WorldWideScience

Sample records for ambient vibration test

  1. Ambient Vibration Test on Reinforced Concrete Bridges

    Directory of Open Access Journals (Sweden)

    Idris Nurul Shazwin

    2016-01-01

    Full Text Available An investigation was carried out to determine dynamic characteristic of reinforced concrete (RC bridges by using ambient vibration test (AVT. The ambient vibration sources on bridges may come from traffic, wind, wave motion and seismic events. AVT describes the dynamic characteristics of the bridge and ground by measuring the natural frequencies using highly sensitive seismometer sensor. This test is beneficial due to light weight equipment and smaller number of operator required, cheap and easy to be handled. It is able to give a true picture of the bridge dynamic behavior without any artificial force excitation when vibration data is recorded. A three-span reinforced concrete bridge located in Sri Medan, Batu Pahat, Johor was measured by using microtremor equipment consist of three units of 1 Hz eigenfrequency passive sensors used in this test was performed in normal operating condition without excitation required from any active sources or short period noise perturbations. Ten measurements were conducted on the bridge deck and ten measurements on the ground surface in order to identify the natural frequencies of the bridge. Several peak frequencies were identified from three components of Fourier Amplitude Spectra (FAS in transverse (North-South, longitudinal (East-West and vertical (Up-Down direction as well as squared average Horizontal to Vertical Spectral Ratio (HVSR of ground response, computed by using Geopsy software. From the result, it was expected the bridge have five vibration modes frequencies in the range of 1.0 Hz and 7.0 Hz with the first two modes in the transverse and longitudinal direction having a frequency 1.0 Hz, the third mode is 2.2 Hz in transverse direction, fourth and fifth mode is 5.8 Hz and 7.0 Hz. For ground natural frequencies are in range 1.0 Hz to 1.3 Hz for North-South direction and 1.0 Hz to 1.6 Hz for East-West direction. Finally the results are compared with several empirical formulas for simple

  2. Damping Estimation Using Free Decays and Ambient Vibration Tests

    DEFF Research Database (Denmark)

    Magalhães, Filipe; Brincker, Rune; Cunha, Álvaro

    2007-01-01

    The accurate identification of modal damping ratios of Civil Engineering structures is a subject of major importance, as the amplitude of structural vibrations in resonance is inversely proportional to these coefficients. Their experimental identification can be performed either from ambient...... vibration or from free vibration tests. In the last case, the structural response after application of an impulse or after the application of harmonic loads can be used. Ambient vibration tests have the strong advantage of being more practical and economical. However, recent applications of both approaches...

  3. On Modal Parameter Estimates from Ambient Vibration Tests

    DEFF Research Database (Denmark)

    Agneni, A.; Brincker, Rune; Coppotelli, B.

    2004-01-01

    Modal parameter estimates from ambient vibration testing are turning into the preferred technique when one is interested in systems under actual loadings and operational conditions. Moreover, with this approach, expensive devices to excite the structure are not needed, since it can be adequately...

  4. NIF Ambient Vibration Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Noble, C.R.; Hoehler, M.S., S.C. Sommer

    1999-11-29

    LLNL has an ongoing research and development project that includes developing data acquisition systems with remote wireless communication for monitoring the vibrations of large civil engineering structures. In order to establish the capability of performing remote sensing over an extended period of time, the researchers needed to apply this technology to a real structure. The construction of the National Ignition Facility provided an opportunity to test the data acquisition system on a large structure to monitor whether the facility is remaining within the strict ambient vibration guidelines. This document will briefly discuss the NIF ambient vibration requirements and summarize the vibration measurements performed during the Spring and Summer of 1999. In addition, a brief description of the sensors and the data acquisition systems will be provided in Appendix B.

  5. NIF Ambient Vibration Measurements

    International Nuclear Information System (INIS)

    LLNL has an ongoing research and development project that includes developing data acquisition systems with remote wireless communication for monitoring the vibrations of large civil engineering structures. In order to establish the capability of performing remote sensing over an extended period of time, the researchers needed to apply this technology to a real structure. The construction of the National Ignition Facility provided an opportunity to test the data acquisition system on a large structure to monitor whether the facility is remaining within the strict ambient vibration guidelines. This document will briefly discuss the NIF ambient vibration requirements and summarize the vibration measurements performed during the Spring and Summer of 1999. In addition, a brief description of the sensors and the data acquisition systems will be provided in Appendix B

  6. The Health Monitoring Method of Concrete Dams Based on Ambient Vibration Testing and Kernel Principle Analysis

    Directory of Open Access Journals (Sweden)

    Lin Cheng

    2015-01-01

    Full Text Available The ambient vibration testing (AVT measurement of concrete dams on full-scale can show the practical dynamic properties of structure in the operation state. For most current researches, the AVT data is generally analyzed to identify the structural vibration characteristics, that is, modal parameters. The identified modal parameters, which can provide the global damage information or the damage location information of structure, can be used as the basis of structure health monitoring. Therefore, in this paper, the health monitoring method of concrete dams based on the AVT is studied. The kernel principle analysis (KPCA based method is adopted to eliminate the effect of environmental variables and monitor the health of dam under varying environments. By taking full advantage of the AVT data obtained from vibration observation system of dam, the identification capabilities and the warning capabilities of structural damage can be improved. With the simulated AVT data of the numerical model of a concrete gravity dam and the measured AVT data of a practical engineering, the performance of the dam health monitoring method proposed in this paper is verified.

  7. FEM Updating of Tall Buildings using Ambient Vibration Data

    DEFF Research Database (Denmark)

    Ventura, C. E.; Lord, J. F.; Turek, M.;

    2005-01-01

    Ambient vibration testing is the most economical non-destructive testing method to acquire vibration data from large civil engineering structures. The purpose of this paper is to demonstrate how ambient vibration Modal Identification techniques can be effectively used with Model Updating tools...... and the corresponding mode shapes. The degree of torsional coupling between the modes was also investigated. The modal identification results obtained from ambient vibration measurements of each building were used to update a finite element model of the structure. The starting model of each structure was developed from...... an ambient vibration modal identification....

  8. 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.

  9. Ambient Vibration Tests of an Arch Dam with Different Reservoir Water Levels: Experimental Results and Comparison with Finite Element Modelling

    Directory of Open Access Journals (Sweden)

    Sergio Vincenzo Calcina

    2014-01-01

    Full Text Available This paper deals with the ambient vibration tests performed in an arch dam in two different working conditions in order to assess the effect produced by two different reservoir water levels on the structural vibration properties. The study consists of an experimental part and a numerical part. The experimental tests were carried out in two different periods of the year, at the beginning of autumn (October 2012 and at the end of winter (March 2013, respectively. The measurements were performed using a fast technique based on asynchronous records of microtremor time-series. In-contact single-station measurements were done by means of one single high resolution triaxial tromometer and two low-frequency seismometers, placed in different points of the structure. The Standard Spectral Ratio method has been used to evaluate the natural frequencies of vibration of the structure. A 3D finite element model of the arch dam-reservoir-foundation system has been developed to verify analytically determined vibration properties, such as natural frequencies and mode shapes, and their changes linked to water level with the experimental results.

  10. Structural Health Monitoring Using Wireless Technologies: An Ambient Vibration Test on the Adolphe Bridge, Luxembourg City

    Directory of Open Access Journals (Sweden)

    Adrien Oth

    2012-01-01

    Full Text Available Major threats to bridges primarily consist of the aging of the structural elements, earthquake-induced shaking and standing waves generated by windstorms. The necessity of information on the state of health of structures in real-time, allowing for timely warnings in the case of damaging events, requires structural health monitoring (SHM systems that allow the risks of these threats to be mitigated. Here we present the results of a short-duration experiment carried out with low-cost wireless instruments for monitoring the vibration characteristics and dynamic properties of a strategic civil infrastructure, the Adolphe Bridge in Luxembourg City. The Adolphe Bridge is a masonry arch construction dating from 1903 and will undergo major renovation works in the upcoming years. Our experiment shows that a network of these wireless sensing units is well suited to monitor the vibration characteristics of such a historical arch bridge and hence represents a low-cost and efficient solution for SHM.

  11. Ambient Vibration Test for a Multi-story Residential Building and the Vibration Mitigation Measures%多层住宅环境振动影响测试与减振措施分析

    Institute of Scientific and Technical Information of China (English)

    朱斌; 陈龙珠; 丁力

    2014-01-01

    Brick-concrete buildings have been extensively used in urban and rural areas.However,this type of building,which frequently contains a shallow foundation,demonstrates poor struc-tural integrity and is susceptible to influence from ambient vibrations.This case is especially validfor buildings that were constructed in previous eras.With the development of modern cities andthe increasing demand for an enhanced quality of life,environmental interference caused by ambi-ent vibrations has become a critical issue.In areas with soft soil,traffic is a primary source ofambient vibrations.Vehicle vibrations caused by road surface roughness or speed changes cancause vibrations throughout the foundation of a building.Therefore,the vibration of brick-con-crete buildings is related not only to the excitation source of the vibration but also the soil charac-teristics,the foundation conditions,and the structural style.The human response to the vibra-tions of housing structures is closely correlated with a person's cognitive level and their currentphysical and psychological conditions.Thus,the potential difference in the reactions amongbuilding occupants is significant.Residents in a six-story brick-concrete building,which is located in an area of Shanghai withsoft ground,frequently complained about the intermittent interference from vibrations,particularly residents on the upper two stories.The measures confirmed that the environmental vibra-tions were generated by heavy vehicles traveling on a road that was located approximately 80 mnorth of the building.The frequency and amplitude characteristics of the ambient vibrations andthe human comfort levels for the different stories of the building were analyzed according to the"standard for allowable vibration of building engineering"(GB50868-2013).To comprehensivelyevaluate the impact induced by the transversely horizontal vibrations,which influences humancomfort levels for the three components of building vibration,a numerical finite

  12. Analysis of soil-structure interaction due to ambient vibration

    Energy Technology Data Exchange (ETDEWEB)

    Tabatabaie, M., Sommer, S.C.

    1998-03-27

    This paper presents the results of a study to evaluate the effects of soil-structure interaction (SSI) on the ambient vibration response of the switchyard/target area (S/TA) buildings at the National Ignition Facility (NIF) presently under construction at the Lawrence Livermore National Laboratory (LLNL) in Livermore, California. This laser facility houses optical and other special equipment whose alignment stability is sensitive to vibrations caused by ambient vibrations or other vibrating sources. In evaluating the deformations and displacements of the S/TA structures, the contribution of the SSI to the overall system flexibility can be very significant. The present study examines the results of fixed-base and SSI analyses of these massive stiff structures to develop an understanding of the potential contribution of SSI to the overall system displacements and deformations. A simple procedure using a set of factors is recommended for scaling the results of fixed-base analyses to approximately account for SSI effects.

  13. Ambient vibrations efficiency for building dynamic characteristics estimate and seismic evaluation.

    OpenAIRE

    Dunand, François

    2005-01-01

    Ambient vibrations are mechanical low amplitude vibrations generated by human and natural activities. By forcing into vibration engineering structures, these vibrations can be used to estimate the structural dynamic characteristics.The goal of this study is to compare building dynamic characteristics derived from ambient vibrations to those derived from more energetic solicitations (e.g. earthquake). This study validates the efficiency of this method and shows that ambient vibrations results ...

  14. Damage localization under ambient vibration using changes in flexibility

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In recent years, Structural Health Monitoring (SHM) has emerged as a new research area in civil engineering. Mostexisting health monitoring methodologies require direct measurement of input excitation for implementation. However, in manycases, there is no easy way to measure these inputs - or alternatively to externally excite the structure. Therefore, SHM methodsbased on ambient vibration have become important in civil engineering. In this paper, an approach is proposed based on the DamageLocation Vector (DLV) method to handle the ambient vibration case. Here, this flexibility-matrix-based damage localization methodis combined with a modal expansion technique to eliminate the need to measure the input excitation. As a by-product of thisapproach, in addition to determining the location of the damage, an estimate of the damage extent also can be determined. Finally, anumerical example analyzing a truss structure with limited sensors and noisy measurement is provided to verify the efficacy of theproposed approach.

  15. Damage localization under ambient vibration using changes in flexibility

    Science.gov (United States)

    Gao, Yong; Spencer, B. F.

    2002-06-01

    In recent years, Structural Health Monitoring (SHM) has emerged as a new research area in civil engineering. Most existing health monitoring methodologies require direct measurement of input excitation for implementation. However, in many cases, there is no easy way to measure these inputs - or alternatively to externally excite the structure. Therefore, SHM methods based on ambient vibration have become important in civil engineering. In this paper, an approach is proposed based on the Damage Location Vector (DLV) method to handle the ambient vibration case. Here, this flexibility-matrix-based damage localization method is combined with a modal expansion technique to eliminate the need to measure the input excitation. As a by-product of this approach, in addition to determining the location of the damage, an estimate of the damage extent also can be determined. Finally, a numerical example analyzing a truss structure with limited sensors and noisy measurement is provided to verify the efficacy of the proposed approach.

  16. 环境振动下的钢管混凝土拱桥试验与分析%Ambient Vibration Testing and Analysis of Concrete Filled Steel Tube Arch Bridge

    Institute of Scientific and Technical Information of China (English)

    王立宪; 狄生奎; 刘云帅; 花尉攀

    2011-01-01

    环境振动试验是检测大型桥梁结构的主要方法,检测得到的模态参数是判定桥梁健康状况的重要依据.本文基于随机振动理论,从雁滩黄河大桥在环境激励下获得的加速度测试信号中提取高信噪比的响应信号,采用频域峰值法和时域随机子空间法识别得到了该桥的固有频率、阻尼比和振型等模态参数,并与有限元模型计算结果进行了对比,验证了识别结果的可靠性,结果可作为该桥的损伤检测、使用状态评估和健康监测的基础.%Ambient vibration test is the main method of detecting a large bridge structure, Modal parameters is important to determine the health status of the bridge. Based on random vibration theory, as a high signal-to-noise ratio response,virtual response is obtained from the measured acceleration signal of Yantan Yellow River Bridge of Lanzhou under ambient excitation. Yantan Yellow River bridge's modal parameters, such as natural frequency, damping ratio and mode of vibration, are identified by using the peak picking and stochastic subspace identification, and are compared with the finite element model results and verified the reliability of recognition results. The identified dynamic properties can be served as the basis in the finite element model updating, damage detection, condition assessment and health monitoring of the bridge.

  17. 14 CFR 33.43 - Vibration test.

    Science.gov (United States)

    2010-01-01

    ... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Block Tests; Reciprocating Aircraft Engines § 33.43 Vibration test. (a) Each engine must undergo a vibration survey to establish the torsional and bending vibration...

  18. Ambient Modal Testing of the Vestvej Bridge using Random Decrement

    DEFF Research Database (Denmark)

    Asmussen, J. C.; Brincker, Rune; Rytter, A.

    This paper presents an ambient vibration study of the Vestvej Bridge. The bridge is a typically Danish two-span concrete bridge which crosses a highway. The purpose of the study is to perform a pre-investigation of the dynamic behavior to obtain information for the design of a demonstration project...... concerning application of vibration based inspection of bridges. The data analysis process of ambient vribration testing of bridges has traditionally been based on auto and cross spectral densities estimated using an FFT algorithm. In the pre-analysis state the spectral densities are all averaged to obtain...

  19. Ambient Modal Testing of the Vestvej Bridge using Random Decrement

    DEFF Research Database (Denmark)

    Asmussen, J. C.; Brincker, Rune; Rytter, A.

    1998-01-01

    This paper presents an ambient vibration study of the Vestvej Bridge. The bridge is a typically Danish two-span concrete bridge which crosses a highway. The purpose of the study is to perform a pre-investigation of the dynamic behavior to obtain information for the design of a demonstration project...... concerning application of vibration based inspection of bridges. The data analysis process of ambient vribration testing of bridges has traditionally been based on auto and cross spectral densities estimated using an FFT algorithm. In the pre-analysis state the spectral densities are all averaged to obtain...

  20. Natural Frequencies and Modal Damping Ratios Identification of Civil Structures from Ambient Vibration Data

    Directory of Open Access Journals (Sweden)

    Minh-Nghi Ta

    2006-01-01

    Full Text Available Damping is a mechanism that dissipates vibration energy in dynamic systems and plays a key role in dynamic response prediction, vibration control as well as in structural health monitoring during service. In this paper a time domain and a time-scale domain approaches are used for damping estimation of engineering structures, using ambient response data only. The use of tests under ambient vibration is increasingly popular today because they allow to measure the structural response in service. In this paper we consider two engineering structures excited by ambient forces. The first structure is the 310 m tall TV tower recently constructed in the city of Nanjing in China. The second example concerns the Jinma cable-stayed bridge that connects Guangzhou and Zhaoqing in China. It is a single tower, double row cable-stayed bridge supported by 112 stay cables. Ambient vibration of each cable is carried out using accelerometers. From output data only, the modal parameter are extracted using a subspace method and the wavelet transform method.

  1. Comparison of System Identification Methods using Ambient Bridge Test Data

    DEFF Research Database (Denmark)

    Andersen, P.; Peeters, B.; Hermans, L.;

    In this paper the performance of four different system identification methods is compared using operational data obtained from an ambient vibration test of the Swiss Z24 highway bridge. The four methods are the frequency domain based peak-picking methods, the polyreference LSCE method...

  2. Comparison of System Identification Methods using Ambient Bridge Test Data

    DEFF Research Database (Denmark)

    Andersen, P.; Brincker, Rune; Peeters, B.;

    1999-01-01

    In this paper the performance of four different system identification methods is compared using operational data obtained from an ambient vibration test of the Swiss Z24 highway bridge. The four methods are the frequency domain based peak-picking methods, the polyreference LSCE method...

  3. 33 CFR 159.103 - Vibration test.

    Science.gov (United States)

    2010-07-01

    ...) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.103 Vibration test. The device... subjected to a sinusoidal vibration for a period of 12 hours, 4 hours in each of the x, y, and z planes,...

  4. Ambient Vibration Based Damage Diagnosis Using Statistical Modal Filtering and Genetic Algorithm: A Bridge Case Study

    Directory of Open Access Journals (Sweden)

    S. El-Ouafi Bahlous

    2013-01-01

    Full Text Available The authors recently developed a damage identification method which combines ambient vibration measurements and a Statistical Modal Filtering approach to predict the location and degree of damage. The method was then validated experimentally via ambient vibration tests conducted on full-scale reinforced concrete laboratory specimens. The main purpose of this paper is to demonstrate the feasibility of the identification method for a real bridge. An important challenge in this case is to overcome the absence of vibration measurements for the structure in its undamaged state which corresponds ideally to the reference state of the structure. The damage identification method is, therefore, modified to adapt it to the present situation where the intact state was not subjected to measurements. An additional refinement of the method consists of using a genetic algorithm to improve the computational efficiency of the damage localization method. This is particularly suited for a real case study where the number of damage parameters becomes significant. The damage diagnosis predictions suggest that the diagnosed bridge is damaged in four elements among a total of 168 elements with degrees of damage varying from 6% to 18%.

  5. 49 CFR 178.985 - Vibration test.

    Science.gov (United States)

    2010-10-01

    ... Testing of Large Packagings § 178.985 Vibration test. (a) General. All rigid Large Packaging and flexible Large Packaging design types must be capable of withstanding the vibration test. (b) Test method. (1) A sample Large Packaging, selected at random, must be filled and closed as for shipment. Large...

  6. Studies Of Residual Flexibility And Vibration Testing

    Science.gov (United States)

    Admire, John R.; Tinker, Michael L.; Bookout, Paul S.; Ivey, Edward W.

    1995-01-01

    Collection of reports presents theoretical and experimental studies in which concept of residual flexibility applied to modal vibration testing and verification of mathematical models of vibrations of flexible structure constrained by another structure. "Residual flexibility" denotes that part of interface flexibility due to mode shapes out of frequency range of test. Studies directed toward assessing residual-flexibility approach as substitute for fixed-base vibrational testing of payloads installed in spacecraft.

  7. Ground test for vibration control demonstrator

    Science.gov (United States)

    Meyer, C.; Prodigue, J.; Broux, G.; Cantinaud, O.; Poussot-Vassal, C.

    2016-09-01

    In the objective of maximizing comfort in Falcon jets, Dassault Aviation is developing an innovative vibration control technology. Vibrations of the structure are measured at several locations and sent to a dedicated high performance vibration control computer. Control laws are implemented in this computer to analyse the vibrations in real time, and then elaborate orders sent to the existing control surfaces to counteract vibrations. After detailing the technology principles, this paper focuses on the vibration control ground demonstration that was performed by Dassault Aviation in May 2015 on Falcon 7X business jet. The goal of this test was to attenuate vibrations resulting from fixed forced excitation delivered by shakers. The ground test demonstrated the capability to implement an efficient closed-loop vibration control with a significant vibration level reduction and validated the vibration control law design methodology. This successful ground test was a prerequisite before the flight test demonstration that is now being prepared. This study has been partly supported by the JTI CleanSky SFWA-ITD.

  8. Analysis of three-component ambient vibration array measurements

    Science.gov (United States)

    Fäh, Donat; Stamm, Gabriela; Havenith, Hans-Balder

    2008-01-01

    Both synthetic and observed ambient vibration array data are analysed using high-resolution beam-forming. In addition to a classical analysis of the vertical component, this paper presents results derived from processing horizontal components. We analyse phase velocities of fundamental and higher mode Rayleigh and Love waves, and particle motions (ellipticity) retrieved from H/V spectral ratios. A combined inversion with a genetic algorithm and a strategy for selecting possible model parameters allow us to define structural models explaining the data. The results from synthetic data for simple models with one or two layers of sediments suggest that, in most cases, the number of layers has to be reduced to a few sediment strata to find the original structure. Generally, reducing the number of soft-sediment layers in the inversion process with genetic algorithms leads to a class of models that are less smooth. They have a stronger impedance contrast between sediments and bedrock. Combining Love and Rayleigh wave dispersion curves with the ellipticity of the fundamental mode Rayleigh waves has some advantages. Scatter is reduced when compared to using structural models obtained only from Rayleigh wave phase velocity curves. By adding information from Love waves some structures can be excluded. Another possibility for constraining inversion results is to include supplementary geological or borehole information. Analysing radial components also can provide segments of Rayleigh wave dispersion curves for modes not seen on the vertical component. Finally, using ellipticity information allows us to confine the total depth of the soft sediments. For real sites, considerable variability in the measured phase velocity curves is observed. This comes from lateral changes in the structure or seismic sources within the array. Constraining the inversion by combining Love and Rayleigh wave information can help reduce such problems. Frequency bands in which the Rayleigh wave

  9. Vibration of a Cantilever Beam in Ambient Fluid

    CERN Document Server

    Metzger, C; Zypman, F

    2016-01-01

    Here we obtain analytical expressions for the frequency response of a cantilever beam in the presence of ambient fluid. The advantage of our approach, besides its simplicity of use, is that it explicitly contains the viscosity and the density of the ambient fluid. Thus, if measuring the frequency spectrum, the expression can be used in the design of viscometers. Conversely, if the ambient fluid is known, the expression can be used in the design of force gauges such as in Atomic Force Microscopy.

  10. Materials for Damping Ambient Acoustic and Vibration Signals Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Long-term exposure to even relatively low levels of acoustic and vibration signals has been shown to be potentially harmful to humans. A new class of piezoelectric...

  11. Identifying damage locations under ambient vibrations utilizing vector autoregressive models and Mahalanobis distances

    Science.gov (United States)

    Mosavi, A. A.; Dickey, D.; Seracino, R.; Rizkalla, S.

    2012-01-01

    This paper presents a study for identifying damage locations in an idealized steel bridge girder using the ambient vibration measurements. A sensitive damage feature is proposed in the context of statistical pattern recognition to address the damage detection problem. The study utilizes an experimental program that consists of a two-span continuous steel beam subjected to ambient vibrations. The vibration responses of the beam are measured along its length under simulated ambient vibrations and different healthy/damage conditions of the beam. The ambient vibration is simulated using a hydraulic actuator, and damages are induced by cutting portions of the flange at two locations. Multivariate vector autoregressive models were fitted to the vibration response time histories measured at the multiple sensor locations. A sensitive damage feature is proposed for identifying the damage location by applying Mahalanobis distances to the coefficients of the vector autoregressive models. A linear discriminant criterion was used to evaluate the amount of variations in the damage features obtained for different sensor locations with respect to the healthy condition of the beam. The analyses indicate that the highest variations in the damage features were coincident with the sensors closely located to the damages. The presented method showed a promising sensitivity to identify the damage location even when the induced damage was very small.

  12. Embedding human annoyance rate models in wireless smart sensors for assessing the influence of subway train-induced ambient vibration

    Science.gov (United States)

    Sun, Ke; Zhang, Wei; Ding, Huaping; Kim, Robin E.; Spencer, Billie F., Jr.

    2016-10-01

    The operation of subway trains induces ambient vibrations, which may cause annoyance and other adverse effects on humans, eventually leading to physical, physiological, and psychological problems. In this paper, the human annoyance rate (HAR) models, used to assess the human comfort under the subway train-induced ambient vibrations, were deduced and the calibration curves for 5 typical use circumstances were addressed. An autonomous measurement system, based on the Imote2, wireless smart sensor (WSS) platform, plus the SHM-H, high-sensitivity accelerometer board, was developed for the HAR assessment. The calibration curves were digitized and embedded in the computational core of the WSS unit. Experimental validation was conducted, using the developed system on a large underground reinforced concrete frame structure adjoining the subway station. The ambient acceleration of both basement floors was measured; the embedded computation was implemented and the HAR assessment results were wirelessly transmitted to the central server, all by the WSS unit. The HAR distributions of the testing areas were identified, and the extent to which both basements will be influenced by the close-up subway-train’s operation, in term of the 5 typical use circumstances, were quantitatively assessed. The potential of the WSS-based autonomous system for the fast environment impact assessment of the subway train-induced ambient vibration was well demonstrated.

  13. High force vibration testing with wide frequency range

    Science.gov (United States)

    Romero, Edward F.; Jepsen, Richard A.; Gregory, Danny Lynn

    2013-04-02

    A shaker assembly for vibration testing includes first and second shakers, where the first shaker includes a piezo-electric material for generating vibration. A support structure permits a test object to be supported for vibration of the test object by both shakers. An input permits an external vibration controller to control vibration of the shakers.

  14. 14 CFR 33.83 - Vibration test.

    Science.gov (United States)

    2010-01-01

    ... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Block Tests; Turbine Aircraft Engines § 33.83 Vibration test. (a) Each engine... throughout the declared flight envelope. The engine surveys shall be based upon an appropriate combination...

  15. Vibrational Stability of SRF Accelerator Test Facility at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    McGee, M.W.; Volk, J.T.; /Fermilab

    2009-05-01

    Recently developed, the Superconducting Radio Frequency (SRF) Accelerator Test Facilities at Fermilab support the International Linear Collider (ILC), High Intensity Neutrino Source (HINS), a new high intensity injector (Project X) and other future machines. These facilities; Meson Detector Building (MDB) and New Muon Lab (NML) have very different foundations, structures, relative elevations with respect to grade level and surrounding soil composition. Also, there are differences in the operating equipment and their proximity to the primary machine. All the future machines have stringent operational stability requirements. The present study examines both near-field and ambient vibration in order to develop an understanding of the potential contribution of near-field sources (e.g. compressors, ultra-high and standard vacuum equipment, klystrons, modulators, utility fans and pumps) and distant noise sources to the overall system displacements. Facility vibration measurement results and methods of possible isolation from noise sources are presented and discussed.

  16. 49 CFR 178.819 - Vibration test.

    Science.gov (United States)

    2010-10-01

    ... qualification of all rigid IBC design types. Flexible IBC design types must be capable of withstanding the... be performed for one hour at a frequency that causes the package to be raised from the vibrating... methods at least equally effective may be used (see § 178.801(i)). (c) Criteria for passing the test....

  17. A METHOD OF ONLINE DAMAGE IDENTIFICATION FOR STRUCTURES BASED ON AMBIENT VIBRATION

    Institute of Scientific and Technical Information of China (English)

    YAO Zhi-yuan; WANG Feng-quan; ZHAO Chun-sheng

    2005-01-01

    A method of damage identification for engineering structures based on ambient vibration is put forward, in which output data are used only. Firstly, it was identification of the statistic parameters to associate with the exterior excitation for undamaged structures.Then it was detection and location of the structural damages for damaged structures. The ambient identification method includes a theoretical model and numerical method. The numerical experiment results show the method is precise and effective. This method may be used in health monitoring for bridges and architectures.

  18. A three-dimensional electret-based micro power generator for low-level ambient vibrational energy harvesting

    Science.gov (United States)

    Tao, Kai; Liu, Shuwei; Woh Lye, Sun; Miao, Jianmin; Hu, Xiao

    2014-06-01

    A novel three-dimensional (3D) electret-based micro power generator with multiple vibration modes has been developed, which is capable of converting low-level ambient kinetic energy to electrical energy. The device is based on a rotational symmetrical resonator which consists of a movable disc-shaped seismic mass suspended by three sets of spiral springs. Experimental analysis shows that the proposed generator operates at an out-of-plane direction at mode I of 66 Hz and two in-plane directions at mode II of 75 Hz and mode III of 78.5 Hz with a phase difference of about 90°. A corona localized charging method is also proposed that employs a shadow mask and multiple discharge needles for the production of micro-sized electret array. From tests conducted at an acceleration of 0.05 g, the prototype can generate a maximum power of 4.8 nW, 0.67 nW and 1.2 nW at vibration modes of I, II and III, respectively. These values correspond to the normalized power densities of 16 µW cm-3 g-2, 2.2 µW cm-3 g-2 and 4 µW cm-3 g-2, respectively. The results show that the generator can potentially offer an intriguing alternative for scavenging low-level ambient energy from 3D vibration sources.

  19. In Situ Experiment and Modelling of RC-Structure Using Ambient Vibration and Timoshenko Beam

    CERN Document Server

    Michel, Clotaire; Guéguen, Philippe; Boutin, Claude

    2007-01-01

    Recently, several experiments were reported using ambient vibration surveys in buildings to estimate the modal parameters of buildings. Their modal properties are full of relevant information concerning its dynamic behaviour in its elastic domain. The main scope of this paper is to determine relevant, though simple, beam modelling whose validity could be easily checked with experimental data. In this study, we recorded ambient vibrations in 3 buildings in Grenoble selected because of their vertical structural homogeneity. First, a set of recordings was done using a 18 channels digital acquisition system (CityShark) connected to six 3C Lennartz 5s sensors. We used the Frequency Domain Decomposition (FDD) technique to extract the modal parameters of these buildings. Second, it is shown in the following that the experimental quasi-elastic behaviour of such structure can be reduced to the behaviour of a vertical continuous Timoshenko beam. A parametric study of this beam shows that a bijective relation exists bet...

  20. Study of the Ambient Vibration Energy Harvesting Based on Piezoelectric Effect

    Science.gov (United States)

    Si, Hongyu; Dong, Jinlu; Chen, Lei; Sun, Laizhi; Zhang, Xiaodong; Gao, Mintian

    2014-01-01

    The resonance between piezoelectric vibrator and the vibration source is the key to maximize the ambient vibration energy harvesting by using piezoelectric generator. In this paper, the factors that influence the output power of a single piezoelectric vibrator are analyzed. The effect of geometry size (length, thickness, width of piezoelectric chip and thickness of metal shim) of a single cantilever piezoelectric vibrator to the output power is analyzed and simulated with the help of MATLAB (matrix laboratory). The curves that output power varies with geometry size are obtained when the displacement and load at the free end are constant. Then the paper points out multi-resonant frequency piezoelectric power generation, including cantilever multi-resonant frequency piezoelectric power generation and disc type multi-resonant frequency piezoelectric generation. Multi-resonant frequency of cantilever piezoelectric power generation can be realized by placing different quality mass at the free end, while disc type multi-resonant frequency piezoelectric generation can be realized through series and parallel connection of piezoelectric vibrator.

  1. A hybrid indoor ambient light and vibration energy harvester for wireless sensor nodes.

    Science.gov (United States)

    Yu, Hua; Yue, Qiuqin; Zhou, Jielin; Wang, Wei

    2014-05-19

    To take advantage of applications where both light and vibration energy are available, a hybrid indoor ambient light and vibration energy harvesting scheme is proposed in this paper. This scheme uses only one power conditioning circuit to condition the combined output power harvested from both energy sources so as to reduce the power dissipation. In order to more accurately predict the instantaneous power harvested from the solar panel, an improved five-parameter model for small-scale solar panel applying in low light illumination is presented. The output voltage is increased by using the MEMS piezoelectric cantilever arrays architecture. It overcomes the disadvantage of traditional MEMS vibration energy harvester with low voltage output. The implementation of the maximum power point tracking (MPPT) for indoor ambient light is implemented using analog discrete components, which improves the whole harvester efficiency significantly compared to the digital signal processor. The output power of the vibration energy harvester is improved by using the impedance matching technique. An efficient mechanism of energy accumulation and bleed-off is also discussed. Experiment results obtained from an amorphous-silicon (a-Si) solar panel of 4.8 × 2.0 cm2 and a fabricated piezoelectric MEMS generator of 11 × 12.4 mm2 show that the hybrid energy harvester achieves a maximum efficiency around 76.7%.

  2. A Hybrid Indoor Ambient Light and Vibration Energy Harvester for Wireless Sensor Nodes

    Directory of Open Access Journals (Sweden)

    Hua Yu

    2014-05-01

    Full Text Available To take advantage of applications where both light and vibration energy are available, a hybrid indoor ambient light and vibration energy harvesting scheme is proposed in this paper. This scheme uses only one power conditioning circuit to condition the combined output power harvested from both energy sources so as to reduce the power dissipation. In order to more accurately predict the instantaneous power harvested from the solar panel, an improved five-parameter model for small-scale solar panel applying in low light illumination is presented. The output voltage is increased by using the MEMS piezoelectric cantilever arrays architecture. It overcomes the disadvantage of traditional MEMS vibration energy harvester with low voltage output. The implementation of the maximum power point tracking (MPPT for indoor ambient light is implemented using analog discrete components, which improves the whole harvester efficiency significantly compared to the digital signal processor. The output power of the vibration energy harvester is improved by using the impedance matching technique. An efficient mechanism of energy accumulation and bleed-off is also discussed. Experiment results obtained from an amorphous-silicon (a-Si solar panel of 4.8 × 2.0 cm2 and a fabricated piezoelectric MEMS generator of 11 × 12.4 mm2 show that the hybrid energy harvester achieves a maximum efficiency around 76.7%.

  3. A hybrid indoor ambient light and vibration energy harvester for wireless sensor nodes.

    Science.gov (United States)

    Yu, Hua; Yue, Qiuqin; Zhou, Jielin; Wang, Wei

    2014-01-01

    To take advantage of applications where both light and vibration energy are available, a hybrid indoor ambient light and vibration energy harvesting scheme is proposed in this paper. This scheme uses only one power conditioning circuit to condition the combined output power harvested from both energy sources so as to reduce the power dissipation. In order to more accurately predict the instantaneous power harvested from the solar panel, an improved five-parameter model for small-scale solar panel applying in low light illumination is presented. The output voltage is increased by using the MEMS piezoelectric cantilever arrays architecture. It overcomes the disadvantage of traditional MEMS vibration energy harvester with low voltage output. The implementation of the maximum power point tracking (MPPT) for indoor ambient light is implemented using analog discrete components, which improves the whole harvester efficiency significantly compared to the digital signal processor. The output power of the vibration energy harvester is improved by using the impedance matching technique. An efficient mechanism of energy accumulation and bleed-off is also discussed. Experiment results obtained from an amorphous-silicon (a-Si) solar panel of 4.8 × 2.0 cm2 and a fabricated piezoelectric MEMS generator of 11 × 12.4 mm2 show that the hybrid energy harvester achieves a maximum efficiency around 76.7%. PMID:24854054

  4. Virtual Shaker Testing: Simulation Technology Improves Vibration Test Performance

    Science.gov (United States)

    Ricci, Stefano; Peeters, Bart; Fetter, Rebecca; Boland, Doug; Debille, Jan

    2008-01-01

    In the field of vibration testing, the interaction between the structure being tested and the instrumentation hardware used to perform the test is a critical issue. This is particularly true when testing massive structures (e.g. satellites), because due to physical design and manufacturing limits, the dynamics of the testing facility often couples with the test specimen one in the frequency range of interest. A further issue in this field is the standard use of a closed loop real-time vibration control scheme, which could potentially shift poles and change damping of the aforementioned coupled system. Virtual shaker testing is a novel approach to deal with these issues. It means performing a simulation which closely represents the real vibration test on the specific facility by taking into account all parameters which might impact the dynamic behavior of the specimen. In this paper, such a virtual shaker testing approach is developed. It consists of the following components: (1) Either a physical-based or an equation-based coupled electro-mechanical lumped parameter shaker model is created. The model parameters are obtained from manufacturer's specifications or by carrying out some dedicated experiments; (2) Existing real-time vibration control algorithm are ported to the virtual simulation environment; and (3) A structural model of the test object is created and after defining proper interface conditions structural modes are computed by means of the well-established Craig-Bampton CMS technique. At this stage, a virtual shaker test has been run, by coupling the three described models (shaker, control loop, structure) in a co-simulation routine. Numerical results have eventually been correlated with experimental ones in order to assess the robustness of the proposed methodology.

  5. Estimation of Subjective Difficulty and Psychological Stress by Ambient Sensing of Desk Panel Vibrations

    Science.gov (United States)

    Hamaguchi, Nana; Yamamoto, Keiko; Iwai, Daisuke; Sato, Kosuke

    We investigate ambient sensing techniques that recognize writer's psychological states by measuring vibrations of handwriting on a desk panel using a piezoelectric contact sensor attached to its underside. In particular, we describe a technique for estimating the subjective difficulty of a question for a student as the ratio of the time duration of thinking to the total amount of time spent on the question. Through experiments, we confirm that our technique correctly recognizes whether or not a person writes something down on paper by measured vibration data at the accuracy of over 80 %, and that the order of computed subjective difficulties of three questions is coincident with that reported by the subject in 60 % of experiments. We also propose a technique to estimate a writer's psychological stress by using the standard deviation of the spectrum of the measured vibration. Results of a proof-of-concept experiment show that the proposed technique correctly estimates whether or not the subject feels stress at least 90 % of the time.

  6. Peri-prosthetic fracture vibration testing

    Energy Technology Data Exchange (ETDEWEB)

    Cruce, Jesse R [Los Alamos National Laboratory; Erwin, Jenny R [Los Alamos National Laboratory; Remick, Kevin R [Los Alamos National Laboratory; Cornwell, Phillip J [Los Alamos National Laboratory; Menegini, R. Michael [INDIANA UNIV.; Racanelli, Joe [STRYKER ORTHOPARDICS

    2010-11-08

    The purpose of this study was to establish a test setup and vibration analysis method to predict femoral stem seating and prevent bone fracture using accelerometer and force response data from an instrumented stem and impactor. This study builds upon earlier studies to identify a means to supplement a surgeon's tactile and auditory senses by using damage identification techniques normally used for civil and mechanical structures. Testing was conducted using foam cortical shell sawbones prepared for stems of different geometries. Each stem was instrumented with an accelerometer. Two impactor designs were compared: a monolithic impactor and a two-piece impactor, each with an integrated load cell and accelerometer. Acceleration and force measurements were taken in the direction of impaction. Comparisons between different methods of applying an impacting force were made, including a drop tower and a surgical hammer. The effect of varying compliance on the data was also investigated. The ultimate goal of this study was to assist in the design of an integrated portable data acquisition system capable of being used in future cadaveric testing. This paper will discuss the experimental setup and the subsequent results of the comparisons made between impactors, prosthetic geometries, compliances, and impact methods. The results of this study can be used for both future replicate testing as well as in a cadaveric environment.

  7. 46 CFR 162.050-37 - Vibration test.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 6 2010-10-01 2010-10-01 false Vibration test. 162.050-37 Section 162.050-37 Shipping...: SPECIFICATIONS AND APPROVAL ENGINEERING EQUIPMENT Pollution Prevention Equipment § 162.050-37 Vibration test. (a... paragraph (b) of this section. The test must be performed at an independent laboratory that has...

  8. Peri-prosthetic fracture vibration testing

    Energy Technology Data Exchange (ETDEWEB)

    Cruce, Jesse R [Los Alamos National Laboratory; Erwin, Jenny R [Los Alamos National Laboratory; Remick, Kevin R [Los Alamos National Laboratory; Cornwell, Phillip J [Los Alamos National Laboratory; Menegini, R. Michael [INDIANA UNIV.; Racanelli, Joe [STRYKER ORTHOPAEDICS

    2011-01-28

    The purpose of this study is to establish a test setup and vibration analysis method to predict femoral stem seating and prevent bone fracture using accelerometer or force response data from an instrument stem and impactor. This study builds upon earlier studies to identify a means to supplement a surgeon's tactile and auditory senses by using damage identification techniques normally used for civil and mechanical structures. Testing will be conducted using foam cortical shell sawbones prepared for stems of different geometries. Each stem will be instrumented with an accelerometer. Two impactor designs will be compared: a monolithic impactor with an integrated load cell and accelerometer and a two piece impactor. Acceleration and force measurements will be taken in the direction of impaction. Signal processing techniques will be applied to the acceleration time histories to determine features that can be used to assess device seating and potential fracture. A consistent energy input will be applied using a drop tower. The effect of introducing compliance under the bone support vise will also be investigated. The ultimate goal of this study is to design an integrated portable data acquisition system capable of being used in future cadaveric testing. This paper will discuss the experimental set-up, the signal processing techniques used and the subsequent results.

  9. Modeling and analysis of a micromachined piezoelectric energy harvester stimulated by ambient random vibrations

    Science.gov (United States)

    Alamin Dow, Ali B.; Al-Rubaye, Hasan A.; Koo, David; Schneider, Michael; Bittner, Achim; Schmid, Ulrich; Kherani, Nazir P.

    2011-06-01

    Piezoelectric energy microgenerators are devices that continuously generate electricity when they are subjected to varying mechanical strain due to vibrations. They can generate electrical power up to 100 μW which can be used to drive various sensing and actuating MEMS devices. Today, piezoelectric energy harvesters are considered autonomous and reliable energy sources to actuate low power microdevices such as wireless sensor networks, indoor-outdoor monitoring, facility management and biomedical applications. The advantages of piezoelectric energy harvesters including high power density, moderate output power and CMOS compatible fabrication in particular with aluminum nitride (AlN) have fuelled and motivated researchers to develop MEMS based energy harvesters. Recently, the use of AlN as a piezoelectric material has increased fabrication compatibility, enabling the realization of smart integrated systems on chip which include sensors, actuators and energy storage. Piezoelectric MEMS energy microgenerator is used to capture and transform the available ambient mechanical vibrations into usable electric energy via resonant coupling in the thin film piezoelectric material. Analysis and modeling of piezoelectric energy generators are very important aspects for improved performance. Aluminum nitride as the piezoelectric material is sandwiched between two electrodes. The device design includes a silicon cantilever on which the AlN film is deposited and which features a seismic mass at the end of the cantilever. Beam theory and lumped modeling with circuit elements are applied for modeling and analysis of the device operation at various acceleration values. The model shows good agreement with the experimental findings, thus giving confidence in the model.

  10. Energy Harvesting from Ambient Vibrations with Arbitrary In-Plane Motion Directions Using a Magnetostrictive/Piezoelectric Laminate Composite Transducer

    Science.gov (United States)

    Yang, Jin; Wen, Yumei; Li, Ping; Yue, Xihai; Yu, Qiangmo

    2014-07-01

    A magnetoelectric (ME) vibration energy harvester has been designed to scavenge sufficient energy from ambient vibration with arbitrary motion directions in a plane and over a range of frequencies. In the harvester, a circular-cross-section cantilever rod is adopted to extract the vibration energy due to its ability to host accelerations in arbitrary in-plane motion directions. The magnetic coupling between the magnet and the ME transducer results in nonlinear oscillation of the cantilever rod with increased frequency bandwidth. To achieve optimal vibration energy harvesting performance, the effects of the nonlinear vibration and the harvester parameters including the magnetic circuit and the separation distance on the electrical output and the␣working bandwidth are analyzed. The experimental results show that the harvester can scavenge vibration energy in arbitrary in-plane directions, exhibiting a bandwidth of 4.0 Hz and maximum power of 0.22 mW at acceleration of 0.6 g (with g = 9.8 m s-2).

  11. Development of seismic technology and reliability based on vibration tests

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Youichi [Nuclear Power Engineering Corp., Tokyo (Japan)

    1997-03-01

    This paper deals with some of the vibration tests and investigations on the seismic safety of nuclear power plants (NPPs) in Japan. To ensure the reliability of the seismic safety of nuclear power plants, nuclear power plants in Japan have been designed according to the Technical Guidelines for Aseismic Design of Nuclear Power Plants. This guideline has been developed based on technical date base and findings which were obtained from many vibration tests and investigations. Besides the tests for the guideline, proving tests on seismic reliability of operating nuclear power plants equipment and systems have been carried out. In this paper some vibration tests and their evaluation results are presented. They have crucially contributed to develop the guideline. (J.P.N.)

