering, frustration-limited domain theory, and recent important empirical findings that are relevant to the nature of metallic liquids at large. Furthermore, important dynamical landmarks such as the breakdown
CODSTRAN: Composite durability structural analysis
Chamis, C. C.; Smith, G. T.
1978-01-01
CODSTRAN (COmposite Durability STRuctural ANalysis) is an integrated computer program being developed for the prediction of defect growth and fracture of composite structures subjected to service loads and environments. CODSTRAN is briefly described with respect to organization, capabilities and present status. Application of CODSTRAN current capability to a flat composite laminate with a center slit which was subjected to axial tension loading predicted defect growth which is in good agreement with C-scan ultrasonic test records.
Dynamic analysis of large suspended LMFBR reactor vessels
International Nuclear Information System (INIS)
Large breeder reactor vessels are often designed under the top-suspended condition. Since the vessel contains a large volume of liquid sodium as reactor coolant, the structural integrity of the vessel bottom head and its effect on the vessel dynamic response are of great importance to the safety and reliability of the reactor systems. This paper presents a dynamic analysis of the large suspended reactor vessel subjected to the horizontal earthquake excitation with the emphasis on the effect of bottom head vibration on fluid pressure and sloshing response. Unlike the conventional lumped mass method, the present analysis treats the liquid sodium as a continuum medium. As a result, the important effects ignored in the lumped mass method such as fluid coupling, fluid-structure interaction, interaction between sloshing and vessel vibration, etc. can be accounted into the analysis
Mechanistic role of structurally dynamic regions in Dicistroviridae IGR IRESs.
Pfingsten, Jennifer S; Castile, Alice E; Kieft, Jeffrey S
2010-01-01
Dicistroviridae intergenic region (IGR) internal ribosome entry site(s) (IRES) RNAs drive a cap-independent pathway of translation initiation, recruiting both small and large ribosomal subunits to viral RNA without the use of any canonical translation initiation factors. This ability is conferred by the folded three-dimensional structure of the IRES RNA, which has been solved by X-ray crystallography. Here, we report the chemical probing of Plautia stali intestine virus IGR IRES in the unbound form, in the 40S-subunit-bound form, and in the 80S-ribosome-bound form. The results, when combined with an analysis of crystal structures, suggest that parts of the IRES RNA change structure as the preinitiation complex forms. Using mutagenesis coupled with native gel electrophoresis, preinitiation complex assembly assays, and translation initiation assays, we show that these potentially structurally dynamic elements of the IRES are involved in different steps in the pathway of ribosome recruitment and translation initiation. Like tRNAs, it appears that the IGR IRES undergoes local structural changes that are coordinated with structural changes in the ribosome, and these are critical for the IRES mechanism of action. PMID:19878683
Dynamic Event Tree Analysis Through RAVEN
Energy Technology Data Exchange (ETDEWEB)
A. Alfonsi; C. Rabiti; D. Mandelli; J. Cogliati; R. A. Kinoshita; A. Naviglio
2013-09-01
Conventional Event-Tree (ET) based methodologies are extensively used as tools to perform reliability and safety assessment of complex and critical engineering systems. One of the disadvantages of these methods is that timing/sequencing of events and system dynamics is not explicitly accounted for in the analysis. In order to overcome these limitations several techniques, also know as Dynamic Probabilistic Risk Assessment (D-PRA), have been developed. Monte-Carlo (MC) and Dynamic Event Tree (DET) are two of the most widely used D-PRA methodologies to perform safety assessment of Nuclear Power Plants (NPP). In the past two years, the Idaho National Laboratory (INL) has developed its own tool to perform Dynamic PRA: RAVEN (Reactor Analysis and Virtual control ENvironment). RAVEN has been designed in a high modular and pluggable way in order to enable easy integration of different programming languages (i.e., C++, Python) and coupling with other application including the ones based on the MOOSE framework, developed by INL as well. RAVEN performs two main tasks: 1) control logic driver for the new Thermo-Hydraulic code RELAP-7 and 2) post-processing tool. In the first task, RAVEN acts as a deterministic controller in which the set of control logic laws (user defined) monitors the RELAP-7 simulation and controls the activation of specific systems. Moreover, RAVEN also models stochastic events, such as components failures, and performs uncertainty quantification. Such stochastic modeling is employed by using both MC and DET algorithms. In the second task, RAVEN processes the large amount of data generated by RELAP-7 using data-mining based algorithms. This paper focuses on the first task and shows how it is possible to perform the analysis of dynamic stochastic systems using the newly developed RAVEN DET capability. As an example, the Dynamic PRA analysis, using Dynamic Event Tree, of a simplified pressurized water reactor for a Station Black-Out scenario is presented.
Fourier Transform Infrared Spectroscopic Analysis of Protein Secondary Structures
Institute of Scientific and Technical Information of China (English)
Jilie KONG; Shaoning YU
2007-01-01
Infrared spectroscopy is one of the oldest and well established experimental techniques for the analysis of secondary structure of polypeptides and proteins. It is convenient, non-destructive, requires less sample preparation, and can be used under a wide variety of conditions. This review introduces the recent developments in Fourier transform infrared (FTIR) spectroscopy technique and its applications to protein structural studies. The experimental skills, data analysis, and correlations between the FTIR spectroscopic bands and protein secondary structure components are discussed. The applications of FTIR to the secondary structure analysis, conformational changes, structural dynamics and stability studies of proteins are also discussed.
Dynamical Structure of a Traditional Amazonian Social Network
Directory of Open Access Journals (Sweden)
Paul L. Hooper
2013-11-01
Full Text Available Reciprocity is a vital feature of social networks, but relatively little is known about its temporal structure or the mechanisms underlying its persistence in real world behavior. In pursuit of these two questions, we study the stationary and dynamical signals of reciprocity in a network of manioc beer (Spanish: chicha; Tsimane’: shocdye’ drinking events in a Tsimane’ village in lowland Bolivia. At the stationary level, our analysis reveals that social exchange within the community is heterogeneously patterned according to kinship and spatial proximity. A positive relationship between the frequencies at which two families host each other, controlling for kinship and proximity, provides evidence for stationary reciprocity. Our analysis of the dynamical structure of this network presents a novel method for the study of conditional, or non-stationary, reciprocity effects. We find evidence that short-timescale reciprocity (within three days is present among non- and distant-kin pairs; conversely, we find that levels of cooperation among close kin can be accounted for on the stationary hypothesis alone.
Photon echo spectroscopy reveals structure-dynamics relationships in carotenoids
Christensson, N.; Polivka, T.; Yartsev, A.; Pullerits, T.