  12. Stereovision vibration measurement test of a masonry building model

    Science.gov (United States)

    Shan, Baohua; Gao, Yunli; Shen, Yu

    2016-04-01

    To monitor 3D deformations of structural vibration response, a stereovision-based 3D deformation measurement method is proposed in paper. The world coordinate system is established on structural surface, and 3D displacement equations of structural vibration response are acquired through coordinate transformation. The algorithms of edge detection, center fitting and matching constraint are developed for circular target. A shaking table test of a masonry building model under Taft and El Centro earthquake at different acceleration peak is performed in lab, 3D displacement time histories of the model are acquired by the integrated stereovision measurement system. In-plane displacement curves obtained by two methods show good agreement, this suggests that the proposed method is reliable for monitoring structural vibration response. Out-of-plane displacement curves indicate that the proposed method is feasible and useful for monitoring 3D deformations of vibration response.

  13. Fatigue evaluation of piping systems with limited vibration test data

    International Nuclear Information System (INIS)

    The safety-related piping in a nuclear power plant may be subjected to pump- or fluid-induced vibrations that, in general, affect only local areas of the piping systems. Pump- or fluid-induced vibrations typically are characterized by low levels of amplitudes and a high number of cycles over the lifetime of plant operation. Thus, the resulting fatigue damage to the piping systems could be an important safety concern. In general, tests and/or analyses are used to evaluate and qualify the piping systems. Test data, however, may be limited because of lack of instrumentation in critical piping locations and/or because of difficulty in obtaining data in inaccessible areas. This paper describes and summarizes a method to use limited pipe vibration test data, along with analytical harmonic response results from finite-element analyses, to assess the fatigue damage of nuclear power plant safety-related piping systems. 5 refs., 2 figs., 11 tabs

  14. Vibration testing of a 1/4-scale containment model

    International Nuclear Information System (INIS)

    This paper presents programs for the validation of soil-structure interaction (SSI) analysis methods with data that include ground and structural response motions during natural earthquakes and structural response from low-level vibration tests. The primary source of the data is the 1/4-scale containment building situated in Lotung in a seismically active region of Taiwan. The analysis validation program involves blind predictions of site and structural response to the vibration test excitations and to a selected strong-motion seismic event, and the subsequent comparison of predictions with corresponding measurements. This paper focuses on the vibration testing of the model containment structure and the determination of its dynamic characteristics from the experimental data. The 1/4-scale reinforced concrete containment structure, built by EPRI in cooperation with Taiwan Power Company, is located within an array of strong-motion seismographs, known as the SMART-1 array

  15. Numerical modeling of the dynamic response of prone-to-fall columns to ambient vibrations: comparison with measurements and potential application

    Science.gov (United States)

    Capron, Alexandre; Valentin, Johann; Jongmans, Denis; Baillet, Laurent; Larose, Eric; Bottelin, Pierre; Donze, Frédéric; Mangeney, Anne

    2015-04-01

    During the last two decades, seismic noise measurements have been increasingly used in gravitational hazard assessment for both investigation and monitoring purposes. The wide frequency range allows ambient vibrations to be applied for investigating geological and civil engineering structures in a great variety of sizes, from the lithospheric or crust scale to a few m-thick landslide and rock column or buildings. On unstable slopes, ambient vibrations have been applied in very different ways for reconnaissance, depending on the investigation purpose and the landslide type. The simplest way to extract information from ambient vibrations on a given site is to perform single-station measurements with a 3-C sensor and to process the records computing Fourier spectra of the three components or the spectral ratio between the horizontal and vertical components (the so-called H/V method). On landslide sites, several studies revealed significant spectral amplification at given frequency and polarization of the wave-field in the direction of maximum slope displacement. They show that different characteristics of the seismic noise (resonant frequencies, polarization, and spectral amplification) could be used from the spectral analysis of the motion or of spectral ratios for characterizing the landslides. For cliff-like sites, this study aims to identify the pertinent and applicable parameters that could be extracted from ambient vibrations and used to gain information on the prone-to-fall column geometry. We first use 2D numerical modeling for better understanding the influence of the rear fracture characteristics (wideness w and depth L) on the horizontal motion H(f), as well as on the spectral ratios H(f)/V(f) and H(f)/Hr(f), where Hr(f) is the horizontal motion measured at a reference site. We then identify the seismic parameters able to characterize the column decoupling and we compare numerical results to data acquired at two rocky sites exhibiting cliff-like geometry

  16. Active Blade Vibration Control Being Developed and Tested

    Science.gov (United States)

    Johnson, Dexter

    2003-01-01

    Gas turbine engines are currently being designed to have increased performance, lower weight and manufacturing costs, and higher reliability. Consequently, turbomachinery components, such as turbine and compressor blades, have designs that are susceptible to new vibration problems and eventual in-service failure due to high-cycle fatigue. To address this problem, researchers at the NASA Glenn Research Center are developing and testing innovative active blade vibration control concepts. Preliminary results of using an active blade vibration control system, involving a rotor supported by an active magnetic bearing in Glenn's Dynamic Spin Rig, indicate promising results (see the photograph). Active blade vibration control was achieved using feedback of blade strain gauge signals within the magnetic bearing control loop. The vibration amplitude was reduced substantially (see the graphs). Also, vibration amplitude amplification was demonstrated; this could be used to enhance structural mode identification, if desired. These results were for a nonrotating two-bladed disk. Tests for rotating blades are planned. Current and future active blade vibration control research is planned to use a fully magnetically suspended rotor and smart materials. For the fully magnetically suspended rotor work, three magnetic bearings (two radial and one axial) will be used as actuators instead of one magnetic bearing. This will allow additional degrees of freedom to be used for control. For the smart materials work, control effectors located on and off the blade will be considered. Piezoelectric materials will be considered for on-the-blade actuation, and actuator placement on a stator vane, or other nearby structure, will be investigated for off-the-blade actuation. Initial work will focus on determining the feasibility of these methods by performing basic analysis and simple experiments involving feedback control.

  17. ambiental

    Directory of Open Access Journals (Sweden)

    Roque Leal Salcedo

    2008-01-01

    Full Text Available El derecho internacional ambiental es un conocimiento de carácter transversal, que entre otras consideraciones refleja las preocupaciones de la sociedad por la implementación de un modelo de desarrollo sustentable para el respeto a las reglas del medio natural que garantizan la integridad y renovación de los sistemas naturales. El presente artículo enfoca esta visión a través del análisis de material documental revisado, entre ellos tratados internacionales que permiten distinguir el desarrollo del derecho internacional ambiental y el papel de Organización de las Naciones Unidas (ONU, en el propósito común del derecho individual y colectivo de disfrutar de una vida, un ambiente seguro, sano y ecológicamente equilibrado. En función a estas disertaciones las consideraciones finales exponen parte de la visión que ha estructurado la ONU y que representan un aporte considerable en el fomento de la conciencia mundial sobre la necesidad de establecer vínculos entre las naciones para el continuo desarrollo de esta rama del derecho.

  18. CENTRIFUGAL VIBRATION TEST OF RC PILE FOUNDATION

    Science.gov (United States)

    Higuchi, Shunichi; Tsutsumiuchi, Takahiro; Otsuka, Rinna; Ito, Koji; Ejiri, Joji

    It is necessary that nonlinear responses of structures are clarified by soil-structure interaction analysis for the purpose of evaluating the seismic performances of underground structure or foundation structure. In this research, centrifuge shake table tests of reinforced concrete pile foundation installed in the liquefied ground were conducted. Then, finite element analyses for the tests were conducted to confirm an applicability of the analytical method by comparing the experimental results and analytical results.

  19. An equipment test for grading lumber by transverse vibration technique

    Directory of Open Access Journals (Sweden)

    Marcelo Rodrigo Carreira

    2008-08-01

    Full Text Available Due to the great variability of its mechanical properties, the rational use of lumber for structural purposes is directly conditioned to its grading. There are several techniques available for grading structural lumber. The most relevant one is the transverse vibration technique which obtained reliable results in non-destructive evaluation of lumber. The purpose of this work is to present the bases for the mechanical grading of lumber and the results of the calibration test of the frst transverse vibration equipment developed in Brazil. In this research 30 beams of cupiúba (Goupia glabra with nominal dimensions of 5 cm X 10 cm X 300 cm, were used. The tests were accomplished at the Wood and Timber Structures Laboratory (LaMEM of the University of São Paulo (USP. The results showed a strong correlation between the elasticity modulus measured by the static bending test and the one obtained with the transverse vibration equipment, showing the high reliability of the vibration method for the grading of structural lumber. A determination coeffcient (R² of 0.896 was obtained with the Brazilian equipment, showing that it can be used in the grading of lumber.

  20. Water Power Calculator Temperature and Analog Input/Output Module Ambient Temperature Testing

    Energy Technology Data Exchange (ETDEWEB)

    Mark D. McKay

    2011-02-01

    Water Power Calculator Temperature and Analog input/output Module Ambient Temperature Testing A series of three ambient temperature tests were conducted for the Water Power Calculator development using the INL Calibration Laboratory’s Tenney Environmental Chamber. The ambient temperature test results demonstrate that the Moore Industries Temperature Input Modules, Analog Input Module and Analog Output Module, ambient temperature response meet or exceed the manufactures specifications

  1. Forced vibration test of the Hualien large scale SSI model

    International Nuclear Information System (INIS)

    A Large-Scale Seismic Test (LSST) Program has been conducted at Hualien, Taiwan (Tang et al., 1991), to obtain earthquake-induced soil-structure interaction (SSI) data in a stiff soil site environment The Hualien program is a follow on of the Lotung program which is of soft soil site. Forced vibration tests of the Hualien 1/4-scale containment SSI test model were conducted in October, 1992 before backfill (without embedment) and in February, 1993 after backfill (with embedment) for the purpose of defining basic dynamic characteristics of the soil-structure system. Two horizontal directions excitation (NS, EW) are applied on the roof floor and on the basemat. Vertical excitation is applied on the basemat only. This paper describes the results of the forced vibration tests of the model without embedment. (author)

  2. Improving the shear wave velocity structure beneath Bucharest (Romania) using ambient vibrations

    Science.gov (United States)

    Manea, Elena Florinela; Michel, Clotaire; Poggi, Valerio; Fäh, Donat; Radulian, Mircea; Balan, Florin Stefan

    2016-11-01

    Large earthquakes from the intermediate-depth Vrancea seismic zone are known to produce in Bucharest ground motion characterized by predominant long periods. This phenomenon has been interpreted as the combined effect of both seismic source properties and site response of the large sedimentary basin. The thickness of the unconsolidated Quaternary deposits beneath the city is more than 200 m, the total depth of sediments is more than 1000 m. Complex basin geometry and the low seismic wave velocities of the sediments are primarily responsible for the large amplification and long duration experienced during earthquakes. For a better understanding of the geological structure under Bucharest, a number of investigations using non-invasive methods have been carried out. With the goal to analyse and extract the polarization and dispersion characteristics of the surface waves, ambient vibrations and low-magnitude earthquakes have been investigated using single station and array techniques. Love and Rayleigh dispersion curves (including higher modes), Rayleigh waves ellipticity and SH-wave fundamental frequency of resonance (f0SH) have been inverted simultaneously to estimate the shear wave velocity structure under Bucharest down to a depth of about 8 km. Information from existing borehole logs was used as prior to reduce the non-uniqueness of the inversion and to constrain the shallow part of the velocity model (Physics and by the Karlsruhe Institute of Technology during 10 months in the period 2003-2004. The array consisted of 32 three-component seismological stations, deployed in the urban area of Bucharest and adjacent zones. The large size of the array and the broad-band nature of the available sensors gave us the possibility to characterize the surface wave dispersion at very low frequencies (0.05-1 Hz) using frequency-wavenumber techniques. This is essential to explore and resolve the deeper portions of the basin. The horizontal to vertical spectral ratio (H/V) curves

  3. Frequency and damping ratio assessment of high-rise buildings using an Automatic Model-Based Approach applied to real-world ambient vibration recordings

    Science.gov (United States)

    Nasser, Fatima; Li, Zhongyang; Gueguen, Philippe; Martin, Nadine

    2016-06-01

    This paper deals with the application of the Automatic Model-Based Approach (AMBA) over actual buildings subjected to real-world ambient vibrations. In a previous paper, AMBA was developed with the aim of automating the estimation process of the modal parameters and minimizing the estimation error, especially that of the damping ratio. It is applicable over a single-channel record, has no parameters to be set, and no manual initialization phase. The results presented in this paper should be regarded as further documentation of the approach over real-world ambient vibration signals.

  4. Random Vibration Testing of Advanced Wet Tantalum Capacitors

    Science.gov (United States)

    Teverovsky, Alexander

    2015-01-01

    Advanced wet tantalum capacitors allow for improved performance of power supply systems along with substantial reduction of size and weight of the systems that is especially beneficial for space electronics. Due to launch-related stresses, acceptance testing of all space systems includes random vibration test (RVT). However, many types of advanced wet tantalum capacitors cannot pass consistently RVT at conditions specified in MIL-PRF-39006, which impedes their use in space projects. This requires a closer look at the existing requirements, modes and mechanisms of failures, specifics of test conditions, and acceptance criteria. In this work, different lots of advanced wet tantalum capacitors from four manufacturers have been tested at step stress random vibration conditions while their currents were monitored before, during, and after the testing. It has been shown that the robustness of the parts and their reliability are mostly due to effective self-healing processes and limited current spiking or minor scintillations caused by RVT do not increase the risk of failures during operation. A simple model for scintillations events has been used to simulate current spiking during RVT and optimize test conditions. The significance of scintillations and possible effects of gas generation have been discussed and test acceptance criteria for limited current spiking have been suggested.

  5. Vibration phenomena in large scale pressure suppression tests

    International Nuclear Information System (INIS)

    Structure and fluid vibration phenomena were observed during blow-down experiments simulating a LOCA in the GKSS full scale multivent pressure suppression test facility. The source related excitations during the two regimes of condensation oscillation and of chugging are described together with the response vibrations of the facility's wetwell. Modal analyses of the wetwell were run using excitation by hammer and by shaker in order to separate phenomena that are particular to the GKSS facility from more general ones, i.e. phenomena specific to the fluid related parameters of blow-down and to the geometry of the vent pipes only. The lowest periodicities at about 12 and 16 Hz stem from the vent acoustics. A frequency of about 36 to 38 Hz prominent during chugging seems to result from the lowest local modes of two of the wetwell's walls when coupled by the wetwell pool. Further peaks found during blow-down in the spectra of signals at higher frequencies correspond to global vibration modes of the wetwell. (author)

  6. USED FUEL RAIL SHOCK AND VIBRATION TESTING OPTIONS ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Steven B.; Best, Ralph E.; Klymyshyn, Nicholas A.; Jensen, Philip J.; Maheras, Steven J.

    2014-09-29

    The objective of the rail shock and vibration tests is to complete the framework needed to quantify loads of fuel assembly components that are necessary to guide materials research and establish a technical basis for review organizations such as the U.S. Nuclear Regulatory Commission (NRC). A significant body of experimental and numerical modeling data exists to quantify loads and failure limits applicable to normal conditions of transport (NCT) rail transport, but the data are based on assumptions that can only be verified through experimental testing. The test options presented in this report represent possible paths for acquiring the data that are needed to confirm the assumptions of previous work, validate modeling methods that will be needed for evaluating transported fuel on a case-by-case basis, and inform material test campaigns on the anticipated range of fuel loading. The ultimate goal of this testing is to close all of the existing knowledge gaps related to the loading of used fuel under NCT conditions and inform the experiments and analysis program on specific endpoints for their research. The options include tests that would use an actual railcar, surrogate assemblies, and real or simulated rail transportation casks. The railcar carrying the cradle, cask, and surrogate fuel assembly payload would be moved in a train operating over rail track modified or selected to impart shock and vibration forces that occur during normal rail transportation. Computer modeling would be used to help design surrogates that may be needed for a rail cask, a cask’s internal basket, and a transport cradle. The objective of the design of surrogate components would be to provide a test platform that effectively simulates responses to rail shock and vibration loads that would be exhibited by state-of-the-art rail cask, basket, and/or cradle structures. The computer models would also be used to help determine the placement of instrumentation (accelerometers and strain gauges

  7. A Novel Vibration Mode Testing Method for Cylindrical Resonators Based on Microphones

    Directory of Open Access Journals (Sweden)

    Yongmeng Zhang

    2015-01-01

    Full Text Available Non-contact testing is an important method for the study of the vibrating characteristic of cylindrical resonators. For the vibratory cylinder gyroscope excited by piezo-electric electrodes, mode testing of the cylindrical resonator is difficult. In this paper, a novel vibration testing method for cylindrical resonators is proposed. This method uses a MEMS microphone, which has the characteristics of small size and accurate directivity, to measure the vibration of the cylindrical resonator. A testing system was established, then the system was used to measure the vibration mode of the resonator. The experimental results show that the orientation resolution of the node of the vibration mode is better than 0.1°. This method also has the advantages of low cost and easy operation. It can be used in vibration testing and provide accurate results, which is important for the study of the vibration mode and thermal stability of vibratory cylindrical gyroscopes.

  8. Underdetermined blind modal identification of structures by earthquake and ambient vibration measurements via sparse component analysis

    Science.gov (United States)

    Amini, Fereidoun; Hedayati, Yousef

    2016-03-01

    Sparse component analysis (SCA) approach was adopted to handle underdetermined blind modal identification of structures, where the number of sensors is less than the number of active modes. To exploit the sparsity of structural responses in time-frequency domain, Short Time Fourier Transform (STFT) was used in this study. The proposed SCA-based approach has two main stages: modal matrix estimation and modal displacement estimation. In the first stage, hierarchical clustering algorithm was used to estimate the modal matrix. The clustering algorithm was preceded by a preprocessing step to select the points in time-frequency domain that only one mode makes contribution in the responses. These points were fed to the clustering algorithm as an input. Performing this analysis enhanced the modal matrix estimation accuracy and reduced the computational cost while conducting clustering analysis. Having estimated mixing matrix, the complex-valued modal responses in the transformed domain were recovered via Smoothed zero-norm (SL-0) algorithm. In a broad sense, using the SL-0 algorithm permits researchers to use any kind of transform in seeking sparsity, regardless of obtaining real-valued or complex-valued signals in transformed domain. Natural frequencies and damping ratios were extracted from the recovered modal responses. Performance of the proposed method was investigated using a synthetic example and a benchmark structure with earthquake and ambient excitation, respectively.

  9. Tailoring of Vibration Test Specifications for a Flight Vehicle

    Directory of Open Access Journals (Sweden)

    Manoj Kumar

    2002-01-01

    Full Text Available Most equipment are subjected to vibration environment during their useful life. It is seen that nearly half of the failures observed during the flights of. satellite launch vehicles or missiles are due to mechanical vibration and shock. Thus, these stresses must be carefully considered while defining the specifications. Specifications are established for a system for use during a simulation test to show that a product meets the requirements concerning resistance to the environment. If the equipment operates smoothly during a test, there should be a very strong probability that it will perform its intended task correctly in the real environment and vice versa. Hence, the specification must be at least as severe as the real environment and also representative of the real environment. It is also required that no other item of the equipment built according to the same design should fail in operation. Specifications should take care of this and thus the envelop of data obtained during the real world environment should be considered. Generally at the design stage and the initial development stage, existing standards like the Military Specifications or Joint Service Specifications are used as guidelines for formulating the specifications. This causes either an overtest or an undertest with regards to the overall spectrum or in specific frequency bands for any given structure. To overcome this, it is essential to develop a correct specification using the telemetry data acquired for a few flights and a method is required to be formulated for deriving the specifications out of the telemetry data so obtained. This paper discusses the formulation of a specification methodology, and algorithm in general. The above method is applied to a series of flight data obtained for a particular flight vehicle to derive a specification representative of the real world environmental conditions (tailoring.

  10. 40 CFR 86.161-00 - Air conditioning environmental test facility ambient requirements.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Air conditioning environmental test... conditioning environmental test facility ambient requirements. The goal of an air conditioning test facility is..., within the test cell, during all phases of the air conditioning test sequence to 95 ±2 °F on average...

  11. VIBRATION TESTING OF A SIXTEEN-STORIED BUILDING THAT HAS A PRECAST CONCRETE BOX STRUCTURE

    Directory of Open Access Journals (Sweden)

    Rumyantsev Anton Andreevich

    2012-10-01

    Full Text Available This article covers the problems of theoretical assessment of the seismic stability of a 16-storied building made of precast concrete box units by full-scale experimental testing through the employment of a powerful unbalance-type vibration machine. The authors provide the results of the experimental testing and scale them to assess the effects of an earthquake. The testing procedure that consists in the assessment of the seismic stability of buildings through employment of the vibration testing performed by a powerful vibration machine installed on the soil surface, have proven its high efficiency. As a result of the vibration testing, specific values of accelerations and shifts in terms of the building height and length were identified in lateral and longitudinal directions. The results of extrapolation of the seismic effect of the vibration testing onto the 9-grade seismic load scale have proven that the buildings of this type can be considered seismically stable.

  12. Telemetry test of blade shaft coupled torsional vibration at the Tsuruga No. 2 power plant

    International Nuclear Information System (INIS)

    The Tsuruga No. 2 nuclear power plant was synchronized on June 19, 1986, and started the commercial operation on February 2, 1987. During the trial operation, a field telemetry test was carried out in order to confirm the last blade vibration characteristics including super-synchronous torsional vibration. Results of this test are presented

  13. Vibration-Induced Conductance Fluctuation (VICOF) Testing of Soils

    CERN Document Server

    Kish, L B; Kishne, A S; Kish, Laszlo B.; Morgan, Cristine L.S.; Kishne, Andrea Sz.

    2005-01-01

    In this Letter, we propose and experimentally demonstrate a simple method to provide additional information by conductance measurements of soils. While the AC electrical conductance of the soil is measured, it is exposed to a periodic vibration. The vibration-induced density fluctuation implies a corresponding conductivity fluctuation that can be seen as combination frequency components, the sum and the difference of the mean AC frequency and the vibration frequency, in the current response. The method is demonstrated by measurements on two different soil types.

  14. Analysis of Vibration Modal Testing for the Full-size Artificial Board

    Directory of Open Access Journals (Sweden)

    Lujing Zhou

    2014-06-01

    Full Text Available The vibration method is one of the most effective methods for nondestructively testing the elasticity modulus of wood. But the past research was mostly concentrated in the small size specimens. In order to better prepare for the nondestructive testing of the elasticity modulus of full-size artificial board, here tests and analyzes its vibration modal. In order to solve the modal parameters of full-size artificial board in free vibration, it uses 6 full-scale artificial boards of two kinds of materials, and for each kind there are 3 kinds of thicknesses, in which including the particle board and medium density fiberboard as the test objects. Then it props them at the first order pitch line of free vibration, namely the 22.4% and 77.6% of the full-length of the full-size artificial board. After exciting by the pulse hammer and vibration picking by the acceleration sensor, it can measure the vibration mode, the vibration frequency and the damping ratio of the full-size artificial boards at each order. It obtains the vibration mode, the frequency and the damping ratio of the full-size artificial board at the first 3 orders in the free vibration form. The results show that: 1 for the three materials of full-size artificial boards with all thicknesses, their vibration modes at the first order are bending along with the length direction; 2 the vibration modes of the full-size artificial boards with the same thickness are the same at the same order, and are all bending vibration

  15. Integrated Vibration and Acceleration Testing to Reduce Payload Mass, Cost and Mission Risk Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a capability to provide integrated acceleration, vibration, and shock testing using a state-of-the-art centrifuge, allowing for the test of...

  16. Sum frequency generation vibrational spectroscopy at solid gas interfaces: CO adsorption on Pd model catalysts at ambient pressure

    Science.gov (United States)

    Rupprechter, Günther; Unterhalt, Holger; Morkel, Matthias; Galletto, Paolo; Hu, Linjie; Freund, Hans-Joachim

    2002-04-01

    Carbon monoxide adsorption on Pd(1 1 1) and Pd nanoparticles supported by Al 2O 3/NiAl(1 1 0) was examined by vibrational sum frequency generation spectroscopy from 10 -8 to 1000 mbar, and from 100 to 400 K. Identical CO saturation structures were observed on Pd(1 1 1) under ultrahigh vacuum (˜10 -7 mbar, 95 K) and at high pressure (e.g. ⩾1 mbar, 190 K) with no indications of pressure-induced surface rearrangements. Special attention was paid to experimental artifacts that may occur under elevated pressure and may be misinterpreted as "high pressure effects". Vibrational spectra of CO on defect-rich Pd(1 1 1) exhibited an additional peak that originated from CO bound to defect (step or edge) sites. The CO adsorbate structure on supported Pd nanoparticles was different from Pd(1 1 1) but more similar to stepped Pd(1 1 1). At low pressure (10 -7 mbar CO) the adsorbate structure depended strongly on the Pd morphology revealing specific differences in the adsorption properties of supported nanoparticles and single crystal surfaces. At high pressure (e.g. 200 mbar CO) these differences were even more pronounced. Prominent high coverage CO structures on Pd(1 1 1) could not be established on Pd particles. However, in spite of structural differences between well faceted and rough Pd nanoparticles nearly identical adsorption site occupancies were observed in both cases at 200 mbar CO. Initial tests of the catalytic activity of Pd/Al 2O 3/NiAl(1 1 0) for ethylene hydrogenation at 1 bar revealed a remarkable activity and stability of the model system with catalytic properties similar to impregnated catalysts.

  17. Design of Ingenious Randlet, Sinelet and Shocklets for Compression of Satellites Vibration Test Data

    OpenAIRE

    B. R. Nagendra; Dr. A. M. Khan; M. Madeswaran; V. Ramesh Naidu; S. N. Prakash; Dr. N. K. Misra

    2013-01-01

    Vibration tests on satellites generate huge amount of data of the order of few Giga bytes per test and about tens of Terra bytes of data every year. This data represents vibration levels monitored at various locations of the satellite during the test. The files storing this huge data are archived in the data server computer system. Presently, it is not practical to access this mammoth data over intranet for post processing the data at a later time. Hence, the post-processing of vibration data...

  18. Flow-induced vibration signal analysis of the FIV test loop

    International Nuclear Information System (INIS)

    Vibration spectrums of the test loop according to flow conditions were analyzed in order to identify the sources of vibration at peak frequencies. While a flow condition of the sweep test was changed by varying pump rotational speed from 450 rpm to 1500 rpm by the step 150 rpm, mid span acceleration of the test section in width-direction and dynamic pressure perturbation in the test section were measured. Other sources of vibration due to the flow structure interactions, such as acoustic resonance, blade pulsing frequency and bellows wrinkles, were investigated. Pressure perturbation in the section and acoustic resonance due to branch pipe give major effects to the vibration of the test section in high frequency range of 1.5 kHz to 2.8 kHz

  19. A General Purpose Digital System for Field Vibration Testing

    DEFF Research Database (Denmark)

    Brincker, Rune; Larsen, Jesper Abildgaard; Ventura, Carlos

    2007-01-01

    This paper describes the development and concept implementation of a highly sensitive digital recording system for seismic applications and vibration measurements on large Civil Engineering structures. The system is based on highly sensitive motion transducers that have been used by seismologists...

  20. Low frequency vibration tests on a floating slab track in an underground laboratory

    Institute of Scientific and Technical Information of China (English)

    De-yun DING; Wei-ning LIU; Ke-fei LI; Xiao-jing SUN; Wei-feng LIU

    2011-01-01

    Low frequency vibrations induced by underground railways have attracted increasing attention in recent years. To obtain the characteristics of low frequency vibrations and the low frequency performance of a floating slab track (FST), low frequency vibration tests on an FST in an underground laboratory at Beijing Jiaotong University were carried out. The FST and an unbalanced shaker SBZ30 for dynamic simulation were designed for use in low frequency vibration experiments. Vibration measurements were performed on the bogie of the unbalanced shaker, the rail, the slab, the tunnel invert, the tunnel wall, the tunnel apex, and on the ground surface at distances varying from 0 to 80 m from the track. Measurements were also made on several floors of an adjacent building. Detailed results of low frequency vibration tests were reported. The attenuation of low frequency vibrations with the distance from the track was presented, as well as the responses of different floors of the building. The experimental results could be regarded as a reference for developing methods to control low frequency vibrations and for adopting countermeasures.

  1. Field tests of the vibration characteristics of two types of OPGW

    Energy Technology Data Exchange (ETDEWEB)

    Bourdon, P.; Van Dyke, P.; Hardy, C.

    1993-01-01

    This paper presents the vibration results of two structurally different OPGW conductors of similar diameter tested on a full scale basis under comparable aeolian exposure. Both cables were strung at 16% of their RTS and both carried monomode optical fibres.

  2. Relative sensory sparing in the diabetic foot implied through vibration testing

    Directory of Open Access Journals (Sweden)

    Todd O'Brien

    2013-09-01

    Full Text Available Background: The dorsal aspect of the hallux is often cited as the anatomic location of choice for vibration testing in the feet of diabetic patients. To validate this preference, vibration tests were performed and compared at the hallux and 5th metatarsal head in diabetic patients with established neuropathy. Methods: Twenty-eight neuropathic, diabetic patients and 17 non-neuropathic, non-diabetic patients underwent timed vibration testing (TVT with a novel 128 Hz electronic tuning fork (ETF at the hallux and 5th metatarsal head. Results: TVT values in the feet of diabetic patients were found to be reduced at both locations compared to controls. Unexpectedly, these values were significantly lower at the hallux (P < 0.001 compared to the 5th metatarsal head. Conclusion: This study confirms the hallux as the most appropriate location for vibration testing and implies relative sensory sparing at the 5th metatarsal head, a finding not previously reported in diabetic patients.

  3. Innovative vibration technique applied to polyurethane foam as a viable substitute for conventional fatigue testing

    Science.gov (United States)

    Peralta, Alexander; Just-Agosto, Frederick; Shafiq, Basir; Serrano, David

    2012-12-01

    Lifetime prediction using three-point bending (TPB) can at times be prohibitively time consuming and costly, whereas vibration testing at higher frequency may potentially save time and revenue. A vibration technique that obtains lifetimes that reasonably match those determined under flexural TPB fatigue is developed. The technique designs the specimen with a procedure based on shape optimization and finite element analysis. When the specimen is vibrated in resonance, a stress pattern that mimics the stress pattern observed under conventional TPB fatigue testing is obtained. The proposed approach was verified with polyurethane foam specimens, resulting in an average error of 4.5% when compared with TPB.

  4. Correlation of finite element free vibration predictions using random vibration test data. M.S. Thesis - Cleveland State Univ.

    Science.gov (United States)

    Chambers, Jeffrey A.

    1994-01-01

    Finite element analysis is regularly used during the engineering cycle of mechanical systems to predict the response to static, thermal, and dynamic loads. The finite element model (FEM) used to represent the system is often correlated with physical test results to determine the validity of analytical results provided. Results from dynamic testing provide one means for performing this correlation. One of the most common methods of measuring accuracy is by classical modal testing, whereby vibratory mode shapes are compared to mode shapes provided by finite element analysis. The degree of correlation between the test and analytical mode shapes can be shown mathematically using the cross orthogonality check. A great deal of time and effort can be exhausted in generating the set of test acquired mode shapes needed for the cross orthogonality check. In most situations response data from vibration tests are digitally processed to generate the mode shapes from a combination of modal parameters, forcing functions, and recorded response data. An alternate method is proposed in which the same correlation of analytical and test acquired mode shapes can be achieved without conducting the modal survey. Instead a procedure is detailed in which a minimum of test information, specifically the acceleration response data from a random vibration test, is used to generate a set of equivalent local accelerations to be applied to the reduced analytical model at discrete points corresponding to the test measurement locations. The static solution of the analytical model then produces a set of deformations that once normalized can be used to represent the test acquired mode shapes in the cross orthogonality relation. The method proposed has been shown to provide accurate results for both a simple analytical model as well as a complex space flight structure.

  5. 40 CFR 1065.910 - PEMS auxiliary equipment for field testing.

    Science.gov (United States)

    2010-07-01

    ...) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Field Testing and Portable Emission Measurement...) Electromagnetic radiation. (4) Mechanical shock and vibration. (5) Ambient hydrocarbons—if using a FID...

  6. Vibration test report on crossover piping system in seismic isolation nuclear facilities

    Energy Technology Data Exchange (ETDEWEB)

    Uryu, Mitsuru; Shinohara, Takaharu; Terada, Shuji; Yamazaki, Toshihiko; Tomita, Tsuneo; Kondo, Toshinari

    1999-03-01

    In a seismic isolation nuclear facility, crossover piping system is subjected to large relative displacement and inertia forces during earthquakes. Hinged bellows expansion joints are utilized for accommodation to such the large displacement. This report describes tests for validation of developed simulation code with analytical models. Seismic experiments by a vibration test machine were conducted using actual size piping system models. A comparison between test results and analytical results showed a favorable agreement. The vibration test demonstrated that the structural integrity of this piping system would be maintained during earthquakes. (H. Itami)

  7. Ground vibration test results for Drones for Aerodynamic and Structural Testing (DAST)/Aeroelastic Research Wing (ARW-1R) aircraft

    Science.gov (United States)

    Cox, T. H.; Gilyard, G. B.

    1986-01-01

    The drones for aerodynamic and structural testing (DAST) project was designed to control flutter actively at high subsonic speeds. Accurate knowledge of the structural model was critical for the successful design of the control system. A ground vibration test was conducted on the DAST vehicle to determine the structural model characteristics. This report presents and discusses the vibration and test equipment, the test setup and procedures, and the antisymmetric and symmetric mode shape results. The modal characteristics were subsequently used to update the structural model employed in the control law design process.

  8. Vibration Mitigation without Dissipative Devices: First Large-Scale Testing of a State Switched Inducer

    Directory of Open Access Journals (Sweden)

    Daniel Tirelli

    2014-01-01

    Full Text Available A new passive device for mitigating cable vibrations is proposed and its efficiency is assessed on 45-meter long taut cables through a series of free and forced vibration tests. It consists of a unilateral spring attached perpendicularly to the cable near the anchorage. Because of its ability to change the cable dynamic behaviour through intermittent activation, the device has been called state switched inducer (SSI. The cable behaviour is shown to be deeply modified by the SSI: the forced vibration response is anharmonicc and substantially reduced in amplitude whereas the free vibration decay is largely sped up through a beating phenomenon. The vibration mitigation effect is mainly due to the activation and coupling of various vibration modes, as evidenced in the response spectra of the equipped cable. This first large-scale experimental campaign shows that the SSI outperforms classical passive devices, thus paving the way to a new kind of low-cost vibration mitigation systems which do not rely on dissipation.

  9. Cross sectional study of a workforce exposed to hand-arm vibration: with objective tests and the Stockholm workshop scales

    OpenAIRE

    McGeoch, K.; Gilmour, W

    2000-01-01

    OBJECTIVES—Medical surveillance of workforces exposed to vibration has been recommended with the Stockholm workshop scales. The aims of this study were (a) to evaluate how the results of the objective tests individually and jointly associated with the final Stockholm workshop staging, (b) how this staging related to the history of exposure to vibration, and (c) how different trades were affected by the hazards from vibrating tools.
METHODS—All workers exposed to vibration in a heavy engineeri...

  10. Incorporating Vibration Test Results for the Advanced Stirling Convertor into the System Dynamic Model

    Science.gov (United States)

    Meer, David W.; Lewandowski, Edward J.

    2010-01-01

    The U.S. Department of Energy (DOE), Lockheed Martin Corporation (LM), and NASA Glenn Research Center (GRC) have been developing the Advanced Stirling Radioisotope Generator (ASRG) for use as a power system for space science missions. As part of the extended operation testing of this power system, the Advanced Stirling Convertors (ASC) at NASA GRC undergo a vibration test sequence intended to simulate the vibration history that an ASC would experience when used in an ASRG for a space mission. During these tests, a data system collects several performance-related parameters from the convertor under test for health monitoring and analysis. Recently, an additional sensor recorded the slip table position during vibration testing to qualification level. The System Dynamic Model (SDM) integrates Stirling cycle thermodynamics, heat flow, mechanical mass, spring, damper systems, and electrical characteristics of the linear alternator and controller. This Paper presents a comparison of the performance of the ASC when exposed to vibration to that predicted by the SDM when exposed to the same vibration.

  11. A New Large Vibration Test Facility Concept for the James Webb Space Telescope

    Science.gov (United States)

    Ross, Brian P.; Johnson, Eric L.; Hoksbergen, Joel; Lund, Doug

    2014-01-01

    The James Webb Space Telescope consists of three main components, the Integrated Science Instrument Module (ISIM) Element, the Optical Telescope Element (OTE), and the Spacecraft Element. The ISIM and OTE are being assembled at the National Aeronautics and Space Administration's Goddard Spaceflight Center (GSFC). The combined OTE and ISIM Elements, called OTIS, will undergo sine vibration testing before leaving Goddard. OTIS is the largest payload ever tested at Goddard and the existing GSFC vibration facilities are incapable of performing a sine vibration test of the OTIS payload. As a result, a new large vibration test facility is being designed. The new facility will consist of a vertical system with a guided head expander and a horizontal system with a hydrostatic slip table. The project is currently in the final design phase with installation to begin in early 2015 and the facility is expected to be operational by late 2015. This paper will describe the unique requirements for a new large vibration test facility and present the selected final design concepts.

  12. Evaluation and study on PMD performance of OPGW optical cables in wind induced vibration and galloping test environment

    Science.gov (United States)

    Li, Jie; Zhao, Ziyuan

    2010-08-01

    This paper describes the concepts of wind induced vibration and galloping of power transmission lines, indicates the necessity of evaluation in wind induced vibration and galloping test environment, proposes the evaluation method of wind induced vibration and galloping, summarizes and analyzes the measured PMD performance data of OPGW optical fiber obtained from wind induced vibration and galloping tests on OPGW, and reaches a conclusion that the PMD performance parameters of OPGW cable stocks meet the industry standard in wind induced vibration and galloping environment, and will play an important role in project construction guidance and operation maintenance.

  13. Study on forced vibration tests for large scale SSI model. Test results and their analysis

    International Nuclear Information System (INIS)

    A Large-Scale Seismic Test (LSST) Program has been conducted at Hualien, Taiwan, to obtain earthquake-induced soil-structure interaction (SSI) data in a stiff soil site environment. Forced vibration tests of the Hualien 1/4-scale containment SSI test model were conducted in October, 1992 before backfill (without embedment) and in February, 1993 after backfill (with embedment) for the purpose of defining basic dynamic characteristics of the soil-structure system. As results, peak frequencies were obtained as 4.1 and 4.3 Hz with twin peaks for both NS and EW horizontal excitation before backfill and as 6.1 and 6.3 Hz for NS and EW excitation respectively after backfill and orthogonal components were rather large. This results suggested existence of principal axes which were different from excitation directions. They were estimated 34 degree before backfill and 30 degree after backfill counterclockwise from NS direction, respectively. After transformed to the principal axes, each resonance curve had single peak and the orthogonal component became negligible. Based on this transformed results, the basic dynamic characteristics of the soil-structure system were obtained, namely, natural frequencies and damping factors. Soil impedances were also obtained by the method minimizing error function defined newly. (author)

  14. Test of oxidation behavior of sulfide ores at ambient temperature for fire control

    Institute of Scientific and Technical Information of China (English)

    WU Chao; LI Zi-jun; LI Ming; WU Guo-min

    2007-01-01

    The coincidence of relevant factors, e.g. oxygen absorption quantity, weight increment, water soluble iron ions and sulfate ion of sulfide ore samples in the oxidation process, was tested through experiment. Based on a large number of tests for a group sample of sulfide ores from a mine, some important conclusions were obtained. The results obtained by the investigation indicate that there is no general interpretation relative to the oxygen absorption and the formation products of sulfate ion and water soluble iron ions during the oxidation process of sulfide ores at ambient temperature. However, the weight increment of the sulfide ore samples in the oxidation process at ambient temperature has a linear relationship with the quantity of oxygen absorption.

  15. Applicability of ambient toxicity testing to national or regional water-quality assessment

    Science.gov (United States)

    Elder, John F.

    1990-01-01

    Comprehensive assessment of the quality of natural waters requires a multifaceted approach. Descriptions of existing conditions may be achieved by various kinds of chemical and hydrologic analyses, whereas information about the effects of such conditions on living organisms depends on biological monitoring. Toxicity testing is one type of biological monitoring that can be used to identify possible effects of toxic contaminants. Based on experimentation designed to monitor responses of organisms to environmental stresses, toxicity testing may have diverse purposes in water-quality assessments. These purposes may include identification of areas that warrant further study because of poor water quality or unusual ecological features, verification of other types of monitoring, or assessment of contaminant effects on aquatic communities. Toxicity-test results are most effective when used as a complement to chemical analyses, hydrologic measurements, and other biological monitoring. However, all toxicity-testing procedures have certain limitations that must be considered in developing the methodology and applications of toxicity testing in any large-scale water-quality-assessment program. A wide variety of toxicity-test methods have been developed to fulfill the needs of diverse applications. The methods differ primarily in the selections made relative to four characteristics: (1) test species, (2) endpoint (acute or chronic), (3) test-enclosure type, and (4) test substance (toxicant) that functions as the environmental stress. Toxicity-test approaches vary in their capacity to meet the needs of large-scale assessments of existing water quality. Ambient testing, whereby the test organism is exposed to naturally occurring substances that contain toxicant mixtures in an organic or inorganic matrix, is more likely to meet these needs than are procedures that call for exposure of the test organisms to known concentrations of a single toxicant. However, meaningful

  16. Site responses based on ambient vibrations and earthquake data: a case study from the meizoseismal area of the 2001 Bhuj earthquake

    Science.gov (United States)

    Natarajan, Thulasiraman; Rajendran, Kusala

    2016-08-01

    The 2001 Mw 7.6 earthquake sourced in the Kachchh rift of northwest India led to extensive damage in the city of Bhuj, located ~70 km southwest of its epicenter. The building stock of this densely populated city was a mix of modern, single, and multistoried structures as well as traditional and non-engineered abodes, most of which were not designed to withstand severe shaking effects. Although there was extensive liquefaction and ground failure in the meizoseismal area, they were not observed in Bhuj, but the damage was severe here. In this study, we apply horizontal to vertical spectral ratio method to ambient vibrations (HVSR-AV) to obtain fundamental resonance frequency (f0) and H/V peak amplitude (A0) to examine if site response had any significant role in the observed damage. The patterns of H/V curves as well as spatial distributions of f0 (0.6-1.4 Hz) and A0 (1.5-4.4) suggest absence of any strong impedance contrast within the subsurface. Similar results obtained for ambient vibrations and earthquake signals suggest the efficacy of the HVSR-AV method as most useful for regions of low-level seismicity. The weathered sandstone that is generally exposed in the city represents the resonating layer whose thickness is approximately estimated as ~66-155 m, based on 1D assumption. The current set of available data precludes any quantitative modeling, but our preliminary inference is that site effects were not significant during the 2001 earthquake damage observed in Bhuj.

  17. A Coupling Vibration Test Bench and the Simulation Research of a Maglev Vehicle

    Directory of Open Access Journals (Sweden)

    Weihua Ma

    2015-01-01

    Full Text Available To study the characteristics of the coupling vibration between a maglev vehicle and its track beam system and to improve the performance of the levitation system, a new type of vibration test bench was developed. Take a single maglev frame as the study object; simulation of the coupling vibration of the maglev vehicle, levitation system, and track beam were achieved. In addition, all types of real track irregularity excitations can be simulated using hydraulic actuators of the test bench. To expand the research scope, a simulation model was developed that can conduct the simulation research synergistically with the test bench. Based on a dynamics model of the test bench, the dynamics simulation method determined the influence on the levitation control performance of three factors: the track beam support stiffness, the track beam mass, and the track irregularity. The vibration resonance phenomenon of the vehicle/track system was reproduced by the dynamics simulation, and a portion of the simulation results were validated by the test results. By combining the test bench and the dynamics model, experiments can be guided by the simulation results, and the experimental results can validate the dynamics simulation results.

  18. Dynamic parameters of structures extracted from ambient vibration measurements: an aid for the seismic vulnerability assessment of existing buildings in moderate seismic hazard regions

    CERN Document Server

    Michel, Clotaire; Bard, Pierre-Yves

    2007-01-01

    During the past two decades, the use of ambient vibrations for modal analysis of structures has increased as compared to the traditional techniques (forced vibrations). The Frequency Domain Decomposition method is nowadays widely used in modal analysis because of its accuracy and simplicity. In this paper, we first present the physical meaning of the FDD method to estimate the modal parameters. We discuss then the process used for the evaluation of the building stiffness deduced from the modal shapes. The models considered here are 1D lumped-mass beams and especially the shear beam. The analytical solution of the equations of motion makes it possible to simulate the motion due to a weak to moderate earthquake and then the inter-storey drift knowing only the modal parameters (modal model). This process is finally applied to a 9-storey reinforced concrete (RC) dwelling in Grenoble (France). We successfully compared the building motion for an artificial ground motion deduced from the model estimated using ambien...