2009-06-01
Based on simultaneous analysis of the frequency-resolved transient grating, peak shift, and echo width signals, we present a model for the third-order optical response of carotenoids including population dynamics and system-bath interactions. Our frequency-resolved photon echo experiments show that the model needs to incorporate the excited-state absorption from both the S2 and the S1 states. We apply our model to analyze the experimental results on astaxanthin and lycopene, aiming to elucidate the relation between structure and system-bath interactions. Our analysis allows us to relate structural motifs to changes in the energy-gap correlation functions. We find that the terminal rings of astaxanthin lead to increased coupling between slow molecular motions and the electronic transition. We also find evidence for stronger coupling to higher frequency overdamped modes in astaxanthin, pointing to the importance of the functional groups in providing coupling to fluctuations influencing the dynamics in the passage through the conical intersection governing the S2-S1 relaxation.
Dynamic Modeling Method of a Whole Structure with Joints
Directory of Open Access Journals (Sweden)
Xu-Sheng Gan
2013-06-01
Full Text Available The aim of this study was to study an improved dynamic modeling method of a whole structure with joints by the Boundary Element Method (BEM. The dynamic model was composed of the elements such as the beam element, plate element, joint element, lumped mass and spring element by the BEM, joints characteristics were introduced to boundary dynamic equations by flexible constraint conditions on boundary. Finally, an improved dynamic model of a whole structure with joints was established based on plate-beam element system mainly. As a result, the dynamic characteristics of a whole structure with joints were analyzed and the comparison of computational and experimental results showed the modeling method was effective. The analyses indicate that the introduced method inaugurates a good way for analyzing dynamic characteristics of a whole structure with joints efficiently.
International Nuclear Information System (INIS)
The dynamics and structure of plasma production are stated by the results of two experiments such as the radio frequency thermal plasmas produced by inductively coupled plasma technique at atmospheric pressure and the second harmonic ECH. The first experiment results explained transition from the electrostatic discharge mode of forming streamer to the induced discharge mode after forming the discharge channel that the streamer connected to in the azimuth direction. The other experiment explained the dynamics which the initial plasma produced at the ECH resonance point spread in the direction of radius. The divergence and transition related to the nonlinear process were observed independently existing the magnetic field or incident power. The experiment devices, conditions, results, and modeling are reported. (S.Y.)
Dynamic analysis of C/C composite finger seal
Institute of Scientific and Technical Information of China (English)
Chen Guoding; Wang Li’na; Yu Qiangpeng; Su Hua
2014-01-01
A seal device as an important component of aeroengines has decisive influence on per-formance, reliability, and working life of aeroengines. With the development of aeroengines, demands on the performance characteristics of seal devices are made strictly. Finger seal as a novel kind of sealing device, recently attracts more and more attentions in academic circles and engineer-ing fields at home and abroad. Research on finger seals has been extensively developed, especially on leakage and wear performances under dynamic conditions. However, it is a pity that the work on finger seals has been limited with a single approach that is improving the performance by structural optimization;in addition, the technology of dynamic analysis on finger seals is weak. Aiming at the problems mentioned above, a distributed mass equivalent dynamic model of finger seals considering the coupling effect of overlaid laminates is established in the present paper, the dynamic perfor-mance of 2.5 dimension C/C composite finger seal is analyzed with the model, and then the effects of fiber bundle density and fiber bundle preparation direction on finger seal’s dynamic performance are discussed, as well as compared with those of Co-based alloy finger seal. The current work is about dynamic analysis of finger seals and application of C/C composite in this paper may have much academic significance and many engineering values for improving research level of finger seal dynamics and exploring feasibility of C/C composite being used for finger seals.
Dynamic analysis of C/C composite finger seal
Directory of Open Access Journals (Sweden)
Chen Guoding
2014-06-01
Full Text Available A seal device as an important component of aeroengines has decisive influence on performance, reliability, and working life of aeroengines. With the development of aeroengines, demands on the performance characteristics of seal devices are made strictly. Finger seal as a novel kind of sealing device, recently attracts more and more attentions in academic circles and engineering fields at home and abroad. Research on finger seals has been extensively developed, especially on leakage and wear performances under dynamic conditions. However, it is a pity that the work on finger seals has been limited with a single approach that is improving the performance by structural optimization; in addition, the technology of dynamic analysis on finger seals is weak. Aiming at the problems mentioned above, a distributed mass equivalent dynamic model of finger seals considering the coupling effect of overlaid laminates is established in the present paper, the dynamic performance of 2.5 dimension C/C composite finger seal is analyzed with the model, and then the effects of fiber bundle density and fiber bundle preparation direction on finger seal’s dynamic performance are discussed, as well as compared with those of Co-based alloy finger seal. The current work is about dynamic analysis of finger seals and application of C/C composite in this paper may have much academic significance and many engineering values for improving research level of finger seal dynamics and exploring feasibility of C/C composite being used for finger seals.
Structural analysis for LMFBR applications
International Nuclear Information System (INIS)
Firstly, we discuss the use of elastic analysis for structural design of LMFBR components. The elastic analysis methods have been used for structural design of the Fast Breeder Test Reactor as well as the proposed prototype Test Breeder Reactor. The design of Fast Breeder Test Reactor which is nearing completion is the same as that of Rapsodie. Nevertheless, the design had to he checked against the latest design codes available, namely the ASME Code case 1592. This paper however, is confined to Structural analysis of PFBR components. The problems faced in the design of some of the components, in particular, the inner vessel (plenum separator) are discussed. As far as design codes are concerned, we make use of ASME Code Section III and the Code Case N-47, for high temperature design. The problem faced in the use of these rules are also described along with the description of analysis. Studies in the field of cyclic loading include extension of Bree's breakdown and plastic cycling criteria for ratchet free operation to biaxial stress fields. In other fields, namely, inelastic analysis, piping analysis in the creep regime etc. we are only at a start
Old age couples household: structure, dynamics and values
Filipa D. Marques; Liliana Sousa
2012-01-01
This exploratory study examines old age couples household in terms of structure, relational dynamics and values. A questionnaire was applied to 136 old Portuguese couples of middle socio-economic class. Results suggest: i) structure composed by old couples who live mostly alone, ii) family dynamic characterized by affection, friendship and dialogue iii) values based on love, dialogue and family convivial.
Dynamics of Localized Structures in Systems with Broken Parity Symmetry
Javaloyes, J.; Camelin, P.; Marconi, M.; Giudici, M.
2016-04-01
A great variety of nonlinear dissipative systems are known to host structures having a correlation range much shorter than the size of the system. The dynamics of these localized structures (LSs) has been investigated so far in situations featuring parity symmetry. In this Letter we extend this analysis to systems lacking this property. We show that the LS drifting speed in a parameter varying landscape is not simply proportional to the parameter gradient, as found in parity preserving situations. The symmetry breaking implies a new contribution to the velocity field which is a function of the parameter value, thus leading to a new paradigm for LSs manipulation. We illustrate this general concept by studying the trajectories of the LSs found in a passively mode-locked laser operated in the localization regime. Moreover, the lack of parity affects significantly LSs interactions which are governed by asymmetrical repulsive forces.
Dynamics of Localized Structures in Systems with Broken Parity Symmetry
Javaloyes, J; Marconi, M; Giudici, M
2016-01-01
A great variety of nonlinear dissipative systems are known to host structures having a correlation range much shorter than the size of the system. The dynamics of these Localized Structures (LSs) have been investigated so far in situations featuring parity symmetry. In this letter we extend this analysis to systems lacking of this property. We show that the LS drifting speed in a parameter varying landscape is not simply proportional to the parameter gradient, as found in parity preserving situations. The symmetry breaking implies a new contribution to the velocity field which is a function of the parameter value, thus leading to a new paradigm for LSs manipulation. We illustrate this general concept by studying the trajectories of the LSs found in a passively mode-locked laser operated in the localization regime. Moreover, the lack of parity affects significantly LSs interactions which are governed by asymmetrical repulsive forces.
Automating the parallel processing of fluid and structural dynamics calculations
Arpasi, Dale J.; Cole, Gary L.
1987-01-01
The NASA Lewis Research Center is actively involved in the development of expert system technology to assist users in applying parallel processing to computational fluid and structural dynamic analysis. The goal of this effort is to eliminate the necessity for the physical scientist to become a computer scientist in order to effectively use the computer as a research tool. Programming and operating software utilities have previously been developed to solve systems of ordinary nonlinear differential equations on parallel scalar processors. Current efforts are aimed at extending these capabilties to systems of partial differential equations, that describe the complex behavior of fluids and structures within aerospace propulsion systems. This paper presents some important considerations in the redesign, in particular, the need for algorithms and software utilities that can automatically identify data flow patterns in the application program and partition and allocate calculations to the parallel processors. A library-oriented multiprocessing concept for integrating the hardware and software functions is described.
Dynamic Actuator for Centrifuge Modeling of Soil-Structure Interaction
CABRERA, Miguel Angel; Caicedo, Bernardo; THOREL, Luc
2012-01-01
This paper presents a new dynamic actuator useful to study soil-structure interactions in a centrifuge. This new dynamic apparatus is based on an amplified piezoelectric actuator. Using this device it is possible to create vibrations in the soil sample of different frequencies and amplitudes. The dynamic actuator consists of a set of weights in a single degree of freedom system plus a piezoelectric actuator and a piezoelectric load cell, which measures the dynamic load. A description of the d...
Dynamic Chest Image Analysis: Model-Based Perfusion Analysis in Dynamic Pulmonary Imaging
Kiuru Aaro; Kormano Martti; Svedström Erkki; Liang Jianming; Järvi Timo
2003-01-01
The "Dynamic Chest Image Analysis" project aims to develop model-based computer analysis and visualization methods for showing focal and general abnormalities of lung ventilation and perfusion based on a sequence of digital chest fluoroscopy frames collected with the dynamic pulmonary imaging technique. We have proposed and evaluated a multiresolutional method with an explicit ventilation model for ventilation analysis. This paper presents a new model-based method for pulmonary perfusion ana...
Mapping the structural and dynamical features of kinesin motor domains.
Directory of Open Access Journals (Sweden)
Guido Scarabelli
Full Text Available Kinesin motor proteins drive intracellular transport by coupling ATP hydrolysis to conformational changes that mediate directed movement along microtubules. Characterizing these distinct conformations and their interconversion mechanism is essential to determining an atomic-level model of kinesin action. Here we report a comprehensive principal component analysis of 114 experimental structures along with the results of conventional and accelerated molecular dynamics simulations that together map the structural dynamics of the kinesin motor domain. All experimental structures were found to reside in one of three distinct conformational clusters (ATP-like, ADP-like and Eg5 inhibitor-bound. These groups differ in the orientation of key functional elements, most notably the microtubule binding α4-α5, loop8 subdomain and α2b-β4-β6-β7 motor domain tip. Group membership was found not to correlate with the nature of the bound nucleotide in a given structure. However, groupings were coincident with distinct neck-linker orientations. Accelerated molecular dynamics simulations of ATP, ADP and nucleotide free Eg5 indicate that all three nucleotide states could sample the major crystallographically observed conformations. Differences in the dynamic coupling of distal sites were also evident. In multiple ATP bound simulations, the neck-linker, loop8 and the α4-α5 subdomain display correlated motions that are absent in ADP bound simulations. Further dissection of these couplings provides evidence for a network of dynamic communication between the active site, microtubule-binding interface and neck-linker via loop7 and loop13. Additional simulations indicate that the mutations G325A and G326A in loop13 reduce the flexibility of these regions and disrupt their couplings. Our combined results indicate that the reported ATP and ADP-like conformations of kinesin are intrinsically accessible regardless of nucleotide state and support a model where neck
The Dynamic Similitude Design Method of Thin Walled Structures and Experimental Validation
Directory of Open Access Journals (Sweden)
Zhong Luo
2016-01-01
Full Text Available For the applicability of dynamic similitude models of thin walled structures, such as engine blades, turbine discs, and cylindrical shells, the dynamic similitude design of typical thin walled structures is investigated. The governing equation of typical thin walled structures is firstly unified, which guides to establishing dynamic scaling laws of typical thin walled structures. Based on the governing equation, geometrically complete scaling law of the typical thin walled structure is derived. In order to determine accurate distorted scaling laws of typical thin walled structures, three principles are proposed and theoretically proved by combining the sensitivity analysis and governing equation. Taking the thin walled annular plate as an example, geometrically complete and distorted scaling laws can be obtained based on the principles of determining dynamic scaling laws. Furthermore, the previous five orders’ accurate distorted scaling laws of thin walled annular plates are presented and numerically validated. Finally, the effectiveness of the similitude design method is validated by experimental annular plates.
Visualizing Structure and Dynamics of Disaccharide Simulations
Energy Technology Data Exchange (ETDEWEB)
Matthews, J. F.; Beckham, G. T.; Himmel, M. E.; Crowley, M. F.
2012-01-01
We examine the effect of several solvent models on the conformational properties and dynamics of disaccharides such as cellobiose and lactose. Significant variation in timescale for large scale conformational transformations are observed. Molecular dynamics simulation provides enough detail to enable insight through visualization of multidimensional data sets. We present a new way to visualize conformational space for disaccharides with Ramachandran plots.
(Inter-)network structure and dynamics
Rutten, R.J.
2001-01-01
The dynamical nature of the low solar atmosphere outside active regions is emphasized by recent observations an simulations alike. La Palma images,MDI maps,SUMER spectra,TRACE movies,hydro- dynamic shock simulations and magnetohy rodynamic sheet simulations all impart non-quiet behavior to the "quie
Structural analysis of aligned RNAs.