  19. Fixed Base Modal Testing Using the NASA GRC Mechanical Vibration Facility

    Science.gov (United States)

    Staab, Lucas D.; Winkel, James P.; Suarez, Vicente J.; Jones, Trevor M.; Napolitano, Kevin L.

    2016-01-01

    The Space Power Facility at NASA's Plum Brook Station houses the world's largest and most powerful space environment simulation facilities, including the Mechanical Vibration Facility (MVF), which offers the world's highest-capacity multi-axis spacecraft shaker system. The MVF was designed to perform sine vibration testing of a Crew Exploration Vehicle (CEV)-class spacecraft with a total mass of 75,000 pounds, center of gravity (cg) height above the table of 284 inches, diameter of 18 feet, and capability of 1.25 gravity units peak acceleration in the vertical and 1.0 gravity units peak acceleration in the lateral directions. The MVF is a six-degree-of-freedom, servo-hydraulic, sinusoidal base-shake vibration system that has the advantage of being able to perform single-axis sine vibration testing of large structures in the vertical and two lateral axes without the need to reconfigure the test article for each axis. This paper discusses efforts to extend the MVF's capabilities so that it can also be used to determine fixed base modes of its test article without the need for an expensive test-correlated facility simulation.

  20. Uma estratégia de teste de software para ambiente cliente-servidor

    OpenAIRE

    Volpi, Lisiane Maes

    2012-01-01

    Resumo: O teste é uma atividade fundamental para garantir a qualidade do software e tem sido uma meta nas empresas de desenvolvimento de sistemas. Nessas empresas, o uso da tecnologia cliente-servidor também tem se intensificado nos últimos anos. Entretanto, este tipo de arquitetura cliente-servidor dificulta a atividade de teste por dividir o software em camadas. Muitos autores têm enfatizado a importância de testar o software para o ambiente cliente-servidor de uma maneira diferente. Este t...

  1. Lessons learned from CIRFT testing on SNF vibration integrity study

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jy-An John [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wang, Hong [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jiang, Hao [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bevard, Bruce Balkcom [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Howard, Rob L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Scaglione, John M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-01-01

    A cyclic integrated reversible-bending fatigue tester (CIRFT) was developed to support U.S. NRC and DOE Used Fuel Disposition Campaign studies on high burn-up (HBU) spent nuclear fuel (SNF) transportation during normal conditions of transport (NCT). Two devices were developed; the first CIRFT was successfully installed and operated in the ORNL hot-cells in September 2013. Since hot cell testing commenced several HBU SNF samples from both Zr-4 and M5 clads were investigated. The second CIRFT device was developed in February 2014, and has been used to test clad/fuel surrogate rods (stainless steel with alumina pellet inserts). The second CIRFT machine has also been used for sensor development and test sensitivity analyses, as well as loading boundary condition parameter studies. The lessons learned from CIRFT testing will be presented in this paper.

  2. Wind-Tunnel Tests of a Bridge Model with Active Vibration Control

    DEFF Research Database (Denmark)

    Hansen, H. I.; Thoft-Christensen, Palle; Mendes, P. A.;

    The application of active control systems to reduce wind vibrations in bridges is a new area of research. This paper presents the results that were obtained on a set of wind tunnel tests of a bridge model equipped with active movable flaps. Based on the monitored position and motion of the deck...

  3. Design of Ingenious Randlet, Sinelet and Shocklets for Compression of Satellites Vibration Test Data

    Directory of Open Access Journals (Sweden)

    B. R. Nagendra

    2013-09-01

    Full Text Available Vibration tests on satellites generate huge amount of data of the order of few Giga bytes per test and about tens of Terra bytes of data every year. This data represents vibration levels monitored at various locations of the satellite during the test. The files storing this huge data are archived in the data server computer system. Presently, it is not practical to access this mammoth data over intranet for post processing the data at a later time. Hence, the post-processing of vibration data encounters two challenges: archival of huge data in server system and accessing the mammoth data over intranet backbone of the organization. In the present work, an efficient compression algorithm using unique wavelets, proposed to be named as randlet, sinelet, and shocklet. These wavelets are designed using perfect reconstruction filter banks, to compress the satellite vibration test data which reduces the storage requirement and access time for retrieval of the data from the server system. A comparison is made between the algorithms using standard transformations such as Discrete Cosine Transform, Fast Fourier Transform, Haar Wavelet Transformation and the transformation using the proposed wavelets. It is concluded in this paper that the proposed wavelets provide optimal performance in terms of compression ratio, reconstruction error compared to existing transformation techniques.

  4. Vibration tests on some models of PEC reactor core elements

    International Nuclear Information System (INIS)

    This paper describes the aims of the experimental tests carried out at ISMES, within an agreement with the Department of Fast Reactors of ENEA, on some models of the elements of PEC Fast Nuclear Reactor Core in the frame of the activities for the seismic verification of the PEC core. The seismic verification is briefly described with particular attention to the problems arising from the shocks among the various elements during an earthquake, as well as the computer code used, the purpose and the techniques used to perform tests, some results and the first comparison between the theory and the experimental data

  5. An evaluation of iced bridge hanger vibrations through wind tunnel testing and quasi-steady theory

    DEFF Research Database (Denmark)

    Gjelstrup, Henrik; Georgakis, Christos T.; Larsen, A.

    2012-01-01

    Bridge hanger vibrations have been reported under icy conditions. In this paper, the results from a series of static and dynamic wind tunnel tests on a circular cylinder representing a bridge hanger with simulated thin ice accretions are presented. The experiments focus on ice accretions produced...... roughness is also examined. The static force coefficients are used to predict parameter regions where aerodynamic instability of the iced bridge hanger might be expected to occur, through use of an adapted theoretical 3- DOF quasi-steady galloping instability model, which accounts for sectional axial......-indicating the possible inability of quasi-steady theory to fully predict these vibrational instabilities....

  6. Experimental Nondestructive Test for Estimation of Buckling Load on Unstiffened Cylindrical Shells Using Vibration Correlation Technique

    Directory of Open Access Journals (Sweden)

    Kaspars Kalnins

    2015-01-01

    Full Text Available Nondestructive methods, to calculate the buckling load of imperfection sensitive thin-walled structures, such as large-scale aerospace structures, are one of the most important techniques for the evaluation of new structures and validation of numerical models. The vibration correlation technique (VCT allows determining the buckling load for several types of structures without reaching the instability point, but this technique is still under development for thin-walled plates and shells. This paper presents and discusses an experimental verification of a novel approach using vibration correlation technique for the prediction of realistic buckling loads of unstiffened cylindrical shells loaded under axial compression. Four different test structures were manufactured and loaded up to buckling: two composite laminated cylindrical shells and two stainless steel cylinders. In order to characterize a relationship with the applied load, the first natural frequency of vibration and mode shape is measured during testing using a 3D laser scanner. The proposed vibration correlation technique allows one to predict the experimental buckling load with a very good approximation without actually reaching the instability point. Additional experimental tests and numerical models are currently under development to further validate the proposed approach for composite and metallic conical structures.

  7. Performance Studies of the Vibration Wire Monitor on the Test Stand with Low Energy Electron Beam

    Science.gov (United States)

    Okabe, Kota; Yoshimoto, Masahiro; Kinsho, Michikazu

    In the high intensity proton accelerator as the Japan Proton Accelerator Research Complex (J-PARC) accelerators, serious radiation and residual dose is induced by a small beam loss such a beam halo. Therefore, diagnostics of the beam halo formation is one of the most important issues to control the beam loss. For the beam halo monitor, the vibration wire monitor (VWM) has a potential for investigating the beam halo and weak beam scanning. The VWM has a wide dynamic range, high resolution and the VWM is not susceptible to secondary electrons and electric noises. We have studied the VWM features as a new beam-halo monitor on the test stand with low energy electron gun. The frequency shift of the irradiated vibration wire was confirmed about wire material and the electron beam profile measured by using the VWM was consistent with the results of the Faraday cup measurement. Also we calculated a temperature distribution on the vibration wire which is irradiated by the electron beam with the numerical simulation. The simulations have been fairly successful in reproducing the transient of the irradiated vibration wire frequency measured by test stand experiments. In this paper, we will report a result of performance evaluation for the VWM on the test stands and discuss the VWM for beam halo diagnostic

  8. Integrated Vehicle Ground Vibration Testing in Support of Launch Vehicle Loads and Controls Analysis

    Science.gov (United States)

    Askins, Bruce R.; Davis, Susan R.; Salyer, Blaine H.; Tuma, Margaret L.

    2008-01-01

    All structural systems possess a basic set of physical characteristics unique to that system. These unique physical characteristics include items such as mass distribution and damping. When specified, they allow engineers to understand and predict how a structural system behaves under given loading conditions and different methods of control. These physical properties of launch vehicles may be predicted by analysis or measured by certain types of tests. Generally, these properties are predicted by analysis during the design phase of a launch vehicle and then verified by testing before the vehicle becomes operational. A ground vibration test (GVT) is intended to measure by test the fundamental dynamic characteristics of launch vehicles during various phases of flight. During the series of tests, properties such as natural frequencies, mode shapes, and transfer functions are measured directly. These data will then be used to calibrate loads and control systems analysis models for verifying analyses of the launch vehicle. NASA manned launch vehicles have undergone ground vibration testing leading to the development of successful launch vehicles. A GVT was not performed on the inaugural launch of the unmanned Delta III which was lost during launch. Subsequent analyses indicated had a GVT been performed, it would have identified instability issues avoiding loss of the vehicle. This discussion will address GVT planning, set-up, execution and analyses, for the Saturn and Shuttle programs, and will also focus on the current and on-going planning for the Ares I and V Integrated Vehicle Ground Vibration Test (IVGVT).

  9. Evaluation of soil-structure interaction based on forced vibration tests of three reactor buildings within a site

    International Nuclear Information System (INIS)

    Three BWR type reactor buildings (Unit No. 1, 2, 3) have been constructed at Hamaoka site in Shizuoka prefecture, Japan, during the past fifteen years. In order to confirm and verify the seismic design procedure, forced vibration tests were performed for the completed three reactor buildings. Enough test data have been accumulated and consequently, it is now possible to consolidate these data and compare the differences of vibrational characteristics of the three reactor of soil-structure interaction effects through the simulation study of vibrational characteristics of the three reactor buildings and explores realistic vibration models

  10. Diagnostic tests in Raynaud's phenomena in workers exposed to vibration: a comparative study

    DEFF Research Database (Denmark)

    Olsen, N

    1988-01-01

    greater than 0.20). The results indicate that a finger colour test may be as valuable as a FSP(0) test for diagnostic purposes. FSP(A) only indicates if a cold response is exaggerated and does not diagnose RP. The pressure measurements may further be of guidance in evaluating preventive measures......Four objective tests to evaluate Raynaud's phenomena (RP) in workers exposed to handarm vibrations were applied on 23 exposed men with RP (vibration induced white finger 18, primary Raynaud's phenomenon 5), 56 exposed men without RP, and 15 male controls. Finger systolic blood pressure was measured...... by a cuff and strain gauge technique after combined body cooling and finger cooling during five minute ischaemia to 30 degrees, 15 degrees, and 6 degrees C. An attack of RP was detected as a zero pressure, FSP(0) test, whereas a pressure, reduced to a value below the normal 95% confidence limit at 6 degrees...

  11. Response prediction for large scale model structure under forced vibration test

    International Nuclear Information System (INIS)

    This paper presents the analytical prediction for the responses of the forced vibration test on a quarter-scale containment model structure built at Hualien, Taiwan. The prediction is performed blindly by using the computer program HASSI-8 which is developed for solving the soil-structure interaction problem using the method of hybrid modeling. The results obtained show very good correlation with the field test results

  12. Analysis modeling for plate buckling load of vibration test

    Institute of Scientific and Technical Information of China (English)

    SUNG Wen-pei; LIN Cheng-I; SHIH Ming-hsiang; GO Cheer-germ

    2005-01-01

    In view of the recent technological development, the pursuit of safe high-precision structural designs has been the goal of most structural designers. To bridge the gap between the construction theories and the actual construction techniques, safety factors are adopted for designing the strength loading of structural members. If safety factors are too conservative, the extra building materials necessary will result in high construction cost. Thus, there has been a tendency in the construction field to derive a precise buckling load analysis model of member in order to establish accurate safety factors. A numerical analysis model, using modal analysis to acquire the dynamic function calculated by dynamic parameter to get the buckling load of member, is proposed in this paper. The fixed and simple supports around the circular plate are analyzed by this proposed method. And then, the Monte Carlo method and the normal distribution method are used for random sampling and measuring errors of numerical simulation respectively. The analysis results indicated that this proposed method only needs to apply modal parameters of 7×7 test points to obtain a theoretical value of buckling load. Moreover, the analysis method of inequality-distant test points produces better analysis results than the other methods.

  13. Vibrational measurement for commissioning SRF Accelerator Test Facility at Fermilab

    CERN Document Server

    McGee, M W; Martinez, A; Pischalnikov, Y; Schappert, W

    2012-01-01

    The commissioning of two cryomodule components is underway at Fermilab's Superconducting Radio Frequency (SRF) Accelerator Test Facility. The research at this facility supports the next generation high intensity linear accelerators such as the International Linear Collider (ILC), a new high intensity injector (Project X) and other future machines. These components, Cryomodule #1 (CM1) and Capture Cavity II (CC2), which contain 1.3 GHz cavities are connected in series in the beamline and through cryogenic plumbing. Studies regarding characterization of ground motion, technical and cultural noise continue. Mechanical transfer functions between the foundation and critical beamline components have been measured and overall system displacement characterized. Baseline motion measurements given initial operation of cryogenic, vacuum systems and other utilities are considered.

  14. Vibrational measurement for commissioning SRF Accelerator Test Facility at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    McGee, M.W.; Leibfritz, J.; Martinez, A.; Pischalnikov, Y.; Schappert, W.; /Fermilab

    2011-03-01

    The commissioning of two cryomodule components is underway at Fermilab's Superconducting Radio Frequency (SRF) Accelerator Test Facility. The research at this facility supports the next generation high intensity linear accelerators such as the International Linear Collider (ILC), a new high intensity injector (Project X) and other future machines. These components, Cryomodule No.1 (CM1) and Capture Cavity II (CC2), which contain 1.3 GHz cavities are connected in series in the beamline and through cryogenic plumbing. Studies regarding characterization of ground motion, technical and cultural noise continue. Mechanical transfer functions between the foundation and critical beamline components have been measured and overall system displacement characterized. Baseline motion measurements given initial operation of cryogenic, vacuum systems and other utilities are considered.

  15. Evaluation of Alternative Methods for Testing the Bioefficacy of Household Ambient Insecticide Products Against Aedes albopictus.

    Science.gov (United States)

    Cassini, Rudi; Scremin, Mara; Contiero, Barbara; Drago, Andrea; Vettorato, Christian; Marcer, Federica; di Regalbono, Antonio Frangipane

    2016-06-01

    Ambient insecticides are receiving increasing attention in many developed countries because of their value in reducing mosquito nuisance. As required by the European Union Biocidal Products Regulation 528/2012, these devices require appropriate testing of their efficacy, which is based on estimating the knockdown and mortality rates of free-flying (free) mosquitoes in a test room. However, evaluations using free mosquitoes present many complexities. The performances of 6 alternative methods with mosquitoes held in 2 different cage designs (steel wire and gauze/plastic) with and without an operating fan for air circulation were monitored in a test room through a closed-circuit television system and were compared with the currently recommended method using free mosquitoes. Results for caged mosquitoes without a fan showed a clearly delayed knockdown effect, whereas outcomes for caged mosquitoes with a fan recorded higher mortality at 24 h, compared to free mosquitoes. Among the 6 methods, cages made of gauze and plastic operating with fan wind speed at 2.5-2.8 m/sec was the only method without a significant difference in results for free mosquitoes, and therefore appears as the best alternative to assess knockdown by ambient insecticides accurately. PMID:27280352

  16. One stacked-column vibration test and analysis for VHTR core

    International Nuclear Information System (INIS)

    The paper describes experimental results of the vibration test on a single stacked-column and compares them with the analytical results. A 1/2 scale model of the core element of a very high temperature gas-cooled reactor (VHTR) was set on a shaking table. Sinusoidal waves, response time history waves, a beat wave and a step wave of input acceleration 100 to 900 gal in the frequency of 0.5 to 15 Hertz were used to vibrate the table horizontally. Results are as follows: (1) the column has a nonlinear resonance and exhibits a hysteresis response with jump points; (2) the column vibration characteristics is similar to that of the finite beams connected with nonlinear soft spring; (3) the column resonance frequency decreases with increasing input acceleration; (4) the impact force increases with increasing input acceleration and boundary gap width; (5) good correlation in vibration behavior of the stacked column and impact force on the boundary between test and analysis was obtained

  17. Standard test method for ambient temperature fatigue life of metallic bonded resistance strain gages

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2003-01-01

    1.1 This test method covers a uniform procedure for the determination of strain gage fatigue life at ambient temperature. A suggested testing equipment design is included. 1.2 This test method does not apply to force transducers or extensometers that use bonded resistance strain gages as sensing elements. 1.3 Strain gages are part of a complex system that includes structure, adhesive, gage, leadwires, instrumentation, and (often) environmental protection. As a result, many things affect the performance of strain gages, including user technique. A further complication is that strain gages, once installed, normally cannot be reinstalled in another location. Therefore, it is not possible to calibrate individual strain gages; performance characteristics are normally presented on a statistical basis. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices ...

  18. Psychophysics of a nociceptive test in the mouse: ambient temperature as a key factor for variation.

    Directory of Open Access Journals (Sweden)

    Ivanne Pincedé

    Full Text Available BACKGROUND: The mouse is increasingly used in biomedical research, notably in behavioral neurosciences for the development of tests or models of pain. Our goal was to provide the scientific community with an outstanding tool that allows the determination of psychophysical descriptors of a nociceptive reaction, which are inaccessible with conventional methods: namely the true threshold, true latency, conduction velocity of the peripheral fibers that trigger the response and latency of the central decision-making process. METHODOLOGY/PRINCIPAL FINDINGS: Basically, the procedures involved heating of the tail with a CO(2 laser, recording of tail temperature with an infrared camera and stopping the heating when the animal reacted. The method is based mainly on the measurement of three observable variables, namely the initial temperature, the heating rate and the temperature reached at the actual moment of the reaction following random variations in noxious radiant heat. The initial temperature of the tail, which itself depends on the ambient temperature, very markedly influenced the behavioral threshold, the behavioral latency and the conduction velocity of the peripheral fibers but not the latency of the central decision-making. CONCLUSIONS/SIGNIFICANCE: We have validated a psychophysical approach to nociceptive reactions for the mouse, which has already been described for rats and Humans. It enables the determination of four variables, which contribute to the overall latency of the response. The usefulness of such an approach was demonstrated by providing new fundamental findings regarding the influence of ambient temperature on nociceptive processes. We conclude by challenging the validity of using as "pain index" the reaction time of a behavioral response to an increasing heat stimulus and emphasize the need for a very careful control of the ambient temperature, as a prevailing environmental source of variation, during any behavioral testing of

  19. Sensor design for outdoor racing bicycle field testing for human vibration comfort evaluation

    International Nuclear Information System (INIS)

    This paper is concerned with the vibrational comfort evaluation of the cyclist when cycling a rough surface. Outdoor comfort tests have so far only been done through instrumenting the bicycle with accelerometers. This work instruments a racing bicycle with custom-made contact force sensors and velocity sensors to acquire human comfort through the absorbed power method. Comfort evaluation is assessed at the hand–arm and seat interface of the cyclist with the bicycle. By means of careful finite-element analysis for designing the force gauges at the handlebar and the seat combined with precise calibration of both force and velocity sensors, all sensors have proven to work properly. Initial field tests are focused on the proper functioning of the designed sensors and their suitability for vibration comfort measurements. Tests on a cobblestone road reveal that the outcome of the absorbed power values is within the same range as those from laboratory tests found in the literature. This sensor design approach for outdoor testing with racing bicycles may give a new interpretation on evaluating the cyclist's comfort since the vibrational load is not only quantified in terms of acceleration but also in terms of force and velocity at the bicycle–cyclist contact points. (paper)

  20. Study on vibration alleviating properties of glass fiber reinforced polymer concrete through orthogonal tests

    International Nuclear Information System (INIS)

    Polymer concrete (PC), because of its good vibration alleviating properties, is a proper material for elementary machine parts in high-precision machine tools. Glass fiber was applied in PC to improve its mechanical properties, and the material obtained is called glass fiber reinforced polymer concrete (GFRPC). The best parameter to estimate the vibration alleviating property is damping ratio. Orthogonal tests were carried out to prepare GFRPC specimens with different component proportions. Damping ratio of the GFRPC specimens was measured. The effect of the factors considered in the experiments on damping ratio of GFRPC was studied. Results of the tests show that granite proportion plays the most important role in determining damping ratio of GFRPC, then flexibilizer dosage and glass fiber length, while epoxy resin dosage and glass fiber dosage play a comparatively less important part. Detailed descriptions were made about how the considered factors affect damping ratio of GFRPC in this paper

  1. Study on vibration alleviating properties of glass fiber reinforced polymer concrete through orthogonal tests

    Energy Technology Data Exchange (ETDEWEB)

    Bai Wenfeng [School of Mechanical Engineering, Shandong University, Jinan, Shandong Province 250061 (China)], E-mail: wfbai@yahoo.com.cn; Zhang Jianhua [School of Mechanical Engineering, Shandong University, Jinan, Shandong Province 250061 (China)], E-mail: jhzhang@sdu.edu.cn; Yan Peng [School of Mechanical Engineering, Shandong University, Jinan, Shandong Province 250061 (China); Wang Xinli [Design Department, Shanghai Haima Automobile R and D Co., Ltd., Shanghai 201201 (China)

    2009-04-15

    Polymer concrete (PC), because of its good vibration alleviating properties, is a proper material for elementary machine parts in high-precision machine tools. Glass fiber was applied in PC to improve its mechanical properties, and the material obtained is called glass fiber reinforced polymer concrete (GFRPC). The best parameter to estimate the vibration alleviating property is damping ratio. Orthogonal tests were carried out to prepare GFRPC specimens with different component proportions. Damping ratio of the GFRPC specimens was measured. The effect of the factors considered in the experiments on damping ratio of GFRPC was studied. Results of the tests show that granite proportion plays the most important role in determining damping ratio of GFRPC, then flexibilizer dosage and glass fiber length, while epoxy resin dosage and glass fiber dosage play a comparatively less important part. Detailed descriptions were made about how the considered factors affect damping ratio of GFRPC in this paper.

  2. Model Test Study on Ice Induced Vibration of A Compliant Conical Structure

    Institute of Scientific and Technical Information of China (English)

    HUNAG Yan; SHI Qing-zeng; SONG An

    2005-01-01

    The problem of ice induced vibration is common to ocean engineering of cold region countries. To study the ice induced vibration of a compliant conical structure, a series of model tests have been performed and some breakthrough progresses made. The ice sheet before the compliant conical structure is found to fail by two-time breaking in the tests. The process of two-time breaking behaves in two modes, and the general control of the ice and structural conditions determine the mode in which the ice force would behave. Two dynamic ice force functions are established respectively for the two modes of two-time breaking process in this paper. The numerical simulation results are in good agreement with the measured results, indicating that the dynamic ice force functions given in this paper can fully reflect the real situation of the dynamic ice force on a compliant conical structure.

  3. Over-the-road shock and vibration testing of the radioisotope thermoelectric generator transportation system

    International Nuclear Information System (INIS)

    Radioisotope Thermoelectric Generators (RTG) convert heat generated by radioactive decay into electricity through the use of thermocouples. The RTGs have a long operating life, are reasonably lightweight, and require little or no maintenance, which make them particularly attractive for use in spacecraft. However, because RTGs contain significant quantities of radioactive materials, normally plutonium-238 and its decay products, they must be transported in packages built in accordance with Title 10, Code of Federal Regulations, Part 71 (10 CFR 71). To meet these regulations, a RTG Transportation System (RTGTS) that fully complies with 10 CFR 71 has been developed, which protects RTGs from adverse environmental conditions during normal conditions of transport (e.g., shock, vibration, and heat). To ensure the protection of RTGs from shock and vibration loadings during transport, extensive over-the-road testing was conducted on the RTG'S to obtain real-time recordings of accelerations of the air-ride suspension system trailer floor, packaging, and support structure. This paper provides an overview of the RTG'S, a discussion of the shock and vibration testing, and a comparison of the test results to the specified shock response spectra and power spectral density acceleration criteria

  4. Vibration Durability Testing of Nickel Cobalt Aluminum Oxide (NCA Lithium-Ion 18650 Battery Cells

    Directory of Open Access Journals (Sweden)

    James Michael Hooper

    2016-04-01

    Full Text Available This paper outlines a study undertaken to determine if the electrical performance of Nickel Cobalt Aluminum Oxide (NCA 3.1 Ah 18650 battery cells can be degraded by road induced vibration typical of an electric vehicle (EV application. This study investigates if a particular cell orientation within the battery assembly can result in different levels of cell degradation. The 18650 cells were evaluated in accordance with Society of Automotive Engineers (SAE J2380 standard. This vibration test is synthesized to represent 100,000 miles of North American customer operation at the 90th percentile. This study identified that both the electrical performance and the mechanical properties of the NCA lithium-ion cells were relatively unaffected when exposed to vibration energy that is commensurate with a typical vehicle life. Minor changes observed in the cell’s electrical characteristics were deemed not to be statistically significant and more likely attributable to laboratory conditions during cell testing and storage. The same conclusion was found, irrespective of cell orientation during the test.

  5. Experimental testing on free vibration behaviour for silicone rubbers proposed within lumbar disc prosthesis

    Energy Technology Data Exchange (ETDEWEB)

    Rotaru, Iuliana, E-mail: rotaruiuliana2000@gmail.com [“Gheorghe Asachi” Technical University of Iasi, Faculty of Mechanical Engineering, Department of Mechanical Engineering, Mechatronics and Robotics, 61-63 Bd. Dimitrie Mangeron, 700050 Iasi (Romania); “Gr. T. Popa” University of Medicine and Pharmacy of Iasi, Faculty of Medical Bioengineering, Department of Biomedical Sciences, 9-13 M. Kogalniceanu Street, 700454 Iasi (Romania); Bujoreanu, Carmen [“Gheorghe Asachi” Technical University of Iasi, Faculty of Mechanical Engineering, Department of Mechanical Engineering, Mechatronics and Robotics, 61-63 Bd. Dimitrie Mangeron, 700050 Iasi (Romania); Bele, Adrian; Cazacu, Maria [“Petru Poni” Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41 A, 700487 Iasi (Romania); Olaru, Dumitru [“Gheorghe Asachi” Technical University of Iasi, Faculty of Mechanical Engineering, Department of Mechanical Engineering, Mechatronics and Robotics, 61-63 Bd. Dimitrie Mangeron, 700050 Iasi (Romania)

    2014-09-01

    This research was focused on the damping capacity study of two types of silicone rubbers proposed as layers within total lumbar disc prostheses of ball-and-socket model. In order to investigate the damping capacity, the two silicone rubber types mainly differing by the molecular mass of polymeric matrix and the filler content, as was emphasized by scanning electron microscopy and differential scanning calorimetry, were subjected to free vibration testing. Using an adapted experimental installation, three kinds of damping testing were realised: tests without samples and tests with three samples of each type of silicone rubber (69 ShA and 99 ShA). The free vibration tests were performed at a frequency of about 6 Hz using a weight of 11.8 kg. The relative damping coefficient was determined by measuring of two successive amplitudes on the vibrogram and calculating of the logarithmic decrement. The test results with silicone rubber samples showed a relative damping coefficient of 0.058 and respectively 0.077, whilst test results without samples showed a relative damping coefficient of 0.042. These silicone rubbers were found to have acceptable damping properties to be used as layers placed inside the prosthetic components. - Highlights: • Two types of silicone rubber were proposed within the total lumbar disc prostheses. • The filler content of elastomers was highlighted by microscopy investigation. • Damping capacity of the two elastomers was evaluated using free vibration analysis. • The logarithmic decrement and the relative damping coefficient were determined. • The silicone rubbers prepared in our work showed acceptable damping properties.

  6. Experimental testing on free vibration behaviour for silicone rubbers proposed within lumbar disc prosthesis

    International Nuclear Information System (INIS)

    This research was focused on the damping capacity study of two types of silicone rubbers proposed as layers within total lumbar disc prostheses of ball-and-socket model. In order to investigate the damping capacity, the two silicone rubber types mainly differing by the molecular mass of polymeric matrix and the filler content, as was emphasized by scanning electron microscopy and differential scanning calorimetry, were subjected to free vibration testing. Using an adapted experimental installation, three kinds of damping testing were realised: tests without samples and tests with three samples of each type of silicone rubber (69 ShA and 99 ShA). The free vibration tests were performed at a frequency of about 6 Hz using a weight of 11.8 kg. The relative damping coefficient was determined by measuring of two successive amplitudes on the vibrogram and calculating of the logarithmic decrement. The test results with silicone rubber samples showed a relative damping coefficient of 0.058 and respectively 0.077, whilst test results without samples showed a relative damping coefficient of 0.042. These silicone rubbers were found to have acceptable damping properties to be used as layers placed inside the prosthetic components. - Highlights: • Two types of silicone rubber were proposed within the total lumbar disc prostheses. • The filler content of elastomers was highlighted by microscopy investigation. • Damping capacity of the two elastomers was evaluated using free vibration analysis. • The logarithmic decrement and the relative damping coefficient were determined. • The silicone rubbers prepared in our work showed acceptable damping properties

  7. Vibration Testing of Electrical Cables to Quantify Loads at Tie-Down Locations

    Science.gov (United States)

    Dutson, Joseph D.

    2013-01-01

    The standard method for defining static equivalent structural load factors for components is based on Mile s equation. Unless test data is available, 5% critical damping is assumed for all components when calculating loads. Application of this method to electrical cable tie-down hardware often results in high loads, which often exceed the capability of typical tie-down options such as cable ties and P-clamps. Random vibration testing of electrical cables was used to better understand the factors that influence component loads: natural frequency, damping, and mass participation. An initial round of vibration testing successfully identified variables of interest, checked out the test fixture and instrumentation, and provided justification for removing some conservatism in the standard method. Additional testing is planned that will include a larger range of cable sizes for the most significant contributors to load as variables to further refine loads at cable tie-down points. Completed testing has provided justification to reduce loads at cable tie-downs by 45% with additional refinement based on measured cable natural frequencies.

  8. Vibration test methods and their experimental research on the performance of the lead-acid battery

    Science.gov (United States)

    He, Baoxiang; Wang, Hua; He, Xie

    2014-12-01

    As we know, Lead-acid battery is difficult to balance many factors such as the accuracy and the on-line testing requirement. The detecting system, as stated in this article, is based on the vibration test procedure, dynamically following the electrochemical process of the Lead-acid Battery, and collects the real-time state parameters for calculation, analysis and judgment. It also quantizes precisely the degradation and chargeability of the battery and therefore self-adapts to the ideal target values. During the test, it has not charged and discharged large current to the lead-acid battery, it only plus a smaller and shorter time of impulse voltage signal on both ends of lead-acid battery, so the battery measured is damage free, and the system energy consumption is small; Using the load compensation technology, it has solved the influence of load on the test results. What's more, the load characteristics are improved at the same time, it realized the online detection. The vibration detection is based on the adaptive fuzzy inference model which has taken various factors into account, concerning the choices of input aspects which may influence the output value. It realized a number of Lead-acid Battery voltage self-adaption and accomplished a variety of high-precise tests.

  9. Estimates of site response based on spectral ratio between horizontal and vertical components of ambient vibrations in the source zone of 2001 Bhuj earthquake

    Science.gov (United States)

    Natarajan, Thulasiraman; Rajendran, Kusala

    2015-02-01

    We investigated the site response characteristics of Kachchh rift basin over the meizoseismal area of the 2001, Mw 7.6, Bhuj (NW India) earthquake using the spectral ratio of the horizontal and vertical components of ambient vibrations. Using the available knowledge on the regional geology of Kachchh and well documented ground responses from the earthquake, we evaluated the H/V curves pattern across sediment filled valleys and uplifted areas generally characterized by weathered sandstones. Although our H/V curves showed a largely fuzzy nature, we found that the hierarchical clustering method was useful for comparing large numbers of response curves and identifying the areas with similar responses. Broad and plateau shaped peaks of a cluster of curves within the valley region suggests the possibility of basin effects within valley. Fundamental resonance frequencies (f0) are found in the narrow range of 0.1-2.3 Hz and their spatial distribution demarcated the uplifted regions from the valleys. In contrary, low H/V peak amplitudes (A0 = 2-4) were observed on the uplifted areas and varying values (2-9) were found within valleys. Compared to the amplification factors, the liquefaction indices (kg) were able to effectively indicate the areas which experienced severe liquefaction. The amplification ranges obtained in the current study were found to be comparable to those obtained from earthquake data for a limited number of seismic stations located on uplifted areas; however the values on the valley region may not reflect their true amplification potential due to basin effects. Our study highlights the practical usefulness as well as limitations of the H/V method to study complex geological settings as Kachchh.

  10. Modal Parameter Identification of Offshore Platforms under Ambient Excitation

    Institute of Scientific and Technical Information of China (English)

    Yang Hezhen(杨和振); Li Huajun

    2004-01-01

    This paper intends to identify the modal parameters of an offshore platform under ambient excitation, and to compare the identified results with theoretical solutions. Using ambient sources of excitation to determine the modal characteristics of large civil engineering structures is desirable for several reasons. The forced vibration testing of such structures generally requires a large amount of specialized equipment and makes the tests quite expensive. Also, an automated health monitoring system for a large civil structure will most likely use ambient excitation. The Eigensystem Realization Algorithm (ERA) is applied in conjunctied acceleration information. Finally, offshore platform numerical model gets output response data under ambient excitation. Simulated data from numerical model of an offshore platform under ambient excitation is used for the identification of the system. According to the comparison results, the proposed method is shown to be effective for modal parameter identification under ambient excitation.

  11. AVM branch vibration test equipment; Moyens d`essais vibratoires au sein du departement AMV

    Energy Technology Data Exchange (ETDEWEB)

    Anne, J.P.

    1995-12-31

    An inventory of the test equipment of the AVM Branch ``Acoustic and Vibratory Mechanics Analysis Methods`` group has been undertaken. The purpose of this inventory is to enable better acquaintance with the technical characteristics of the equipment, providing an accurate definition of their functionalities, ad to inform potential users of the possibilities and equipment available in this field. The report first summarizes the various experimental surveys conduced. Then, using the AVM equipment database to draw up an exhaustive list of available equipment, it provides a full-scope picture of the vibration measurement systems (sensors, conditioners and exciters) and data processing resources commonly used on industrial sites and in laboratories. A definition is also given of a mobile test unit, called `shelter`, and a test bench used for the testing and performance rating of the experimental analysis methods developed by the group. The report concludes with a description of two fixed installations: - the calibration bench ensuring the requisite quality level for the vibration measurement systems ; - the training bench, whereby know-how acquired in the field in the field of measurement and experimental analysis processes is made available to others. (author). 27 refs., 15 figs., 2 appends.

  12. Serological Tests for Diagnosis and Staging of Hand–Arm Vibration Syndrome (HAVS)

    OpenAIRE

    Kao, Dennis S.; Yan, Ji-Geng; Zhang, Lin-Ling; Kaplan, Rachel E.; Riley, Danny A.; Matloub, Hani S

    2007-01-01

    The current gold standard for the diagnosis and staging of hand–arm vibration syndrome (HAVS) is the Stockholm workshop scale, which is subjective and relies on the patient’s recalling ability and honesty. Therefore, great potentials exist for diagnostic and staging errors. The purpose of this study is to determine if objective serum tests, such as levels of soluble thrombomodulin (sTM) and soluble intercellular adhesion molecule-1 (sICAM-1), may be used in the diagnosis and staging of HAVS. ...

  13. Wavelet analysis to decompose a vibration simulation signal to improve pre-distribution testing of packaging

    Science.gov (United States)

    Griffiths, K. R.; Hicks, B. J.; Keogh, P. S.; Shires, D.

    2016-08-01

    In general, vehicle vibration is non-stationary and has a non-Gaussian probability distribution; yet existing testing methods for packaging design employ Gaussian distributions to represent vibration induced by road profiles. This frequently results in over-testing and/or over-design of the packaging to meet a specification and correspondingly leads to wasteful packaging and product waste, which represent 15bn per year in the USA and €3bn per year in the EU. The purpose of the paper is to enable a measured non-stationary acceleration signal to be replaced by a constructed signal that includes as far as possible any non-stationary characteristics from the original signal. The constructed signal consists of a concatenation of decomposed shorter duration signals, each having its own kurtosis level. Wavelet analysis is used for the decomposition process into inner and outlier signal components. The constructed signal has a similar PSD to the original signal, without incurring excessive acceleration levels. This allows an improved and more representative simulated input signal to be generated that can be used on the current generation of shaker tables. The wavelet decomposition method is also demonstrated experimentally through two correlation studies. It is shown that significant improvements over current international standards for packaging testing are achievable; hence the potential for more efficient packaging system design is possible.

  14. About a sequential method for non destructive testing of structures by mechanical vibrations

    International Nuclear Information System (INIS)

    The presence and growth of cracks voids or fields of pores under applied forces or environmental actions can produce a meaningful lowering in the proper frequencies of normal modes of mechanical vibration in structures.A quite general expression for the square of modes proper frequency as a functional of displacement field,density field and elastic moduli fields is used as a starting point.The effect of defects on frequency are modeled as equivalent changes in density and elastic moduli fields,introducing the concept of region of influence of each defect.An approximate expression is obtained which relates the relative lowering in the square of modes proper frequency with position,size,shape and orientation of defects in mode displacement field.Some simple examples of structural elements with cracks or fields of pores are considered.the connection with linear elastic fracture mechanics is briefly exemplified.A sequential method is proposed for non-destructive testing of structures using mechanical vibrations combined with properly chosen local nondestructive testing methods

  15. Theory and Techniques for Vibration-Induced Conductivity Fluctuation testing of Soils

    CERN Document Server

    Chang, Hung-Chih; Kishne, Andrea; Morgan, Cristine; Kwan, Chiman; 10.1142/S021947750800443X

    2009-01-01

    First we present and theoretically analyze the phenomenological physical picture behind Vibration-Induced Conductivity Fluctuations. We identify the relevant tensors characterizing the electromechanical response against the vibrations for both longitudinal and transversal responses. We analyze the conductivity response with acceleration type vibrations and a new scheme, measurements with more advantageous compression type vibrations that are first introduced here. Compression vibrations provide sideband spectral lines shifted by the frequency of the vibration instead of its second harmonics; moreover the application of this method is less problematic with loose electrodes. Concerning geometry and electrodes, the large measurement errors in earlier experiment indicated electrode effects which justify using four-electrode type measurements. We propose and analyze new arrangements for the longitudinal and transversal measurements with both compression vibration and acceleration vibration for laboratory and field...

  16. Rail Shock and Vibration Pre-Test Modeling of a Used Nuclear Fuel Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Steven B.; Klymyshyn, Nicholas A.; Jensen, Philip J.; Best, Ralph E.; Maheras, Steven J.; McConnell, Paul E.; Orchard, John

    2015-04-01

    The U.S. Department of Energy Office of Nuclear Energy (DOE-NE), Office of Fuel Cycle Technology, has established the Used Fuel Disposition Campaign (UFDC) to conduct the research and development activities related to storage, transportation, and disposal of used nuclear fuel (UNF) and high-level radioactive waste (HLW). The mission of the UFDC is to identify alternatives and conduct scientific research and technology development to enable storage, transportation and disposal of used nuclear fuel and HLW generated by existing and future nuclear fuel cycles. The Storage and Transportation staff within the UFDC is responsible for addressing issues regarding the long-term or extended storage (ES) of UNF and its subsequent transportation. Available information is not sufficient to determine the ability of ES UNF, including high-burnup fuel, to withstand shock and vibration forces that could occur when the UNF is shipped by rail from nuclear power plant sites to a storage or disposal facility. There are three major gaps in the available information – 1) the forces that UNF assemblies would be subjected to when transported by rail, 2) the mechanical characteristics of fuel rod cladding, which is an essential structure for controlling the geometry of the UNF, a safety related feature, and 3) modeling methodologies to evaluate multiple possible degradation or damage mechanisms over the UNF lifetime. In order to address the first gap, options for tests to determine the physical response of surrogate UNF assemblies subjected to shock and vibration forces that are expected to be experienced during normal conditions of transportation (NCT) by rail must be identified and evaluated. The objective of the rail shock and vibration tests is to obtain data that will help researchers understand the mechanical loads that ES UNF assemblies would be subjected to under normal conditions of transportation and to fortify the computer modeling that will be necessary to evaluate the impact

  17. Development of a hand- transmitted vibration measurement instrument to perform tests in medical equipment according to the international standard IEC 60601-1-2005 Ed.3

    Science.gov (United States)

    de Lima, F. F.; Moriya, H. T.; Moraes, J. C. T. B.

    2016-07-01

    According to the sub clause 9.6.3 of the international standard IEC 60601-1-2005, medical electrical equipment must provide means of protection against hazardous hand- transmitted vibrations. Compliance of this sub clause is checked by using a vibration measurement instrument in accordance with ISO 5349-1-2001 standard. The present article describes the development of a vibration measurement instrument to perform vibration measurements tests in medical equipments.

  18. Force Limiting Vibration Tests Evaluated from both Ground Acoustic Tests and FEM Simulations of a Flight Like Vehicle System Assembly

    Science.gov (United States)

    Smith, Andrew; LaVerde, Bruce; Waldon, James; Hunt, Ron

    2014-01-01

    Marshall Space Flight Center has conducted a series of ground acoustic tests with the dual goals of informing analytical judgment, and validating analytical methods when estimating vibroacoustic responses of launch vehicle subsystems. The process of repeatedly correlating finite element-simulated responses with test-measured responses has assisted in the development of best practices for modeling and post-processing. In recent work, force transducers were integrated to measure interface forces at the base of avionics box equipment. Other force data was indirectly measured using strain gauges. The combination of these direct and indirect force measurements has been used to support and illustrate the advantages of implementing the Force Limiting approach for equipment qualification tests. The comparison of force response from integrated system level tests to measurements at the same locations during component level vibration tests provides an excellent illustration. A second comparison of the measured response cases from the system level acoustic tests to finite element simulations has also produced some principles for assessing the suitability of Finite Element Models (FEMs) for making vibroacoustics estimates. The results indicate that when FEM models are employed to guide force limiting choices, they should include sufficient detail to represent the apparent mass of the system in the frequency range of interest.

  19. Integrated Vehicle Ground Vibration Testing in Support of NASA Launch Vehicle Loads and Controls Analysis

    Science.gov (United States)

    Tuma, Margaret L.; Davis, Susan R.; Askins, Bruce R.; Salyer, Blaine H.

    2008-01-01

    The National Aeronautics and Space Administration (NASA) Ares Projects Office (APO) is continuing to make progress toward the final design of the Ares I crew launch vehicle and Ares V cargo launch vehicle. Ares I and V will form the space launch capabilities necessary to fulfill NASA's exploration strategy of sending human beings to the Moon, Mars, and beyond. As with all new space vehicles there will be a number of tests to ensure the design can be Human Rated. One of these is the Integrated Vehicle Ground Vibration Test (IVGVT) that will be measuring responses of the Ares I as a system. All structural systems possess a basic set of physical characteristics unique to that system. These unique characteristics include items such as mass distribution, frequency and damping. When specified, they allow engineers to understand and predict how a structural system like the Ares I launch vehicle behaves under given loading conditions. These physical properties of launch vehicles may be predicted by analysis or measured through certain types of tests. Generally, these properties are predicted by analysis during the design phase of a launch vehicle and then verified through testing before the vehicle is Human Rated. The IVGVT is intended to measure by test the fundamental dynamic characteristics of Ares I during various phases of operational/flight. This testing includes excitations of the vehicle in lateral, longitudinal, and torsional directions at vehicle configurations representing different trajectory points. During the series of tests, properties such as natural frequencies, mode shapes, and transfer functions are measured directly. These data will then be used to calibrate loads and Guidance, Navigation, and Controls (GN&C) analysis models for verifying analyses of Ares I. NASA launch vehicles from Saturn to Shuttle have undergone Ground Vibration Tests (GVTs) leading to successful launch vehicles. A GVT was not performed on the unmanned Delta III. This vehicle was

  20. Vibration test and analysis of Laoshan bicycle gymnasium for the Olympic Games under multi-support excitations

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The vibration tests of Laoshan bicycle gymnasium for the Olympic Games are performed under multi-support excitations in order to verify the effectiveness of multi-support time history method. The excitation sources come from the impact forces acting on the ring beam of the reticulated structure, on the basis of which the records of motions of each excited point and corresponding structural vibration responses are all collected. The theoretical analytical model of the structure is further established and the structural dynamic responses are obtained subjected to the same excitation case via multi-support time history method. The calculation results are generally in agreement with those of the test in both time domain and frequency domain, which verify the effectiveness of multi-support time history method. The vibration test can also provide references for long-span structures under multi-support excitations.