Voss, Björn
2006-01-01
The knowledge about classes of non-coding RNAs (ncRNAs) is growing very fast and it is mainly the structure which is the common characteristic property shared by members of the same class. For correct characterization of such classes it is therefore of great importance to analyse the structural features in great detail. In this manuscript I present RNAlishapes which combines various secondary structure analysis methods, such as suboptimal folding and shape abstraction, with a comparative approach known as RNA alignment folding. RNAlishapes makes use of an extended thermodynamic model and covariance scoring, which allows to reward covariation of paired bases. Applying the algorithm to a set of bacterial trp-operon leaders using shape abstraction it was able to identify the two alternating conformations of this attenuator. Besides providing in-depth analysis methods for aligned RNAs, the tool also shows a fairly well prediction accuracy. Therefore, RNAlishapes provides the community with a powerful tool for structural analysis of classes of RNAs and is also a reasonable method for consensus structure prediction based on sequence alignments. RNAlishapes is available for online use and download at http://rna.cyanolab.de. PMID:17020924
Sensitivity Analysis of Fire Dynamics Simulation
DEFF Research Database (Denmark)
Brohus, Henrik; Nielsen, Peter V.; Petersen, Arnkell J.; Sommerlund-Larsen, Kim
2007-01-01
In case of fire dynamics simulation requirements to reliable results are most often very high due to the severe consequences of erroneous results. At the same time it is a well known fact that fire dynamics simulation constitutes rather complex physical phenomena which apart from flow and energy...... equations require solution of the issues of combustion and gas radiation to mention a few. This paper performs a sensitivity analysis of a fire dynamics simulation on a benchmark case where measurement results are available for comparison. The analysis is performed using the method of Elementary Effects...... (Morris method). The parameters considered are selected among physical parameters and program specific parameters. The influence on the calculation result as well as the CPU time is considered. It is found that the result is highly sensitive to many parameters even though the sensitivity varies...
Dynamic test and finite element model updating of bridge structures based on ambient vibration
Institute of Scientific and Technical Information of China (English)
2008-01-01
The dynamic characteristics of bridge structures are the basis of structural dynamic response and seismic analysis,and are also an important target of health condition monitoring.In this paper,a three-dimensional finite-element model is first established for a highway bridge over a railroad on No.312 National Highway.Based on design drawings,the dynamic characteristics of the bridge are studied using finite element analysis and ambient vibration measurements.Thus,a set of data is selected based on sensitivity analysis and optimization theory;the finite element model of the bridge is updated.The numerical and experimental results show that the updated method is more simple and effective,the updated finite element model can reflect the dynamic characteristics of the bridge better,and it can be used to predict the dynamic response under complex external forces.It is also helpful for further damage identification and health condition monitoring.
Evol and ProDy for bridging protein sequence evolution and structural dynamics
Bakan, Ahmet; Dutta, Anindita; Mao, Wenzhi; Liu, Ying; Chennubhotla, Chakra; Lezon, Timothy R.; Bahar, Ivet
2014-01-01
Correlations between sequence evolution and structural dynamics are of utmost importance in understanding the molecular mechanisms of function and their evolution. We have integrated Evol, a new package for fast and efficient comparative analysis of evolutionary patterns and conformational dynamics, into ProDy, a computational toolbox designed for inferring protein dynamics from experimental and theoretical data. Using information-theoretic approaches, Evol coanalyzes conservation and coevolu...
Spectral response of multilayer optical structures to dynamic mechanical loading
Scripka, David; LeCroy, Garrett; Summers, Christopher J.; Thadhani, Naresh N.
2015-05-01
A computational study of Distributed Bragg Reflectors (DBR) and Optical Microcavities (OMC) was conducted to ascertain their potential as time-resolved mesoscale sensors due to their unique structure-driven spectral characteristics. Shock wave propagation simulations of polymer-based DBRs and glass/ceramic-based OMCs were coupled with spectral response calculations to demonstrate the combined dynamic mechanical and spectral response of the structures. Clear spectral shifts in both structures are predicted as a function of dynamic loading magnitude. Potential applications of the structures include high spatial and temporal resolution surface maps of material states, and in-situ probing of material interfaces during dynamic loading.
BERSAFE: (BERkeley Structural Analysis by Finite Elements)
International Nuclear Information System (INIS)
BERSAFE is a well-known finite element system which has been under continuous use and development for over 20 years. The BERSAFE system comprises an inter-compatible set of program modules covering static stress analysis, linear dynamics and thermal analysis. Data generation and results presentation modules are also available, along with special supporting functions including automatic crack growth through a model with adaptive meshing. The functionality of BERSAFE, is nowadays very advanced, both in engineering scope and finite element technology. It has seen many firsts, including the front solution and Virtual Crack Extension methods (VCE). More recent additions which have developed out of the Power Industry's requirements are a finite element computational fluid dynamics code, FEAT, and engineering design assessment procedures. These procedures include R6 and R5 for the assessment of the integrity of structures containing defects below and within the creep regime. To use all this software in a user-friendly manner, a new computational environment has been developed, called 'The Harness' which takes advantage of modern hardware and software philosophies. This provides the tool-kit to undertake complete problems, covering determination of fluid loads, structural analysis and failure assessment. In the following sections we describe briefly various components of the BERSAFE suite. (author)
Energy Technology Data Exchange (ETDEWEB)
BHARDWAJ, MANLJ K.; REESE,GARTH M.; DRIESSEN,BRIAN; ALVIN,KENNETH F.; DAY,DAVID M.
2000-04-06
As computational needs for structural finite element analysis increase, a robust implicit structural dynamics code is needed which can handle millions of degrees of freedom in the model and produce results with quick turn around time. A parallel code is needed to avoid limitations of serial platforms. Salinas is an implicit structural dynamics code specifically designed for massively parallel platforms. It computes the structural response of very large complex structures and provides solutions faster than any existing serial machine. This paper gives a current status of Salinas and uses demonstration problems to show Salinas' performance.
Earthquake Analysis of Structure by Base Isolation Technique in SAP
T. Subramani; J. Jothi
2014-01-01
This paper presents an overview of the present state of base isolation techniques with special emphasis and a brief on other techniques developed world over for mitigating earthquake forces on the structures. The dynamic analysis procedure for isolated structures is briefly explained. The provisions of FEMA 450 for base isolated structures are highlighted. The effects of base isolation on structures located on soft soils and near active faults are given in brief. Simple case s...
Directory of Open Access Journals (Sweden)
Paul L. Fackler
1988-03-01
Full Text Available Vector Autoregresive Techniques for Structural Analysis Vector Autoregressive (VAR] models which do not rely on a recursive model srtructure are discussed. Linkages to traditional dynamic simultaneous equations models are developed which emphasize the nature of the identifying restrictions that characterize VAR models. Explicit expressions for the Score and Informtion functions are derived and their role in model identification, estimation and hypothesis testing is discussed.
The Transient Modal Dynamic Analysis of a Coke Tower
Institute of Scientific and Technical Information of China (English)
XIE Teng-teng; SUN Tie; XING Ling; ZHANG Su-xiang
2012-01-01
Dynamic analysis must be performed when the duration of the applied load is short or if the load is dynamic in nature. Wind load, as a random load, can lead to the vibration of the coke tower. In order to study the influence to the strength of the coke tower by wind, ABAQUS was used to conduct the transient modal dynamic analysis of the wind load. The response of the structure during loading and unloading was mainly observed. The results indicate that, with the effect of wind, the maximal nodal displacement appears at the top of the tower, which is 0.79 mm; while the maximal stress locates at the node around the skirt, the maximum is 3.26 MPa. Both of the displacement and stress cannot cause the failure of the structure. After loading and unloading, the structure engenders vibration along the loading direction. The frequency is 10 Hz, under the effect of external loads, it may easily cause the resonance of the structure, which can cause damage to the structure. So it must be taken into consideration during the process of design and operation.
Effects on dynamic characters of antenna structures in satellite induced by disordered parameters
Institute of Scientific and Technical Information of China (English)
Liu Xiangqiu; Wang Cong; Wang Weiyuan; Zou Zhenzhu
2009-01-01
A simplified dynamic model of a dish antenna in satellite is established in this article. The model can be easily used to analyze the dynamic behaviour of the antenna structure. In terms of the simplified model, effects on dynamic characters due to the disorder of parameters are investigated in details. The frequencies calculated by the simplified model accord with those computed by ANSYS. Based on the mode shapes of disordered and perfect structure, the influence law and varying trend of dynamic characters of antenna structures in satellites produced by stiffness and mass of antenna ribs, stiffness of antenna membranes and angles between adjacent ribs, are obtained. The analyses in the paper indicate that the effects by disordered parameters can not be ignored in the dynamic analysis of such structures.
Transient dynamic analysis of dolphin structure under ship collision%船舶撞击靠船墩结构的瞬态动力分析
Institute of Scientific and Technical Information of China (English)
潘莹莹; 陶桂兰; 束梁
2014-01-01
Based on the dolphin structure of the ship lock in Jiangsu,the finite analysis soft-ware ABAQUS integral algorithm was used to establish the 3D finite element model of ship,dolphin and foundation,the process of collision was simulated to obtain the impact force-time curve and the stress and strain of the dolphin in two different working conditions of high and low water level.The results show that the maximum compressive stress is on the contact surface,the tensile stress is both in dolphin floor and back surface of the dol-phin,and the maximum tensile stress is in the front teeth of dolphin floor.The stress of the dolphin in low water level is greater and the dolphin is more dangerous.%为了解靠船墩结构在船舶撞击作用下的动力响应，以江苏某船闸靠船墩结构为例，采用大型有限元分析软件 ABAQUS中的 Explicit模块，建立了船舶、靠船墩及地基土的三维有限元模型，对船舶撞击靠船墩过程进行瞬态动力分析，得到了高、低水位两种不同工况下撞击力的时程曲线和靠船墩的应力位移等结果。研究结果表明，在两种水位工况条件下，船舶撞击靠船墩时最大压应力均位于船舶与靠船墩接触面上，在靠船墩底板及墩身背水面均产生拉应力，且底板前齿的拉应力较大；在低水位工况下，靠船墩应力大于高水位工况，靠船墩受力更为不利。
Structure network analysis to gain insights into GPCR function.
Fanelli, Francesca; Felline, Angelo; Raimondi, Francesco; Seeber, Michele
2016-04-15
G protein coupled receptors (GPCRs) are allosteric proteins whose functioning fundamentals are the communication between the two poles of the helix bundle. Protein structure network (PSN) analysis is one of the graph theory-based approaches currently used to investigate the structural communication in biomolecular systems. Information on system's dynamics can be provided by atomistic molecular dynamics (MD) simulations or coarse grained elastic network models paired with normal mode analysis (ENM-NMA). The present review article describes the application of PSN analysis to uncover the structural communication in G protein coupled receptors (GPCRs). Strategies to highlight changes in structural communication upon misfolding, dimerization and activation are described. Focus is put on the ENM-NMA-based strategy applied to the crystallographic structures of rhodopsin in its inactive (dark) and signalling active (meta II (MII)) states, highlighting changes in structure network and centrality of the retinal chromophore in differentiating the inactive and active states of the receptor. PMID:27068978
Static and Dynamic Analyses of Long-Span Spatial Steel-Cable-Membrane Hybrid Structures
Institute of Scientific and Technical Information of China (English)
丁阳; 彭翼; 李忠献
2003-01-01
With the increment of the complexity of structural systems and the span of spatial structures, the interactions between parts of the structures, especially between some flexible substructures, become too complex to be analyzed clearly. In this paper, taking an actual gymnasium of a long-span spatial steel-cable-membrane hybrid structure as the calculation model, the static and dynamic analyses of the hybrid structures are performed by employing the global analysis of the whole hybrid structure and the substructural analysis of the truss arch substructure, the cable-membrane substructure, etc. In addition, the comparison of stresses and displacements of structural members in the global and substructural analyses is made. The numerical results show that serious errors exist in the substructural analysis of the hybrid structure, and the global analysis is necessary for the hybrid structure under the excitation of static loads and seismic loads.
Laser fields in dynamically ionized plasma structures for coherent acceleration
Luu-Thanh, Ph.; Pukhov, A.; Kostyukov, I.
2015-01-01
With the emergence of the CAN (Coherent Amplification Network) laser technology, a new scheme for direct particle acceleration in periodic plasma structures has been proposed. By using our full electromagnetic relativistic particle-in-cell (PIC) simulation code equipped with ionisation module, we simulate the laser fields dynamics in the periodic structures of different materials. We study how the dynamic ionization influences the field structure.
Generating functional analysis of CDMA detection dynamics
International Nuclear Information System (INIS)
We investigate the detection dynamics of the parallel interference canceller (PIC) for code-division multiple-access (CDMA) multiuser detection, applied to a randomly spread, fully synchronous base-band uncoded CDMA channel model with additive white Gaussian noise (AWGN) under perfect power control in the large-system limit. It is known that the predictions of the density evolution (DE) can fairly explain the detection dynamics only in the case where the detection dynamics converge. At transients, though, the predictions of DE systematically deviate from computer simulation results. Furthermore, when the detection dynamics fail to converge, the deviation of the predictions of DE from the results of numerical experiments becomes large. As an alternative, generating functional analysis (GFA) can take into account the effect of the Onsager reaction term exactly and does not need the Gaussian assumption of the local field. We present GFA to evaluate the detection dynamics of PIC for CDMA multiuser detection. The predictions of GFA exhibit good consistency with the computer simulation result for any condition, even if the dynamics fail to converge
The dynamic responses of the soil-auxiliary buildings structure interaction system
International Nuclear Information System (INIS)
The dynamic responses of the soil-auxiliary buildings structure interaction system in the nuclear power plant are concerned. The main distinguished feature of this study is that the extreme un-symmetry of the auxiliary buildings and reactor containment are considered. A Synthetical mechanical model for study is established. Finally, the analysis of the dynamic response of the Qinshan Nuclear Power Plant structure is taken as a simple example of applying this method and the numerical results are given
Flight Dynamics Analysis Branch 2005 Technical Highlights
2005-01-01
This report summarizes the major activities and accomplishments carried out by the Flight Dynamics Analysis Branch (FDAB), Code 595, in support of flight projects and technology development initiatives in Fiscal Year (FY) 2005. The report is intended to serve as a summary of the type of support carried out by the FDAB, as well as a concise reference of key accomplishments and mission experience derived from the various mission support roles. The primary focus of the FDAB is to provide expertise in the disciplines of flight dynamics including spacecraft navigation (autonomous and ground based); spacecraft trajectory design and maneuver planning; attitude analysis; attitude determination and sensor calibration; and attitude control subsystem (ACS) analysis and design. The FDAB currently provides support for missions and technology development projects involving NASA, other government agencies, academia, and private industry.