  1. Results of NASTRAN modal analyses and ground vibration tests on the YF-12A airplane

    Science.gov (United States)

    Kordes, E. E.; Curtis, A. R.

    1975-01-01

    The YF-12A aircraft, a delta-winged vehicle powered by two jet engines, was utilized in an investigation of the structural dynamic characteristics of a large, flexible, supersonic research vehicle. A large NASA structural analysis (NASTRAN) finite-element model was used to compute the ten lowest frequency symmetric and ten lowest frequency antisymmetric modes for the YF-12A aircraft. The results of the analysis were compared with experimental data obtained in a ground vibration test conducted with the completed aircraft. It was found that the finite-element structural model employed provides an adequate prediction of the dynamic behavior of the aircraft structure in the case of basic wing and body modes.

  2. Ensuring Safe Exploration: Ares Launch Vehicle Integrated Vehicle Ground Vibration Testing

    Science.gov (United States)

    Tuma, M. L.; Chenevert, D. J.

    2010-01-01

    Integrated vehicle ground vibration testing (IVGVT) will be a vital component for ensuring the safety of NASA's next generation of exploration vehicles to send human beings to the Moon and beyond. A ground vibration test (GVT) measures the fundamental dynamic characteristics of launch vehicles during various phases of flight. The Ares Flight & Integrated Test Office (FITO) will be leading the IVGVT for the Ares I crew launch vehicle at Marshall Space Flight Center (MSFC) from 2012 to 2014 using Test Stand (TS) 4550. MSFC conducted similar GVT for the Saturn V and Space Shuttle vehicles. FITO is responsible for performing the IVGVT on the Ares I crew launch vehicle, which will lift the Orion crew exploration vehicle to low Earth orbit, and the Ares V cargo launch vehicle, which can launch the lunar lander into orbit and send the combined Orionilander vehicles toward the Moon. Ares V consists of a six-engine core stage with two solid rocket boosters and an Earth departure stage (EDS). The same engine will power the EDS and the Ares I second stage. For the Ares IVGVT, the current plan is to test six configurations in three unique test positions inside TS 4550. Position 1 represents the entire launch stack at liftoff (using inert first stage segments). Position 2 consists of the entire launch stack at first stage burn-out (using empty first stage segments). Four Ares I second stage test configurations will be tested in Position 3, consisting of the Upper Stage and Orion crew module in four nominal conditions: J-2X engine ignition, post Launch Abort System (LAS) jettison, critical slosh mass, and J-2X burn-out. Because of long disuse, TS 4550 is being repaired and reactivated to conduct the Ares I IVGVT. The Shuttle-era platforms have been removed and are being replaced with mast climbers that provide ready access to the test articles and can be moved easily to support different positions within the test stand. The electrical power distribution system for TS 4550 was

  3. Forced vibration test of the Hualien large scale soil structure interaction model (pt. 2)

    International Nuclear Information System (INIS)

    A large-scale seismic test (LSST) programme conducted at Hualien (stiff soil site), Taiwan, has started (Tang et al., 1991) to provide earthquake-induced soil-structure interaction (SSI) data as an extension of the same kind of program conducted at Lotung (soft soil site) (EPRI, 1989). Two tests have been performed: a forced vibration test (FVT) without embedment (Morishita et al., 1993) and the same test with embedment. Horizontal excitations were applied in two different directions both on the roof slab and on the basemat of a 1/4-scale containment model. Vertical excitations were applied on the basemat only. The concept of 'principal axes (D1, D2)' was introduced for the SSI system, and the basic dynamic characteristics of the soil-structure system were obtained for D1 and D2. As an example, resonance frequencies for horizontal excitations were 4.1 and 4.6 Hz without embedment, and 6.1 and 6.3 Hz with embedment for D1 and D2 based on results transformed to principal axes. Finally, a soil impedance function was obtained by a newly defined error minimizing method. This function also simulates the classic embedment effect. (orig.)

  4. Forced vibration test of the Hualien large scale soil structure interaction model (pt. 2)

    Energy Technology Data Exchange (ETDEWEB)

    Sugawara, Y.; Uetake, T. [Tokyo Electr. Power Co., Yokohama (Japan); Kobayashi, T.; Yamaya, H. [Kajima Technical Res. Inst., Tokyo (Japan)

    1997-10-01

    A large-scale seismic test (LSST) programme conducted at Hualien (stiff soil site), Taiwan, has started (Tang et al., 1991) to provide earthquake-induced soil-structure interaction (SSI) data as an extension of the same kind of program conducted at Lotung (soft soil site) (EPRI, 1989). Two tests have been performed: a forced vibration test (FVT) without embedment (Morishita et al., 1993) and the same test with embedment. Horizontal excitations were applied in two different directions both on the roof slab and on the basemat of a 1/4-scale containment model. Vertical excitations were applied on the basemat only. The concept of `principal axes (D{sub 1}, D{sub 2})` was introduced for the SSI system, and the basic dynamic characteristics of the soil-structure system were obtained for D{sub 1} and D{sub 2}. As an example, resonance frequencies for horizontal excitations were 4.1 and 4.6 Hz without embedment, and 6.1 and 6.3 Hz with embedment for D{sub 1} and D{sub 2} based on results transformed to principal axes. Finally, a soil impedance function was obtained by a newly defined error minimizing method. This function also simulates the classic embedment effect. (orig.) 4 refs.

  5. Forced vibration test of the Hualien large scale soil-structure interaction (SSI) model: part 2

    Energy Technology Data Exchange (ETDEWEB)

    Sugawara, Y.; Uetake, T. [Tokyo Electric Power Co., Inc. (Japan); Kobayashi, T.; Yamaya, H. [Kajima Technical Research Inst., Tokyo (Japan)

    1995-12-31

    A Large-Scale Seismic Test (LSST) Program conducted at Hualien (stiff soil site). Taiwan, has started to obtain earthquake-induced soil-structure interaction (SSI) data as an extension of the same kind of program conducted at Lotung (soft soil site). Two tests have been performed: a Forced Vibration Test without embedment and the same test with embedment. Horizontal excitations were applied in two different directions both on the roof slab and on the basemat of a 1/4-scale containment model. Vertical excitations were applied on the basemat only. The concept of Principal Axes (D{sub 1}, D{sub 2}) was introduced for the SSI system, and the basic dynamic characteristics of the soil-structure system were obtained for D{sub 1} and D{sub 2}. As an example, peak frequencies for horizontal excitation were 4.1 and 4.6 Hz without embedment, and 6.1 and 6.3 Hz with embedment for D{sub 1} and D{sub 2} based on results transformed to principal axes. Finally, a soil impedance function was obtained by a newly defined error minimizing method. This function also simulates the classic embedment effect. (author). 5 refs., 9 figs., 1 tab.

  6. Forced vibration test of the Hualien large scale soil-structure interaction (SSI) model: part 2

    International Nuclear Information System (INIS)

    A Large-Scale Seismic Test (LSST) Program conducted at Hualien (stiff soil site). Taiwan, has started to obtain earthquake-induced soil-structure interaction (SSI) data as an extension of the same kind of program conducted at Lotung (soft soil site). Two tests have been performed: a Forced Vibration Test without embedment and the same test with embedment. Horizontal excitations were applied in two different directions both on the roof slab and on the basemat of a 1/4-scale containment model. Vertical excitations were applied on the basemat only. The concept of Principal Axes (D1, D2) was introduced for the SSI system, and the basic dynamic characteristics of the soil-structure system were obtained for D1 and D2. As an example, peak frequencies for horizontal excitation were 4.1 and 4.6 Hz without embedment, and 6.1 and 6.3 Hz with embedment for D1 and D2 based on results transformed to principal axes. Finally, a soil impedance function was obtained by a newly defined error minimizing method. This function also simulates the classic embedment effect. (author). 5 refs., 9 figs., 1 tab

  7. Small-scale rotor test rig capabilities for testing vibration alleviation algorithms

    Science.gov (United States)

    Jacklin, Stephen A.; Leyland, Jane Anne

    1987-01-01

    A test was conducted to assess the capabilities of a small scale rotor test rig for implementing higher harmonic control and stability augmentation algorithms. The test rig uses three high speed actuators to excite the swashplate over a range of frequencies. The actuator position signals were monitored to measure the response amplitudes at several frequencies. The ratio of response amplitude to excitation amplitude was plotted as a function of frequency. In addition to actuator performance, acceleration from six accelerometers placed on the test rig was monitored to determine whether a linear relationship exists between the harmonics of N/Rev control input and the least square error (LSE) identification technique was used to identify local and global transfer matrices for two rotor speeds at two batch sizes each. It was determined that the multicyclic control computer system interfaced very well with the rotor system and kept track of the input accelerometer signals and their phase angles. However, the current high speed actuators were found to be incapable of providing sufficient control authority at the higher excitation frequencies.

  8. Dynamic Properties of the Painter Street Overpass at Different Levels of Vibration

    DEFF Research Database (Denmark)

    Ventura, C. E.; Brincker, Rune; Andersen, P.

    2005-01-01

    This paper describes the results from a series of ambient vibration studies conducted on the Painter Street Overpass in Rio Dell, California. Painter Street is a two-span, skewed reinforced concrete bridge with two single piers near the middle and monolithic abutments, typical of bridge overpasses...... in California. Strong motion instruments were installed on the bridge in 1977, and since then it has recorded the motions from more than ten significant earthquakes. Because of the valuable amount of strong motion data available, the aim of the ambient vibration tests was to determine the dynamic...... characteristics of the bridge at low levels of vibration and to compare these with those measured during the strong motion events. In this paper, a description of the recorded strong motion events is presented first, then the ambient vibration tests are described and the results are compared with those obtained...

  9. Updating the Finite Element Model of the Aerostructures Test Wing using Ground Vibration Test Data

    Science.gov (United States)

    Lung, Shun-fat; Pak, Chan-gi

    2009-01-01

    Improved and/or accelerated decision making is a crucial step during flutter certification processes. Unfortunately, most finite element structural dynamics models have uncertainties associated with model validity. Tuning the finite element model using measured data to minimize the model uncertainties is a challenging task in the area of structural dynamics. The model tuning process requires not only satisfactory correlations between analytical and experimental results, but also the retention of the mass and stiffness properties of the structures. Minimizing the difference between analytical and experimental results is a type of optimization problem. By utilizing the multidisciplinary design, analysis, and optimization (MDAO) tool in order to optimize the objective function and constraints; the mass properties, the natural frequencies, and the mode shapes can be matched to the target data to retain the mass matrix orthogonality. This approach has been applied to minimize the model uncertainties for the structural dynamics model of the Aerostructures Test Wing (ATW), which was designed and tested at the National Aeronautics and Space Administration (NASA) Dryden Flight Research Center (DFRC) (Edwards, California). This study has shown that natural frequencies and corresponding mode shapes from the updated finite element model have excellent agreement with corresponding measured data.

  10. Characterization Testing of H20-SO2 Electrolyzer at Ambient Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Steimke, J

    2005-07-29

    are included to allow variation of the operating pressure in the range of 1 to 2 bar. Hydrogen generated at the cathode of the cell can be collected for the purpose of flow measurement and composition analysis. The test facility proved to be easy to operate, versatile, and reliable. Two slightly different SDE's were designed, procured and tested. The first electrolyzer was based on a commercially available PEM water electrolyzer manufactured by Proton Energy Systems, Inc. (PES). The PES electrolyzer was built with Hastelloy B and Teflon wetted parts, a PEM electrolyte, and porous titanium electrodes. The second electrolyzer was assembled for SRNL by the University of South Carolina (USC). It was constructed with platinized carbon cloth electrodes, a Nafion 115 PEM electrolyte, carbon paper flow fields, and solid graphite back plates. Proof-of-concept testing was performed on each electrolyzer at near-ambient pressure and room temperature under various feed conditions. SDE operation was evidenced by hydrogen production at the cathode and sulfuric acid production at the anode (witnessed by the absence of oxygen generation) and with cell voltages substantially less than the theoretical reversible voltage for simple water electrolysis (1.23 V). Cell performance at low currents equaled or exceeded that achieved in the two-compartment cells built by Westinghouse Electric Corporation during the original development of the HyS Process. Performance at higher currents was less efficient due to mass transfer and hydraulic issues associated with the use of cells not optimized for liquid feed. Test results were analyzed to determine performance trends, improvement needs, and long-term SDE potential. The PES cell failed after several days of operation due to internal corrosion of the titanium electrodes in the presence of sulfuric acid. Although it was anticipated that the titanium would react in the presence of acid, the rapid deterioration of the electrodes was unexpected

  11. Vortex-induced vibration of two parallel risers: Experimental test and numerical simulation

    Science.gov (United States)

    Huang, Weiping; Zhou, Yang; Chen, Haiming

    2016-04-01

    The vortex-induced vibration of two identical rigidly mounted risers in a parallel arrangement was studied using Ansys- CFX and model tests. The vortex shedding and force were recorded to determine the effect of spacing on the two-degree-of-freedom oscillation of the risers. CFX was used to study the single riser and two parallel risers in 2-8 D spacing considering the coupling effect. Because of the limited width of water channel, only three different riser spacings, 2 D, 3 D, and 4 D, were tested to validate the characteristics of the two parallel risers by comparing to the numerical simulation. The results indicate that the lift force changes significantly with the increase in spacing, and in the case of 3 D spacing, the lift force of the two parallel risers reaches the maximum. The vortex shedding of the risers in 3 D spacing shows that a variable velocity field with the same frequency as the vortex shedding is generated in the overlapped area, thus equalizing the period of drag force to that of lift force. It can be concluded that the interaction between the two parallel risers is significant when the risers are brought to a small distance between them because the trajectory of riser changes from oval to curve 8 as the spacing is increased. The phase difference of lift force between the two risers is also different as the spacing changes.

  12. Modal Parameters Estimation of Building Structures from Vibration Test Data Using Observability Measurement

    Directory of Open Access Journals (Sweden)

    Jae-Seung Hwang

    2015-01-01

    Full Text Available The load distribution to each mode of a structure under seismic loading depends on the modal participation factors and mode shapes and thus the exact estimation of modal participation factors and mode shapes is essential to analyze the seismic response of a structure. In this study, an identification procedure for modal participation factors and mode shapes from a vibration test is proposed. The modal participation factors and mode shapes are obtained from the relationship between observability matrices realized from the system identification. Using the observability matrices, it is possible to transform an arbitrarily identified state space model obtained from the experimental data into a state space model which is defined in a domain with physical meaning. Then, the modal participation factor can be estimated based on the transformation matrix between two state space models. The numerical simulation is performed to evaluate the proposed procedure, and the results show that the modal participation factor and mode shapes are estimated from the structural responses accurately. The procedure is also applied to the experimental data obtained from the shaking table test of a three-story shear building model.

  13. Vibration Durability Testing of Nickel Manganese Cobalt Oxide (NMC Lithium-Ion 18,650 Battery Cells

    Directory of Open Access Journals (Sweden)

    James Michael Hooper

    2016-01-01

    Full Text Available Electric vehicle (EV manufacturers are employing cylindrical format cells in the construction of the vehicles’ battery systems. There is evidence to suggest that both the academic and industrial communities have evaluated cell degradation due to vibration and other forms of mechanical loading. The primary motivation is often the need to satisfy the minimum requirements for safety certification. However, there is limited research that quantifies the durability of the battery and in particular, how the cells will be affected by vibration that is representative of a typical automotive service life (e.g., 100,000 miles. This paper presents a study to determine the durability of commercially available 18,650 cells and quantifies both the electrical and mechanical vibration-induced degradation through measuring changes in cell capacity, impedance and natural frequency. The impact of the cell state of charge (SOC and in-pack orientation is also evaluated. Experimental results are presented which clearly show that the performance of 18,650 cells can be affected by vibration profiles which are representative of a typical vehicle life. Consequently, it is recommended that EV manufacturers undertake vibration testing, as part of their technology selection and development activities to enhance the quality of EVs and to minimize the risk of in-service warranty claims.

  14. Characterisation of an Electrostatic Vibration Harvester

    CERN Document Server

    Sterken, T; Fiorini, P; Puers, R

    2008-01-01

    Harvesting energy from ambient vibration is proposed as an alternative to storage based power supplies for autonomous systems. The system presented converts the mechanical energy of a vibration into electrical energy by means of a variable capacitor, which is polarized by an electret. A lumped element model is used to study the generator and design a prototype. The device has been micromachined in silicon, based on a two-wafer process. The prototype was successfully tested, both using an external polarization source and an electret.

  15. High level seismic/vibrational tests at the HDR: An overview

    Energy Technology Data Exchange (ETDEWEB)

    Kot, C.A.; Srinivasan, M.G.; Hsieh, B.J. [Argonne National Lab., IL (United States); Schrammel, D.; Malcher, L. [Kernforschungszentrum Karlsruhe GmbH (Germany); Steinhilber, H. [Fachhochschule Giessen-Friedberg, Giessen (Germany); Costello, J.F. [Nuclear Regulatory Commission, Washington, DC (United States). Office of Nuclear Regulatory Research

    1991-12-31

    As part of the Phase II testing at the HDR Test Facility in Kahl/Main, FRG, two series of high-level seismic/vibrational experiments were performed. In the first of these (SHAG) a coast-down shaker, mounted on the reactor operating floor and capable of generating 1000 tonnes of force, was used to investigate full-scale structural response, soil-structure interaction (SSI), and piping/equipment response at load levels equivalent to those of a design basis earthquake. The HDR soil/structure system was tested to incipient failure exhibiting highly nonlinear response. In the load transmission from structure to piping/equipment significant response amplifications and shifts to higher frequencies occurred. The performance of various pipe support configurations was evaluated. This latter effort was continued in the second series of tests (SHAM), in which an in-plant piping system was investigated at simulated seismic loads (generated by two servo-hydraulic actuators each capable of generating 40 tonnes of force), that exceeded design levels manifold and resulted in considerable pipe plastification and failure of some supports (snubbers). The evaluation of six different support configurations demonstrated that proper system design (for a given spectrum) rather than number of supports or system stiffness is essential to limiting pipe stresses. Pipe strains at loads exceeding the design level eightfold were still tolerable, indicating that pipe failure even under extreme seismic loads is unlikely inspite of multiple support failures. Conservatively, an excess capacity (margin) of at least four was estimated for the piping system, and the pipe damping was found to be 4%. Comparisons of linear and nonlinear computational results with measurements showed that analytical predictions have wide scatter and do not necessarily yield conservative responses, underpredicting, in particular, peak support forces.

  16. High level seismic/vibrational tests at the HDR: An overview

    Energy Technology Data Exchange (ETDEWEB)

    Kot, C.A.; Srinivasan, M.G.; Hsieh, B.J. (Argonne National Lab., IL (United States)); Schrammel, D.; Malcher, L. (Kernforschungszentrum Karlsruhe GmbH (Germany)); Steinhilber, H. (Fachhochschule Giessen-Friedberg, Giessen (Germany)); Costello, J.F. (Nuclear Regulatory Commission, Washington, DC (United States). Office of Nuclear Regulatory Research)

    1991-01-01

    As part of the Phase II testing at the HDR Test Facility in Kahl/Main, FRG, two series of high-level seismic/vibrational experiments were performed. In the first of these (SHAG) a coast-down shaker, mounted on the reactor operating floor and capable of generating 1000 tonnes of force, was used to investigate full-scale structural response, soil-structure interaction (SSI), and piping/equipment response at load levels equivalent to those of a design basis earthquake. The HDR soil/structure system was tested to incipient failure exhibiting highly nonlinear response. In the load transmission from structure to piping/equipment significant response amplifications and shifts to higher frequencies occurred. The performance of various pipe support configurations was evaluated. This latter effort was continued in the second series of tests (SHAM), in which an in-plant piping system was investigated at simulated seismic loads (generated by two servo-hydraulic actuators each capable of generating 40 tonnes of force), that exceeded design levels manifold and resulted in considerable pipe plastification and failure of some supports (snubbers). The evaluation of six different support configurations demonstrated that proper system design (for a given spectrum) rather than number of supports or system stiffness is essential to limiting pipe stresses. Pipe strains at loads exceeding the design level eightfold were still tolerable, indicating that pipe failure even under extreme seismic loads is unlikely inspite of multiple support failures. Conservatively, an excess capacity (margin) of at least four was estimated for the piping system, and the pipe damping was found to be 4%. Comparisons of linear and nonlinear computational results with measurements showed that analytical predictions have wide scatter and do not necessarily yield conservative responses, underpredicting, in particular, peak support forces.

  17. EXPERIMENTAL TECHNIQUE TO INVESTIGATE VIBRATION MONITORING IN REVOLVING STRUCTURES USING OSCILLOSCOPIC /MODAL TESTING

    Directory of Open Access Journals (Sweden)

    H.A.H.AL-KHAZALI

    2011-10-01

    Full Text Available Linear structures for the purpose of vibration analysis may be modelled either as a continuous system or a discrete one.In the case of the latter method the mass of the system is lumped into a finite number of masses connected by springs and dampers representing the stiffness and damping in the system respectively. The system is then said to possess an finite number of degrees of freedom.In this paper search of finding a new technique for interpret the results obtained from experiment measurement of dynamic performance of machineryfor condition monitoring,it is envisage that a database could be created. This database consisting of complete mathematical model of the machine which includes both the supporting structures as well as the moving parts and is based on the structural dynamics characteristics of the system. The experimental technique used thus far is called Modal Testing, a well known and widely used technique inresearch and industry to obtain the modal and Dynamic response properties of structures.The technique has recently been applied to rotating structures and some research papers been published, however the full implementation of Modal Testing in active structures and the implications are not fully understood and are therefore in need of much further and more in depth investigations. The raw data obtained from experiment was used in Simulation finite element (FE model (ANSYS 12 for comparison,it has good capability for Eigen analysis and also good graphical facility and obtained good result.The objective of the paper is using modal testing and analysis results for structural health monitoring purpose.

  18. Dynamic analysis and modal test of long-span cable-stayed bridge based on ambient excitation

    Institute of Scientific and Technical Information of China (English)

    CHEN Chang-song; YAN Dong-huang

    2007-01-01

    To study the stifilless distilbution of girder and the method to identify modal parameters of cable-stayed bridge, a simplified dynamical finite element method model named three beams model was established for the girder with double ribs.Based on the simplified model four stiffness formulae were deduced according to Hamilton principle.These formulae reflect well the contribution of the flexural, shearing, free torsion and restricted torsion deformation, respectively.An identification method about modal parameters was put forward by combining method of peak value and power spectral density according to modal test under ambient excitation.The dynamic finite element method analysis and modal test were carried out in a long-span concrete cable-stayed bridge.The results show that the errors of frequencies between theoretical analysis and test results are less than 10%mostly,and the most important modal parameters for cable-stayed bridge are determined to be the longitudinal floating mode, the first vertical flexural mode and the first torsional mode, which demonstrate that the method of stifiness distribution for three beams model is accurate and method to identify modal parameters is effective under ambient excitation modal test.

  19. Strain-controlled fatigue tests on welded joints with super position of different types of vibration

    International Nuclear Information System (INIS)

    In order to be able to study the effect of a harmonic on the service life, a low frequency fundamental of high strain amplitude had a high frequency harmonic of small strain amplitude, which acted during the whole of the fundamental cycles of vibration, superimposed on it. Such stresses can occur, for example on starting or stopping electrical machines in various dynamiclly stressed components. As many welded structures are manufactured from unalloyed ferritic/perlitic carbon steels, structural steel of type St 360 C according to the OeNORM M 3116 for investigations in the short term fatigue range was selected. Strain-controlled experiments were carried out between 0.25% and 3% total strain. There were cases where there was a considerable drop in the service life for stressing with fundamental and harmonics in comparison with a stress without harmonics in the total strain-controlled fatigue tests. A prediction of the service life is only possible with a considerably greater number of samples than previously used, because of the many parameters affecting welded joints. As the scatter of probability of fracture in the area of short term fatigue is relatively narrow compared to experiments in the fatigue area, one can at least recognize clear trends. (orig.)

  20. Flow-induced vibration test of an advanced water reactor model. Part 2: Turbulence-induced structural response

    International Nuclear Information System (INIS)

    A 1/9-scale model flow-induced vibration test of a proposed advanced water reactor (AWR) was performed. The main objectives of the test program were: (1) to derive an empirical equation for the turbulence-induced forcing function that can be applied to the full-sized prototype; (2) to study the effect of viscosity on the turbulence forcing function generation and dissipation and to verify the superposition assumption widely used in dynamic analysis of weakly coupled fluid-shell systems; (3) to measure the shell response due to turbulence-induced excitation so that the data can be used to verify methods and computer programs used in the flow-induced vibration design analysis of the prototype. This paper describes Objective (3) of the test program

  1. Identification of aeroelastic forces and static drag coefficients of a twin cable bridge stay from full-scale ambient vibration measurements

    DEFF Research Database (Denmark)

    Acampora, Antonio; Georgakis, Christos T.; Macdonald, J.H.G.;

    2014-01-01

    Despite much research in recent years, large amplitude vibrations of inclined cables continue to be of concern for cable-stayed bridges. Various excitation mechanisms have been suggested, including rain-wind excitation, dry inclined cable galloping, high reduced velocity vortex shedding and excit......Despite much research in recent years, large amplitude vibrations of inclined cables continue to be of concern for cable-stayed bridges. Various excitation mechanisms have been suggested, including rain-wind excitation, dry inclined cable galloping, high reduced velocity vortex shedding......-scale measurements are compared with the theoretical damping matrices based on the quasi-steady theory, using three different sets of wind tunnel measurements of static force coefficients on similar shaped twin or single cables, with good agreement. The damping terms are found to be dependent on Reynolds number...... in dry conditions.Finally, static drag coefficients are back-calculated from the full-scale vibration measurements, for first time, with reasonable agreement with direct wind tunnel measurements. The remaining discrepancies are believed to be due to the higher turbulence intensity on site than...

  2. Urban vibrations

    DEFF Research Database (Denmark)

    Morrison, Ann; Knudsen, L.; Andersen, Hans Jørgen

    2012-01-01

      lab   studies   in   that   we   found   a   decreased   detection   rate   in   busy   environments.   Here   we   test   with   a   much   larger   sample   and   age   range,   and   contribute   with   the   first   vibration  sensitivity  testing  outside  the  lab  in  an  urban   public......In   this   paper   we   describe   a   field   study   conducted   with   a   wearable   vibration   belt   where   we   test   to   determine   the   vibration   intensity   sensitivity   ranges   on   a   large   diverse   group   of   participants   with   evenly   distributed  ages  and...

  3. Experimental Analysis of a Piezoelectric Energy Harvesting System for Harmonic, Random, and Sine on Random Vibration

    Directory of Open Access Journals (Sweden)

    Jackson W. Cryns

    2013-01-01

    Full Text Available Harvesting power with a piezoelectric vibration powered generator using a full-wave rectifier conditioning circuit is experimentally compared for varying sinusoidal, random, and sine on random (SOR input vibration scenarios; the implications of source vibration characteristics on harvester design are discussed. The rise in popularity of harvesting energy from ambient vibrations has made compact, energy dense piezoelectric generators commercially available. Much of the available literature focuses on maximizing harvested power through nonlinear processing circuits that require accurate knowledge of generator internal mechanical and electrical characteristics and idealization of the input vibration source, which cannot be assumed in general application. Variations in source vibration and load resistance are explored for a commercially available piezoelectric generator. The results agree with numerical and theoretical predictions in the previous literature for optimal power harvesting in sinusoidal and flat broadband vibration scenarios. Going beyond idealized steady-state sinusoidal and flat random vibration input, experimental SOR testing allows for more accurate representation of real world ambient vibration. It is shown that characteristic interactions from more complex vibration sources significantly alter power generation and processing requirements by varying harvested power, shifting optimal conditioning impedance, inducing voltage fluctuations, and ultimately rendering idealized sinusoidal and random analyses incorrect.

  4. 40 CFR 53.56 - Test for effect of variations in ambient pressure.

    Science.gov (United States)

    2010-07-01

    ... coefficient of variation of the discrete measurements as follows: Equation 19 ER18jy97.081 (ii) To successfully pass this test, the calculated coefficient of variation for the certified flow rates must not... test run. (4) Flow rate CV measurement accuracy. (i) Using the flow rate coefficient of...

  5. Flexural Vibration Test of a Cantilever Beam with a Force Sensor: Fast Determination of Young's Modulus

    Science.gov (United States)

    Digilov, Rafael M.

    2008-01-01

    We describe a simple and very inexpensive undergraduate laboratory experiment for fast determination of Young's modulus at moderate temperatures with the aid of a force sensor. A strip-shaped specimen rigidly bolted to the force sensor forms a clamped-free cantilever beam. Placed in a furnace, it is subjected to free-bending vibrations followed by…

  6. Design and laboratory testing of a new flow-through directional passive air sampler for ambient particulate matter.

    Science.gov (United States)

    Lin, Chun; Solera Garcia, Maria Angeles; Timmis, Roger; Jones, Kevin C

    2011-03-01

    A new type of directional passive air sampler (DPAS) is described for collecting particulate matter (PM) in ambient air. The prototype sampler has a non-rotating circular sampling tray that is divided into covered angular channels, whose ends are open to winds from sectors covering the surrounding 360°. Wind-blown PM from different directions enters relevant wind-facing channels, and is retained there in collecting pools containing various sampling media. Information on source direction and type can be obtained by examining the distribution of PM between channels. Wind tunnel tests show that external wind velocities are at least halved over an extended area of the collecting pools, encouraging PM to settle from the air stream. Internal and external wind velocities are well-correlated over an external velocity range of 2.0-10.0 m s⁻¹, which suggests it may be possible to relate collected amounts of PM simply to ambient concentrations and wind velocities. Measurements of internal wind velocities in different channels show that velocities decrease from the upwind channel round to the downwind channel, so that the sampler effectively resolves wind directions. Computational fluid dynamics (CFD) analyses were performed on a computer-generated model of the sampler for a range of external wind velocities; the results of these analyses were consistent with those from the wind tunnel. Further wind tunnel tests were undertaken using different artificial particulates in order to assess the collection performance of the sampler in practice. These tests confirmed that the sampler can resolve the directions of sources, by collecting particulates preferentially in source-facing channels.

  7. A vibration powered wireless mote on the Forth Road Bridge

    Science.gov (United States)

    Jia, Yu; Yan, Jize; Feng, Tao; Du, Sijun; Fidler, Paul; Soga, Kenichi; Middleton, Campbell; Seshia, Ashwin A.

    2015-12-01

    The conventional resonant-approaches to scavenge kinetic energy are typically confined to narrow and single-band frequencies. The vibration energy harvester device reported here combines both direct resonance and parametric resonance in order to enhance the power responsiveness towards more efficient harnessing of real-world ambient vibration. A packaged electromagnetic harvester designed to operate in both of these resonant regimes was tested in situ on the Forth Road Bridge. In the field-site, the harvester, with an operational volume of ∼126 cm3, was capable of recovering in excess of 1 mW average raw AC power from the traffic-induced vibrations in the lateral bracing structures underneath the bridge deck. The harvester was integrated off-board with a power conditioning circuit and a wireless mote. Duty- cycled wireless transmissions from the vibration-powered mote was successfully sustained by the recovered ambient energy. This limited duration field test provides the initial validation for realising vibration-powered wireless structural health monitoring systems in real world infrastructure, where the vibration profile is both broadband and intermittent.

  8. Analysis and testing of an integrated semi-active seat suspension for both longitudinal and vertical vibration control

    Science.gov (United States)

    Bai, Xian-Xu; Jiang, Peng; Pan, Hui; Qian, Li-Jun

    2016-04-01

    An integrated semi-active seat suspension for both longitudinal and vertical vibration control is analyzed and tested in this paper. The seat suspension consists of a switching mechanism transforming both longitudinal and vertical motions into a rotary motion and a real-time damping-controllable system-a rotary magnetorheological (MR) damper working in pure shear mode and its corresponding control system. The switching mechanism employs the parallelogram frames as a motion guide which keeps the seat moving longitudinally and vertically. At the same time, both longitudinal and vertical motions are transformed into a reciprocating rotary motion that is transmitted to the rotary MR damper after an amplification by a gear mechanism. Both the longitudinal and vertical vibrations can be attenuated in real time through controlling the damping force (or torque) of the rotary MR damper. The mathematical model of the seat suspension system is established, simulated, and analyzed. The experimental test based on the test rig in Hefei University of Technology is implemented, and the results of simulation and experimental test are compared and analyzed.

  9. The Hualien large-scale seismic test for soil-structure interaction research. Response analysis of embedded structure during forced vibration tests and during earthquakes

    International Nuclear Information System (INIS)

    Predictive and correlative analyses of the forced vibration tests of the large-scale model structure embedded in the gravelly layer before and after backfill were performed. Also similar analyses of the same structure subjected to earthquakes were performed. As the result, the following was clarified; (1) Predicted fundamental system frequency of the forced vibration test before backfill by means of three-dimensional FEM complex dynamic response analysis code (named 'TB3D') was 9% higher than the test result. The predictive analysis also showed the applicability of 'TB3D', getting well predicted result of the basic characteristics of the response difference appearing in the tests due to the excitation position difference in the horizontal excitation cases, getting well simulated result of the test where phase lag frequency response curve is a convex function downward, and so on. The analysis with the ground model incorporating the Vs change following the construction stage progress brought good fundamental system frequency agreement with the test, indicating the importance of the appropriate incorporation of such Vs change into the ground model. (author)

  10. The Hualien large-scale seismic test for soil-structure interaction research. Response analysis of embedded structure during forced vibration tests and during earthquakes

    Energy Technology Data Exchange (ETDEWEB)

    Ueshima, Teruyuki; Tanaka, Yukihisa; Okamoto, Toshiro; Tohma, Junichi; Kokusho, Takeharu [Central Research Inst. of Electric Power Industry, Abiko, Chiba (Japan). Abiko Research Lab.

    1997-08-01

    Predictive and correlative analyses of the forced vibration tests of the large-scale model structure embedded in the gravelly layer before and after backfill were performed. Also similar analyses of the same structure subjected to earthquakes were performed. As the result, the following was clarified; (1) Predicted fundamental system frequency of the forced vibration test before backfill by means of three-dimensional FEM complex dynamic response analysis code (named `TB3D`) was 9% higher than the test result. The predictive analysis also showed the applicability of `TB3D`, getting well predicted result of the basic characteristics of the response difference appearing in the tests due to the excitation position difference in the horizontal excitation cases, getting well simulated result of the test where phase lag frequency response curve is a convex function downward, and so on. The analysis with the ground model incorporating the Vs change following the construction stage progress brought good fundamental system frequency agreement with the test, indicating the importance of the appropriate incorporation of such Vs change into the ground model. (author)

  11. Experimental Analysis of a Piezoelectric Energy Harvesting System for Harmonic, Random, and Sine on Random Vibration

    Energy Technology Data Exchange (ETDEWEB)

    Cryns, Jackson W.; Hatchell, Brian K.; Santiago-Rojas, Emiliano; Silvers, Kurt L.

    2013-07-01

    Formal journal article Experimental analysis of a piezoelectric energy harvesting system for harmonic, random, and sine on random vibration Abstract: Harvesting power with a piezoelectric vibration powered generator using a full-wave rectifier conditioning circuit is experimentally compared for varying sinusoidal, random and sine on random (SOR) input vibration scenarios. Additionally, the implications of source vibration characteristics on harvester design are discussed. Studies in vibration harvesting have yielded numerous alternatives for harvesting electrical energy from vibrations but piezoceramics arose as the most compact, energy dense means of energy transduction. The rise in popularity of harvesting energy from ambient vibrations has made piezoelectric generators commercially available. Much of the available literature focuses on maximizing harvested power through nonlinear processing circuits that require accurate knowledge of generator internal mechanical and electrical characteristics and idealization of the input vibration source, which cannot be assumed in general application. In this manuscript, variations in source vibration and load resistance are explored for a commercially available piezoelectric generator. We characterize the source vibration by its acceleration response for repeatability and transcription to general application. The results agree with numerical and theoretical predictions for in previous literature that load optimal resistance varies with transducer natural frequency and source type, and the findings demonstrate that significant gains are seen with lower tuned transducer natural frequencies for similar source amplitudes. Going beyond idealized steady state sinusoidal and simplified random vibration input, SOR testing allows for more accurate representation of real world ambient vibration. It is shown that characteristic interactions from more complex vibrational sources significantly alter power generation and power processing

  12. Flow-induced vibration test of an advanced water reactor model. Part 1: Turbulence-induced forcing function

    International Nuclear Information System (INIS)

    A 1/9 scale model of a proposed advanced water reactor was tested for flow-induced vibration. The main objectives of this test were to (1) derive an empirical equation for the turbulence forcing function which can be applied to the full-sized prototype; (2) study the effect of viscosity on the turbulence; (3) verify the superposition assumption widely used in dynamic analysis of weakly coupled fluid-shell systems; and (4) measure the shell responses to verify methods and computer programs used in the flow-induced vibration analysis of the prototype. This paper describes objectives (1), (2), and (3). Objective (4) will be discussed in a companion paper. The turbulence-induced fluctuating pressure was measured at 49 locations over the surface of a thick-walled, non-responsive scale model of the reactor vessel/core support cylinders. An empirical equation relating the fluctuating pressure, the frequency, and the distance from the inlet nozzle center line was derived to fit the test data. This equation involves only non-dimensional, fluid mechanical parameters that are postulated to represent the full-sized, geometrically similar prototype. While this postulate cannot be verified until similar measurements are taken on the full-sized unit, a similar approach using a 1/6 scale model of a commercial pressurized water reactor was verified in the mid-seventies by field measurements on the full-sized reactor

  13. The vibrational progressions of the N-->V electronic transition of ethylene: a test case for the computation of Franck-Condon factors of highly flexible photoexcited molecules.

    Science.gov (United States)

    Borrelli, Raffaele; Peluso, Andrea

    2006-11-21

    The vibrational progressions of the N-->V electronic transition of ethylene--a test case for the computation of Franck-Condon factors between electronic states exhibiting very different equilibrium geometries--have been calculated by using both the Cartesian and the curvilinear internal coordinate representations of the normal modes of vibration. The comparison of the theoretical spectra with the experimental one shows that the Cartesian representation yields vibrational progressions which are not observed in the experimental spectrum, whereas the curvilinear one gives a very satisfying agreement, even in harmonic approximation.

  14. Random vibration tests of the anticoincidence system of the PAMELA satellite experiment

    International Nuclear Information System (INIS)

    PAMELA is a general purpose cosmic ray satellite experiment which will be launched early in 2003. An anticoincidence system surrounds the PAMELA silicon tracker to reject particles not clearly entering the acceptance of the experiment. The engineering model of the PAMELA anticounter system uses plastic scintillator which is read out by Hamamatsu R5900U photomultipliers. The anticounters have been subjected to the random vibration spectrum expected during the launch of PAMELA. The integrated amplitude experienced by the photomultipliers was O(20) g RMS. No degradation to the photomultiplier operation or mechanical assembly was observed

  15. Durability evaluation of perfluoropolyether-lubricant-coated protective diamond-like carbon film by the lateral vibration friction test

    International Nuclear Information System (INIS)

    An investigation of the perfluoropolyether (PFPE) lubricant effect on the tribological properties of diamond-like carbon (DLC) film magnetic hard disks was conducted. On the basis of friction force microscopy techniques, we carried out lateral oscillation wear tests to detect DLC film disks with and without PFPE lubricant. The results reveal that the DLC film without lubricant easily fractures and swells. In contrast, the transfer of free lubricant and the progressive destruction of bonding lubricant were observed on the DLC film coated with a PFPE lubricant. The dynamic deformation and durability evaluation of the PFPE lubricant and DLC film system were observed in the lateral oscillation wear test by changing the experimental load and amplitude of lateral vibration applied to a cantilever tip. The destruction of the PFPE-DLC film occurred in the test of the 10 nm oscillation amplitude due to the breaking off of the molecular chain of PFPE

  16. Field test of four methods for gas-phase ambient nitric acid

    Science.gov (United States)

    Arnold, J. R.; Hartsell, Benjamin E.; Luke, Winston T.; Rahmat Ullah, S. M.; Dasgupta, Purnendu K.; Greg Huey, L.; Tate, Paul

    Three semi-continuous methods for detecting nitric acid (HNO 3) were tested against the annular denuder + filter pack (ADS) integrated collection technique at the Tampa Bay Regional Atmospheric Chemistry Experiment (BRACE) Sydney research station ˜20km downwind of the Tampa, Florida, urban core. The semi-continuous instruments included: two slightly differing implementations of the NOY-NO (total oxides of nitrogen minus that total denuded of HNO 3) denuder difference technique, one from the NOAA Air Resources Lab (ARL), and one from Atmospheric Research and Analysis, Inc. (ARA); the parallel plate wet diffusion scrubber + online ion chromatography technique from Texas Tech University (TTU); and the chemical ionization mass spectrometer from the Georgia Institute of Technology (GIT). Twelve hour ADS samples were collected by the University of South Florida (USF). Results for 10 min samples computed from the various higher sampling frequencies of each semi-continuous instrument showed good agreement (R2>0.7) for afternoon periods of the highest production and accumulation of HNO 3. Further, agreement was within ±30% for these instruments even at HNO 3 concentrations 60% for the nighttime samples; ADS results were below the corporate mean maximum HNO 3 concentration by >30% as well. The four instruments using semi-continuous methods, by contrast, were all within 10% of each other's 12 h mean mixing ratios. While only ARA employed a formal minimum detection limit at 0.050 ppb, error analysis with the other techniques established that at the same level of precision, TTU's effective limit was approximately the same as ARA's and that ARL's limit was 0.030 ppb; analysis for GIT showed no apparent effective limit at the levels of HNO 3 encountered in this field study. The importance of sample inlet height for HNO 3 measurements was indirectly shown through comparison to previous field work at this site when sample inlet heights ranged from 1.5-10 m and produced systematic

  17. Investigation of multilayer printed circuit board (PCB) film warpage using viscoelastic properties measured by a vibration test

    International Nuclear Information System (INIS)

    Woven glass fabric/BT (bismaleimide triazine) composite laminate (BT core), copper (Cu), and photoimageable solder resist (PSR) are the most widely used materials for semiconductors in electronic devices. Among these materials, BT core and PSR contain polymeric materials that exhibit viscoelastic behavior. For this reason, these materials are considered to have time- and temperature-dependent moduli during warpage analysis. However, the thin geometry of multilayer printed circuit board (PCB) film makes it difficult to identify viscoelastic characteristics. In this work, a vibration test method was proposed for measuring the viscoelastic properties of a multilayer PCB film at different temperatures. The beam-shaped specimens, composed of a BT core, Cu laminated on a BT core, and PSR and Cu laminated on a BT core, were used in the vibration test. The frequency-dependent variation of the complex bending stiffness was determined using a transfer function method. The storage modulus (E′) of the BT core, Cu, and PSR as a function of temperature and frequency were obtained, and their temperature-dependent variation was identified. The obtained properties were fitted using a viscoelastic model for the BT core and the PSR, and a linear elastic model for the Cu. Warpage of a line pattern specimen due to temperature variation was measured using a shadow Moiré analysis and compared to predictions using a finite element model. The results provide information on the mechanism of warpage, especially warpage due to temperature-dependent variation in viscoelastic properties. (paper)

  18. Investigation of multilayer printed circuit board (PCB) film warpage using viscoelastic properties measured by a vibration test

    Science.gov (United States)

    Joo, Sung-Jun; Park, Buhm; Kim, Do-Hyoung; Kwak, Dong-Ok; Song, In-Sang; Park, Junhong; Kim, Hak-Sung

    2015-03-01

    Woven glass fabric/BT (bismaleimide triazine) composite laminate (BT core), copper (Cu), and photoimageable solder resist (PSR) are the most widely used materials for semiconductors in electronic devices. Among these materials, BT core and PSR contain polymeric materials that exhibit viscoelastic behavior. For this reason, these materials are considered to have time- and temperature-dependent moduli during warpage analysis. However, the thin geometry of multilayer printed circuit board (PCB) film makes it difficult to identify viscoelastic characteristics. In this work, a vibration test method was proposed for measuring the viscoelastic properties of a multilayer PCB film at different temperatures. The beam-shaped specimens, composed of a BT core, Cu laminated on a BT core, and PSR and Cu laminated on a BT core, were used in the vibration test. The frequency-dependent variation of the complex bending stiffness was determined using a transfer function method. The storage modulus (E‧) of the BT core, Cu, and PSR as a function of temperature and frequency were obtained, and their temperature-dependent variation was identified. The obtained properties were fitted using a viscoelastic model for the BT core and the PSR, and a linear elastic model for the Cu. Warpage of a line pattern specimen due to temperature variation was measured using a shadow Moiré analysis and compared to predictions using a finite element model. The results provide information on the mechanism of warpage, especially warpage due to temperature-dependent variation in viscoelastic properties.

  19. A novel approach for simulating the optical misalignment caused by satellite platform vibration in the ground test of satellite optical communication systems.

    Science.gov (United States)

    Wang, Qiang; Tan, Liying; Ma, Jing; Yu, Siyuan; Jiang, Yijun

    2012-01-16

    Satellite platform vibration causes the misalignment between incident direction of the beacon and optical axis of the satellite optical communication system, which also leads to the instability of the laser link and reduces the precision of the system. So how to simulate the satellite platform vibration is a very important work in the ground test of satellite optical communication systems. In general, a vibration device is used for simulating the satellite platform vibration, but the simulation effect is not ideal because of the limited randomness. An approach is reasonable, which uses a natural random process for simulating the satellite platform vibration. In this paper, we discuss feasibility of the concept that the effect of angle of arrival fluctuation is taken as an effective simulation of satellite platform vibration in the ground test of the satellite optical communication system. Spectrum characteristic of satellite platform vibration is introduced, referring to the model used by the European Space Agency (ESA) in the SILEX program and that given by National Aeronautics and Space Development Agency (NASDA) of Japan. Spectrum characteristic of angle of arrival fluctuation is analyzed based on the measured data from an 11.16km bi-directional free space laser transmission experiment. Spectrum characteristic of these two effects is compared. The results show that spectra of these two effects have similar variation trend with the variation of frequency and feasibility of the concept is proved by the comparison results. At last the procedure of this method is proposed, which uses the power spectra of angle of arrival fluctuation to simulate that of the satellite platform vibration. The new approach is good for the ground test of satellite optical communication systems. PMID:22274450

  20. Ambient Space and Ambient Sensation

    DEFF Research Database (Denmark)

    Schmidt, Ulrik

    The ambient is the aesthetic production of the sensation of being surrounded. As a concept, 'ambient' is mostly used in relation to the music genre 'ambient music' and Brian Eno's idea of environmental background music. However, the production of ambient sensations must be regarded as a central...... aspect of the aesthetization of modern culture in general, from architecture, transport and urbanized lifeforms to film, sound art, installation art and digital environments. This presentation will discuss the key aspects of ambient aesthetization, including issues such as objectlessness...

  1. Obtaining and Estimating Low Noise Floors in Vibration Sensors

    DEFF Research Database (Denmark)

    Brincker, Rune; Larsen, Jesper Abildgaard

    2007-01-01

    For some applications like seismic applications and measuring ambient vibrations in structures, it is essential that the noise floors of the sensors and other system components are low and known to the user. Some of the most important noise sources are reviewed and it is discussed how the sensor...... can be designed in order to obtain a low noise floor. Techniques to estimate the noise floors for sensors are reviewed and are demonstrated on a commercial commonly used sensor for vibration testing. It is illustrated how the noise floor can be calculated using the coherence between simultaneous...

  2. Synchronous test study of two adjacent transmission tower undergoing ambient excitation%两相邻输电塔的同步环境脉动实测试验研究

    Institute of Scientific and Technical Information of China (English)

    何敏娟; 闫祥梅; 张益国; 马人乐

    2009-01-01

    基于随机振动及系统识别理论,对两相邻自立式直线输电塔进行同步环境脉动实测,识别两相邻输电塔耦合导地线的动力特性及绝缘子在输电塔的横向和纵向的振动频率.试验结果表明:在塔两侧导地线的初始张拉力一致的情况下,相邻直线输电塔的动力特性较为接近,与输电塔档距无关;同时分析得出输电塔的阻尼比均大于(GB50135-2006)规定的阻尼比0.01.由于导线的影响,测试出绝缘子在塔-线体系横向振动频率大于输电塔的振动频率,而在纵向小于输电塔的振动频率,频率的差异对输电塔-线体系在风荷载作用下的振动情况不利.%The ambient vibration tests of two adjacent transmission towers were carried out based on the theory of random vibration and system identification. The vibration mode of the two adjacent towers coupled with the cable effects and the transverse & vertical vibration frequencies of the insulators were identified. The experimental results indicate: two adjacent tangant towers have the same dynamic properties basically. The span of transmission tower has little effect on its dynamic feature under the same initial stress. Damping ratios of the two transmission towers are more than 0.01 which is recommended by the code for design of high-rise structures. It is further indicated that the natural frequencies of the insulators are different to those of towers in both longitudinal and lateral directions. This is not beneficial to the wind-excited dynamic responses of transmission tower-line system.

  3. Note: A kinematic shaker system for high amplitude, low frequency vibration testing

    Science.gov (United States)

    Swaminathan, Anand; Poese, Matthew E.; Smith, Robert W. M.; Garrett, Steven L.

    2015-11-01

    This note describes a shaker system capable of high peak-velocity, large amplitude, low frequency, near-sinusoidal excitation that has been constructed and employed in experiments on the inhibition of Rayleigh-Bénard convection using acceleration modulation. The production of high peak-velocity vibration is of interest in parametric excitation problems of this type and reaches beyond the capabilities of standard electromagnetic shakers. The shaker system described employs a kinematic linkage to two counter-rotating flywheels, driven by a variable-speed electrical motor, producing peak-to-peak displacements of 15.24 cm to a platform mounted on two guide rails. In operation, this shaker has been demonstrated to produce peak speeds of up to 3.7 m/s without failure.

  4. A MEMS-Based Piezoelectric Power Generator for Low Frequency Vibration Energy Harvesting

    Institute of Scientific and Technical Information of China (English)

    FANG Hua-Bin; LIU Jing-Quan; XU Zheng-Yi; DONG Lu; CHEN Di; CAI Bing-Chu; LIU Yue

    2006-01-01

    @@ A novel power generator has been achieved to convert vibration to electrical energy via the piezoelectric effect. The generator obtained by micro fabrication process mainly consists of silicon based frame and composite cantilever.The prototype tested at resonant vibration generates 1.15 μ W of effective power to a 20.4-kΩ resistance load. The potential of this work is to offer miniaturization solutions for power generators, and with the proposed method the ambient ubiquitous vibration can be harvested effectively as endless energy source to form an integrated self-powering system.

  5. Prototype development and test results of a continuous ambient air monitoring system for hydrazine at the 10 ppb level

    Science.gov (United States)

    Meneghelli, Barry; Parrish, Clyde; Barile, Ron; Lueck, Dale E.

    1995-01-01

    A Hydrazine Vapor Area Monitor (HVAM) system is currently being field tested as a detector for the presence of hydrazine in ambient air. The MDA/Polymetron Hydrazine Analyzer has been incorporated within the HVAM system as the core detector. This analyzer is a three-electrode liquid analyzer typically used in boiler feed water applications. The HVAM system incorporates a dual-phase sample collection/transport method which simultaneously pulls ambient air samples containing hydrazine and a very dilute sulfuric acid solution (0.0001 M) down a length of 1/4 inch outside diameter (OD) tubing from a remote site to the analyzer. The hydrazine-laden dilute acid stream is separated from the air and the pH is adjusted by addition of a dilute caustic solution to a pH greater than 10.2 prior to analysis. Both the dilute acid and caustic used by the HVAM are continuously generated during system operation on an "as needed" basis by mixing a metered amount of concentrated acid/base with dilution water. All of the waste water generated by the analyzer is purified for reuse by Barnstead ion-exchange cartridges so that the entire system minimizes the generation of waste materials. The pumping of all liquid streams and mixing of the caustic solution and dilution water with the incoming sample are done by a single pump motor fitted with the appropriate mix of peristaltic pump heads. The signal to noise (S/N) ratio of the analyzer has been enhanced by adding a stirrer in the MDA liquid cell to provide mixing normally generated by the high liquid flow rate designed by the manufacturer. An onboard microprocessor continuously monitors liquid levels, sample vacuum, and liquid leak sensors, as well as handles communications and other system functions (such as shut down should system malfunctions or errors occur). The overall system response of the HVAM can be automatically checked at regular intervals by measuring the analyzer response to a metered amount of calibration standard injected

  6. Prototype development and test results of a continuous ambient air monitoring system for hydrazine at the 10 ppb level

    Science.gov (United States)

    Meneghelli, Barry; Parrish, Clyde; Barile, Ron; Lueck, Dale E.

    1995-01-01

    A Hydrazine Vapor Area Monitor (HVAM) system is currently being field tested as a detector for the presence of hydrazine in ambient air. The MDA/Polymetron Hydrazine Analyzer has been incorporated within the HVAM system as the core detector. This analyzer is a three-electrode liquid analyzer typically used in boiler feed water applications. The HVAM system incorporates a dual-phase sample collection/transport method which simultaneously pulls ambient air samples containing hydrazine and a very dilute sulfuric acid solution (0.0001 M) down a length of 1/4 inch outside diameter (OD) tubing from a remote site to the analyzer. The hydrazine-laden dilute acid stream is separated from the air and the pH is adjusted by addition of a dilute caustic solution to a pH greater than 10.2 prior to analysis. Both the dilute acid and caustic used by the HVAM are continuously generated during system operation on an "as needed" basis by mixing a metered amount of concentrated acid/base with dilution water. All of the waste water generated by the analyzer is purified for reuse by Barnstead ion-exchange cartridges so that the entire system minimizes the generation of waste materials. The pumping of all liquid streams and mixing of the caustic solution and dilution water with the incoming sample are done by a single pump motor fitted with the appropriate mix of peristaltic pump heads. The signal to noise (S/N) ratio of the analyzer has been enhanced by adding a stirrer in the MDA liquid cell to provide mixing normally generated by the high liquid flow rate designed by the manufacturer. An onboard microprocessor continuously monitors liquid levels, sample vacuum, and liquid leak sensors, as well as handles communications and other system functions (such as shut down should system malfunctions or errors occur). The overall system response of the HVAM can be automatically checked at regular intervals by measuring the analyzer response to a metered amount of calibration standard injected

  7. Ambient Sensors

    NARCIS (Netherlands)

    Börner, Dirk; Specht, Marcus

    2014-01-01

    This software sketches comprise two custom-built ambient sensors, i.e. a noise and a movement sensor. Both sensors measure an ambient value and process the values to a color gradient (green > yellow > red). The sensors were built using the Processing 1.5.1 development environment. Available under th

  8. Det ambiente

    DEFF Research Database (Denmark)

    Schmidt, Ulrik

    Om begrebet "det ambiente", der beskriver, hvad der sker, når vi fornemmer baggrundsmusikkens diskrete beats, betragter udsigten gennem panoramavinduet eller tager 3D-brillerne på og læner os tilbage i biografsædet. Bogen analyserer, hvorfan ambiente oplevelser skabes, og hvilke konsekvenser det...

  9. 减振运输箱道路运输仿真与试验%Simulation and Test of Road Transit for the Vibration Damping Transportation Boxes

    Institute of Scientific and Technical Information of China (English)

    苏俊刚; 蒋美华

    2015-01-01

    The vibration damping transportation boxes with steel-wire rope isolators were studied by simulation and test. The roughness signals of road surface were simulated and used as the input signals of the virtual vibration test bench. Then, the process of transportation of the vibration damping box was simulated by means of ADAMS and the damping effect was obtained. The road transportation tests were carried out. The vibration signals were collected by sensors, and analyzed in frequency domain and time domain. Good damping effect of the vibration damping transportation boxes was verified.%通过仿真与试验,对钢丝绳隔振器减振运输箱进行研究。模拟路面的不平度信号,作为虚拟振动台的输入信号,运用ADAMS模拟减振运输箱在道路运输时的减振效果;进行道路运输试验,通过传感器来采集振动信号,对振动信号进行频域和时域分析,验证减振运输箱良好的减振效果。

  10. Ring exciting thin layer method applied to the forced vibration test of the Hualien large scale soil-structure interactions (SSI) model

    International Nuclear Information System (INIS)

    The blind prediction and post-test correlation analyses are conducted on the forced vibration tests of the 1/4 scale reinforced concrete cylindrical containment model both before and after backfill. In the present paper described for the case after backfill, the ring exciting thin layer technique was introduced to account realistically for the axisymmetrical irregularity of the soil condition due to the backfill. The computed results demonstrated that the proposed method has a great potential for simulating the dynamic responses of the soil-structure system to the forced vibration. (author). 5 refs., 8 figs

  11. Numerical and Experimental Study of Free Vibration Characteristics of a Cable-Stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    Zi Jianmin; Wang Yuanhan; Zhu Hongping

    2006-01-01

    The main aim of this study is to understand the dynamic behavior of a cable-stayed bridge,using both numerical and experimental analysis. A three-dimensionai finite element model for the bridge was developed for the free vibration analysis and the ambient vibration properties of the bridge were determined through field testing. The experimental and numerical results of natural frequencies and the associated mode shapes were compared, and the high accuracy between them shows that the 3D model is capable of approximately representing the dynamic behavior of the bridge and the use of ambient vibration survives in future testing of the bridge. These dynamic characteristics can be used as the basis for updating the finite element model and also for global damage detection.

  12. Earthquake experiments at the HDR (Heissdampf Reaktor) test facility using an eccentric mass vibrator

    International Nuclear Information System (INIS)

    As part of he earthquake investigations carried out by the Karlsruhe Nuclear Research Center, Project HDR, at the HDR Test Facility near Frankfurt/Main, high level shaker test were performed during June/July 1986. The purpose of these tests, supported by the German and U.S. governments was to investigate full scale structural response involving significant concrete and soil strain as well as strong indirect excitation of vessels, pipes and other mechanical equipment. The calculational efforts included predictions of the building and piping response stress analyses. Within these test series, the reactor building was brought to its ultimate loading capacity. (author)

  13. In-situ testing of the liquefaction potential of soft ground using an s-wave vibrator and seismic cones. Part 1. System, concept and preliminary test result; S ha vibrator oyobi seismic cone wo mochiita gen`ichi jiban ekijoka potential no hyoka. 1. System kosei oyobi genchi yosatsu keisoku kekka

    Energy Technology Data Exchange (ETDEWEB)

    Inazaki, T. [Public Works Research Institute, Tsukuba (Japan)

    1996-05-01

    For the purpose of evaluating liquefaction in situ, it was proposed that an S-wave vibrator designed to serve as a source in a reflection exploration method be utilized as a strong vibration generating source, and measurement was conducted in this connection. Equipment used in this test included an S-wave vibrator, static cone penetration machine, and various measuring cones. A multiplicity of measuring cones had been inserted beforehand into the target layers and comparison layers, and changes upon vibrator activation were measured. On a dry bed of the Tonegawa river, a 40m{sup 2} field was set up, and 41 cone penetration tests were conducted, with the cones positioned zigzag at 5m intervals. In this way, the ground structure was disclosed from the surface to the 10m-deep level. For the measurement, 3-component cones and seismic cones were placed at prescribed depths, and fluctuations and waveforms presented by pore water pressure at each level were determined with the vibration source changing its place. It was found that the changes in the pore water pressure exposed to vibration assume characteristic patterns corresponding to the conditions of vibration application. 5 figs., 1 tab.

  14. Development of a Vibration Powered Micro Generator and its Application to Harvest the Vibration Energy of the KRI KKP-811’s Engine

    Directory of Open Access Journals (Sweden)

    Harus L.G.

    2010-01-01

    Full Text Available Vibration energy harvesting has been receiving a considerable amount of interest as a means of powering wireless sensors and low-power devices. In this paper, an energy harvester is presented to convert ambient mechanical vibration into electrical energy employing magnetoelectric generator. The harvester uses single magnet-spring attached on the coil. When the harvester is excited, the magnet moves relative to the coil, undergoes magnetic field variations and produces a power output. To obtain a maximum power output, the mass of magnet is varied. The magnetoelectric generator with various masses of magnets was tested by a harmonic exciter with various frequencies and amplitudes. The one with maximum power output was then applied to harvest the ambient vibration energy of KRI KKP-811’s Engine. The results show that this prototype can harvest maximum energy of 2μW when it is placed at the base/foundation of the engine.

  15. Det Ambiente

    DEFF Research Database (Denmark)

    Schmidt, Ulrik

    Det ambiente er iscenesættelsen af en karakteristisk sanseoplevelse, der er kendetegnet ved fornemmelsen af at være omgivet. I dag bliver begrebet om det ambiente mest anvendt i forbindelse med musikgenren ’ambient musik’. Det ambiente er dog ikke essentielt knyttet til det musikalske, men må...... forstås som et betydeligt bredere fænomen i den moderne æstetiske kultur, der spiller en væsentlig rolle i oplevelsen af moderne transportformer, arkitektur, film, lydkunst, installationskunst og digitale multimedieiscenesættelser. En forståelse af det ambiente er derfor centralt for forståelsen af en...... moderne æstetiseret oplevelseskultur i almindelighed. Da det ambiente ikke hidtil har været gjort til genstand for en mere indgående teoretisk behandling, er der dog stor usikkerhed omkring, hvad fænomenet overhovedet indebærer. Hovedformålet med Det ambiente – Sansning, medialisering, omgivelse er derfor...

  16. An Evaluation of Test and Physical Uncertainty of Measuring Vibration in Wooden Junctions

    DEFF Research Database (Denmark)

    Dickow, Kristoffer Ahrens; Kirkegaard, Poul Henning; Andersen, Lars Vabbersgaard

    2012-01-01

    In the present paper a study of test and material uncertainty in modal analysis of certain wooden junctions is presented. The main structure considered here is a T-junction made from a particleboard plate connected to a spruce beam of rectangular cross section. The size of the plate is 1.2 m by 0.......6 m. The T-junctions represent cut-outs of actual full size floor assemblies. The aim of the experiments is to investigate the underlying uncertainties of both the test method as well as variation in material and craftmanship. For this purpose, ten nominally identical junctions are tested and compared...... to each other in terms of modal parameters such as natural frequencies, modeshapes and damping. Considerations regarding the measurement procedure and test setup are discussed. The results indicate a large variation of the response at modes where the coupling of torsion in the beam to bending of the plate...

  17. Vibrational configuration interaction using a tiered multimode scheme and tests of approximate treatments of vibrational angular momentum coupling: a case study for methane.

    Science.gov (United States)

    Mielke, Steven L; Chakraborty, Arindam; Truhlar, Donald G

    2013-08-15

    We present vibrational configuration interaction calculations employing the Watson Hamiltonian and a multimode expansion. Results for the lowest 36 eigenvalues of the zero total angular momentum rovibrational spectrum of methane agree with the accurate benchmarks of Wang and Carrington to within a mean unsigned deviation of 0.68, 0.033, and 0.014 cm(-1) for 4-mode, 5-mode, and 6-mode representations, respectively. We note that in the case of the 5-mode results, this is a factor of 10 better agreement than for 5-mode calculations reported earlier by Wu, Huang, Carter, and Bowman for the same set of eigenvalues, which indicates that the multimode expansion is even more rapidly convergent than previously demonstrated. Our largest calculations employ a tiered approach with matrix elements treated using a variable-order multimode expansion with orders ranging from 4-mode to 7-mode; strategies for assigning matrix elements to particular multimode tiers are discussed. Improvements of 7-mode coupling over 6-mode coupling are small (averaging 0.002 cm(-1) for the first 36 eigenvalues) suggesting that 7-mode coupling is sufficient to fully converge the results. A number of approximate treatments of the computationally expensive vibrational angular momentum terms are explored. The use of optimized vibrational quadratures allows rapid integration of the matrix elements, especially the vibrational angular momentum terms, which require significantly fewer quadrature points than are required to integrate the potential. We assign the lowest 243 states and compare our results to those of Wang and Carrington, who provided assignments for the same set of states. Excellent agreement is observed for most states, but our results are lower for some of the higher-energy states by as much as 20 cm(-1), with the largest deviations being for the states with six quanta of excitation in the F2 bends, suggesting that the earlier results were not fully converged with respect to the basis set. We

  18. Ambient Gestures

    OpenAIRE

    Karam, Maria; Hare, Jonathon; Lewis, Paul; schraefel, m.c.

    2006-01-01

    We present Ambient Gestures, a novel gesture-based system designed to support ubiquitous ‘in the environment’ interactions with everyday computing technology. Hand gestures and audio feedback allow users to control computer applications without reliance on a graphical user interface, and without having to switch from the context of a non-computer task to the context of the computer. The Ambient Gestures system is composed of a vision recognition software application, a set of gestures to be p...

  19. FY 2014 Status Report: of Vibration Testing of Clad Fuel (M4FT-14OR0805033)

    Energy Technology Data Exchange (ETDEWEB)

    Bevard, Bruce Balkcom [ORNL

    2014-03-28

    The DOE Used Fuel Disposition Campaign (UFDC) tasked Oak Ridge National Laboratory (ORNL) to investigate the behavior of light-water-reactor (LWR) fuel cladding material performance related to extended storage and transportation of UNF. ORNL has been tasked to perform a systematic study on UNF integrity under simulated normal conditions of transportation (NCT) by using the recently developed hot-cell testing equipment, Cyclic Integrated Reversible-Bending Fatigue Tester (CIRFT). To support the testing on actual high-burnup UNF, fast-neutron irradiation of pre-hydrided zirconium-alloy cladding in the High Flux Isotope Reactor (HFIR) at elevated temperatures will be used to simulate the effects of high-burnup on fuel cladding for help in understanding the cladding materials properties relevant to extended storage and subsequent transportation. The irradiated pre-hydrided metallic materials testing will generate baseline data to benchmark hot-cell testing of the actual high-burnup UNF cladding. More importantly, the HFIR-irradiated samples will be free of alpha contamination and can be provided to researchers who do not have hot cell facilities to handle highly contaminated high-burnup UNF cladding to support their research projects for the UFDC.

  20. Advanced LIGO Two-Stage Twelve-Axis Vibration Isolation and Positioning Platform. Part 2: Experimental Investigation and Tests Results

    CERN Document Server

    Matichard, Fabrice; Mason, Kenneth; Mittleman, Richard; Abbott, Benjamin; Abbott, Samuel; Allwine, Eric; Barnum, Samuel; Birch, Jeremy; Biscans, Sebastien; Clark, Daniel; Coyne, Dennis; DeBra, Dan; DeRosa, Ryan; Foley, Stephany; Fritschel, Peter; Giaime, Joseph A; Gray, Corey; Grabeel, Gregory; Hanson, Joe; Hillard, Michael; Kissel, Jeffrey; Kucharczyk, Christopher; Roux, Adrien Le; Lhuillier, Vincent; Macinnis, Myron; OReilly, Brian; Ottaway, David; Paris, Hugo; Puma, Michael; Radkins, Hugh; Ramet, Celine; Robinson, Mitchell; Ruet, Laurent; Sareen, Pradeep; Shoemaker, Daivid; Stein, Andy; Thomas, Jeremy; Vargas, Michael; Warner, Jimmy

    2014-01-01

    This paper presents the results of the past seven years of experimental investigation and testing done on the two-stage twelve-axis vibration isolation platform for Advanced LIGO gravity waves observatories. This five-ton two-and-half-meter wide system supports more than a 1000 kg of very sensitive equipment. It provides positioning capability and seismic isolation in all directions of translation and rotation. To meet the very stringent requirements of Advanced LIGO, the system must provide more than three orders of magnitude of isolation over a very large bandwidth. It must bring the motion below 10^(-11) m/(Hz)^0.5 at 1 Hz and 10^(-12) m/(Hz)^0.5 at 10 Hz. A prototype of this system has been built in 2006. It has been extensively tested and analyzed during the following two years. This paper shows how the experimental results obtained with the prototype were used to engineer the final design. It highlights how the engineering solutions implemented not only improved the isolation performance but also greatl...

  1. 地铁物业减振降噪设计及测试分析%Design and Test Analysis on Vibration and Noise Reduction of Metro Property

    Institute of Scientific and Technical Information of China (English)

    王建

    2013-01-01

    The paper summarizes the design programme on the vibration and noise reduction for metro property-Nanhai Financial Center.Tests were carried out for the vibration induced by metro operation to analyze the frequency domain and time domain and transmission characteristics of vibration.Results can provide reliable evidence for putting the project into operation smoothly and can also be of help to designers and assessors.%分析南海金融城地铁物业减振降噪设计方案,并对地铁引起的建筑结构振动进行现场测试,分析振动的时域、频域特性及传播规律.分析结果可为该项目顺利投入运营提供可靠依据,并为工程设计人员、评估人员提供参考.

  2. Vibration Analysis of a Residential Building

    Directory of Open Access Journals (Sweden)

    Sampaio Regina Augusta

    2015-01-01

    Full Text Available The aim of this paper is to present the results of a study regarding vibration problems in a 17 storey residential building during pile driving in its vicinity. The structural design of the building was checked according to the Brazilian standards NBR6118 and NBR6123, and using commercial finite element software. An experimental analysis was also carried out using low frequency piezo-accelerometers attached to the building structure. Structure vibrations were recorded under ambient conditions. Four monitoring tests were performed on different days. The objective of the first monitoring test was an experimental modal analysis. To obtain de modal parameters, data was processed in the commercial software ARTEMIS employing two methods: the Stochastic Subspace Identification and the Frequency Domain Decomposition. Human comfort was investigated considering the International Standard ISO 2631. The Portuguese standard, NP2074, was also used as a reference, since it aims to limit the adverse effects of vibrations in structures caused by pile driving in the vicinity of the structure. The carried out experimental tests have shown that, according to ISO2301, the measure vibration levels are above the acceptance limits. However, velocity peaks are below the limits established by NP2074. It was concluded that, although the structure has adequate capacity to resist internal forces according to normative criteria, it has low horizontal stiffness, which could be verified by observing the vibration frequencies and mode shapes obtained with the finite element models, and its similarity with the experimental results. Thus, the analyses indicate the occurrence of discomfort by the residents.

  3. Assessment of nonlinear distortions in modal testing and analysis of vibrating automotive structures

    Science.gov (United States)

    Verboven, P.; Guillaume, P.; Vanlanduit, S.; Cauberghe, B.

    2006-05-01

    In this paper, new developments for the nonparametric processing of modal test data are presented. Classically, random noise signals are applied to deal with possible nonlinear distortions during frequency response function measurements of linear dynamic systems. However, the use of multisine excitation signals allows the engineer to control much more his experiments. First of all, the nonparametric estimation of multivariable frequency response functions can be more easily based on an "errors-in-variables" stochastic framework. In addition, the application of a well-chosen multisine excitation permits improvement of the data quality, as well as the detection, qualification and quantification of nonlinear distortions during FRF measurements. To make the presented techniques available for multi-input modal testing, attention is paid to the design of optimal multi-input excitations by maximizing the Fisher information matrix as well as minimizing the crest factor of the applied excitation.

  4. An experimental study on advancement of damping performance of foundations in soft ground. Pt.1: Forced vibration tests of a foundation block constructed on improved soil medium

    International Nuclear Information System (INIS)

    Purpose of this study is to enhance attenuation performance of structures that will be constructed in the soft ground area. We conducted material tests to obtain basic properties of the soil cement column. The forced vibration tests then were carried out to acquire dynamic feature of the reinforced concrete block constructed on improved soil mediums. Additional forced vibration tests for various conditions of trenches dug along the block were conducted to obtain fundamental features of damping effect of the side surfaces of the test block. According to results of the material testing, densities of the soil cement columns were 1.45-1.52 g/cm3 and the unconfined compressive strengths were 2.4-4.2 times as large as the specified design strength (1 MPa). In comparison of resonance curves by experiments and simulation analysis, simulation analysis results estimated by the hybrid approach were in good agreement with experiment ones for both the X and Y-directions. From the results of the forced vibration test focusing on various condition of the trenches dug along the test block, it was indicated that response of tamping by the rammer decreased compared with that of treading. (authors)

  5. Analysis and testing of an inner bypass magnetorheological damper for shock and vibration mitigation

    Science.gov (United States)

    Bai, Xian-Xu; Hu, Wei; Wereley, Norman M.

    2013-04-01

    Aiming at fundamentally improving the performance of MR dampers, including maximizing dynamic range (i.e., ratio of field-on to field-off damping force) while simultaneously minimizing field-off damping force, this study presents the principle of an inner bypass magnetorheological damper (IBMRD). The IBMRD is composed of a pair of twin tubes, i.e., the inner tube and outer concentric tube, a movable piston-shaft arrangement, and an annular MR fluid flow gap sandwiched between the concentric tubes. In the IBMRD, the inner tube serves simultaneously as the guide for the movable piston and the bobbin for the electromagnetic coil windings, and five active rings on the inner tube, annular MR fluid flow gap, and outer tube forms five closed magnetic circuits. The annular fluid flow gap is an inner bypass annular valve where the rheology of the MR fluids, and hence the damping force of the MR damper, is controlled. Based on the structural principle of the IBMRD, the IBMRD is configured and its finite element analysis (FEA) is implemented. After theoretically constructing the hydro-mechanical model for the IBMRD, its mathematical model is established using a Bingham-plastic nonlinear fluid model. The characteristics of the IBMRD are theoretically evaluated and compared to those of a conventional piston-bobbin MR damper with an identical active length and cylinder diameter. In order to validate the theoretical results predicted by the mathematical model, the prototype IBMRD is designed, fabricated, and tested. The servo-hydraulic testing machine (type: MTS 810) and rail-guided drop tower are used to provide sinusoidal displacement excitation and shock excitation to the IBMRD, respectively.

  6. Analysis, Design and Testing of a Novel Quasi-Zero-Stiffness based Sensor System for Measurement of Absolute Vibration Motion

    CERN Document Server

    Wang, Yu

    2015-01-01

    This study presents the analysis and design of a novel quasi-zero-stiffness (QZS) based vibration sensor system for measuring absolute displacement of vibrating platforms/objects. The sensor system is constructed by using positive and negative-stiffness springs, which makes it possible to achieve an equivalent QZS and consequently to create a broadband vibration-free point for absolute displacement measurement in vibrating platforms. Theoretic analysis is conducted for the analysis and design of the influence of structure parameters on system measurement performance. A prototype is designed which can avoid the drawback of instability in existing QZS systems with negative stiffness, and the corresponding data-processing software is developed to fulfill time domain and frequency domain measurements simultaneously. Both simulation and experiment results verify the effectiveness of this novel sensor system.

  7. Testing an e2v CCD230-42 sensor for dark current performance at ambient temperatures - Final Paper

    Energy Technology Data Exchange (ETDEWEB)

    Dungee, Ryan [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-20

    The design of the Guidance Focus and Alignment (GFA) system for the Dark Energy Spectroscopic Instrument (DESI) project calls for a set of charge-coupled devices (CCDs) which operate at ambient temperature. Here we assess the performance of these CCDs under such conditions. Data was collected from –21°C to 28°C and used to determine the effect of temperature on the effectiveness of dark current subtraction. Comparing the dark current uncertainty to our expected signal has shown that the DESI design specifications will be met without need for significant changes.

  8. Ambient oxygen promotes tumorigenesis.

    Directory of Open Access Journals (Sweden)

    Ho Joong Sung

    Full Text Available Oxygen serves as an essential factor for oxidative stress, and it has been shown to be a mutagen in bacteria. While it is well established that ambient oxygen can also cause genomic instability in cultured mammalian cells, its effect on de novo tumorigenesis at the organismal level is unclear. Herein, by decreasing ambient oxygen exposure, we report a ∼50% increase in the median tumor-free survival time of p53-/- mice. In the thymus, reducing oxygen exposure decreased the levels of oxidative DNA damage and RAG recombinase, both of which are known to promote lymphomagenesis in p53-/- mice. Oxygen is further shown to be associated with genomic instability in two additional cancer models involving the APC tumor suppressor gene and chemical carcinogenesis. Together, these observations represent the first report directly testing the effect of ambient oxygen on de novo tumorigenesis and provide important physiologic evidence demonstrating its critical role in increasing genomic instability in vivo.

  9. Nondestructive Evaluation of Railway Bridge by System Identification Using Field Vibration Measurement

    International Nuclear Information System (INIS)

    This paper presents a nondestructive evaluation approach for system identification (SID) of real railway bridges using field vibration test results. First, a multi-phase SID scheme designed on the basis of eigenvalue sensitivity concept is presented. Next, the proposed multi-phase approach is evaluated from field vibration tests on a real railway bridge (Wondongcheon bridge) located in Yangsan, Korea. On the steel girder bridge, a few natural frequencies and mode shapes are experimentally measured under the ambient vibration condition. The corresponding modal parameters are numerically calculated from a three-dimensional finite element (FE) model established for the target bridge. Eigenvalue sensitivities are analyzed for potential model-updating parameters of the FE model. Then, structural subsystems are identified phase-by-phase using the proposed model-updating procedure. Based on model-updating results, a baseline model and a nondestructive evaluation of test bridge are identified

  10. Electrorheological vibration system

    Science.gov (United States)

    Korobko, Evguenia V.; Shulman, Zinovy P.; Korobko, Yulia O.

    2001-07-01

    The present paper is devoted to de3velopment and testing of an active vibration system. The system is intended for providing efficient motion of a piston in a hydraulic channel for creation of shocks and periodic vibrations in a low frequency range by means of the ER-valves based on an electrosensitive working me dium, i.e. electrorheological fluids. The latter manifests the electrorheological (ER) effect, i.e. a reversible change in the rheological characteristics of weak-conducting disperse compositions in the presence of constant and alternating electric fields. As a result of the experimental study of the dependence of viscoelastic properties of the ER-fluid on the magnitude and type of an electric field, the optimum dimensions of the vibrator and the its valves characteristics of the optimal electrical signal are determined. For control of an ER- vibrator having several valves we have designed a special type of a high-voltage two-channel impulse generator. Experiments were conducted at the frequencies ranged from 1- 10 Hz. It has been shown, that a peak force made 70% of the static force exercised by the vibrator rod. A phase shift between the input voltage and the load acceleration was less than 45 degree(s)C which allowed servocontrol and use of the vibrator for attendant operations. It was noted that a response of the vibrator to a stepwise signal has a delay only of several milliseconds.

  11. Progress Letter Report on Bending Fatigue Test System Development for Spent Nuclear Fuel Vibration Integrity Study (Out-of-cell fatigue testing development - Task 2.4)

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jy-An John [ORNL; Wang, Hong [ORNL; Cox, Thomas S [ORNL; Baldwin, Charles A [ORNL; Bevard, Bruce Balkcom [ORNL

    2013-08-01

    Vibration integrity of high burn-up spent nuclear fuel in transportation remains to be a critical component of US nuclear waste management system. The structural evaluation of package for spent fuel transportation eventually will need to see if the content or spent fuel is in a subcritical condition. However, a system for testing and characterizing such spent fuel is still lacking mainly due to the complication involved with dealing radioactive specimens in a hot cell environment. Apparently, the current state-of-the-art in spent fuel research and development is quite far away from the delivery of reliable mechanical property data for the assessment of spent fuels in the transport package evaluation. Under the sponsorship of US NRC, ORNL has taken the challenge in developing a robust testing system for spent fuel in hot cell. An extensive literature survey was carried out and unique requirements of such testing system were identified. The U-frame setup has come to the top among various designs examined for reverse bending fatigue test of spent fuel rod. The U-frame has many features that deserve mentioned here: Easy to install spent fuel rod in test; Less linkages than in conventional bending test setup such as three-point or four-point bending; Target the failure mode relevant to the fracture of spent fuel rod in transportation by focusing on pure bending; The continuous calibrations and modifications resulted in the third generation (3G) U-frame testing setup. Rigid arms are split along the LBB axis at rod sample ends. For each arm, this results in a large arm body and an end piece. Mating halves of bushings were modified into two V-shaped surfaces on which linear roller bearings (LRB) are embedded. The rod specimen is installed into the test fixture through opening and closing slide end-pieces. The 3G apparently has addressed major issues of setup identified in the previous stage and been proven to be eligible to be further pursued in this project. On the other

  12. Similar Experimental Study of Test Model and Prototype of Vibrating Screen%振动筛试验模型和原型相似试验研究

    Institute of Scientific and Technical Information of China (English)

    王永岩; 张则荣

    2011-01-01

    The six order natural frequencies are extracted from amplitude-frequency curve and modal shapes are tested through the experimental modal analysis carried out by the 1:10 scale similar test model and the prototype of 27 m2 large-scale linear vibrating screen. According to the similarity theory the relative error of the natural frequencies between the prototype of vibrating screen and the similar test model is less than 8.62%. The modal shapes of all orders are consistent between the prototype of vibrating screen and the similar test model The results show that the inherent parameters of the linear vibrating screen can be obtained visually and effectively by using modal analysis method, which provides theoretical foundation for improving service life, reliability and structural optimization of the linear vibrating screen. The modal experimental results of the 1:10 scale similar test model are proved to be correct and valid compared with the data of the prototype of vibrating screen and the consistency and reliability of the experimental data are verified. The experimental modal analysis can be carried out by the similar test model instead of the prototype of the large-scale linear vibrating screen approximately, which provides reference for similar experimental studies.%通过对27 m2大型直线振动筛及缩比为1:10的相似试验模型筛的试验模态分析,得到其幅频特性曲线并提取其中6阶固有频率,测试分析出其模态振型.根据相似理论,通过对原型筛与相似试验模型筛的固有频率对比,得出二者固有频率的相对误差小于8.62%.通过对原型筛及其相似试验模型筛的振型分析对比,发现二者各阶振型基本一致.结果表明,用模态分析法可以直观有效地得到直线振动筛的固有特性参数,为提高直线振动筛的使用寿命和可靠性以及结构优化设计提供了理论依据,证实了利用缩小比例的相似试验模型筛进行试验模态分析的有效性,

  13. Ship Vibrations

    DEFF Research Database (Denmark)

    Sørensen, Herman

    1997-01-01

    Methods for calculating natural frequencies for ship hulls and for plates and panels.Evaluation of the risk for inconvenient vibrations on board......Methods for calculating natural frequencies for ship hulls and for plates and panels.Evaluation of the risk for inconvenient vibrations on board...

  14. Investigation for parametric vibration of rolling mill

    Institute of Scientific and Technical Information of China (English)

    唐华平; 丁睿; 吴运新; 钟掘

    2002-01-01

    The vibration unsteady condition of rolling mill caused by flexural vibration of strip has been investigated. The parametric flexural vibration equation of rolled strip has been established. The parametric flexural vibration stability of rolled strip has been studied and the regions of stability and unstability have been determined based on Floquet theory and perturbation method. The flexural-vibration of strip is unstable when the frequency of variable tension is two times as the natural frequency of flexural-vibration strip. The characteristic of current in a temp driving motor's main loop has been studied and tested, it has been proved that there are 6 harmonic component and 12 harmonic component in main loop of driving motor electricity. The vertical vibration of working roller has been tested, the test result approves that the running unsteady is caused by parametric vibration. It attaches importance to the parametric vibration of rolling mill.

  15. Rotation-vibration interactions in the spectra of polycyclic aromatic hydrocarbons: Quinoline as a test-case species.

    Science.gov (United States)

    Pirali, O; Kisiel, Z; Goubet, M; Gruet, S; Martin-Drumel, M A; Cuisset, A; Hindle, F; Mouret, G

    2015-03-14

    Polycyclic aromatic hydrocarbons (PAHs) are highly relevant for astrophysics as possible, though controversial, carriers of the unidentified infrared emission bands that are observed in a number of different astronomical objects. In support of radio-astronomical observations, high resolution laboratory spectroscopy has already provided the rotational spectra in the vibrational ground state of several molecules of this type, although the rotational study of their dense infrared (IR) bands has only recently become possible using a limited number of experimental set-ups. To date, all of the rotationally resolved data have concerned unperturbed spectra. We presently report the results of a high resolution study of the three lowest vibrational states of quinoline C9H7N, an N-bearing naphthalene derivative. While the pure rotational ground state spectrum of quinoline is unperturbed, severe complications appear in the spectra of the ν45 and ν44 vibrational modes (located at about 168 cm(-1) and 178 cm(-1), respectively). In order to study these effects in detail, we employed three different and complementary experimental techniques: Fourier-transform microwave spectroscopy, millimeter-wave spectroscopy, and Fourier-transform far-infrared spectroscopy with a synchrotron radiation source. Due to the high density of states in the IR spectra of molecules as large as PAHs, perturbations in the rotational spectra of excited states should be ubiquitous. Our study identifies for the first time this effect and provides some insights into an appropriate treatment of such perturbations. PMID:25770543

  16. Vibration energy harvester optimization using artificial intelligence

    Science.gov (United States)

    Hadas, Z.; Ondrusek, C.; Kurfurst, J.; Singule, V.

    2011-06-01

    This paper deals with an optimization study of a vibration energy harvester. This harvester can be used as autonomous source of electrical energy for remote or wireless applications, which are placed in environment excited by ambient mechanical vibrations. The ambient energy of vibrations is usually on very low level but the harvester can be used as alternative source of energy for electronic devices with an expected low level of power consumption of several mW. The optimized design of the vibration energy harvester was based on previous development and the sensitivity of harvester design was improved for effective harvesting from mechanical vibrations in aeronautic applications. The vibration energy harvester is a mechatronic system which generates electrical energy from ambient vibrations due to precision tuning up generator parameters. The optimization study for maximization of harvested power or minimization of volume and weight are the main goals of our development. The optimization study of such complex device is complicated therefore artificial intelligence methods can be used for tuning up optimal harvester parameters.

  17. 40 CFR 53.55 - Test for effect of variations in power line voltage and ambient temperature.

    Science.gov (United States)

    2010-07-01

    ... METHODS Procedures for Testing Physical (Design) and Performance Characteristics of Reference Methods and... sampler to enter the sampler inlet and pass through the sample filter, measured in actual volume units at... for continuous (analog) recording capability or digital recording at intervals not to exceed 5...

  18. 立车变速箱振动噪声产生的机理及测试%Vibration noise generation mechanism and test of vertical lathe gearbox

    Institute of Scientific and Technical Information of China (English)

    王世杰; 焦卫兵

    2014-01-01

    Noise is the most important factor in measuring the quality level of vertical lathe gearbox. The noise generation mechanism of vertical lathe gearbox was analyzed during the transmission. And then the noise measuring system was determined. Finally, the vibration testing system was designed.%对立车变速箱传动过程中的噪声产生机理进行了分析,确定了箱体噪声测量系统,最后对振动测试系统进行了设计。

  19. 关于振动法测试碾压混凝土 填筑密实程度的研究%About the research of test roller compacted concrete filling compaction degree by vibration method

    Institute of Scientific and Technical Information of China (English)

    陈志远; 王振振; 陈军琪

    2015-01-01

    文章介绍了一种用振动法测试碾压混凝土填筑密实程度的研究过程和成果,提出了用土体振动参数表征密实程度的观点,对土体振动传播速度、主振频率、振动幅度多种参数与密实度的关系进行了探究,发现了振动频率、振动幅度与土体密实程度之间存在的规律,并以此为基础形成了一种新的碾压混凝土密度程度测试方法,有望在业内得以应用.%This paper introduces the research process and result about testing roller compacted concrete filling compaction degree using vibration method, put forward with the view of characterizing soil dense degree by its parameter, and to explore the relationship between a variety of soil vibration parameters and compactness of soil, including the soil vibration propagation speed, the main vibration frequency, the vibration amplitude etc, and to find the rule between the soil vibration frequency, vibration amplitude and soil compaction degree. On this basis, to form the new testing method for density degree of roller compacted concrete, is expected to application in the industry.

  20. The multi-axis vibration environment and man.

    Science.gov (United States)

    Lovesey, E J

    1970-12-01

    Many investigations into the effects of vibration on man have been performed since Mallock's first study of London Underground vibrations in 1902. The vibration research has tended to be confined to the vertical (heave) axis, yet recent experiments have indicated that low frequency vibration along the lateral (sway) axis has a greater adverse effect upon comfort and performance. Measurements of the vibration environments in current forms of transport including motor vehicles, hovercraft and aircraft etc have shown that appreciable quantities of vibration along all three axes exist. Further vibration research should consider the effects of multi-axis vibrations upon man rather than limit tests to single axis vibration. PMID:15676336

  1. Rotation-vibration interactions in the spectra of polycyclic aromatic hydrocarbons: Quinoline as a test-case species

    Energy Technology Data Exchange (ETDEWEB)

    Pirali, O.; Gruet, S. [AILES Beamline, Synchrotron SOLEIL, l’Orme des Merisiers, Saint-Aubin, 91192 Gif-sur-Yvette cedex (France); Institut des Sciences Moléculaires d’Orsay, UMR8214 CNRS – Université Paris-Sud, Bât. 210, 91405 Orsay cedex (France); Kisiel, Z. [Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw (Poland); Goubet, M. [Laboratoire de Physique des Lasers, Atomes et Molécules, UMR 8523 CNRS - Université Lille 1, Bâtiment P5, F-59655 Villeneuve d’Ascq Cedex (France); Martin-Drumel, M. A.; Cuisset, A.; Hindle, F.; Mouret, G. [Laboratoire de Physico-Chimie de l’Atmosphère, EA-4493, Université du Littoral – Côte d’Opale, 59140 Dunkerque (France)

    2015-03-14

    Polycyclic aromatic hydrocarbons (PAHs) are highly relevant for astrophysics as possible, though controversial, carriers of the unidentified infrared emission bands that are observed in a number of different astronomical objects. In support of radio-astronomical observations, high resolution laboratory spectroscopy has already provided the rotational spectra in the vibrational ground state of several molecules of this type, although the rotational study of their dense infrared (IR) bands has only recently become possible using a limited number of experimental set-ups. To date, all of the rotationally resolved data have concerned unperturbed spectra. We presently report the results of a high resolution study of the three lowest vibrational states of quinoline C{sub 9}H{sub 7}N, an N-bearing naphthalene derivative. While the pure rotational ground state spectrum of quinoline is unperturbed, severe complications appear in the spectra of the ν{sub 45} and ν{sub 44} vibrational modes (located at about 168 cm{sup −1} and 178 cm{sup −1}, respectively). In order to study these effects in detail, we employed three different and complementary experimental techniques: Fourier-transform microwave spectroscopy, millimeter-wave spectroscopy, and Fourier-transform far-infrared spectroscopy with a synchrotron radiation source. Due to the high density of states in the IR spectra of molecules as large as PAHs, perturbations in the rotational spectra of excited states should be ubiquitous. Our study identifies for the first time this effect and provides some insights into an appropriate treatment of such perturbations.