Structural Analysis of Complex Networks
Dehmer, Matthias
2011-01-01
Filling a gap in literature, this self-contained book presents theoretical and application-oriented results that allow for a structural exploration of complex networks. The work focuses not only on classical graph-theoretic methods, but also demonstrates the usefulness of structural graph theory as a tool for solving interdisciplinary problems. Applications to biology, chemistry, linguistics, and data analysis are emphasized. The book is suitable for a broad, interdisciplinary readership of researchers, practitioners, and graduate students in discrete mathematics, statistics, computer science,
PGA and structural dynamics input motion at a given site
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
The computation of the representative ground motions, to be used as input for the dynamic analyses of a struc-ture at a particular site, can be approached by several methods. The choice of the approach depends on two factors: the da-ta available and the type of problem to be solved. This paper reports the experience of the authors in approaching a specificcase study: the Southern Memnon Colossus, located in Luxor, Egypt. The results are of interest when the hazard analysisestimation in developing countries and the safeguard of cultural heritage are concerned. Monuments have to be treated asimportant structures, due to their historical and economical value. Hence, standard procedures of probabilistic seismic haz-ard analysis for the seismic classification of common buildings have to be disregarded. On the other hand, the consequencesof the collapse of a monument are not comparable to those related to structures such as nuclear power plants and large dams,for which the deterministic seismic hazard analysis provides a straightforward framework for evaluation of the worst caseone, is adopted. Its stochastic component can capture significant characteristics of earthquakes, primarily the frequencycontents which depend on the magnitude (often referred to as the earthquake scaling law).
Constrained maximum likelihood modal parameter identification applied to structural dynamics
El-Kafafy, Mahmoud; Peeters, Bart; Guillaume, Patrick; De Troyer, Tim
2016-05-01
A new modal parameter estimation method to directly establish modal models of structural dynamic systems satisfying two physically motivated constraints will be presented. The constraints imposed in the identified modal model are the reciprocity of the frequency response functions (FRFs) and the estimation of normal (real) modes. The motivation behind the first constraint (i.e. reciprocity) comes from the fact that modal analysis theory shows that the FRF matrix and therefore the residue matrices are symmetric for non-gyroscopic, non-circulatory, and passive mechanical systems. In other words, such types of systems are expected to obey Maxwell-Betti's reciprocity principle. The second constraint (i.e. real mode shapes) is motivated by the fact that analytical models of structures are assumed to either be undamped or proportional damped. Therefore, normal (real) modes are needed for comparison with these analytical models. The work done in this paper is a further development of a recently introduced modal parameter identification method called ML-MM that enables us to establish modal model that satisfies such motivated constraints. The proposed constrained ML-MM method is applied to two real experimental datasets measured on fully trimmed cars. This type of data is still considered as a significant challenge in modal analysis. The results clearly demonstrate the applicability of the method to real structures with significant non-proportional damping and high modal densities.
Wind-induced response analysis of conical membrane structures
Institute of Scientific and Technical Information of China (English)
CHEN Bo; WU Yue; SHEN Shi-zhao
2005-01-01
Conical membrane structures are a typical form of tensile membrane structures. In the past, most studies focused on the static performance, but few on dynamic performance. In this paper, systematic parameter analysis of wind-induced response of conical membrane structures has been performed with nonlinear random simulation method in a time domain, by considering some parameters, such as span, rise-span ratio, prestress of membrane, and characteristic of the approaching wind flow. Moreover, formulas of the dynamic coefficient and nonlinear adjustment factor are advised, which can be conveniently used in wind-resistant design of conical membrane structures.
Structural Analysis of Plate Based Tensegrity Structures
DEFF Research Database (Denmark)
Hald, Frederik; Kirkegaard, Poul Henning; Damkilde, Lars
2013-01-01
Plate tensegrity structures combine tension cables with a cross laminated timber plate and can then form e.g. a roof structure. The topology of plate tensegrity structures is investigated through a parametric investigation. Plate tensegrity structures are investigated, and a method for...... determination of the structures pre-stresses is used. A parametric investigation is performed to determine a more optimized form of the plate based tensegrity structure. Conclusions of the use of plate based tensegrity in civil engineering and further research areas are discussed....
Employment of CB models for non-linear dynamic analysis
Klein, M. R. M.; Deloo, P.; Fournier-Sicre, A.
1990-01-01
The non-linear dynamic analysis of large structures is always very time, effort and CPU consuming. Whenever possible the reduction of the size of the mathematical model involved is of main importance to speed up the computational procedures. Such reduction can be performed for the part of the structure which perform linearly. Most of the time, the classical Guyan reduction process is used. For non-linear dynamic process where the non-linearity is present at interfaces between different structures, Craig-Bampton models can provide a very rich information, and allow easy selection of the relevant modes with respect to the phenomenon driving the non-linearity. The paper presents the employment of Craig-Bampton models combined with Newmark direct integration for solving non-linear friction problems appearing at the interface between the Hubble Space Telescope and its solar arrays during in-orbit maneuvers. Theory, implementation in the FEM code ASKA, and practical results are shown.
Analysis of dynamic conflicts by techniques of artificial intelligence
Shinar, Josef
1989-01-01
Dynamic conflicts exhibit differentiel game characteristics and their analysis by any method which disregards this feature may be, by definition, futile. Unfortunately, realistic conflicts may have an intricate information structure and a complex hierarchy which don't fit in the classical differential game formulation. Moreover, in many cases even well formulated differential games are not solvable. In the recent years great progress has been made in artificial intelligence techniques, put in...
Offline analysis of HEP events by ''dynamic perceptron'' neural network
International Nuclear Information System (INIS)
In this paper we start from a critical analysis of the fundamental problems of the parallel calculus in linear structures and of their extension to the partial solutions obtained with non-linear architectures. Then, we present shortly a new dynamic architecture able to solve the limitations of the previous architectures through an automatic re-definition of the topology. This architecture is applied to real-time recognition of particle tracks in high-energy accelerators. (orig.)