  2. Buckling tests on axially compressed cylindrical shells made of various austenitic stainless steels at ambient and elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Hautala, K.; Schmidt, H.

    1998-12-01

    The buckling test program comprised 37 axially loaded cylinders made of austenitic stainless steels and 6 reference cylinders made of mild steel. The three test parameters were the steel grade, the shell slenderness and the operating temperature. The chosen steel grades are typical for practical applications: AISI 304 (No. 1.4301) as the basic austenitic stainless steel, AISI 316 L (No. 1.4404) as a molybdenum alloyed and AISI 316 Ti (No. 1.4571) as a molybdenum and titanium alloyed austenitic stainless steel. The chosen shell slendernesses are typical for the above-mentioned elastic-plastic region: r/t=50, 150 and 400, approximately corresponding to non-dimensional slenderness parameters {lambda}=0.3, 0.5 and 0.9 respectively. The chosen testing temperatures cover a wide range of applications: T=20 C, 100 C, 250 C and 400 C. The test cylinders were manufactured from 3.0 mm, 1.0 mm and 0.5 mm steel sheets, cold rolled into the cylindrical shape and longitudianlly TIG-welded. The radii were 150 mm and 200 mm, the length was 350 mm. (orig.) [German] Das Beulversuchsprogramm bestand aus 37 axialbelasteten Zylindern aus austenitischen rostfreien Staehlen und sechs Referenzzylindern aus Baustahl. Die drei Versuchsparameter waren die Stahlsorte, die Schalenschlankheit und die Betriebstemperatur. Die drei ausgewaehlten Stahlsorten sind typisch fuer baupraktische Anwendungen: WNr. 1.4301 (AISI 304) als einfachster, WNr. 1.4404 (AISI 316L) als ein Molybdaen-legierter und WNr. 1.4571 (AISI 316Ti) als ein Molybdaen- und Titanium-legierter austenitischer rostfreier Stahl. Die ausgewaehlten Schalenschlankheiten sind typisch fuer den oben erwaehnten elastisch-plastischen Bereich: r/t=50, 150 und 400, entsprechend dimensionslosen Schlankheitsparametern von naeherungsweise {lambda}=0.3, 0.5 und 0.9. Die ausgewaehlten Versuchstemperaturen decken ein breites Spektrum von Anwendungen ab: T=20 C, 100 C, 250 C und 400 C. Die Versuchszylinder wurden aus 3 mm, 1 mm, und 0.5 mm

  3. Precision measurements and test of molecular theory in highly-excited vibrational states of H$_2$ $(v=11)$

    CERN Document Server

    Trivikram, T Madhu; Wcisło, P; Ubachs, W; Salumbides, E J

    2016-01-01

    Accurate $EF{}^1\\Sigma^+_g-X{}^1\\Sigma^+_g$ transition energies in molecular hydrogen were determined for transitions originating from levels with highly-excited vibrational quantum number, $v=11$, in the ground electronic state. Doppler-free two-photon spectroscopy was applied on vibrationally excited H$_2^*$, produced via the photodissociation of H$_2$S, yielding transition frequencies with accuracies of $45$ MHz or $0.0015$ cm$^{-1}$. An important improvement is the enhanced detection efficiency by resonant excitation to autoionizing $7p\\pi$ electronic Rydberg states, resulting in narrow transitions due to reduced ac-Stark effects. Using known $EF$ level energies, the level energies of $X(v=11, J=1,3-5)$ states are derived with accuracies of typically 0.002 cm$^{-1}$. These experimental values are in excellent agreement with, and are more accurate than the results obtained from the most advanced ab initio molecular theory calculations including relativistic and QED contributions.

  4. Problemas para la elaboración y tipificación de tests en distintos ambientes culturales

    Directory of Open Access Journals (Sweden)

    Nuria Cortada de Kohan

    1972-01-01

    Full Text Available This paper points out the difficulties of translating and standardizing several tests of verbal and general ability, specific aptitudes and personality inventories. The problems are mainly Iinguistic. They indude difficulties in correct translation and varying frequency of use in the different languages. A number of examples are given of responses to items by normals and psychiatric patients in Argentina. Because of the many problems involved, the suggestion is made that serious considerations be given to the construction of a new type of instrument. References are made to the work of Dunker, Bloom, Píaget and Rimoldi ho emphasize the study of processes rather than produces. The methodology presented by Rimoldi appears to be more devoid of cultural biases and should have greater usefulness in cross cultural studies.

  5. Research on cylindrical shell vibration reduction systems

    Institute of Scientific and Technical Information of China (English)

    XING Xiao-liang; WANG Min-qing

    2008-01-01

    Longitudinal and horizontal vibration must both be reduced in an effective vibration isolation system. We present a cylindrical shell vibration isolator as a dynamic system composed of four springs and dampers. Vibration is directly produced by the motion of machinery, and more is subsequently generated by harmonic frequencies within their structure. To test the effectiveness of our isolator, we first determined equations for the transmission of vibration from the machine to its cylindrical shell. Damping effects produced by the vibration parameters of our system are then analyzed.

  6. Results of an investigation of the acoustic and vibrational environment of a full scale space shuttle orbiter structural test panel with simulated TPS in the Ames unitary plan wind tunnel, model 81-0, test OS8A and B

    Science.gov (United States)

    Kingsland, R. B.

    1977-01-01

    Results of tests OS8A and B and pertinent test and model information are presented. The test was conducted in two parts. Test OS8A was performed in the NASA/ARC unitary 11-foot section and OS8B was conducted in the NASA/ARC unitary 9 x 7 tunnel. Test objectives were to investigate thermal protection system (TPS) tile sensitivity to extreme pressure gradients and vibration and to define the TPS aerodynamic environment. The model utilized for OS8 was a full-scale representation of a portion of the space shuttle orbiter lower wing carry-through structure forward of the aft tank strut and propellant lines. Thermal protection tiles were simulated on the model. The model was instrumented with static pressure orifices, accelerometers, and dynamic pressure transducers (Kulites). A total rake was utilized to obtain boundary layer surveys.

  7. 振动流化床干燥机运转引起的楼面振动测试及分析%THE SPOT TESTING AND FEA OF THE VIBRATION BEHAVIOR OF BEAM-PLATES SYSTEM CAUSED BY THE VIBRATION OF FLUIDIZED BED DRYER

    Institute of Scientific and Technical Information of China (English)

    王蕊; 郭昭胜; 崔娟玲

    2014-01-01

    对振动流化床干燥机运转导致的楼面振动响应进行现场测试,得到了振动设备的扰力、频率、隔振支座的工作性能以及楼面强迫振动响应的规律。基于现场测试结果,利用ANSYS 有限元软件对4种不同工况下楼面的强迫振动进行了仿真分析,得到梁板结构的振动和传递规律。结果表明:楼面振动响应在布置振动设备的框架区格内较大,框架梁上测点的振动响应明显小于次梁;振动响应沿楼面纵向测点迅速衰减,并可将多台振动设备的综合振动效应视为单台振动设备振动效应的线性叠加;强迫共振是引起楼面较大振动的内在原因。利用简化连续正交各向异性板模型和结构自振频率灵敏度分析技术快速地获得了结构刚度的最佳修改位置和修改量。最后,采用有限元模型,经试算提出了合理经济的楼板减振处理方案。%The vibration behavior of beam-plates system caused by the vibration of fluidized bed dryer was tested .The disturbing force and frequency of vibrating equipment , working performance of the existing isolation bearing and response of floor vibration was obtained .According to the spot test results ,finite element analysis of simple harmonic vibration was carried out by ANSYS software .The test results show that floor vibration response is larger in frame regions having vibration equipment;vibration response of monitoring points on frame beam is much less than that of monitoring points on secondary beam , vibration response of measuring points decay soon along the floor longitudinal points.The linear superposition comprehensive vibration effect of multiple vibration equipment can be regarded as a single vibration equipment vibration effect , the main cause of factory floor of big vibration is forced resonance .Based on a simply continuous orthotropic plate model and the eigenfrequency sensitivity analysis technique , the optimal

  8. Testing a new analytical approach for determination of vibrational transition moment directions in low symmetry planar molecules: 1-D- and 2-D-naphthalene.

    Science.gov (United States)

    Rogojerov, Marin; Keresztury, Gábor; Kamenova-Nacheva, Mariana; Sundius, Tom

    2012-12-01

    A new analytical approach for improving the precision in determination of vibrational transition moment directions of low symmetry molecules (lacking orthogonal axes) is discussed in this paper. The target molecules are partially uniaxially oriented in nematic liquid crystalline solvent and are studied by IR absorption spectroscopy using polarized light. The fundamental problem addressed is that IR linear dichroism measurements of low symmetry molecules alone cannot provide sufficient information on molecular orientation and transition moment directions. It is shown that computational prediction of these quantities can supply relevant complementary data, helping to reveal the hidden information content and achieve a more meaningful and more precise interpretation of the measured dichroic ratios. The combined experimental and theoretical/computational method proposed by us recently for determination of the average orientation of molecules with C(s) symmetry has now been replaced by a more precise analytical approach. The new method introduced and discussed in full detail here uses a mathematically evaluated angle between two vibrational transition moment vectors as a reference. The discussion also deals with error analysis and estimation of uncertainties of the orientational parameters. The proposed procedure has been tested in an analysis of the infrared linear dichroism (IR-LD) spectra of 1-D- and 2-D-naphthalene complemented with DFT calculations using the scaled quantum mechanical force field (SQM FF) method. PMID:22981590

  9. Development and Test of Magnetic Column with Pulsating Vibration Magnetic Field%脉冲振动磁场磁选柱的研制与试验

    Institute of Scientific and Technical Information of China (English)

    袁志涛; 郑龙熙

    2001-01-01

    介绍了脉冲振动磁场磁选柱组成、基本原理以及实验室小型试验结果。该设备利用充电和放电过程产生较高的磁场,并采取控制电路使充电和放电过程强制中断,产生一定频率的振动磁场。它既利用磁团聚又强烈破坏磁团聚,分选效果明显优于现行的弱磁选设备。%The composition,the basic principle and the laboratory test results of magnetic column with pulsating vibration magnetic field are described.The equipment makes use of the high intemsity magnetic field formed during the process of charge and discharge and uses the control electric circuit to make the charge and discharge process interrupted so as to produce a magnetic field vibrating at certain frequency,It both makes use of and strongly destroys the magnetic agglomeration and has a separation efficiency remarkable better than that of the existing low intensity magnetic separators.

  10. Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE): Emissions of particulate matter from wood and dung cooking fires, brick kilns, generators, trash and crop residue burning

    Science.gov (United States)

    Stone, Elizabeth; Jayarathne, Thilina; Stockwell, Chelsea; Christian, Ted; Bhave, Prakash; Siva Praveen, Puppala; Panday, Arnico; Adhikari, Sagar; Maharjan, Rashmi; Goetz, Doug; DeCarlo, Peter; Saikawa, Eri; Yokelson, Robert

    2016-04-01

    The Nepal Ambient Monitoring and Source Testing Experiment (NAMASTE) field campaign targeted the in situ characterization of widespread and under-sampled combustion sources. In Kathmandu and the Terai, southern Nepal's flat plains, samples of fine particulate matter (PM2.5) were collected from wood and dung cooking fires (n = 22), generators (n = 2), groundwater pumps (n = 2), clamp kilns (n = 3), zig-zag kilns (n = 3), trash burning (n = 4), one heating fire, and one crop residue fire. Co-located measurements of carbon dioxide, carbon monoxide, and volatile organic compounds allowed for the application of the carbon mass balance approach to estimate emission factors for PM2.5, elemental carbon, organic carbon, and water-soluble inorganic ions. Organic matter was chemically speciated using gas chromatography - mass spectrometry for polycyclic aromatic hydrocarbons, sterols, n-alkanes, hopanes, steranes, and levoglucosan, which accounted for 2-8% of the measured organic carbon. These data were used to develop molecular-marker based profiles for use in source apportionment modeling. This study provides quantitative emission factors for particulate matter and its constituents for many important combustion sources in Nepal and South Asia.

  11. Vibration Comprehensive Test and Analysis on Finisher 2 of 1580 Hot Strip Mill%1580热连轧机F2精轧机振动综合测试与分析

    Institute of Scientific and Technical Information of China (English)

    高亚南; 彭艳; 孙建亮; 苏旭涛; 赵林; 李修琨

    2013-01-01

    For the abnormal vibration phenomena frequently occurring in the rolling of thin gauge products on Finisher 2 (F2) of 1580 hot strip mill of Qiangang, a comprehensive test about its torsional vibration, vertical vibration and horizontal vibration was done. The results show that the torsional vibration and vertical vibration are forced vibration, and the excitation is from horizontal vibration of work rolls. The too large gap between the work roll bearing liner and rack liner is the direct cause of the mill vibration. So, to suppress the vibration, a program which is to reduce the gap between the work roll bearing and rack has been suggested. On the site, two sizes liner gasket with thickness of 0. 3 and 0. 7 mm has been installed on the work roll bearing respectively. The tested signal shows that the abnormal vibration is significantly reduced or even disappeared. The results are satisfying.%针对迁钢1580热连轧生产线F2轧机在轧制薄规格产品时频繁出现的异常振动现象,组织了对其扭振、垂振及水平振动的综合测试.分析表明:轧机扭振和垂振是受迫振动,激励来自工作辊水平振动,工作辊轴承座衬板与机架衬板间间隙过大是造成轧机振动的直接原因,提出了减小工作辊轴承座与机架间间隙的振动抑制方案.现场对工作辊轴承座分别加装0.3和0.7mm两种规格的衬板垫片进行了试验,测试信号显示异常振动明显减弱甚至消失,效果令人满意.

  12. Vibrating minds

    CERN Multimedia

    2009-01-01

    Ed Witten is one of the leading scientists in the field of string theory, the theory that describes elementary particles as vibrating strings. This week he leaves CERN after having spent a few months here on sabbatical. His wish is that the LHC will unveil supersymmetry.

  13. Vibrating Manipulation

    Institute of Scientific and Technical Information of China (English)

    SHEN Guo-quan; CUI Yi-jun

    2003-01-01

    @@ As a manipulation with unique therapeutic effect in TCM Tuina manipulations, Vibrating manipulation has significantly stronger effection on viscera, blood vessel, smooth muscle and gland secretion than other Tuina manipulations and it is mainly used in internal medicine, gynecology and miscellaneous diseases.

  14. Vibration sensor

    OpenAIRE

    Matěj, J.

    2015-01-01

    This paper lays out a design of a system for reading the radar antenna gearbox vibrations. Firstly it names different types of sensors and defines their suitability for this usage. It describes their important electric and frequency properties. Secondly it shows a design of the data transmission system from the transducer to a computer and describes measured data changes according to the gearbox faults.

  15. Vibration system identification of Paks and Kozloduy reactor buildings on the basis of the blast test results

    International Nuclear Information System (INIS)

    System identification allows to build mathematical models of a dynamic system based on measured data. System identification is carried out by adjusting parameters within a given model until its output coincides as well as possible with the measured output. The aim of this study is to investigate and model the behavior of complex vibratory systems on the basis of measured excitation and response. The first part of the study describes the theory used in the analysis and the software tools used in the analysis. The second part of the study describes the investigation and modeling of the response of single degree of freedom oscillator excited by sinusoidal and blast excitation. In the third part of the study the system identification of the Kozloduy NPP unit 5 reactor building and Paks NPP unit 1 reactor building is studied and the models are estimated using the method of segmentation of excitation and response. System identification is carried out using MATLAB software by adjusting parameters within a given model until its output coincides as well as possible with the measured output. The types of models used for the were: l) ARX models; 2) ARMAX model; 3) Output-Error (OE) models; 4) Box-Jenkins (BJ) models; 5) State-space models. The model coefficients for different models were calculated using the least-squares and maximum likelihood estimation methods available in MATLAB system identification toolbox. Excitation was in both Paks and Kozloduy case the measured free-field excitation and responses were the vibration responses of the building on the foundation slab level and top of the building. By examining the established models the frequency characteristics of vibration systems were determined with 95 % accuracy and the amplitude response with 80 % accuracy. In case of the steady state response of sinusoidally excited single dof oscillator the modelling gave almost exact results. But in the case of the blast response of the reactor building the obtaining of the

  16. 振动法测试胶合木梁弹性模量的方法研究%Study on vibration-based detection methods for testing elastic modulus of glued laminated beams

    Institute of Scientific and Technical Information of China (English)

    王解军; 夏滴洋; 陈晓

    2015-01-01

    Under the condition of simple-supported, by adopting vibration NDT method, the natural frequency of glued laminated beams were measured and the elastic module values of the beams were also computed. Meanwhile, by using vibration analysis finite element method, the glulam beams frequency values were calculated and the glulam beams elastic modulus were determined through static tests. The comparisons among the results of vibration testing, vibration analysis and static load tests were conducted, the comparative results proved the feasibility and accuracy detecting glued laminated beams’ elastic modulus with vibration methods.%在简支条件下,应用振动无损检测法测定了胶合木梁的固有频率并算得其弹性模量值,同时采用振动分析有限元法计算胶合木梁频率值和用静载试验测定其弹性模量。通过对振动测试、振动分析及静载试验共3种方法得到的结果进行比较,证明了振动法测试胶合木梁弹性模量的可行性和准确性。

  17. Max Launch Abort System (MLAS) Pad Abort Test Vehicle (PATV) II Attitude Control System (ACS) Integration and Pressurization Subsystem Dynamic Random Vibration Analysis

    Science.gov (United States)

    Ekrami, Yasamin; Cook, Joseph S.

    2011-01-01

    In order to mitigate catastrophic failures on future generation space vehicles, engineers at the National Aeronautics and Space Administration have begun to integrate a novel crew abort systems that could pull a crew module away in case of an emergency at the launch pad or during ascent. The Max Launch Abort System (MLAS) is a recent test vehicle that was designed as an alternative to the baseline Orion Launch Abort System (LAS) to demonstrate the performance of a "tower-less" LAS configuration under abort conditions. The MLAS II test vehicle will execute a propulsive coast stabilization maneuver during abort to control the vehicles trajectory and thrust. To accomplish this, the spacecraft will integrate an Attitude Control System (ACS) with eight hypergolic monomethyl hydrazine liquid propulsion engines that are capable of operating in a quick pulsing mode. Two main elements of the ACS include a propellant distribution subsystem and a pressurization subsystem to regulate the flow of pressurized gas to the propellant tanks and the engines. The CAD assembly of the Attitude Control System (ACS) was configured and integrated into the Launch Abort Vehicle (LAV) design. A dynamic random vibration analysis was conducted on the Main Propulsion System (MPS) helium pressurization panels to assess the response of the panel and its components under increased gravitational acceleration loads during flight. The results indicated that the panels fundamental and natural frequencies were farther from the maximum Acceleration Spectral Density (ASD) vibrations which were in the range of 150-300 Hz. These values will direct how the components will be packaged in the vehicle to reduce the effects high gravitational loads.

  18. Effect of vehicle weight on natural frequencies of bridges measured from traffic-induced vibration

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Recently, ambient vibration test (AVT) is widely used to estimate dynamic characteristics of large civil structures. Dynamic characteristics can be affected by various environmental factors such as humidity, intensity of wind, and temperature. Besides these environmental conditions, the mass of vehicles may change the measured values when traffic-induced vibration is used as a source of AVT for bridges. The effect of vehicle mass on dynamic characteristics is investigated through traffic-induced vibration tests on three bridges; (1) three-span suspension bridge (128m+404m+128m), (2) five-span continuous steel box girder bridge (59m+3@95m+59m), (3) simply supported plate girder bridge (46m). Acceleration histories of each measurement location under normal traffic are recorded for 30 minutes at field. These recorded histories are divided into individual vibrations and are combined into two groups according to the level of vibration; one by heavy vehicles such as trucks and buses and the other by light vehicles such as passenger cars. Separate processing of the two groups of signals shows that, for the middle and long-span bridges, the difference can be hardly detected, but, for the short span bridges whose mass is relatively small, the measured natural frequencies can change up to 5.4%.

  19. A study on shaft vibration of gas circulators with gas-bearings for HENDEL helium test facility

    International Nuclear Information System (INIS)

    The gas circulator is a one of the most important component in Gas-Cooled Reactor system. Being low density of the coolant helium gas of HTGR, multi-stage compression or high-speed driving are required for the coolant circulator to accomplish the required head. The gas circulators for the large scale HTGRs with mechanical and buffer-gas sealing in the shaft penetration had encountered troubles at the part more or less. On the other hand, smaller scale electric driven gas circulators with gas bearings as used for HENDEL and former DRAGON reactor enable fully encased construction and provide easier maintainability, however, those types of the circulator need highly precise machining, adjustment and superior operational techniques. Moreover, practical rotor weight seems to be limited up to around 150kg for the gas-bearing machinery. The fine dynamic mass-balancing of the rotor becomes extremely difficult in the large gas-bearing machine. The whirling phenomena of the journal tend to originate and to grow approaching the rotating frequency to the first bending natural frequency or the third critical speed of the rotor. Inspite of many efforts and works on instability of the gas-bearing system, concrete or practical condition and countermeasure to the instability have not clarified. Present report describes the experimental result on shaft vibration and bearing characteristics of typical gas circulators among the five machines which have gas-bearings and are largest class in those types. It is clarified through the experiments that the fine dynamic balancing of the rotor, dynamic response of the bearing pads and gas-film thickness in the bearing clearance are extremely important to suppress the instability. However, it is also found that too much difficulties make them impractical in these machines. So one might conclude that the countermeasure with fine sensing technique of the half-speed whirling must be practical and usefull. (author)

  20. Nonlinear effects in electrostatic vibration energy harvesters: current progress and perspectives

    OpenAIRE

    Galayko, Dimitri; Blokhina, Elena

    2013-01-01

    In this review paper, we discuss the principles of electrostatic (capacitive) vibration energy harvesters and nonlinear techniques that can be applied to improve the performance of harvesters. Electrostatic vibration energy harvesters are devices that contain mechanical resonators driven by ambient vibrations and coupled with conditioning electronic circuits through a capacitive transducer. While the devices can be fabricated using MEMS technology and miniaturised, intern...

  1. Vibration sensors

    International Nuclear Information System (INIS)

    These sensors, which aim is the surveillance of the fast breeder reactor internal structure, were designed considering the following requirements: - long term utilization under low frequencies conditions (1 to 50 Hz) and detection of accelerations lower than 0,01 g, - operation with a temperature up to 6000C and receiving important neutron and gamma flux. Monoaxial sensors with a liquid vibrating mass (sodium) were thus developed, based on the electromagnetic flow meter principles (Faraday effect)

  2. 瞬态振动信号在公路工程检测中的应用%Applied the Transient Vibration Signal in Highway Engineering Tested

    Institute of Scientific and Technical Information of China (English)

    张献民; 刘秀菊; 等

    2001-01-01

    讨论了路面瞬态振动信号分析处理技术.对振动信号反演分析可获得下部 路基结构的剪切波速.建立了4种路基密度与瑞雷波速度的相关模型,研制了最佳 模型自动选取软件,讨论了压实度建立的标准,从而实现了路基压实度的检测. 对振动信号进行频谱分析,可获得路面脱空与否以及路基相对状况的信息.对于 路面存在脱空或存在明显软弱路基,其主频值通常小于50 Hz.对路基加固处理后 ,其剪切波速将会提高,据此可通过对加固前后振动信号的测试,反演路基剪切 波速值,实现对路基加固效果的评价.应用结果表明,该技术在上述几个方面可 取得显著效果.%The process techniques of transient vibration signal are dis cussed.With the inverse analysis to the vibration signal,the shear wav e velocity of roadbed can be obtained.The four kinds of correlation mo dels of roadbed density with surface wave velocity are presented,and t he software is developed of choosing best correlation model.It is disc ussed that how to form the standard of roadbed compaction degree.And s o the test of compaction degree of roadbed can be realized.With the fr equency spectrum analysis to the vibration signal,the information can be obtained about road surface separate from roadbed or the state of r oadbed.Usually the main frequency value is less than 50 Hz in the cond ition of road surface separate from roadbed or soft roadbed.Made reinf orce to roadbed,the shear wave velocity of roadbed will be increase.Ac cording to the theory,through testing the vibration signals before rei nforce roadbed and after reinforce roadbed,and making inverse analysis to the signals to get the shear wave velocity of roadbed,the reinforc e effect of roadbed can be evaluated.Applying results indicate that th e remarkable success can be achieved with the technique.

  3. 振动环境试验控制允差的剪裁应用%Clipping Application of the Control Tolerance of Vibration Environment Test

    Institute of Scientific and Technical Information of China (English)

    朱学旺

    2014-01-01

    This paper analyzes and discusses the requirements of GJB 150.16A for the control tolerance of vibration environment test from the perspective of engineering application. The result shows that the requirements on the control tolerance in GJB 150.16A is flexible. However, due to no stipulation on RMS tolerance, it will easily result in over-test or under-test; and the description on the control tolerance of the PSD (Power Spectral Density) of an acceleration signal is fuzzy to some extent. The suggestion is presented in the paper for clipping the control tolerance.%从工程应用的角度,本文分析讨论了GJB 150.16A对振动环境试验控制允差的要求。结果表明,GJB150.16A对控制允差的要求是灵活的,但是未规定RMS允差,容易造成过试验或欠试验,且对加速度谱密度的控制允差要求的表述存在着一定的模糊。文中给出了解决建议。

  4. The Excitation Vibration Test and Analysis in Cotton Precise Plastic Film Layering Sower%棉花覆膜播种机振动测试试验与激励源分析

    Institute of Scientific and Technical Information of China (English)

    刘媛杰; 胡灿; 朴在林

    2016-01-01

    南疆棉田中大量的田间杂物对播种机造成了较大的振动影响,降低了排种器的排种精度. 为了测试不同作业速度下的播种机振动特性,以2 BMJ-8/2 型机械式棉花精量覆膜播种机为测试点,利用测振仪器布置测点,测试在不同作业速度下的振动位移,并对测试数据进行频谱分析. 结果表明:覆膜播种机作业速度为9.8 ~10.5km/h时,振动幅值主要发生在低频0 ~10Hz 的频率段,受到的振动激励主要为田间杂物的缠绕、土块振动等影响;覆膜播种机作业速度为7 .5 ~8 km/h 时,播种机振动幅值明显减小,能保持较优的作业效率,工作状况为最优;覆膜播种机低速作业时,振动幅值较小,振动频率在0 ~5 0 Hz之间,与柴油机的振动频率接近,振动激励主要来自于拖拉机动力振动.%A large number of field Cotton sundry to drill the larger vibration impact in southern xinjiang , reduce the row of kind of accuracy .To test the machine vibration characteristics under different operation speed , precise coated with 2 BMJ-8/2 mechanical cotton seeding machine for the test point , using vibration instrument measuring point , testing vibra-tion displacement under different operation speed , and frequency spectrum analysis was carried out on the test data .Re-sults show that the effect of seeding machine operation speed is 9.8 10.5km/h, mainly in low frequency vibration ampli-tude of 0 to 10 HZ frequency , are motivated by the vibration of the main clutter for the field winding , clod vibration , etc;Plastic film layering sower operation speed of 7.5~8km/h, the seeder vibration amplitude was decreased , can keep the optimal efficiency and working conditions for the optimal;Plastic film layering sower operation at low speed , small vi-bration amplitude , vibration frequency , between 0 to 50 hz and frequency close to the vibration of the diesel engine , the vibration motivation mainly comes from the tractor vibration power .

  5. Pushing Force Estimation of Random Vibration Test Considering Dynamic Characteristics of Test Specimen and Fixture%考虑试件与夹具动力学特性的随机振动试验推力估算

    Institute of Scientific and Technical Information of China (English)

    刘青林; 朱学旺; 张思箭

    2013-01-01

      分析了随机振动试验中试件和夹具的一阶频率对振动台推力的影响,提出了一种考虑试件、夹具一阶频率的随机振动试验推力估算方法。就一个算例用仿真计算的方法,得到了振动台推力随试件和夹具一阶频率的变化情况。最后通过一个应用实例,验证了该方法的准确性。该方法比传统的刚性假设方法更接近实际,可为大型试件随机振动试验设计提供参考。%The influence of first order frequency of test specimen and fixture on the force of shaking table was analyzed. A method considering first order frequency of test specimen and fixture was put forward in order to estimate the force of shaking table during a random vibration test. The relationship between the force of shaking table and the first order frequencies of test specimen and fixture was obtained through simulation method. The accuracy of the method was proved by an application example. Compared with the traditional rigid assumptions method, this method is more close to the actual, and it can be reference of vibration test design for large-scale specimen.

  6. Magnetic damping of ski vibrations

    Energy Technology Data Exchange (ETDEWEB)

    Yonnet, J.-P. [CNRS, St. Martin d' Heres (France). Lab. d' Electrotech. de Grenoble; Patton, A.C.; Philippe; Arnould; Bressan, C. [CNRS, St. Martin d' Heres (France). Lab. d' Electrotech. de Grenoble]|[Skis Dynastar S.A., Sallanches (France)

    1998-07-01

    An original damping device has been developed to reduce ski vibrations. Ski movement is transmitted to a conductive sheet situated in a multipole magnetic field created by permanent magnets. The conductive sheet is simultaneously submitted to eddy current and friction forces, giving the damping effect. The eddy current damper is more efficient for high frequency than for low frequency vibrations and consequently is very well adapted to ski vibrations. Bench and snow tests show the positive effects of the damper, which will be commercially available before the end of this year. (orig.)

  7. Strength and fatigue testing of large size wind turbines rotors. Vol. II: Full size natural vibration and static strength test, a reference case

    Energy Technology Data Exchange (ETDEWEB)

    Arias, F.; Soria, E.

    1996-12-01

    This report shows the methods and procedures selected to define a strength test for large size wind turbine, anyway in particular it application on a 500 kW blade and it results obtained in the test carried out in july of 1995 in Asinel`s test plant (Madrid). Henceforth, this project is designed in an abbreviate form whit the acronym SFAT. (Author)

  8. Vibration testing and analysis based on DASP of pump station pressure pipe line%基于DASP的泵站压力管道振动测试与分析

    Institute of Scientific and Technical Information of China (English)

    徐存东; 左罗; 张硕; 史国坤

    2013-01-01

    大型泵站的压力管道在运行中的振动问题比较普遍,高频大幅的管道振动会严重影响泵站提水系统的安全稳定运行,特殊的运行工况和管道内不稳定的水流流态是引起压力管道振动的主要原因,对压力管道的振动特性进行测试可以反演分析引起管道振动的机理并评价其运行的稳定性,文中采用DASP软件对大型泵站的压力管道振动特性进行测试,通过对代表性测点的信号采集和信号分析,可得到管道的原位振动特性图像.测试结果表明:将基于DASP的测试技术应用于泵站压力管道的振动测试,不仅能够获得管道振动的实时测试信号和振动特性图谱,还可获得振动机理分析所需的更高的测试精度和效率,在工程实践中具有较好的推广价值.%Vibration problem is relatively common with the pressure pipes in operation in large-scale pump stations. Pipeline vibration with high frequency and large amplitude will seriously affect safe and stable operation of water lift system in pump stations. Special conditions and pipeline unstable flow pattern are the main reason of pressure pipes vibration. By means of testing the vibration characteristics of pressure pipes and inversion analysis, the mechanism of pipeline vibration can be obtained and the stability of operation will be evaluated. In this paper, by using software DASP, the test of pressure pipe vibration characteristics in large pump stations was conducted. By means of signal acquisition and signal analysis on representative measuring point, an in-situ vibration characteristic image of the pipeline could be obtained. Testing result showed that the application of DASP-based testing technique to vibration test of pump station pressure pipes not only could obtain real-time test signal and vibration characteristic spectrum of pipeline vibration but would also obtain higher testing accuracy and efficiency indispensable to vibration mechanism analysis

  9. Scanning slit for HIE-ISOLDE: vibrations test (linear motion actuator from UHV design, MAXON brushless motor, speed = 10 mm/s)

    CERN Document Server

    Bravin, E; Sosa, A

    2014-01-01

    This report summarizes the results of a series of tests performed on the prototype HIE-ISOLDE diagnostic box (HIE-DB) regarding the vibrations and drifts in the transverse position of the scanning blade while moving in and out of beam path in the HIE-ISOLDE short box prototype. To monitor the transverse position of the blade, a series of 0.1 mm diameter holes were drilled on it and their positions were tracked with an optical system. The linear motion actuator was acquired from UHV design (model LSM38-150-SS), and it was adapted to be driven by a brushless EC motor from MAXON. The speed of the scanning blade during the tests was 10 mm/s. The transverse movement of the slit in the direction perpendicular to the movement was lower than 40 m, and is dominated by the displacement of the contact point of the applied force on the lead-screw. An offset on the slit position was observed while changing the direction of movement of the blade, its amplitude being of the order of 30 m. The amplitudes of the displacements...

  10. Scanning slit for HIE-ISOLDE: vibrational test (linear motion actuator from UHV design, speed = 2.5 mm/s)

    CERN Document Server

    Bravin, E; Sosa, A

    2014-01-01

    This report summarizes the results of a series of tests performed on the prototype HIE-ISOLDE diagnostic box (HIE-DB) regarding the vibrations and drifts in the transverse position of the scanning blade while moving inside or outside the box. To monitor the transverse position of the blade, a series of 0.1 mm diameter holes were drilled on it and their positions were tracked with an optical system. The linear motion actuator was acquired from UHV design (model LSM38-150-SS), is driven by a stepper motor and has all the guiding mechanisms outside vacuum. The maximum speed of the scanning blade during the tests was 2.5 mm/s. The transverse movement of the slit in the direction perpendicular to the movement was lower than 50 m, and is dominated by the displacement of the contact point of the applied force on the lead-screw. An offset on the slit position was observed while changing the direction of movement of the blade, its amplitude being of the order of 30 m. The amplitudes of the displacements of the transve...

  11. 刘江黄河大桥主桥运行环境下的振动测试%Vibration Test of the Running Environment of the Main Bridge of Liujiang Yellow River Bridge

    Institute of Scientific and Technical Information of China (English)

    王洁

    2014-01-01

    Based on the vibration test of the running environment of the main bridge of Liujiang Yellow River Bridge measured vibration Liu Jiang Yellow River main bridge operating environment, this paper got the response vibration stability diagram of vertical and lateral acceleration under different frequencies, torsional vibration mode and torsional frequency, judged the effect of the damage of boom on vertical and lateral vibration, so as to predict the current operating status of bridge.%本文通过对刘江黄河大桥主桥运行环境下的振动实测,得到桥梁的在不同频率下的竖向加速度、横向加速度的响应振动稳定图,扭转振型及扭转频率,判断吊杆的损伤对横、竖向振动的影响,推知桥梁目前的运行状态。

  12. DIAGNOSTIC EVALUATION OF NUMBERICAL AIR QUALITY MODELS WITH SPECIALIZED AMBIENT OBSERVATIONS: TESTING THE COMMUNITY MULTISCALE AIR QUALITY MODELING SYSTEM (CMAQ) AT SELECTED SOS 95 GROUND SITES

    Science.gov (United States)

    Three probes for diagnosing photochemical dynamics are presented and applied to specialized ambient surface-level observations and to a numerical photochemical model to better understand rates of production and other process information in the atmosphere and in the model. Howeve...

  13. The effect of operating conditions on resistance parameters of filter media and limestone dust cake for uniformly loaded needle felts in a pilot scale test facility at ambient conditions

    OpenAIRE

    Saleem, Mahmood; Krammer, Gernot; Tahir, M. Suleman

    2012-01-01

    Resistance parameters are essential for the prediction of pressure drop in bag filters. The reported values for limestone dust differ in magnitude and also depend on operating parameters. In this work, experimental data is provided from a pilot scale pulse-jet regenerated bag filter test facility for three types of needle felts using air and limestone dust at ambient conditions. Results reveal that specific resistance of filter media is independent of velocity while the specific resistance of...

  14. Índices de calidad ambiental de aguas del Arroyo Caañabe mediante tests microbiológicos y ecotoxicológico

    Directory of Open Access Journals (Sweden)

    Tomás López Arias

    2016-06-01

    Full Text Available El Arroyo Caañabe, es un curso de agua que corre a través de los Departamentos Central y Paraguarí (República del Paraguay. Las descargas de origen agropecuario, urbano e industrial contaminan sus aguas. En este trabajo se evalúa la calidad del arroyo mediante sus características fisicoquímicas, ecotoxicológicas, microbiológicas y se la comparan con la legislación vigente. Se colectaron muestras en los meses de Julio y Setiembre del año 2014. Se estudiaron tres sitios denominados S1, ubicado en aguas arriba de la Ciudad de Carapegua; S2 en la intersección del arroyo con la Ruta 1, y S3, en la zona límite de las ciudades de Carapegua y Nueva Italia. Se realizaron ensayos de toxicidad aguda con Daphnia magna, Lactuca sativa, y alevines de Danio rerio; además de ensayos crónicos en Tetradesmus wisconsinenesis, D. rerio y Allium cepa. Se evaluaron los grupos y especies microbianos siguientes: aerobios mesófilos, enterobacterias, coliformes totales, coliformes fecales, E. coli, Pseudomona aeruginosa, mohos y levaduras; además se determinaron índices de calidad y de contaminación. Los resultados indican que las aguas del arroyo presentaron características de clase II y de clase III según el padrón establecido por la Secretaría del Ambiente del Paraguay. El índice de calidad de agua (ICA arrojó valores comprendidos entre 52 y 62 lo que otorga la clasificación de "regular"; mientras que el índice de contaminación trófica (ICOTRO presentó valores entre 0,12 y 0.26, indicando "eutrofización". Los recuentos de coliformes fueron superiores en el segundo muestreo, aunque dentro lo establecido por la norma. La presencia de P. aeruginosa en los tres puntos constituye un riesgo para la salud. Ensayos ecotoxicológicos agudos mostraron que las aguas presentan escasos efectos letales, no obstante los ensayos crónicos en A. cepa y el test de micronúcleos en D. rerio indican potenciales efectos citotóxicos y genotóxicos de las

  15. In-situ test and analysis of vibration of subgrade for Wuhan-Guangzhou high-speed railway%武广高速铁路路基振动现场测试与分析

    Institute of Scientific and Technical Information of China (English)

    屈畅姿; 王永和; 魏丽敏; 郭志广

    2012-01-01

    为研究武广高速铁路无砟轨道路基的振动特性,对武昌—咸宁综合试验段路基进行了现场实车测试.获得了各测点在不同列车荷载作用下的竖向振动加速度和动应力幅值,总结了试验段路基动力响应的分布规律,获得了式验段路基的固有频率,并结合小波分析方法对路基的振动特性进行了频域分析.结果表明,车速的提升加剧了基床表层顶面路基的振动,在260~320km/h车速段尤为明显.经过2.7 m高路堤的衰减,路基的动力响应幅值和振动能量已基本不受车速影响.级配碎石层能有效抑制振动沿路基深度的传递.随着车速的提升,转向架固定轴距作用率、轨道不平顺成为引起路基振动的主要原因.轴重对动力响应幅值和振动能量的影响较车速更为显著,轴重的增加使得振动能量在频域内更为集中.%In order to study the vibration characteristics of ballastless-track subgrade for Wuhan-Guangzhou high-speed railway, in-situ train-induced vibration tests are performed in the Huchang-Xianning test section. Magnitudes of vertical vibration acceleration and dynamic stress of all the measuring points are obtained when bullet trains units and track inspection trains run in the test section respectively. Distribution laws of dynamic response in the tested subgrade are summarized. Natural frequencies of the tested subgrade are obtained. Furthermore, incorporating wavelet analysis method, vibration characteristics of the tested subgrade are analyzed in the frequency domain. The results show that the increase in train speed enhances the vibration at the top surface of the tested subgrade, especially at 260-320 km/h. After attenuating over 2.7 m high embankment, magnitudes of dynamic response and vibration energies of the tested subgrade are very little, and the influence of train speeds is not obvious to them. The graded broken stone layer can effectively inhibit the propagation of vibration

  16. Psicologia do Ambiente

    OpenAIRE

    Antunes, Dalila; Bernardo, Fátima; Palma-Oliveira, José-Manuel

    2011-01-01

    Na aplicação da Psicologia à área do AMBIENTE importa em primeiro lugar definir o que se entende, neste contexto, por ambiente. O conceito é entendido como toda a envolvente que rodeia o ser humano. Referimo-nos pois ao espaço físico e aos estímulos que nele existem (som, ar, paisagem…), dirigindo-se a Psicologia do Ambiente ao estudo e intervenção sobre a forma como o ambiente influencia o indivíduo ou grupos, e sobre o modo como o comportamento dos indivíduos e grupos influenciam o ambiente...

  17. 车削过程中刀具振动响应测试及分析%Testing and analysis on vibration responses of cutting tool in tuming process

    Institute of Scientific and Technical Information of China (English)

    孟华; 李顺才; 刘玉庆

    2012-01-01

    利用QLVC-ZSA1振动信号分析仪及加速度传感器,对数控车床在不同切削要素的车削过程中刀具的振动响应进行了测试及量化研究,得到了刀具振动加速度信号的时域曲线及自功率谱密度曲线.研究表明:刀具的振动响应是一个随车削进行的时变过程,在同一走刀相同车削要素的车削过程中,随着去除材料的增加,刀具所受的激振能量减少;随着切削深度的增加,刀具振动的最大自功率谱密度并非单调增加,车削深度对于刀具振动的影响存在一个临界值;随着主轴转速及进给速度的提高,刀具振动的自谱密度值随之增大,而相应的振动频率降低.%By means of the QLVC-ZSA1 analysis instrument of vibration signals and acceleration sensor, the vibration responses of the cutting tool are tested and quantitatively studied for the turning process of the numerically controlled lathe under the different cutting elements, and the time series curves and the self-power spectral density curves of the acceleration vibration signals of the cutting tool are obtained. The study indicates that (1) the vibration response of the cutting tool is a time-varying process with the operating of the turning. For the turning period with same turning parameters in a tool moving path, the hammer vibration energy of the cutting tool decreases with the increase of the material removal; (2) with the increase in cutting depth, the maximum of the self-power spectral density of the tool vibration doesn't increase monotonically and the cutting depth has a critical value for the effect on the tool vibration; (3) with the increase in the spindle speed and feeding velocity, the self-power spectral density of the tool vibration also increases, while the corresponding vibration frequency decreases.

  18. Study on the experiments of the relationship between the geometric dimensions of flexural vibration disk and its vibration characteristics

    OpenAIRE

    Y. Yuan; Ma, Y; Chen, M.; Wang, D.; Zhao, B.

    2006-01-01

    Purpose: The vibration characteristics of flexural vibration disk in ultrasonic honing system were studiedsystematically through experiments.Design/methodology/approach: The vibration of flexural vibration disk was tested using the acoustic systemof ultrasonic honing.Findings: The results showed that the amplitude of vibration disk increases with the reducing of its thickness,when the disk was thin disk (the ratio between the thickness and radius was less than or equal to one fifths) thevibra...

  19. Atmosphere and Ambient Space

    DEFF Research Database (Denmark)

    Schmidt, Ulrik

    Atmosphere and Ambient Space This paper explores the relation between atmosphere and ambient space. Atmosphere and ambient space share many salient properties. They are both ontologically indeterminate, constantly varying and formally diffuse and they are both experienced as a subtle, non......-signifying property of a given space. But from a certain point of view, the two concepts also designate quite dissimilar experiences of space. To be ’ambient’ means to surround. Accordingly, ambient space is that space, which surrounds something or somebody. (Gibson 1987: 65) Since space is essentially...... of a surrounding character, all space can thus be described as having a fundamentally ambient character. So what precisely is an ambient space, then? As I will argue in my presentation, ambient space is a sensory effect of spatiality when a space is experienced as being particularly surrounding: a ‘space effect...