潜水轴流泵结构动应力分析%Structural dynamic stress analysis of submersible axial pump
Institute of Scientific and Technical Information of China (English)
张琳; 施卫东; 张德胜; 张俊杰; 郭艳磊
2015-01-01
The rotor component of submersible axial flow pump was calculated under multiple condi-tions using CFX and Workbench software to analyze the stress and strain distribution by the action of fluid force,centrifugal force and gravity.Moreover,the possibility of failure caused by large deforma-tion and insufficient strength was pointed out.The results showed that the radial force was the mini-mum under the standard condition.The direction of axial force in the hub was opposite to that in the impeller.The axial force was increased with the flow rate increasing.The hub could balance the axial force well under the large flow condition.The radial deformation was extremely smaller than the cir-cumferential deformation which was the main deformation in the impeller.This may mean that the torque plays a primary role in the total deformation.The pressure on the suction surface was signifi-cantly lower than that on the pressure surface.Near the inlet side of the hub appeared the high stress area,in which would emerge stress concentration.The main stress was reduced with the flow rate in-creasing.The static structural analysis and strength assessment of the axial pump could reduce the inci-dence of accidents,and provide a powerful reference for axial flow hydraulic design optimization.%采用 CFX 和 Workbench 软件在多工况下对潜水轴流泵的转子部件进行耦合计算，分析了转子部件在流体作用力、离心力以及重力作用下的应力、应变的分布规律，指出转子部件由于变形过大以及强度不足而引发失效事故的可能性。结果表明：轮毂受到的轴向力方向与叶轮受到的轴向力相反，且其受到的轴向力随着流量的增大而增大，在大流量情况下，轮毂可起到平衡轴向力的作用。从径向、轴向和周向变形可以看出，径向变形极小，周向变形最大，是叶轮的主变形，说明了扭矩在整个变形中占据了主要作用。叶片背面的压力值明显
Nonlinear structural mechanics theory, dynamical phenomena and modeling
Lacarbonara, Walter
2013-01-01
Nonlinear Structural Mechanics: Theory, Dynamical Phenomena and Modeling offers a concise, coherent presentation of the theoretical framework of nonlinear structural mechanics, computational methods, applications, parametric investigations of nonlinear phenomena and their mechanical interpretation towards design. The theoretical and computational tools that enable the formulation, solution, and interpretation of nonlinear structures are presented in a systematic fashion so as to gradually attain an increasing level of complexity of structural behaviors, under the prevailing assumptions on the geometry of deformation, the constitutive aspects and the loading scenarios. Readers will find a treatment of the foundations of nonlinear structural mechanics towards advanced reduced models, unified with modern computational tools in the framework of the prominent nonlinear structural dynamic phenomena while tackling both the mathematical and applied sciences. Nonlinear Structural Mechanics: Theory, Dynamical Phenomena...
Ultrafast Structural Dynamics in Combustion Relevant Model Systems
Energy Technology Data Exchange (ETDEWEB)
Weber, Peter M. [Brown University
2014-03-31
The research project explored the time resolved structural dynamics of important model reaction system using an array of novel methods that were developed specifically for this purpose. They include time resolved electron diffraction, time resolved relativistic electron diffraction, and time resolved Rydberg fingerprint spectroscopy. Toward the end of the funding period, we also developed time-resolved x-ray diffraction, which uses ultrafast x-ray pulses at LCLS. Those experiments are just now blossoming, as the funding period expired. In the following, the time resolved Rydberg Fingerprint Spectroscopy is discussed in some detail, as it has been a very productive method. The binding energy of an electron in a Rydberg state, that is, the energy difference between the Rydberg level and the ground state of the molecular ion, has been found to be a uniquely powerful tool to characterize the molecular structure. To rationalize the structure sensitivity we invoke a picture from electron diffraction: when it passes the molecular ion core, the Rydberg electron experiences a phase shift compared to an electron in a hydrogen atom. This phase shift requires an adjustment of the binding energy of the electron, which is measurable. As in electron diffraction, the phase shift depends on the molecular, geometrical structure, so that a measurement of the electron binding energy can be interpreted as a measurement of the molecule’s structure. Building on this insight, we have developed a structurally sensitive spectroscopy: the molecule is first elevated to the Rydberg state, and the binding energy is then measured using photoelectron spectroscopy. The molecule’s structure is read out as the binding energy spectrum. Since the photoionization can be done with ultrafast laser pulses, the technique is inherently capable of a time resolution in the femtosecond regime. For the purpose of identifying the structures of molecules during chemical reactions, and for the analysis of
Cluster analysis of word frequency dynamics
International Nuclear Information System (INIS)
This paper describes the analysis and modelling of word usage frequency time series. During one of previous studies, an assumption was put forward that all word usage frequencies have uniform dynamics approaching the shape of a Gaussian function. This assumption can be checked using the frequency dictionaries of the Google Books Ngram database. This database includes 5.2 million books published between 1500 and 2008. The corpus contains over 500 billion words in American English, British English, French, German, Spanish, Russian, Hebrew, and Chinese. We clustered time series of word usage frequencies using a Kohonen neural network. The similarity between input vectors was estimated using several algorithms. As a result of the neural network training procedure, more than ten different forms of time series were found. They describe the dynamics of word usage frequencies from birth to death of individual words. Different groups of word forms were found to have different dynamics of word usage frequency variations
Cluster analysis of word frequency dynamics
Maslennikova, Yu S.; Bochkarev, V. V.; Belashova, I. A.
2015-01-01
This paper describes the analysis and modelling of word usage frequency time series. During one of previous studies, an assumption was put forward that all word usage frequencies have uniform dynamics approaching the shape of a Gaussian function. This assumption can be checked using the frequency dictionaries of the Google Books Ngram database. This database includes 5.2 million books published between 1500 and 2008. The corpus contains over 500 billion words in American English, British English, French, German, Spanish, Russian, Hebrew, and Chinese. We clustered time series of word usage frequencies using a Kohonen neural network. The similarity between input vectors was estimated using several algorithms. As a result of the neural network training procedure, more than ten different forms of time series were found. They describe the dynamics of word usage frequencies from birth to death of individual words. Different groups of word forms were found to have different dynamics of word usage frequency variations.
Energy Technology Data Exchange (ETDEWEB)
Solonick, W. [Electric Boat Corp., Groton, CT (United States)
1996-11-01
Rapidly applied transient dynamic loads produce stresses and deflections in structures that typically exceed those from static loading conditions. Previous acceptance criteria for structures designed for rapidly applied transient dynamic loading limited stresses to those determined from elastic analysis. Different stress limits were established for different grades of structure depending upon the amount of permanent set considered acceptable. Structure allowed to sustain very limited permanent set is designed to stress limits not significantly greater than yield stress. Greater permanent set in structure under rapidly applied transient dynamic loading conditions is permitted by establishing stress limits that are significantly greater than yield stress but still provide adequate safety margin (with respect to failure). This paper presents a strain-based elastic-plastic (i.e., inelastic) analysis criterion developed as an alternative to the more conservative stress-based elastic analysis stress criterion for structures subjected to rapidly applied transient dynamic loading. The strain limits established are based on a fraction of the strain at ultimate stress obtained from an engineering stress/strain curve of the material. Strains limits are categorized by type as membrane or surface and by region as general, local, or concentrated. The application of the elastic-plastic criterion provides a more accurate, less conservative design/analysis basis for structures than that used in elastic stress-based analysis criteria, while still providing adequate safety margins.