  20. Analysis of real-time vibration data

    Science.gov (United States)

    Safak, E.

    2005-01-01

    In recent years, a few structures have been instrumented to provide continuous vibration data in real time, recording not only large-amplitude motions generated by extreme loads, but also small-amplitude motions generated by ambient loads. The main objective in continuous recording is to track any changes in structural characteristics, and to detect damage after an extreme event, such as an earthquake or explosion. The Fourier-based spectral analysis methods have been the primary tool to analyze vibration data from structures. In general, such methods do not work well for real-time data, because real-time data are mainly composed of ambient vibrations with very low amplitudes and signal-to-noise ratios. The long duration, linearity, and the stationarity of ambient data, however, allow us to utilize statistical signal processing tools, which can compensate for the adverse effects of low amplitudes and high noise. The analysis of real-time data requires tools and techniques that can be applied in real-time; i.e., data are processed and analyzed while being acquired. This paper presents some of the basic tools and techniques for processing and analyzing real-time vibration data. The topics discussed include utilization of running time windows, tracking mean and mean-square values, filtering, system identification, and damage detection.

  1. The Boltzmann constant from the H2 18O vibration-rotation spectrum: complementary tests and revised uncertainty budget

    Science.gov (United States)

    Fasci, Eugenio; Domenica De Vizia, Maria; Merlone, Andrea; Moretti, Luigi; Castrillo, Antonio; Gianfrani, Livio

    2015-10-01

    We report on complementary tests and measurements regarding our recent determination of the Boltzmann constant, kB, by means of Doppler broadening thermometry, also providing additional information as compared to previous articles. A revised uncertainty budget is illustrated, including some new components that were ignored in previous spectroscopic experiments, and better quantifying other components that were estimated to be negligible. In particular, we consider the relativistic Doppler effect, the perturbation caused by the finite bandwidth of the detection system and the influence of the spontaneous emission content of the probe laser. These new components do not increase the global uncertainty which still amounts to 24 ppm. Our value for the Boltzmann constant is 1.380 631 (33)  ×  10-23 J K-1, which is the best determination reported so far by using an optical method.

  2. Field Tests and Simulation of Lion-Head River Bridge

    Directory of Open Access Journals (Sweden)

    Yao-Min Fang

    2007-01-01

    Full Text Available Lion-Head River Bridge is a twin bridge in parallel position. The east-bounded was designed and constructed as a traditional prestress concrete box girder bridge with pot bearings; and the west-bounded was installed with seismic isolation devices of lead rubber bearings. The behavior of the isolated bridge is compared with that of the traditional bridge through several field tests including the ambient vibration test, the force vibration test induced by shakers, the free vibration test induced by a push and fast release system, and the truck test. The bridges suffered from various extents of damage due to the Chi-Chi and the Chi-I earthquakes of great strength during the construction and had been retrofitted. The damage was reflected by the change of the bridges' natural frequencies obtained from the ambient vibration tests. The models of the two bridges are simulated by the finite element method based on the original design drawings. Soil-structure interaction was also scrutinized in this study. The simulation was then modified based on the results from the field tests. Dynamic parameters of bridges are identified and compared with those from theoretical simulation. The efficiency is also verified to be better for an isolated bridge.

  3. 可用于压电发电的振动测试与复现的研究%Test and Reproduce of Vibration used for Piezoelectric Power Generation

    Institute of Scientific and Technical Information of China (English)

    李洪艳

    2013-01-01

    Introduced the present situation of piezoelectric power generation from vibration, in recent years, as more and more green energy is demanded, using piezoelectric material to harvest vibration energy from environment become the focus of study. Introduced the basic principle of piezoelectric power generation, piezoelectric power generation is realized by using the piezoelectric material's piezoelectric effect. Designed test system and test the roadbed vibration waveform ,discussed a way to re?produce the vibration wave in the laboratory.%该文介绍了压电发电获取振动能的现状,近年来,人们对绿色能源的需求越来越大,利用压电发电获取环境中振动能成为研究焦点.阐述了压电发电基本原理,压电发电是利用了压电材料的正压电效应.设计测试系统实地测试了路基振动波形并探讨了在实验室中复现所测振动波形的方法.

  4. Two-dimensional-vibrational spectroscopy: Development and testing of a two-dimensional ultrafast Raman spectrometer with Time-Frequency Detection

    Science.gov (United States)

    Urbanek, Diana Camila

    The major emphasis of this dissertation will be given toward the theoretical tools necessary to acquire high resolution femtosecond Raman spectra from broadband femtosecond pulses. The theory of simultaneous Time-Frequency Detection (TFD) will be discussed and demonstrated to be a robust technique to acquire the vibrational coherence information. Finally, two experimental cases that demonstrate the feasibility of femtosecond TFD-CARS for acetonitrile and nitrobenzene will be presented. In the introductory first chapter, the motivation and fundamentals for developing 2D-vibrational spectroscopy using femtosecond Raman detection is presented. For coherent Raman spectroscopies, common femtosecond pulses often lie in an intermediate regime: their bandwidth is too wide for measurements in the frequency domain, but their temporal width is too broad for homodyne measurements in the time domain. A recent paper [Phys. Rev. Lett. 97 , 267401 (2006)] showed that complete Raman spectra can be recovered from intermediate length pulses by using simultaneous time and frequency detection (TFD). Heterodyne detection and a phase-stable local oscillator at the anti-Stokes frequency are not needed with TFD. Phase-control, pulse shaping or pulses of widely differing duration are not required. To demonstrate the TFD method, a high resolution Raman spectrum of nitrobenzene obtained from 60 fs pulses is discussed theoretically and experimentally in the second chapter. In the third chapter model calculations illustrate how information on the Raman spectrum is smoothly transferred from the frequency domain to the time domain as the pulse width shortens. When data is collected in both dimensions, the Raman spectrum is completely determined to high resolution, regardless of the probe pulse width. The TFD method is tested on experimental CARS data from acetonitrile in the fourth chapter. Compared to theoretical models, experimental data are complicated by noise and incomplete knowledge of the

  5. Research on Character of Generator Stator Core Vibration Modal Test%发电机定子铁芯模态振动特性试验研究

    Institute of Scientific and Technical Information of China (English)

    杨骏; 马斌; 吴鸿韬

    2013-01-01

    To prevent the resonance between the elliptic modal frequency of stator core and the twice fre-quency of the radial electromagnetic force in the turbo-generators operation , the modal test of the stator core of turbo-generators is necessary .A few factories of generator do some numerical simulations and sta-tor core modal test before the core leaving the factory , stator cores are little tested in the site of power plant .In this paper , through a number of examples of typical turbine power plant unit , some methods and characteristics of the modal test are introduced , and the key points in the process of field test are put forward .It is pointed out that the test of generator core vibration modal is a good method of safety supervi-sory technology of turbine-generators.%对发电机定子铁芯进行模态振动试验是为了防止汽轮发电机组在运行过程中定子铁芯椭圆形模态振动频率与双倍的发电机的径向电磁力频率产生共振。目前只有各个发电机制造厂进行数值模拟和出厂前进行模态振动测试,几乎没有在电厂生产现场进行该项测试。文章通过几个典型汽轮发电机测试实例详细介绍了对于电厂停机检修机组进行发电机定子铁芯模态试验的方法及特性,提出了现场试验过程中的要点。指出发电机铁芯模态振动测试是目前发电机安全监测工作中很好的补充技术手段。

  6. Theory of vibration protection

    CERN Document Server

    Karnovsky, Igor A

    2016-01-01

    This text is an advancement of the theory of vibration protection of mechanical systems with lumped and distributed parameters. The book offers various concepts and methods of solving vibration protection problems, discusses the advantages and disadvantages of different methods, and the fields of their effective applications. Fundamental approaches of vibration protection, which are considered in this book, are the passive, parametric and optimal active vibration protection. The passive vibration protection is based on vibration isolation, vibration damping and dynamic absorbers. Parametric vibration protection theory is based on the Shchipanov-Luzin invariance principle. Optimal active vibration protection theory is based on the Pontryagin principle and the Krein moment method. The book also contains special topics such as suppression of vibrations at the source of their occurrence and the harmful influence of vibrations on humans. Numerous examples, which illustrate the theoretical ideas of each chapter, ar...

  7. Micro energy harvesting from ambient motion : modeling, simulation and design

    Energy Technology Data Exchange (ETDEWEB)

    Blystad, Lars-Cyril

    2012-07-01

    Vibration energy harvesting is the process of converting available ambient kinetic energy into useful electrical energy. It can be done on large scale with e.g. a wind-driven turbine. This thesis deals with small scale energy harvesters that are suitable for fabrication in Micro electromechanical Systems (MEMS) technologies. Such MEMS energy harvesters have the potential to supply power for micro power devices. Modeling, simulation and design of MEMS vibration energy harvesters are the foci of this thesis. Transduction mechanisms that are covered are electrostatic and piezoelectric. Electric equivalent circuits are obtained for the use in electromechanical simulations with the circuit simulator SPICE. The feasibility of simulating both narrow- and broadband vibrations, to model different external driving forces, in a standard circuit simulator is demonstrated. Comparisons of the har- vesters performance for different excitations are presented. A selection of passive and active power conditioning circuits is investigated and their performances compared. The active nonlinear switching conversion circuitry performs better than simple passive circuitry, especially when mechanical end stops are in effect. The active switching circuits give higher electromechanical damping, and thus can be driven at higher acceleration amplitudes before end stops are engaged. Mechanical end stops have to be present in all MEMS vibrational energy harvesters. Either due to space limitations, reliability issues, Simliberate introduction of nonlinearities or a combination of these. ulations in the thesis include mechanical end stops and thus include the corresponding nonlinearities introduced in the system. When the mechanical end stops are hit by the proof mass during high-amplitude vibrations, nonlinear effects such as saturation and jumps are present. The end stops increase the effective bandwidth at large acceleration amplitudes. End stops limit the output power for sinusoidal

  8. Advanced systems and services for ground vibration testing - Application for a research test on an Airbus A340-600 aircraft

    OpenAIRE

    Lau, Jenny; Debille, Jan; Peeters, Bart; Giclais, Stéphane; Lubrina, Pascal; Böswald, Marc; Govers, Yves

    2011-01-01

    Aerospace manufacturers are faced with the challenge of designing systems and components that have to be safer, more reliable, affordable, offer improved passenger comfort and have less environmental impact than their competitors. In addition, they have to systematically reduce development times in order to get new products to market earlier. In the usual case, only a few prototypes are available for testing and experimental verification, in most cases, only towards the end of the development...

  9. 基于无线网桥传输气吸式免耕播种机振动测试系统设计%Tillage Planter Vibration Test System Design Based on Wireless Transmission of Air-suction Bridge

    Institute of Scientific and Technical Information of China (English)

    张旭; 刘飞; 董帅; 赵满全

    2015-01-01

    针对气吸式免耕播种机在空旷的田间试验不便应用有线传输的特点,采用加速度传感器测量振动的方法,设计了一种综合无线传输技术和振动信号采集与分析的振动测量系统。系统选用 Ti3058 k-16 M 的无线网桥、加速度传感器和数据采集卡实现了振动测量信号的采集和无线传送, MatLab 分析处理采集到的数据。试验表明:系统在田间试验稳定性好、抗干扰能力强、网桥传输数据范围广、便捷实用,可为气吸式免耕播种机的田间测振试验提供方便。%For air-suction tillage planter in the open field test cable transmission characteristics inconvenience applica -tions, Measurement method using the acceleration sensor of vibration , designed an integrated wireless transmission tech-nology and vibration signal acquisition and analysis of vibration measurement system , system used Ti3058k-16M wireless bridge , acceleration sensor and data acquisition card for the vibration measurement signal acquisition and wireless trans -mission , MATLAB analysis and processing the collected data .Experimental results show that:system stability in field tri-als, anti-interference ability , bridge a wide range of data transmission , Convenient and practical , To facilitate air-suc-tion tillage planter field vibration tests .

  10. Adaptive Piezoelectric Absorber for Active Vibration Control

    Directory of Open Access Journals (Sweden)

    Sven Herold

    2016-02-01

    Full Text Available Passive vibration control solutions are often limited to working reliably at one design point. Especially applied to lightweight structures, which tend to have unwanted vibration, active vibration control approaches can outperform passive solutions. To generate dynamic forces in a narrow frequency band, passive single-degree-of-freedom oscillators are frequently used as vibration absorbers and neutralizers. In order to respond to changes in system properties and/or the frequency of excitation forces, in this work, adaptive vibration compensation by a tunable piezoelectric vibration absorber is investigated. A special design containing piezoelectric stack actuators is used to cover a large tuning range for the natural frequency of the adaptive vibration absorber, while also the utilization as an active dynamic inertial mass actuator for active control concepts is possible, which can help to implement a broadband vibration control system. An analytical model is set up to derive general design rules for the system. An absorber prototype is set up and validated experimentally for both use cases of an adaptive vibration absorber and inertial mass actuator. Finally, the adaptive vibration control system is installed and tested with a basic truss structure in the laboratory, using both the possibility to adjust the properties of the absorber and active control.

  11. 动力环境下深孔弧形闸门模态参数识别研究%Study of Modal Parameter Identification from Ambient Vibration on a Deep Radial Gate

    Institute of Scientific and Technical Information of China (English)

    张科; 蔡元奇

    2012-01-01

    In the background of the prototype test of a deep radial gate in Three Gorges dam, two methods are provided for the modal parameter identification of the radial gate, one is to apply operation modal analysis (OMA) to a gate which is under flood discharge, the other one is to apply experiment modal analysis (EMA) to an inactive gate while some other gates are under flood discharge. This paper is based on the feasibility of studying on the former method. We use the natural excitation technology (NExT) combined with the eigensystem realization algorithm (ERA) to determine the dynamic characteristics of a gate. Displacement data at 7 locations were processed and NExT-ERA were used to extract the natural frequency and associated damping ratio. The results show the effectiveness of this modal identification methodology and the possibility of implementing it on other hydraulic structure.%以三峡大坝深孔弧形闸门原型试验为背景,提出采用泄洪激励作为环境激励对深孔弧门进行模态参数识别的两种方式,一是对进行泄洪工作的闸门进行工作模态分析;二是在其他闸门泄洪时对退出备用的闸门进行实验模态分析.针对前者,取用泄洪状态下弧门的位移响应,综合自然激励技术和特征系统实现算法,识别深孔弧形闸门的模态参数,同时指出,必须利用EMAC性能指标剔除虚假模态.对比有限元分析,结果表明,在泄洪产生的动力环境下,用该方法对深孔弧形闸门进行工作模态分析是可行的.

  12. 用于结构减振的聚合物混凝土试验研究%Tests of polymer concrete used for structural vibration mitigation

    Institute of Scientific and Technical Information of China (English)

    曹晖; 陈兴华; 华建民; 胡芝茂

    2011-01-01

    对于目前工程中新出现的桥梁-建筑合-的大型结构,如何减小运行荷载产生的振动是颇受关注的问题.该研究通过在混凝土中掺入高分子聚合物以提高其阻尼性能达到减振的目的.采用矩形截面简支梁和以实际大跨复杂箱梁为原型的1/6缩尺模型,分别进行振动测试、静载试验和疲劳试验,对比普通混凝土和聚合物混凝土的阻尼性能、静力性能和疲劳性能.同时测试基准混凝土和各聚灰比的聚合物混凝土试块的抗压强度和弹性模量.试验结果表明,随聚灰比的增大混凝土梁的阻尼比大幅增大,试块抗压强度和弹性模量略有下降,但满足规范的要求.聚合物混凝土梁的静力性能比普通混凝土梁更好,疲劳性能与之相当.聚合物混凝土的施工性能指标如塌落度和扩展度良好.%It is essential for a newly emerging combined structure of railway-bridge and building to alleviate vibration induced by a high speed train.A kind of polymer was mixed with concrete to improve its damping.A series of experiments including vibration test, static loading one and fatigue one were carried out on small specimens, simply supported beams and reduced scale models of a real long span box girder to measure the compression strength, static modulus and damping and to compare the static and fatigue performance of ordinary concrete and polymer concrete.The test results showed that the damping ratio increases with increase in ratio of polymer and cement, but the compression strength and static modulus decrease a little; the static performance of the polymer concrete beams is better than that of the ordinary concrete ones, and the fatigue behavior of the former is the same as that of the latter; the workability of the polymer concrete including slump and slump flow is good.

  13. Applications of super elasticity in vibrational control

    International Nuclear Information System (INIS)

    In this work, the possibilities of using shape memory alloys (SMA) as passive dampers devices in mechanicals vibrations problems are studied.The property that is exploited is the super elastic effect, by wich strains of the order of 10% can be obtained.The relationship between stress and strain means that this is an inelastic process.Nevertheless when load is removed the material recoveries its original dimension, presenting zero or almost zero permanent strain relative to others common materials, describing in its stress-strain diagram an important hysteretic loop.This features occurs basically because in well suited conditions the SMA can undergo martensitic transformations induced by stress.A series of uniaxial tension tests in commercial NiTi wires are performed, in order to characterize the super elastic behavior of the material.The influence of variables as ambient temperature, strain rate, strain levels and number of tension cycles accumulated are studied paying attention to the dissipative capacity of the material defined by means of the shape of the hysteretic loop.The influence on the damping capacity of the thermal effects associated with the martensitic transformation are evaluated by performing experiments at different transformation rates.Results are rationalized in terms of a model considering the interaction between a source term (heat of transformation), heat convection to the ambient and conduction along the wire.Some numerical results are obtained and discussed. For a performance evaluation in devices applications a simplified model of super elasticity is proposed.Then, the response of an elastic frame structure endowed with SMA tensors is evaluated following the model behavior when seismic movement is imposed at the base.The obtained results verify the possibility of using SMA as kernel elements in vibration control.This conclusion is experimentally verified in a prototype of the structure specially designed and constructed for this work

  14. Hypermedia in the Ambient Wood

    OpenAIRE

    Weal, Mark J; Michaelides, Danius T.; Thompson, Mark K.; De Roure, David C

    2003-01-01

    The Ambient Wood project, carried out as part of the Equator IRC, set out to provide an augmented learning experience for children in an outdoor environment. Using a variety of devices, the children gathered information about the woodland habitats performing basic scientific enquiry and hypothesis testing. In this paper we describe the supporting information infrastructure used in the project, focusing on how hypermedia tools and techniques were used to structure and deliver the information t...

  15. Efficiency Enhancement of a Cantilever-Based Vibration Energy Harvester

    Directory of Open Access Journals (Sweden)

    Ali E. Kubba

    2013-12-01

    Full Text Available Extracting energy from ambient vibration to power wireless sensor nodes has been an attractive area of research, particularly in the automotive monitoring field. This article reports the design, analysis and testing of a vibration energy harvesting device based on a miniature asymmetric air-spaced cantilever. The developed design offers high power density, and delivers electric power that is sufficient to support most wireless sensor nodes for structural health monitoring (SHM applications. The optimized design underwent three evolutionary steps, starting from a simple cantilever design, going through an air-spaced cantilever, and ending up with an optimized air-spaced geometry with boosted power density level. Finite Element Analysis (FEA was used as an initial tool to compare the three geometries’ stiffness (K, output open-circuit voltage (Vave, and average normal strain in the piezoelectric transducer (εave that directly affect its output voltage. Experimental tests were also carried out in order to examine the energy harvesting level in each of the three designs. The experimental results show how to boost the power output level in a thin air-spaced cantilever beam for energy within the same space envelope. The developed thin air-spaced cantilever (8.37 cm3, has a maximum power output of 2.05 mW (H = 29.29 μJ/cycle.

  16. Efficiency enhancement of a cantilever-based vibration energy harvester.

    Science.gov (United States)

    Kubba, Ali E; Jiang, Kyle

    2013-01-01

    Extracting energy from ambient vibration to power wireless sensor nodes has been an attractive area of research, particularly in the automotive monitoring field. This article reports the design, analysis and testing of a vibration energy harvesting device based on a miniature asymmetric air-spaced cantilever. The developed design offers high power density, and delivers electric power that is sufficient to support most wireless sensor nodes for structural health monitoring (SHM) applications. The optimized design underwent three evolutionary steps, starting from a simple cantilever design, going through an air-spaced cantilever, and ending up with an optimized air-spaced geometry with boosted power density level. Finite Element Analysis (FEA) was used as an initial tool to compare the three geometries' stiffness (K), output open-circuit voltage (V(ave)), and average normal strain in the piezoelectric transducer (ε(ave)) that directly affect its output voltage. Experimental tests were also carried out in order to examine the energy harvesting level in each of the three designs. The experimental results show how to boost the power output level in a thin air-spaced cantilever beam for energy within the same space envelope. The developed thin air-spaced cantilever (8.37 cm3), has a maximum power output of 2.05 mW (H = 29.29 μJ/cycle). PMID:24366177

  17. Simultaneous Energy Harvesting and Vibration Control via Piezoelectric Materials

    OpenAIRE

    Wang, Ya

    2012-01-01

    This work examines a novel concept and design of simultaneous energy harvesting and vibration control on the same host structure. The motivating application is a multifunctional composite sandwich wing spar for a small Unmanned Aerial Vehicle (UAV) with the goal of providing self-contained gust alleviation. The basic idea is that the wing itself is able to harvest energy from the ambient vibrations along with available sunlight during normal flight. If the wing experiences any strong wind gus...

  18. Study on angular velocity algorithm for vibration test based on sensors array%基于传感器阵列的振动测试角速度算法研究

    Institute of Scientific and Technical Information of China (English)

    汪伟; 焦健超; 唐力伟; 杨通强

    2012-01-01

    Acceleration sensors array can effectively measure 6 -DOF high -frequency vibration parameters of many dimensions linear vibration and angular vibration. In the crucial course of testing three -dimensional angular velocity, the traditional integral method makes the error accumulate fast so that the precision is influenced seriously under the condition of long time test. In this paper, a scheme of applying 3-axis acceleration sensors array was taken as an example. The effect of integration and evolution was compared by model simulation. A kind of combination algorithm was put forward to solve the problem of error accumulation under guaranteeing the prerequisite of precision which offers algorithm guarantee for long time vibration test.%针对较高频率下多维线振动与角振动同时存在的复杂振动,加速度传感器阵列可以有效地测试六自由度参数.在关键的测试三维角速度的过程中,传统的积分方法使误差快速积累,在长时间测试的情况下严重影响精度.该文基于一种利用三轴加速度传感器阵列的四传感器配置方案,通过模型仿真对积分法、开方法等角速度解算算法进行比较,并提出一种组合算法,在保证精度的前提下解决了误差积累的问题,为长时间的振动测试提供了算法保证.

  19. A magnetic-spring-based, low-frequency-vibration energy harvester comprising a dual Halbach array

    Science.gov (United States)

    Salauddin, M.; Halim, M. A.; Park, J. Y.

    2016-09-01

    Energy harvesting that uses low-frequency vibrations is attractive due to the availability of such vibrations throughout the ambient environment. Significant power generation at low-frequency vibrations, however, is challenging because the power flow decreases as the frequency decreases; moreover, designing a spring-mass system that is suitable for low-frequency-vibration energy harvesting is difficult. In this work, our proposed device overcomes both of these challenges by using a dual Halbach array and magnetic springs. Each Halbach array concentrates the magnetic-flux lines on one side of the array while suppressing the flux lines on the other side; therefore, a dual Halbach array allows for an interaction between the concentrated magnetic-flux lines and the same coil so that the maximum flux linkage occurs. During the experiment, vibration was applied in a horizontal direction to reduce the gravity effect on the Halbach-array structure. To achieve an increased power generation at low-amplitude and low-frequency vibrations, the magnetic structure of the dual Halbach array and the magnetic springs were optimized in terms of the operating frequency and the power density; subsequently, a prototype was fabricated and tested. The prototype device offers a normalized power density of 133.45 μW cm-3 g-2 that is much higher than those of recently reported electromagnetic energy harvesters; furthermore, it is capable of delivering a maximum average power of 1093 μW to a 44 Ω optimum load, at an 11 Hz resonant frequency and under a 0.5 g acceleration.

  20. Seismic waves estimation and wavefield decomposition: application to ambient vibrations

    Science.gov (United States)

    Maranò, Stefano; Reller, Christoph; Loeliger, Hans-Andrea; Fäh, Donat

    2012-10-01

    Passive seismic surveying methods represent a valuable tool in local seismic hazard assessment, oil and gas prospection, and in geotechnical investigations. Array processing techniques are used in order to estimate wavefield properties such as dispersion curves of surface waves and ellipticity of Rayleigh waves. However, techniques presently in use often fail to properly merge information from three-components sensors and do not account for the presence of multiple waves. In this paper, a technique for maximum likelihood estimation of wavefield parameters including direction of propagation, velocity of Love waves and Rayleigh waves, and ellipticity of Rayleigh waves is described. This technique models jointly all the measurements and all the wavefield parameters. Furthermore it is possible to model the simultaneous presence of multiple waves. The performance of this technique is evaluated on a high-fidelity synthetic data set and on real data. It is shown that the joint modelling of all the sensor components, decreases the variance of wavenumber estimates and allows the retrieval of the ellipticity value together with an estimate of the prograde/retrograde motion.

  1. Uncertainty law in ambient modal identification-Part I: Theory

    Science.gov (United States)

    Au, Siu-Kui

    2014-10-01

    Ambient vibration test has gained increasing popularity in practice as it provides an economical means for modal identification without artificial loading. Since the signal-to-noise ratio cannot be directly controlled, the uncertainty associated with the identified modal parameters is a primary concern. From a scientific point of view, it is of interest to know on what factors the uncertainty depends and what the relationship is. For planning or specification purposes, it is desirable to have an assessment of the test configuration required to achieve a specified accuracy in the modal parameters. For example, what is the minimum data duration to achieve a 30% coefficient of variation (c.o.v.) in the damping ratio? To address these questions, this work investigates the leading order behavior of the ‘posterior uncertainties’ (i.e., given data) of the modal parameters in a Bayesian identification framework. In the context of well-separated modes, small damping and sufficient data, it is shown rigorously that, among other results, the posterior c.o.v. of the natural frequency and damping ratio are asymptotically equal to ( and 1/(2, respectively; where ζ is the damping ratio; Nc is the data length as a multiple of the natural period; Bf and Bζ are data length factors that depend only on the bandwidth utilized for identification, for which explicit expressions have been derived. As the Bayesian approach allows full use of information contained in the data, the results are fundamental characteristics of the ambient modal identification problem. This paper develops the main theory. The companion paper investigates the implication of the results and verification with field test data.

  2. A influência do ruído ambiental no desempenho de escolares nos testes de padrão tonal de frequência e padrão tonal de duração Environmental noise influence on student performance in the Frequency Pattern Tests and Duration Pattern Tests

    Directory of Open Access Journals (Sweden)

    Ludimila Souza Nascimento

    2012-06-01

    Full Text Available OBJETIVO: caracterizar o desempenho de escolares nos testes de padrão tonal de frequência e padrão tonal de duração no silêncio e na presença de ruído ambiental. METODO: trata-se de estudo experimental transversal, com amostra de conveniência, composta por 70 estudantes, que responderam a um formulário de percepção do ruído ambiental. O nível de ruído da escola foi avaliado com medidor de nível de pressão sonora. Os estudantes foram submetidos à avaliações (fala, motricidade orofacial, linguagem e simplificada do processamento auditivo e distribuídos em dois grupos (G1 sem alteração fonoaudiológica e G2 com alteração fonoaudiológica. Foram realizados também os testes de padrão tonal de frequência e duração (silêncio e ruído. RESULTADOS: o nível médio de pressão sonora da escola variou de 57,2 dB(A na sala de informática a 83,6 dB(A na quadra de esportes. Segundo os estudantes, o que mais interfere em suas atividades é o barulho de conversas durante a aula. Quanto aos testes de padrão tonal de frequência (TPF e duração (TPD, observou-se que a média de acertos no ambiente silencioso foi maior que no ambiente ruidoso. O G1 apresentou melhor desempenho no TPD e TPF que G2. No ruído houve piora no desempenho dos dois grupos (G1 e G2 nos testes. CONCLUSÃO: os níveis de pressão sonora da escola encontram-se elevados e fora do padrão recomendado pelas normas nacionais. No ruído, houve piora no desempenho dos testes nos dois grupos estudados.PURPOSE: to characterize student performance in Frequency Pattern Test (FPT and Duration Pattern Test (DPT in a silent ambient and under noise. METHOD: experimental cross-sectional study, measured in a convenience sample. Survey made up by 70 students who answered a form on their noise perception. School's noise level was evaluated using physical measurements. Students were submitted to previous evaluations (speech, language, and auditory processing and then splinted

  3. DOWNHOLE VIBRATION MONITORING & CONTROL SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Martin E. Cobern

    2004-01-09

    The objective of this program is to develop a system to both monitor the vibration of a bottomhole assembly, and to adjust the properties of an active damper in response to these measured vibrations. Phase I of this program entails modeling and design of the necessary subsystems and design, manufacture and test of a full laboratory prototype. The project continues to advance, but is behind the revised (14-month) schedule. Tasks 1-3 (Modeling, Specification and Design) are all essentially complete. The test bench for the Test and Evaluation (Tasks 4 & 5) has been designed and constructed. The design of the full-scale laboratory prototype and associated test equipment is complete and the components are out for manufacture. Barring any unforeseen difficulties, laboratory testing should be complete by the end of March, as currently scheduled. We anticipate the expenses through March to be approximately equal to those budgeted for Phase I.

  4. Advances in Fatigue Life Prediction and Accelerated Test of Rubber Vibration Isolator%橡胶隔振器寿命预测及加速试验研究进展

    Institute of Scientific and Technical Information of China (English)

    孙伟星; 刘山尖; 欧阳昕; 董兴建

    2013-01-01

    The failure modes of rubber vibration isolator and the factors influencing its fatigue life were introduced.The fatigue life prediction method for rubber materials based on fracture energy and S-N curve approaches were summarized.The recent research on fatigue life accelerated test for rubber vibration isolator was presented and the current development trends in rubber fatigue life prediction were prospected.%介绍了橡胶材料的疲劳失效形式及影响橡胶材料抗疲劳性能的因素,总结了基于撕裂能和基于S-N曲线的橡胶材料疲劳寿命预测方法,阐明了橡胶隔振器加速试验研究的现状,展望了未来值得研究的方向.

  5. Model test of TLD effect on aqueduct structure subjected to strong vibration%强震作用下渡槽 TLD 效应模型试验研究

    Institute of Scientific and Technical Information of China (English)

    黄研昕; 钱向东

    2014-01-01

    通过对矩形截面渡槽的单跨模型进行动力试验研究,探讨了渡槽在刚性地基强震条件下的调谐液体阻尼器(TLD)效应;通过调节槽内水位,研究了水体横向减震作用与深宽比的关系。试验结果表明,水体的晃动及水波破碎对渡槽的横向动力响应起到了 TLD 减震作用。渡槽内水位增加会改变结构的动力特性,使渡槽结构自振频率下降。在强震作用下,TLD 横向减震效果随水位变化发生波动,当槽内水体晃动频率与渡槽结构自振频率接近时,减震作用最为显著。%Based on tests of a rectangular one-span simply supported aqueduct, the tuned liquid damper (TLD) effect on the aqueduct under the condition of a rigid foundation subjected to strong vibration was analyzed. The relationship between the transverse damping effect and the ratio of depth to width were studied by adjusting the water level. The test results demonstrated that water sloshing and wave breaking had a TLD effect on the aqueduct structure; the increase of the water level in the aqueduct changed the dynamic properties of the structure, causing the self-vibration frequency of the structure to decrease; during strong vibration, the TLD effect fluctuated with the change of water level; and the most significant TLD effect occurred when the water sloshing frequency was close to the self-vibration frequency of the structure.

  6. Self-Tuning Active Vibration Control of Flexible Beam Structures

    OpenAIRE

    M.O. Tokhi; Hossain, M A

    1994-01-01

    This paper presents the design and performance evaluation of an adaptive active control mechanism for vibration suppression in flexible beam structures. A cantilever beam system in transverse vibration is considered. First order control finite difference methods are used to study the behaviour of the beam and develop a suitable test and verification platform. An active vibration control algorithm is developed within an adaptive control framework for broadband cancellation of vibration along t...

  7. Vibrations and Stability

    DEFF Research Database (Denmark)

    Thomsen, Jon Juel

    and physics. This edition includes a new chapter on the useful effects of fast vibrations and many new exercise problems. Written for: Students in mechanical or structural engineering. Keywords: Nonlinear Vibrations, Bifurcations, Chaotic Vibrations, Vibrations and Stability.......About this textbook An ideal text for students that ties together classical and modern topics of advanced vibration analysis in an interesting and lucid manner. It provides students with a background in elementary vibrations with the tools necessary for understanding and analyzing more complex...... dynamical phenomena that can be encountered in engineering and scientific practice. It progresses steadily from linear vibration theory over various levels of nonlinearity to bifurcation analysis, global dynamics and chaotic vibrations. It trains the student to analyze simple models, recognize nonlinear...

  8. 上海世博文化中心TMD减轻人致振动分析与实测研究%Analysis and field test for human-induced vibration reduction with TMD in Shanghai EXPO culture center

    Institute of Scientific and Technical Information of China (English)

    吕西林; 丁鲲; 施卫星; 翁大根

    2012-01-01

    上海世博文化中心是2010上海世博会永久性场馆之一,其主体结构由沿环向的36榀悬臂长度不一的钢桁架和矩形钢管混凝土内框架组成.结构六层为悬挑钢结构楼盖,易引起人致振动问题.对采用调谐质量阻尼器(TMD)进行人致振动控制的上海世博文化中心进行了大量的计算分析和现场实测.结果表明结构各榀桁架的竖向共振频率处于2.5 Hz-3.0 Hz之间;当人以2.0 Hz的频率正常行走时,结构竖向振动较小,TMD基本无影响;而当人以结构竖向共振频率快速走动或奔跑时,TMD能有效减小结构的竖向振动响应,减振效率约为15%.这对长悬臂空间结构的舒适度问题和采用TMD进行人致振动控制问题的研究具有参考借鉴意义.%Shanghai Expo culture center is one of the permanent buildings for Expo 2010 Shanghai. Its main structure is composed of 36 hoop cantilever steel trusses with different lengths and inner frames made of rectangle CFST members. The 6-storey steel structure with cantilevered floors easily causes human-induced vibration. A large amount of analysis and field tests were performed for this culture center with tuned mass dampers ( TMDs) used to reduce human-induced vibration. The results showed that the resonance frequencies of each truss are between 2. Ohz and 3. 5Hz; the vertical vibration of the structure is very small and TMDs have no influence on the vibration when people walk normally with frequency 2. Ohz; when people rapidly walk or run with structural resonance frequency, TMDs can reduce the structural vertical vibration about 15% effectively. The results could be a reference for study on serviceability of space structures with long cantilever and human-induced vibration control with TMD.

  9. Test and analysis on floor vibration of Dalian International Conference Center%大连国际会议中心楼盖振动测试与分析

    Institute of Scientific and Technical Information of China (English)

    曹乐; 左清林; 王立长; 郭杏林; 曲鑫蕃; 李凡磷; 纪大海

    2012-01-01

    大连国际会议中心15.30m标高平台周圈均为大悬挑结构形式,各会议厅也主要采用大跨度钢楼盖,对人行激励可能会非常敏感。而该建筑功能对舒适度的要求较高,所以需重视人行激励下的楼盖振动问题。本工程中较多地采用悬挑与大跨度的结构形式,所以楼盖的竖向振动就成为比较重要的问题。对结构自振特性做了初算,并进行了现场测试,根据现场测试结果调校模型,将加速度分析结果与实测结果进行比对。列出了各分区的自振特性,根据各分区的功能情况进行加速度分析,并将达沃斯会议厅随机振动分析的加速度情况和国际标准组织ISO的方法进行了比较。%The 15.30m-platforms of Dalian International Conference Center are large cantilevered structures,and the meeting rooms are mainly large-span steel floors,which are sensitive to human excitation.Due to the high comfort performance requirement of the building,the floor vibration problem is important.In this project,long-cantilever and long-span structures are adopted much more,so the vertical vibration of the floor is an important problem.The structural vibration characteristics were analyzed and the field test was done.Based on the test values,the model was adjusted and the acceleration results of analysis were compared with the test values.The vibration characteristic of every part was introduced,the acceleration analyses of the parts were done,and the random vibration results of the DCC was compared with the method proposed by ISO.

  10. Static renewal tests using Pimephales promelas (fathead minnows). Clinch River-Environmental Restoration Program (CR-ERP) study, ambient water toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Simbeck, D.J.

    1993-12-31

    Clinch River-Environmental Restoration Program (CR-ERP) personnel and Tennessee Valley Authority (TVA) personnel conducted a study during the week of October 21--28, 1993. The organisms specified for testing were larval fathead minnows, Pimephales promelas, and the daphnid, Ceriodaphnia dubia. Due to serious reproduction/embryo abortion problems with the TVA daphnid cultures, TVA conducted tests during this study period using only fathead minnows. Surface water samples were collected by TVA Field Engineering personnel from Poplar Creek Mile 2.9, Mile 4.3, and Mile 5.1 on October 20, 22, and 25. Samples were split and provided to the CR-ERP and TVA toxicology laboratories for testing. Exposure of test organisms to these samples resulted in no toxicity (survival or growth) in testing conducted by TVA. Attachments to this report include: Chain of custody forms -- originals; Toxicity test bench sheets and statistical analyses; and Reference toxicant test information.

  11. Study on Integrated Thermal Cycle and Vibration Profile for HALT

    Institute of Scientific and Technical Information of China (English)

    TAO Jun-yong; CHU Wei-hua; CHEN Xun

    2009-01-01

    Focusing on electronic products, this paper establishes a finite element model for printed circuit board (PCB) assembling with enhanced ball grid array(EBGA)component under vibration environment. Based on this model, it studies relations between fatigue rate of solder joint and temperature, vibration frequency. Moreover, it analyzes propagation of micro-crack produced by thermal cycle under vibration stress. The results offer a method to optimize the thermal cycle and vibration integrated profile and to combine vibration test and thermal cycling for highly accelerated life test (HALT).

  12. Vibration of plates

    CERN Document Server

    Chakraverty, Snehashish

    2008-01-01

    Plates are integral parts of most engineering structures and their vibration analysis is required for safe design. This work provides a comprehensive introduction to vibration theory and analysis of two-dimensional plates. It offers information on vibration problems along with a discussion of various plate geometries and boundary conditions.

  13. The influence of ambient light on the driver

    Science.gov (United States)

    Klinger, Karsten D.; Lemmer, Uli

    2008-04-01

    Increasingly, cars are fitted with interior ambient lighting which is switched on while driving. This special kind of interior light emphasizes the interior design of the car, it makes a car look special and gives the buyers a new option to personalize their automobiles. But how does ambient interior light influence the driver? We conducted a series of over 50 tests to study the influence of interior ambient light on contrast perception under different illumination levels, colors and positions of the illuminated areas. Our tests show that in many cases the ambient lighting can improve the visual contrast for seeing objects in the headlamp beam. But the test persons mentioned that the tested brightness looked too bright and that they felt glared. The measured values instead proved that no disability glare exists. Therefore, provided that the drivers can adjust the intensity of the ambient light to avoid glare, the ambient light has no negative effect on the drivers' contrast perception.

  14. Low power energy harvesting and storage techniques from ambient human powered energy sources

    Science.gov (United States)

    Yildiz, Faruk

    small amounts of electricity to low-power electronic devices. These studies were focused to investigate and obtain power from different energy sources, such as vibration, light, sound, airflow, heat, waste mechanical energy and temperature variations. This research studied forms of ambient energy sources such as waste mechanical (rotational) energy from hydraulic door closers, and fitness exercise bicycles, and its conversion and storage into usable electrical energy. In both of these examples of applications, hydraulic door closers and fitness exercise bicycles, human presence is required. A person has to open the door in order for the hydraulic door closer mechanism to function. Fitness exercise bicycles need somebody to cycle the pedals to generate electricity (while burning calories.) Also vibrations, body motions, and compressions from human interactions were studied using small piezoelectric fiber composites which are capable of recovering waste mechanical energy and converting it to useful electrical energy. Based on ambient energy sources, electrical energy conversion and storage circuits were designed and tested for low power electronic applications. These sources were characterized according to energy harvesting (scavenging) methods, and power and energy density. At the end of the study, the ambient energy sources were matched with possible electronic applications as a viable energy source.

  15. Static renewal tests using Pimephales promelas (fathead minnows) and Ceriodaphnia dubia (daphnids). Clinch River-Environmental Restoration Program (CR-ERP) pilot study, ambient water toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Simbeck, D.J.

    1993-12-31

    Clinch River-Environmental Restoration Program (CR-ERP) personnel and Tennessee Valley Authority (TVA) personnel conducted a pilot study during the week of April 22--29, 1993, prior to initiation of CR-ERP Phase 2 Sampling and Analysis activities. The organisms specified for testing were larval fathead minnows, Pimephales promelas, and the daphnid, Ceriodaphnia dubia. Surface water samples were collected by TVA Field Engineering personnel from Clinch River Mile 9.0 and Poplar Creek Kilometer 1.6 on April 21, 23, and 26. Samples were split and provided to the CR-ERP and TVA toxicology laboratories for testing. Exposure of test organisms to these samples resulted in no toxicity (survival, growth, or reproduction) to either species in testing conducted by TVA. Attachments to this report include: Chain of custody forms -- originals; Toxicity test bench sheets and statistical analyses; Reference toxicant test information; and Personnel training documentation.

  16. Tunneling splittings in vibrational spectra of non-rigid molecules. IX. Malonaldehyde and its isotopomers as a test case for fully coupled multidimensional tunneling dynamics

    Science.gov (United States)

    Benderskii, V. A.; Vetoshkin, E. V.; Irgibaeva, I. S.; Trommsdorff, H. P.

    2000-12-01

    Twenty one dimensional potential energy surfaces (PES) and the tunneling coordinate dependent kinematic matrices of malonaldehyde and of several of its isotopomers (D, 13C) are constructed in the low-energy region (tunneling splitting in the ground state coincides with the experimental value, the corresponding barrier height is determined as 4.30 kcal mol -1 and the vibrational spectrum of the transition state is obtained. The perturbative instanton approach developed in the previous papers of this series is used to solve the dynamical problem without reducing the number of degrees of freedom. The role of all 20 transverse vibrations in proton tunneling is characterized. The tunneling path and globally uniform semiclassical wave functions are evaluated from the fourth-order Hamilton-Jacobi equation and the second-order transport equation. Tunneling splittings in the ground and low-lying excited states are calculated and isotope effects of H/D and 13C/12C substitutions are predicted.

  17. Analysis of the Blast Vibration Test in Malanzhuang Iron Mine%马兰庄铁矿爆破震动测试分析

    Institute of Scientific and Technical Information of China (English)

    张云鹏; 张荣; 王中华

    2001-01-01

    为评价马兰庄铁矿深孔爆破对采场200 m外村庄的影响,对马兰庄铁矿爆破震动进行了观测,分析了爆破地震波传播规律,微差爆破地震波叠加情况及爆破震动对居民心理的影响等,提出了减少爆破震动的方法和措施。%  Abstract To evaluate the effect of the deep hole blast on the villages 200 m away from Malanzhuang Iron Mine,the observation of the blast vibration in Malanzhuang Iron Mine was made,the propagation law of the blast-caused seismic wave,the seismic wave superimposition of short-delay blasting and the affect of blast vibration on the residents' psychology are analyzed.The method and measures for reducing the blast vibration are suggested.

  18. Ambient Dried Aerogels

    Science.gov (United States)

    Jones, Steven M.; Paik, Jong-Ah

    2013-01-01

    A method has been developed for creating aerogel using normal pressure and ambient temperatures. All spacecraft, satellites, and landers require the use of thermal insulation due to the extreme environments encountered in space and on extraterrestrial bodies. Ambient dried aerogels introduce the possibility of using aerogel as thermal insulation in a wide variety of instances where supercritically dried aerogels cannot be used. More specifically, thermoelectric devices can use ambient dried aerogel, where the advantages are in situ production using the cast-in ability of an aerogel. Previously, aerogels required supercritical conditions (high temperature and high pressure) to be dried. Ambient dried aerogels can be dried at room temperature and pressure. This allows many materials, such as plastics and certain metal alloys that cannot survive supercritical conditions, to be directly immersed in liquid aerogel precursor and then encapsulated in the final, dried aerogel. Additionally, the metalized Mylar films that could not survive the previous methods of making aerogels can survive the ambient drying technique, thus making multilayer insulation (MLI) materials possible. This results in lighter insulation material as well. Because this innovation does not require high-temperature or high-pressure drying, ambient dried aerogels are much less expensive to produce. The equipment needed to conduct supercritical drying costs many tens of thousands of dollars, and has associated running expenses for power, pressurized gasses, and maintenance. The ambient drying process also expands the size of the pieces of aerogel that can be made because a high-temperature, high-pressure system typically has internal dimensions of up to 30 cm in diameter and 60 cm in height. In the case of this innovation, the only limitation on the size of the aerogels produced would be in the ability of the solvent in the wet gel to escape from the gel network.