HVDC dynamic modelling for small signal analysis
Energy Technology Data Exchange (ETDEWEB)
Yang, X.; Chen, C. [Shanghai Jiaotong Univ. (China). Dept. of Electrical Engineering
2004-11-01
The conventional quasi-steady model of HVDC is not able to describe the dynamic switching behaviour of HVDC converters. By means of the sampled-data modelling approach, a linear time-invariant (LTI) small-signal dynamic model is developed for the HVDC main circuit in the synchronous rotating d-q reference frame. The linearised model is validated by time-domain simulation, and it can be seen that the model represents the dynamic response of the static switching circuits to perturbations in operating points. The model is valid for analysing oscillations including high frequency modes such as subsynchronous oscillation (SSO) and high frequency instability. The model is applied in two cases: (i) SSO analysis where the results are compared with the quasi-steady approach that has shown its validation for normal SSO analysis; (ii) high frequency eigenvalue analysis for HVDC benchmark system in which the results of root locus analysis and simulation shows that increased gain of rectifier DC PI controller may result in high-frequency oscillatory instability. (author)
Transient dynamic and inelastic analysis of shells of revolution
International Nuclear Information System (INIS)
Advances in the limits of structural use in the aerospace and nuclear power industries over the past years have increased the requirements upon the applicable analytical computer programs to include accurate capabilities for inelastic and transient dynamic analyses. In many minds, however, this advanced capability is unequivocally linked with the large scale, general purpose, finite element programs. This idea is also combined with the view that, therefore, such analyses are prohibitively expensive and should be relegated to the 'last resort' classification. While this, in the general sense, may indeed be the case, if however, the user needs only to analyze structures falling into limited categories, he may find that a variety of smaller special purpose programs are available, which do not put an undue strain upon his resources. One such structural category is shells of revolution. This survey of programs will concentrate upon the analytical tools which have been developed predominantly for shells of revolution. The survey will be subdivided into three parts: a) consideration of programs for transient dynamic analysis, b) consideration of programs for inelastic analysis, and finally, c) consideration of programs capable of dynamic plasticity analysis. In each part, programs based upon finite difference, finite element, and numerical integration methods will be considered. The programs will be compared on the basis of analytical capabilities, and ease of idealization and use. In each part of the survey sample problems will be utilized to exemplify the state-of-the-art. (orig.)
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
Under certain conditions, the dynamic equatioins of membrane shells and the dynamic equations of flexural shells are obtained from dynamic equations of Koiter shells by the method of asymptotic analysis.
THE DYNAMICS OF THE MATRICS STRUCTURE
Directory of Open Access Journals (Sweden)
Dumitru CONSTANTINESCU
2007-01-01
Full Text Available The relationships organization-suppliers-customers have recently known major changes in the structure of services and have made the organization develop its managerial and professional competencies in order to do projects. The qualified organization is the most trust-worthy in the process of doing a project. The participation of an organization in doing projects depends on a multitude of factors. Out of these factors, the structural organization comes forth, as it represents the variable with the most important impact on a project’s quality, costs and lead time. From the organizational point of view, the matrix structure is frequently chosen for projects. The matrix structure generally coexists with the line structure. The two structures are contrastive. The line structure is based on the unity of command principle and is not open to cooperation and dialogue. The matrix structure encourages cooperation and communication, favours conflict, which is considered here a healthy and essential process. The matrix structure and the line structure claim their right to initiative. Conflict and the multidimensional integration of multiple hierarchies can be negotiated through the concept charisma – mediation, sustained by the matrix structure.
A Neural Network Model of the Structure and Dynamics of Human Personality
Read, Stephen J.; Monroe, Brian M.; Brownstein, Aaron L.; Yang, Yu; Chopra, Gurveen; Miller, Lynn C.
2010-01-01
We present a neural network model that aims to bridge the historical gap between dynamic and structural approaches to personality. The model integrates work on the structure of the trait lexicon, the neurobiology of personality, temperament, goal-based models of personality, and an evolutionary analysis of motives. It is organized in terms of two…
Institute of Scientific and Technical Information of China (English)
王博; 申金虎; 徐建国
2012-01-01
At present, aseismic research of aqueduct mostly focus on the fluid-solid coupling between aqueduct and water body and gives less attention to pile-soil dynamic interaction. However, the pile-soil interaction affects the aqueduct structure response to dynamic load especially seismic load. In order to study the impact of pile-soil interaction on dynamic characteristics of aqueduct structure, the large-scale finite element software ABAQUS is used to establish three-dimensional mechanical simulation model of pile-soil-aqueduct-water by taking into account fluid-solid coupling and pile-soil interaction in middle route of South-to-North Water Diversion Project. At the same time, the natural frequencies and vibration is obtained with modal analysis under different operating conditions. Compared with the consolidation model, the results indicate that the pile-soil interaction reduces the natural frequency of aqueduct under the action of earthquake load, and it changes the dynamic characteristics of the aqueduct.%目前,对渡槽抗震性能的研究多集中在槽身与水体的流固耦合问题上,对桩土间的动力相互作用则研究较少,然而桩土相互作用会影响渡槽结构对动荷载尤其是地震荷载的反应.为探究桩土相互作用对渡槽结构动力特性的影响,采用大型有限元软件ABAQUS对南水北调中线工程双洎河渡槽建立了同时考虑流固耦合和桩土相互作用的桩—土—渡槽—水三维仿真力学模型,并进行了不同工况下的自振频率及振动模态分析.结果表明,与固结模型相比,考虑桩土相互作用的渡槽结构在地震荷载作用下自振频率减小,桩土相互作用改变了渡槽结构动力特性.
Structural Integrity Analysis of CEA Change Platform
International Nuclear Information System (INIS)
The Control Element Assembly Change Platform (CEA CP) is similar to a gantry crane. The CEA CP for Shin-Kori units 3 and 4 (SKN 3 and 4) consists of a bridge, which spans the reactor cavity pool and a gantry superstructure mounted on the bridge. The structure is approximately 8.8 m wide, 4.9 m long and 10.6 m high. The gantry superstructure supports one ton capacity hoist trolley and the bridge supports the In Core Instrumentation (ICI) retrieval cart which moves along the bridge. This paper presents the dynamic and structural analysis of CEA CP which is greater than that of the previous nuclear power plants to verify the structural integrity under the application of the earthquake spectrum. The analysis have been performed using the three orthogonal SSE response spectrum for SKN 3 and 4 which shows much higher acceleration value than OPR- 1000 Plants. In addition, the analyses are performed by 3-dimensional finite element analysis using ANSYS software