  19. 两环路核电厂试验支管振动疲劳研究%Vibration Fatigue Study of the Testing Branch Pipes in Two-Loop Nuclear Power Plants

    Institute of Scientific and Technical Information of China (English)

    段永强; 黄学孔; 曾畅; 王帅; 蔡志云

    2015-01-01

    As for the vibration fatigue problems existed in branch pipesused for test of domestic generation Ⅱ+ two-loop nuclear power plant, a measurement and calculation analysis method for identifying fatigue vibration is proposed, which is applied to carry out condition analysis, vibration measurement and maximum effective vibration speed calculation for small branch pipes of a domestic two-loop nuclear power plant. At the same time, the structural mechanics fi-nite element application program ANSYS is used to analyze the vibration fatigue stress of small branch pipes. The result shows that this method can diagnose the first type and the second type of sensitive pipes existed in small branch pipes. Thus, it can provide the theoreticalbasis for de-termining whether there are sensitive pipes in the branch pipes used for test of two-loop nuclear power plant.%针对国内二代改进型的两环路核电厂试验用支管中存在的振动疲劳问题,文章提出了一种确定疲劳振动的测量和计算分析方法,并运用该方法对国内某两环路核电厂小支管进行了工况分析、振动测量和最大有效振动速度计算,同时采用结构力学有限元程序ANSYS软件对小支管的振动疲劳应力进行了分析.结果表明,该方法能够很好地诊断出小支管中存在的第一类敏感管和第二类敏感管,从而为判断在两环路核电厂试验中支管是否为敏感管提供了理论依据.

  20. 两环路核电厂试验支管振动疲劳研究%A Vibration Fatigue Study of the Testing Branch Pipes in Two-Loop Nuclear Power Plants

    Institute of Scientific and Technical Information of China (English)

    段永强; 黄学孔; 曾畅; 王帅; 蔡志云

    2015-01-01

    针对国内二代加的两环路核电厂试验用支管中存在的振动疲劳问题,提出了一种确定疲劳振动的测量和计算分析方法,并运用该方法对国内某两环路核电厂小支管进行了工况分析、振动测量和最大有效振动速度计算,同时采用结构力学有限元程序ANSYS软件对小支管的振动疲劳应力进行了分析.结果表明,该方法能够很好的诊断出小支管中存在的第一类敏感管和第二类敏感管,从而为判断在两环路核电厂中试验中支管是否是敏感管提供了理论依据.%As for the vibration fatigue problems existed in branch pipes used for domestic 2rd+ generation two-loop nuclear power plant testing,a measurement and calculation anal-ysis method for identifying fatigue vibration is proposed,which is applied to carry out con-ditions analysis,vibration measurement and maximum effective vibration speed calculation for small branch pipes of a domestic two-loop nuclear power plant. At the same time,the structural mechanics finite element application program ANSYS is used to analyze the vi-bration fatigue stress of small branch pipes. The result shows,this method can diagnose the first type of sensitive pipes and the second type of sensitive pipes existed in small branch pipes,thus, it can provide theoretical basis for determining whether there are sensitive pipes in the branch pipes used for two-loop nuclear power plant testing.

  1. Vibration Fatigue Study of the Testing Branch Pipes in Two-Loop Nuclear Power Plants%两环路核电厂试验支管振动疲劳研究

    Institute of Scientific and Technical Information of China (English)

    段永强; 黄学孔; 曾畅; 王帅; 蔡志云

    2015-01-01

    As for the vibration fatigue problems existed in branch pipesused for test of domestic generation Ⅱ+ two-loop nuclear power plant, a measurement and calculation analysis method for identifying fatigue vibration is proposed, which is applied to carry out condition analysis, vibration measurement and maximum effective vibration speed calculation for small branch pipes of a domestic two-loop nuclear power plant. At the same time, the structural mechanics fi-nite element application program ANSYS is used to analyze the vibration fatigue stress of small branch pipes. The result shows that this method can diagnose the first type and the second type of sensitive pipes existed in small branch pipes. Thus, it can provide the theoreticalbasis for de-termining whether there are sensitive pipes in the branch pipes used for test of two-loop nuclear power plant.%针对国内二代改进型的两环路核电厂试验用支管中存在的振动疲劳问题,文章提出了一种确定疲劳振动的测量和计算分析方法,并运用该方法对国内某两环路核电厂小支管进行了工况分析、振动测量和最大有效振动速度计算,同时采用结构力学有限元程序ANSYS软件对小支管的振动疲劳应力进行了分析.结果表明,该方法能够很好地诊断出小支管中存在的第一类敏感管和第二类敏感管,从而为判断在两环路核电厂试验中支管是否为敏感管提供了理论依据.

  2. Active Vibration Damping of Solar Arrays

    Science.gov (United States)

    Reinicke, Gunar; Baier, Horst; Grillebeck, Anton; Scharfeld, Frank; Hunger, Joseph; Abou-El-Ela, A.; Lohberg, Andreas

    2012-07-01

    Current generations of large solar array panels are lightweight and flexible constructions to reduce net masses. They undergo strong vibrations during launch. The active vibration damping is one convenient option to reduce vibration responses and limit stresses in facesheets. In this study, two actuator concepts are used for vibration damping. A stack interface actuator replaces a panel hold down and is decoupled from bending moments and shear forces. Piezoelectric patch actuators are used as an alternative, where the number, position and size of actuators are mainly driven by controllability analyses. Linear Quadratic Gaussian control is used to attenuate vibrations of selected mode shapes with both actuators. Simulations as well as modal and acoustic tests show the feasibility of selected actuator concepts.

  3. Physiology responses of Rhesus monkeys to vibration

    Science.gov (United States)

    Hajebrahimi, Zahra; Ebrahimi, Mohammad; Alidoust, Leila; Arabian Hosseinabadi, Maedeh

    Vibration is one of the important environmental factors in space vehicles that it can induce severe physiological responses in most of the body systems such as cardiovascular, respiratory, skeletal, endocrine, and etc. This investigation was to assess the effect of different vibration frequencies on heart rate variability (HRV), electrocardiograms (ECG) and respiratory rate in Rhesus monkeys. Methods: two groups of rhesus monkey (n=16 in each group) was selected as control and intervention groups. Monkeys were held in a sitting position within a specific fixture. The animals of this experiment were vibrated on a table which oscillated right and left with sinusoidal motion. Frequency and acceleration for intervention group were between the range of 1 to 2000 Hz and +0.5 to +3 G during 36 weeks (one per week for 15 min), respectively. All of the animals passed the clinical evaluation (echocardiography, sonography, radiography and blood analysis test) before vibration test and were considered healthy and these tests repeated during and at the end of experiments. Results and discussions: Our results showed that heart and respiratory rates increased significantly in response to increased frequency from 1 to 60 Hz (p controls. There were no significant differences in heart and respiratory rate from 60 t0 2000 Hz among studied groups. All monkeys passed vibration experiment successfully without any arrhythmic symptoms due to electrocardiography analysis. Conclusion: Our results indicate that vibration in low frequency can effect respiratory and cardiovascular function in rhesus monkey. Keywords: Vibration, rhesus monkey, heart rate, respiratory rate

  4. Vibration of hydraulic machinery

    CERN Document Server

    Wu, Yulin; Liu, Shuhong; Dou, Hua-Shu; Qian, Zhongdong

    2013-01-01

    Vibration of Hydraulic Machinery deals with the vibration problem which has significant influence on the safety and reliable operation of hydraulic machinery. It provides new achievements and the latest developments in these areas, even in the basic areas of this subject. The present book covers the fundamentals of mechanical vibration and rotordynamics as well as their main numerical models and analysis methods for the vibration prediction. The mechanical and hydraulic excitations to the vibration are analyzed, and the pressure fluctuations induced by the unsteady turbulent flow is predicted in order to obtain the unsteady loads. This book also discusses the loads, constraint conditions and the elastic and damping characters of the mechanical system, the structure dynamic analysis, the rotor dynamic analysis and the system instability of hydraulic machines, including the illustration of monitoring system for the instability and the vibration in hydraulic units. All the problems are necessary for vibration pr...

  5. DOWNHOLE VIBRATION MONITORING & CONTROL SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Martin E. Cobern

    2004-08-31

    The deep hard rock drilling environment induces severe vibrations into the drillstring, which can cause reduced rates of penetration (ROP) and premature failure of the equipment. The only current means of controlling vibration under varying conditions is to change either the rotary speed or the weight-on-bit (WOB). These changes often reduce drilling efficiency. Conventional shock subs are useful in some situations, but often exacerbate the problems. The objective of this project is development of a unique system to monitor and control drilling vibrations in a ''smart'' drilling system. This system has two primary elements: (1) The first is an active vibration damper (AVD) to minimize harmful axial, lateral and torsional vibrations. The hardness of this damper will be continuously adjusted using a robust, fast-acting and reliable unique technology. (2) The second is a real-time system to monitor drillstring vibration, and related parameters. This monitor adjusts the damper according to local conditions. In some configurations, it may also send diagnostic information to the surface via real-time telemetry. The AVD is implemented in a configuration using magnetorheological (MR) fluid. By applying a current to the magnetic coils in the damper, the viscosity of the fluid can be changed rapidly, thereby altering the damping coefficient in response to the measured motion of the tool. Phase I of this program entailed modeling and design of the necessary subsystems and design, manufacture and test of a full laboratory prototype. Phase I of the project was completed by the revised end date of May 31, 2004. The objectives of this phase were met, and all prerequisites for Phase II have been completed.

  6. Static renewal tests using Pimephales promelas (fathead minnows) and Ceriodaphnia dubia (daphnids). Clinch River-Environmental Restoration Program (CR-ERP) study, ambient water toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Simbeck, D.J.

    1994-12-31

    Clinch River-Environmental Restoration Program (CR-ERP) personnel and Tennessee Valley Authority (TVA) personnel conducted a study during the week of January 25--February 1, 1994. The organisms specified for testing were larval fathead minnows, Pimephales promelas, and the daphnid, Ceriodaphnia dubia. Surface water samples were collected from Clinch River Mile 9.0, Poplar Creek Mile 1.0, and Poplar Creek Mile 2.9 on January 24, 26, and 28. Samples were partitioned and provided to the CR-ERP and TVA toxicology laboratories for testing. Exposure of test organisms to these samples resulted in no toxicity (survival or growth) to fathead minnows; however, toxicity to daphnids was demonstrated in undiluted samples from Poplar Creek Mile 1.0 in testing conducted by TVA based on hypothesis testing of data. Point estimation (IC{sub 25}) analysis of the data, however, showed no toxicity in PCM 1.0 samples. Attachments to this report include: Chain of custody forms -- originals; Toxicity test bench sheets and statistical analyses; Meter calibrations; and Reference toxicant test information.

  7. Composite indices applied to vibration data in rolling tires to detect bead area damage

    Science.gov (United States)

    Johnson, T. J.; Adams, D. E.

    2007-07-01

    The primary objective of this research was to identify an online indicator of tire bead area separation for use in tire durability testing. The dynamics of tires with asymmetric bead area damage and the transmission of vibrations to an axle housing were studied. Experimental results from online data collected on a 67-in diameter roadwheel and a 120-in diameter roadwheel are presented. Statistical measures, trends in frequency content and transient wavelet maps, and composite damage indices were all evaluated as online damage detection features. Trends in statistical measures and frequency content were both indicative of damage progression, but were also sensitive to changes in test conditions. Wavelet maps were indicative of damage progression and showed potential for locating damage circumferentially on a tire. Wavelet analysis of data from both roadwheels indicated that damage increased the amount of higher frequency content in the response signals measured at the spindle arm and axle housing. The increase in broadband content was thought to come from transient vibrations generated when the damaged bead area passed through the contact patch. Composite damage indices that combined frequency and spatial data provided very clear indicators of potential damage initiation events, even predicting the number of ruptures, by drawing out the relevant information in the signals from the ambient vibration. The most effective composite indices multiplied several data signals such that only when all data signals indicated a change would the composite indices also indicate that damage had occurred.

  8. A new occurrence of ambient inclusion trails from the ~1900-million-year-old Gunflint Formation, Ontario: nanocharacterization and testing of potential formation mechanisms.

    Science.gov (United States)

    Wacey, D; Saunders, M; Kong, C; Kilburn, M R

    2016-09-01

    Ambient inclusion trails (AITs) are tubular microstructures thought to form when a microscopic mineral crystal is propelled through a fine-grained rock matrix. Here, we report a new occurrence of AITs from a fossilized microbial mat within the 1878-Ma Gunflint Formation, at Current River, Ontario. The AITs are 1-15 μm in diameter, have pyrite as the propelled crystal, are infilled with chlorite and have been propelled through a microquartz (chert) or chlorite matrix. AITs most commonly originate at the boundary between pyrite- and chlorite-rich laminae and chert-filled fenestrae, with pyrite crystals propelled into the fenestrae. A subset of AITs originate within the fenestrae, rooted either within the chert or within patches of chlorite. Sulphur isotope data ((34) S/(32) S) obtained in situ from AIT pyrite have a δ(34) S of -8.5 to +8.0 ‰, indicating a maximum of ~30 ‰ fractionation from Palaeoproterozoic seawater sulphate (δ(34) S ≈ +20 ‰). Organic carbon is common both at the outer margins of the fenestrae and in patches of chlorite where most AITs originate, and can be found in smaller quantities further along some AITs towards the terminal pyrite grain. We infer that pyrite crystals now found within the AITs formed via the action of heterotrophic sulphate-reducing bacteria during early diagenesis within the microbial mat, as pore waters were becoming depleted in seawater sulphate. Gases derived from this process such as CO2 and H2 S were partially trapped within the microbial mat, helping produce birds-eye fenestrae, while rapid microquartz precipitation closed porosity. We propose that propulsion of the pyrite crystals to form AITs was driven by two complementary mechanisms during burial and low-grade metamorphism: firstly, thermal decomposition of residual organic material providing CO2 , and potentially CH4 , as propulsive gases, plus organic acids to locally dissolve the microquartz matrix; and secondly, reactions involving clay minerals that

  9. CRBRP flow induced vibration program

    International Nuclear Information System (INIS)

    The program to assure the structural adequacy of Clinch River Breeder Reactor (CRBRP) components during its planned 30 years of operation is described. The program includes (1) an assessment of reactor components relative to their susceptibility to FIV, (2) designing to minimize component excitation due to Fluid induced vibrations (FIV), (3) scale model tests to measure structural response during simulated operating conditions and (4) preoperational tests. An overview of the CRBRP test program is described. Additionally, details of scale model testing of reactor internals and the steam generator is described in more detail. (author)

  10. Period of vibration of axially vibrating truly nonlinear rod

    Science.gov (United States)

    Cveticanin, L.

    2016-07-01

    In this paper the axial vibration of a muscle whose fibers are parallel to the direction of muscle compression is investigated. The model is a clamped-free rod with a strongly nonlinear elastic property. Axial vibration is described by a nonlinear partial differential equation. A solution of the equation is constructed for special initial conditions by using the method of separation of variables. The partial differential equation is separated into two uncoupled strongly nonlinear second order differential equations. Both equations, with displacement function and with time function are exactly determined. Exact solutions are given in the form of inverse incomplete and inverse complete Beta function. Using boundary and initial conditions, the frequency of vibration is obtained. It has to be mentioned that the determined frequency represents the exact analytic description for the axially vibrating truly nonlinear clamped-free rod. The procedure suggested in this paper is applied for calculation of the frequency of the longissimus dorsi muscle of a cow. The influence of elasticity order and elasticity coefficient on the frequency property is tested.

  11. Mujer y medio ambiente

    OpenAIRE

    Zuluaga Sánchez, Gloria Patricia

    1998-01-01

    El debate sobre mujer y medio ambiente es bastante nuevo y, por lo tanto, aun no hay consenso sobre como abordarlo, ni análisis muy profundos sobre la interacción de estas dos problemáticas tan complejas y que además atraviesan las demás temáticas. Con ello no se quiere negar el importante aporte que se ha hecho en tal sentido, por parte de colectividades y de algunas personas. Selene Herculano y Jacqueline Pitanguy (1993), mencionan que el medio ambiente no es una categoría específica y que ...

  12. Laser measurement method of forced vibration in optical systems

    International Nuclear Information System (INIS)

    A forced vibration measurement method by laser combining the laser signal and high frequency CCD in optical systems is introduced. The method solves the conversion problem between the vibration signal and laser signal in optical systems, which can not only measure the impact of vibration on the beam stability, but also acquire the frequency characteristics of vibration signals. Forced vibration in an optical system is measured when the frequencies of vibration signals are 150 Hz and 200 Hz by using the method and the attributes of the vibration signals obtained fits those of the input signals. Test and analysis results demonstrate that the method has a time amplitude uncertainty of 6.25 μm and frequency resolution of 2 Hz. The handy and efficient method, whose measurement is precise, has been applied to the beam pointing stability study of the multiplexing excimer MOPA laser targeting test platform accordingly. (authors)

  13. Tests for a whole-spacecraft vibration isolation platform using a magnetorheological damper%采用磁流变阻尼器的整星隔振平台试验研究

    Institute of Scientific and Technical Information of China (English)

    涂奉臣; 张洋; 陈照波; 焦映厚; 刘文涛

    2012-01-01

    为降低卫星受到的来自于运载火箭的振动和冲击载荷,针对柔性卫星整体隔振,提出一种采用高频解耦型磁流变阻尼器的新型整星隔振平台.在理论分析的基础上,设计并制造了新型整星隔振平台、锥壳适配器和模拟卫星,搭建整星隔振系统,进行整星隔振性能试验.对比采用新型整星隔振平台、采用常规磁流变阻尼器隔振平台和采用锥壳适配器时的隔振效果,得到如下结论:新型整星隔振系统的隔振效果明显好于使用传统锥壳适配器时的情况;采用高频解耦型阻尼器能帮助隔振平台减小高频传递率,改善高频隔振性能.试验结果验证了理论分析的正确性.%In order to reduce all kinds of vibration and impact load exerted on a satellite and coming from its carrier rocket, here, a new semi-active whole-spacecraft vibration isolation ( WSVI) platform was presented. In the WSVI platform, the magneto-rheological ( MR) damping technique was adopted and utilized. The proposed WSVIP and the satellite model were designed and manufactured, and then the WSVI system was assembled. The tests of WSVI were conducted. Furthermore, the isolation performances of the WSVI system, a conventional MR damper vibration isolation platform and a conical adapter were evaluated and compared. The results showed that the passive isolation effect of the WSVI system is significantly better than that of the conical adapter; high-frequency decoupled MR dampers in the WSVI system can help the vibration isolation platform to reduce high frequency transmission rate and improve high frequency vibration isolation performance.

  14. 非埋式桩板路基动力特性原位激振试验研究%In-situ forced vibration tests on dynamic characteristics of non-embedded pile-board subgrade

    Institute of Scientific and Technical Information of China (English)

    白皓; 苏谦; 黄俊杰; 郑键斌; 王迅

    2012-01-01

    In-situ vibration test of non-embedded pile-board subgrade needs to be carried out because this structure's dynamic characteristics are quite different from normal subgrade. DTS-1 dynamic test system is used to test the vibration response, internal force and settlement of a subgrade section in Zhengzhou-Xi'an Passenger Dedicated Line. Result shows that sympathetic vibration will not happen in range of exciting frequency, and subgrade settlement mainly happens on loading plate and will be basically stable after 0.7 million times' loading with a final settlement of 1.0mm after 1 million times' loading. Comprehensive dynamic stiffness is related to thickness of board, span, piles and soil, which can provide well vibration characteristics and long-term dynamic stability for the combining structure of pile-board structure, subgrade and foundation.%非埋式桩板结构嵌入路基形成刚性路基结构体系,导致路基结构动态性能发生较大的变化,因此,有必要对其进行专门的原位激振试验研究.利用DTS-1动力试验系统,对郑西客运专线桩板路基试验段进行原位激振试验,测定路基各断面的振动响应、结构内力和累积沉降等,分析非埋式桩板路基的振动特性和动力稳定性.结果表明,非埋式桩板路基在激振频率范围内未发生共振现象,且具有良好的长期稳定性;桩板结构累积沉降主要是由承载板变形引起的,加载75×104次后基本上趋于稳定,加载100×104次后最大累积沉降为1.0 mm;非埋式桩板路基综合动刚度与板厚、跨度、桩基和桩周土等有关,由桩板结构、路堤和地基构成的刚性路基结构体系具有良好的振动特性和长期动力稳定性.

  15. Energy scavenging from environmental vibration.

    Energy Technology Data Exchange (ETDEWEB)

    Galchev, Tzeno (University of Michigan); Apblett, Christopher Alan; Najafi, Khalil (University of Michigan)

    2009-10-01

    The goal of this project is to develop an efficient energy scavenger for converting ambient low-frequency vibrations into electrical power. In order to achieve this a novel inertial micro power generator architecture has been developed that utilizes the bi-stable motion of a mechanical mass to convert a broad range of low-frequency (< 30Hz), and large-deflection (>250 {micro}m) ambient vibrations into high-frequency electrical output energy. The generator incorporates a bi-stable mechanical structure to initiate high-frequency mechanical oscillations in an electromagnetic scavenger. This frequency up-conversion technique enhances the electromechanical coupling and increases the generated power. This architecture is called the Parametric Frequency Increased Generator (PFIG). Three generations of the device have been fabricated. It was first demonstrated using a larger bench-top prototype that had a functional volume of 3.7cm3. It generated a peak power of 558{micro}W and an average power of 39.5{micro}W at an input acceleration of 1g applied at 10 Hz. The performance of this device has still not been matched by any other reported work. It yielded the best power density and efficiency for any scavenger operating from low-frequency (<10Hz) vibrations. A second-generation device was then fabricated. It generated a peak power of 288{micro}W and an average power of 5.8{micro}W from an input acceleration of 9.8m/s{sup 2} at 10Hz. The device operates over a frequency range of 20Hz. The internal volume of the generator is 2.1cm{sup 3} (3.7cm{sup 3} including casing), half of a standard AA battery. Lastly, a piezoelectric version of the PFIG is currently being developed. This device clearly demonstrates one of the key features of the PFIG architecture, namely that it is suitable for MEMS integration, more so than resonant generators, by incorporating a brittle bulk piezoelectric ceramic. This is the first micro-scale piezoelectric generator capable of <10Hz operation. The

  16. La radioactividad ambiental

    Directory of Open Access Journals (Sweden)

    Rafael Núñez-Lagos Roglá

    2011-01-01

    Full Text Available Se explican los conceptos fundamentales relacionados con la radiactividad y se utilizan para describir la radiactividad ambiental. Se explican también los isótopos de largo periodo y las principales familias radioactivas junto con la radiación cósmica y los radionucleidos cosmogénicos.

  17. Effect Of Vibration Amplitude Level On Seated Occupant Reaction Time

    Directory of Open Access Journals (Sweden)

    Amzar Azizan

    2015-08-01

    Full Text Available The past decade has seen the rapid development of vibration comfort in the automotive industry. However little attention has been paid to vibration drowsiness. Eighteen male volunteers were recruited for this experiment. Before commencing the experiment total transmitted acceleration measured at interfaces between the seat cushion and seatback to human body was adjusted to become 0.2 ms-2 r.m.s and 0.4 ms-2 r.m.s for each volunteer. Seated volunteers were exposed to Gaussian random vibration with frequency band 1-15 Hz at two level of amplitude low vibration amplitude and medium vibration amplitude for 20-minutes in separate days. For the purpose of drowsiness measurement volunteers were asked to complete 10-minutes PVT test before and after vibration exposure and rate their subjective drowsiness by giving score using Karolinska Sleepiness Scale KSS before vibration every 5-minutes interval and following 20-minutes of vibration exposure. Strong evidence of drowsiness was found as there was a significant increase in reaction time and number of lapse following exposure to vibration in both conditions. However the effect is more apparent in medium vibration amplitude. A steady increase of drowsiness level can also be observed in KSS in all volunteers. However no significant differences were found in KSS between low vibration amplitude and medium vibration amplitude. The results of this investigation suggest that exposure to vibration has an adverse effect on human alertness level and more pronounced at higher vibration amplitude. Taken together these findings suggest a role of vibration in promoting drowsiness especially at higher vibration amplitude.

  18. Vibrating fuel grapple. [LMFBR

    Science.gov (United States)

    Chertock, A.J.; Fox, J.N.; Weissinger, R.B.

    A reactor refueling method is described which utilizes a vibrating fuel grapple for removing spent fuel assemblies from a reactor core. It incorporates a pneumatic vibrator in the grapple head which allows additional withdrawal capability without exceeding the allowable axial force limit. The only moving part in the vibrator is a steel ball, pneumatically driven by a gas, such as argon, around a track, with centrifugal force created by the ball being transmitted through the grapple to the assembly handling socket.

  19. Ambient-Temperature Passive Magnetic Bearings for Flywheel Energy Storage Systems

    Science.gov (United States)

    Post, R. F.; Bender, D. A.

    2002-05-01

    Based on prior work at the Lawrence Livermore National Laboratory ambient-temperature passive magnetic bearings are being adapted for use in highpower flywheel energy storage systems developed at the Trinity Flywheel Power company. En route to this goal specialized test stands have been built and computer codes have been written to aid in the development of the component parts of these bearing systems. The Livermore passive magnetic bearing system involves three types of elements, as follows: (1) axially symmetric levitation elements, energized by permanent magnets, (2) electrodynamic stabilizers employing axially symmetric arrays of permanent magnet bars (Halbach arrays) on the rotating system, interacting with specially wound electrically shorted stator circuits, and, (3) eddy-current-type vibration dampers, employing axially symmetric rotating pole assemblies interacting with stationary metallic discs. The theory of the Livermore passive magnetic bearing concept describes specific quantitative stability criteria.

  20. Vibrational properties of uracil

    Institute of Scientific and Technical Information of China (English)

    WANG Zhiping; ZHANG Fengshou; ZENG Xianghua; ZHOU Hongyu; GU Bin; CHENG Wei

    2006-01-01

    A semiempirical molecular dynamics model is developed to study the vibrational frequencies of uracil at very low kinetic temperature by using the Fourier transform of velocity autocorrelation function of trajectories of molecular dynamics simulations. The finite difference harmonic method is used to assign the vibrational frequency of each mode. The calculated frequencies are found to be in good agreement with experimental measurements. Moreover, we make up for the lost vibrational modes in experiments self-consistently. A total of 30 vibrational modes and their corresponding frequencies are reported.

  1. Real Aperture Radar interferometry as a tool for buildings vibration monitoring: Limits and potentials from an experimental study

    Science.gov (United States)

    Luzi, Guido; Monserrat, Oriol; Crosetto, Michele

    2012-06-01

    In the last decade several researchers have dealt with the potential of radar interferometry as a remote sensing tool able to provide measurements of vibrations of large structures. More recently the technique has been consolidated thanks to the recent introduction on the market of specifically devoted radar instruments. Exploiting the interferometric capability of coherent radar, successful monitoring of bridges, towers and wind turbine powers has been achieved. This technique allowed looking at the frequency behaviour of civil structures and estimating their amplitude of displacement in the order of fraction of millimetres. The activity here described reports the results of an experimental investigation aimed at evaluating the effectiveness of a coherent Real-Aperture-Radar sensor to estimate the vibration of buildings in an urban environment, through an ambient vibration testing, where the expected amplitude vibration spans within a few to some tens of microns. Critical aspects affecting the retrieval of this information are here discussed, on the basis of some experimental data collected in the last year with a microwave interferometer working at Ku band and available on the market. Preliminary results are shown and suggestions related to the measurement procedures are discussed.

  2. EFFECTOF ISOLATION WALL USING SCRAP TIRE ON GROUND VIBRATION REDUCTION

    Science.gov (United States)

    Kashimoto, Takahiko; Kashimoto, Yusuke; Hayakawa, Kiyoshi; Matsui, Tamotsu; Fujimoto, Hiroaki

    Some countermeasure methods against the environmental ground vibration caused by some traffic vibrations have been proposed so far. The authors have developed a new type ground vibration isolation wall using scrap tire, and evaluated its effectiveness on the ground vibration reduction by full scale field tests. In this paper, the authors discussed and examined the effectiveness of the developed countermeasure method by two field tests. The one concerns on the effect of scrap tire as soft material of vibration isolation wall, and the other on the effect of the developed countermeasure method practically applied in a residential area close to monorail traffic. As the results, it was elucidated that the ground vibration of 2-3 dB was reduced in case of two times volume of the soft material, the conversion ratio of the vibration energy of the soft material to the kinetic energy was higher than that of the core material of PHC pile, the vibration acceleration of 0.19 - 1.26 gal was reduced by the developed countermeasure method in case of the monorail traffic, and the vibration reduction measured behind the isolation wall agreed well with the proposed theoretical value, together with confirming the effectiveness of the ground vibration isolation wall using scrap tire as the countermeasure method against the environmental ground vibration.

  3. Piping vibrations measured during FFTF startup

    International Nuclear Information System (INIS)

    An extensive vibration survey was conducted on the Fast Flux Test Facility piping during the plant acceptance test program. The purpose was to verify that both mechanical and flow induced vibration amplitudes were of sufficiently low level so that pipe and pipe support integrity would not be compromised over the plant design lifetime. Excitation sources included main heat transport sodium pumps, reciprocating auxiliary system pumps, EM pumps, and flow oscillations. Pipe sizes varied from one-inch to twenty-eight-inches in diameter. This paper describes the test plan; the instrumentation and procedures utilized; and the test results

  4. Data Management Techniques for Blade Vibration Analysis

    Directory of Open Access Journals (Sweden)

    Przysowa Radosław

    2016-07-01

    Full Text Available Well-designed procedures are required to handle large amounts of data, generated by complex measurement systems used in engine tests. The paper presents selected methodologies and software tools for characterisation and monitoring of blade vibration. Common file formats and data structures as well as methods to process and visualise tip-timing data are discussed. Report Generation Framework (RGF developed in Python is demonstrated as a flexible tool for processing and publishing blade vibration results.

  5. Space shuttle main engine vibration data base

    Science.gov (United States)

    Lewallen, Pat

    1987-01-01

    In order to evaluate Space Shuttle Main Engine (SSME) vibration data without having to constantly replay analog tapes, the SSME Vibration Data Base was developed. This data base contains data that have been digitized at a high sample rate for the entire test duration. It provides quick and efficient recall capabilities for numerious computation and display routines. The data base components are described as well as some of the compution and display features.

  6. PREFACE: Vibrations at surfaces Vibrations at surfaces

    Science.gov (United States)

    Rahman, Talat S.

    2011-12-01

    This special issue is dedicated to the phenomenon of vibrations at surfaces—a topic that was indispensible a couple of decades ago, since it was one of the few phenomena capable of revealing the nature of binding at solid surfaces. For clean surfaces, the frequencies of modes with characteristic displacement patterns revealed how surface geometry, as well as the nature of binding between atoms in the surface layers, could be different from that in the bulk solid. Dispersion of the surface phonons provided further measures of interatomic interactions. For chemisorbed molecules on surfaces, frequencies and dispersion of the vibrational modes were also critical for determining adsorption sites. In other words, vibrations at surfaces served as a reliable means of extracting information about surface structure, chemisorption and overlayer formation. Experimental techniques, such as electron energy loss spectroscopy and helium-atom-surface scattering, coupled with infra-red spectroscopy, were continually refined and their resolutions enhanced to capture subtleties in the dynamics of atoms and molecules at surfaces. Theoretical methods, whether based on empirical and semi-empirical interatomic potential or on ab initio electronic structure calculations, helped decipher experimental observations and provide deeper insights into the nature of the bond between atoms and molecules in regions of reduced symmetry, as encountered on solid surfaces. Vibrations at surfaces were thus an integral part of the set of phenomena that characterized surface science. Dedicated workshops and conferences were held to explore the variety of interesting and puzzling features revealed in experimental and theoretical investigations of surface vibrational modes and their dispersion. One such conference, Vibrations at Surfaces, first organized by Harald Ibach in Juelich in 1980, continues to this day. The 13th International Conference on Vibrations at Surfaces was held at the University of

  7. EMBEDDED COMPUTER BASED ACTIVE VIBRATION CONTROL SYSTEM FOR VIBRATION REDUCTION OF FLEXIBLE STRUCTURES

    Directory of Open Access Journals (Sweden)

    Venkata Ratnam Tatavolu

    2013-01-01

    Full Text Available Research on Active Vibration Control System (AVCS is being carried out to reduce structural vibrations caused by unwanted vibrations in many application areas such as in space, aircraft structures, satellites, automobiles and civil structures (bridges, particularly at low frequencies. The unwanted vibration may cause damage to the structure or degradation to the structure’s performance. The AVCS comprises physical plant, a sensor to detect the source vibration, a DSP based electronic controller using an actuator connected to the structure generates a counter force that is appropriately out of phase but equal in amplitude to the source vibration. As a result two equal and opposite forces cancel each other by the principle of super position and structure stops vibrating. The main objective of this research work is to develop an embedded computer based real time AVCS for reducing low frequency tonal vibration response of a vibrating flexible cantilever beam by automatic modification of the vibrating beam’s structural response and to verify the performance of the developed system experimentally. The developed AVCS is a generic design platform that can be applied for designing adaptive feed forward AVC and feedback AVC. This study presents the vibration control methodology adapted for reducing tonal vibration generated by a sine generator connected to the primary source actuator attached to one end of the cantilever beam. The secondary actuator is attached to the beam on the other end through the AVCS to reduce primary vibration by destructive interference with the original response of the system, caused by the primary source of vibration. Adaptive feed forward Active Vibration Control (AVC technique is used with Filtered-X Least Mean Square (FxLMS algorithm using FIR digital filter. A cantilever beam was considered as plant and embedded computer based AVCS was tested and evaluated using an experimental setup. The experimental results are

  8. Numerical analysis and tests for vibration response of a reciprocating compressor%往复式压缩机振动的有限元数值分析与实验研究

    Institute of Scientific and Technical Information of China (English)

    仲崇明; 万泉; 蒋伟康

    2011-01-01

    对某型往复式冰箱压缩机的振动进行了有限元数值模拟,研究了曲轴-连杆-活塞运动系统产生的机械激励引起的压缩机振动响应.研究表明,曲轴-连杆-活塞运动系统是压缩机低频振动的主要激励来源,气体力主要引起压缩机泵体的水平扭转振动.通过仿真结果和试验的对比,验证了数值模拟方法应用于压缩机振动响应分析的可行性.通过数值模拟,可得到机械激励引起的壳体表面振速分布,为压缩机的机械噪声预测提供参考.%The FEM method was used to study vibration response of a reciprocating compressor excited by mechanical excitations of a crank-connectingrod-piston system. It was shown that the crank-connectingrod-piston system is the main excitation source for low-frequency vibration of the reciprocating compressor, and the gas force is the main cause of the horizontally torsional vibration of its pump body. Some tests were implemented to validate the feasibility of the FEM method in the dynamic response analysis of the reciprocating compressor. The normal velocity distributions on the compressor shell due to the mechanical excitations were obtained with FEM method, on their basis the prediction of the mechanical noise became possible for the reciprocating compressor.

  9. Vibration characteristics of BWR primary containment vessel

    International Nuclear Information System (INIS)

    This paper reports on a part of a seismic proving test of a BWR Primary Containment Vessel (PCV), a vibration analysis that is carried out considering the effect of reinforcement around attached masses such as equipment hatches and a personnel airlock. A deflected shape with the local attached masses and reinforcement is expanded using free vibration modes of an axisymmetric PCV without attached masses and reinforcement. The free vibration modes are calculated considering a coupling effect between the PCV shell and suppression pool water using conical shell finite elements and ring fluid elements. The same expanding functions and free vibration modes are used to express strain energy, kinetic energy and work done by inertia forces due to input acceleration considering locally varying thickness of the PCV and attached masses. The equations of motion are obtained by substituting the strain energy, kinetic energy, and work done by inertia forces into the Lagrange's equation. Calculated natural frequencies, free vibration modes and frequency response functions are compared with numerical results obtained by a general shell finite element analysis and with test results using the large-scale high-performance vibration table of Tadotsu Engineering Laboratory, Nuclear Power Engineering Test Center (NUPEC). The comparison shows a reasonable agreement, leading to better understanding of the dynamic characteristics of the BWR PCV

  10. Bevel Gearbox Fault Diagnosis using Vibration Measurements

    Directory of Open Access Journals (Sweden)

    Hartono Dennis

    2016-01-01

    Full Text Available The use of vibration measurementanalysis has been proven to be effective for gearbox fault diagnosis. However, the complexity of vibration signals observed from a gearbox makes it difficult to accurately detectfaults in the gearbox. This work is based on a comparative studyof several time-frequency signal processing methods that can be used to extract information from transient vibration signals containing useful diagnostic information. Experiments were performed on a bevel gearbox test rig using vibration measurements obtained from accelerometers. Initially, thediscrete wavelet transform was implementedfor vibration signal analysis to extract the frequency content of signal from the relevant frequency region. Several time-frequency signal processing methods werethen incorporated to extract the fault features of vibration signals and their diagnostic performances were compared. It was shown thatthe Short Time Fourier Transform (STFT could not offer a good time resolution to detect the periodicity of the faulty gear tooth due the difficulty in choosing an appropriate window length to capture the impulse signal. The Continuous Wavelet Transform (CWT, on the other hand, was suitable to detection of vibration transients generated by localized fault from a gearbox due to its multi-scale property. However, both methods still require a thorough visual inspection. In contrast, it was shown from the experiments that the diagnostic method using the Cepstrumanalysis could provide a direct indication of the faulty tooth without the need of a thorough visual inspection as required by CWT and STFT.

  11. Vibration test system for finisher cantilever based on LabVIEW%基于LabVIEW的光饰机悬臂梁振动测试系统

    Institute of Scientific and Technical Information of China (English)

    侯志敏; 邓东花; 夏薇

    2012-01-01

    Based on the graphical virtual instrument programming platform of American NI Company, a virtual vibration measurement instrument is developed for cantilever of finisher. The design of the programming is introduced, including the hardware and software. The system has function of real-time data acquisition, time-frequency domain analysis, data storage and playback.%以基于美国NI公司的LabVIEW为开发平台,针对光饰机悬臂梁的振动,开发了虚拟机械振动信号测试仪,包括虚拟振动仪器的软硬件组成及程序设计,可完成振动信号的实时采集、时域频域分析,以及数据存储和回放功能.

  12. Hybrid isolation of micro vibrations induced by reaction wheels

    Science.gov (United States)

    Lee, Dae-Oen; Park, Geeyong; Han, Jae-Hung

    2016-02-01

    As the technology for precision satellite payloads continues to advance, the requirements for the pointing stability of the satellites are becoming extremely high. In many situations, even small amplitude disturbances generated by the onboard components may cause serious degradation in the performance of high precision payloads. In such situations, vibration isolators can be installed to reduce the vibration transmission. In this work, a hybrid vibration isolator comprising passive and active components is proposed to provide an effective solution to the vibration problems caused by the reaction wheel disturbances. Firstly, mathematical modeling and experimental study of a single axis vibration isolator having high damping and high roll-off rate for the high frequency region and active components that enhance isolation performance for narrow frequency bands are presented. This concept is then extended to multi-axis by forming Stewart platform and the performance is experimentally verified. The tests on a flexible testbed show effective vibration isolation by the proposed vibration isolator.

  13. Damage monitoring and impact detection using optical fiber vibration sensors

    Science.gov (United States)

    Yang, Y. C.; Han, K. S.

    2002-06-01

    Intensity-based optical fiber vibrations sensors (OFVSs) are used in damage monitoring of fiber-reinforced plastics, in vibration sensing, and location of impacts. OFVSs were constructed by placing two cleaved fiber ends in a capillary tube. This sensor is able to monitor structural vibrations. For vibration sensing, the optical fiber sensor was mounted on the carbon fiber reinforced composite beam, and its response was investigated for free and forced vibration. For locating impact points, four OFVSs were placed at chosen positions and the different arrival times of impact-generated vibration signals were recorded. The impact location can be determined from these time delays. Indentation and tensile tests were performed with the measurement of the optical signal and acoustic emission (AE). The OFVSs accurately detected both free and forced vibration signals. Accurate locations of impact were determined on an acrylate plate. It was found that damage information, comparable in quality to AE data, could be obtained from the OFVS signals.

  14. Vibration Superposition in Tunnel Blasting with Millisecond Delay

    Institute of Scientific and Technical Information of China (English)

    ZHENG Jun-jie; LOU Xiao-ming; LUO De-pi

    2009-01-01

    According to explosion dynamics and elastic wave theory,the models of particle vibration velocity for simultaneous blasting and millisecond blasting are built.In the models,influential factors such as delay interval and charge quantity,are considered.The calculated vibration velocity is compared with the field test results,which shows that the theoretical values are close to the experimental ones.Meanwhile,the particle vibration velocity decreases quickly with time due to the damping of rock mass and has a harmonic motion,and the particle vibration velocity of millisecond blasting has short interval.The superposition of particle vibration velocities may reduce vibration because of wave interference,or magnify the surrounding rock response to the blasting-induced vibration.

  15. Ambient Air Quality Data Inventory

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Office of Air and Radiation's (OAR) Ambient Air Quality Data (Current) contains ambient air pollution data collected by EPA, other federal agencies, as well as...

  16. Ambient Air Quality Data Inventory

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Office of Air and Radiation??s (OAR) Ambient Air Quality Data (Current) contains ambient air pollution data collected by EPA, other federal agencies, as well as...

  17. DOWNHOLE VIBRATION MONITORING & CONTROL SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Martin E. Cobern

    2005-01-28

    The objective of this program is to develop a system to both monitor the vibration of a bottomhole assembly, and to adjust the properties of an active damper in response to these measured vibrations. Phase I of this program, which entailed modeling and design of the necessary subsystems and design, manufacture and test of a full laboratory prototype, was completed on May 31, 2004. The principal objectives of Phase II are: more extensive laboratory testing, including the evaluation of different feedback algorithms for control of the damper; design and manufacture of a field prototype system; and, testing of the field prototype in drilling laboratories and test wells. The redesign and upgrade of the laboratory prototype was completed on schedule and it was assembled during the last period. Testing was begin during the first week of October. Initial results indicated that the dynamic range of the damping was less than predicted and that the maximum damping was also less than required. A number of possible explanations for these results were posited, and test equipment was acquired to evaluate the various hypotheses. Testing was just underway at the end of this period.

  18. Vibration energy harvesting in railway tunnels with a wireless sensor node application

    Energy Technology Data Exchange (ETDEWEB)

    Wischke, Martin

    2012-07-01

    Vibration harvesting is a promising concept to prolong the lifetime of batterypowered stand-alone systems, or even to enable their energy-autonomy. This thesis focuses on ambient vibrations converted by electromechanical transducers into electricity. The final goal is energy scavenging from train-induced vibrations in railway tunnels. This is achieved via the development of a suitable harvester for this environment and the practical demonstration of a vibrationpowered wireless sensor node (WSN). At the beginning of this thesis, extensive vibration measurements were performed in several traffic tunnels. The obtained unique data set formed the basis for the design and test of several harvesters. The railway sleeper was chosen as usable harvester location. A shock-resistant double-side suspended piezoelectric cantilever was developed. Several cantilevers with different eigenfrequencies are combined in an array, creating a robust harvester with a broad bandwidth. A field test of 7 days in the Loetschbergbasis-tunnel verified that, on average the sufficient energy for powering a virtual wireless sensor node was scavenged. For application in a real WSN, the harvester array was scaled up to 10 cantilevers. The power management for the sensor node was developed concurrently. The central component is a power switch that monitors the energy level in the system's storage capacitor and only triggers the wireless interface when sufficient energy is available. Combined with a train detection circuit, the presented energy-autonomous WSN reliably reports every passing vehicle. In addition to the development of an energy-autonomous fully integrated WSN, this work investigates nonlinear properties of PZT ceramics. Consideration of the elastostriction and the electrostriction enables a more precises prediction of the tip displacement of a piezoelectric cantilever actuator. Further, the elastostriction is exploited to modify the resonance frequency of a bimorph cantilever. Basing

  19. Mechanical vibration and shock analysis, sinusoidal vibration

    CERN Document Server

    Lalanne, Christian

    2014-01-01

    Everything engineers need to know about mechanical vibration and shock...in one authoritative reference work! This fully updated and revised 3rd edition addresses the entire field of mechanical vibration and shock as one of the most important types of load and stress applied to structures, machines and components in the real world. Examples include everything from the regular and predictable loads applied to turbines, motors or helicopters by the spinning of their constituent parts to the ability of buildings to withstand damage from wind loads or explosions, and the need for cars to m

  20. Picking up good vibrations

    NARCIS (Netherlands)

    Eijk, A.

    2010-01-01

    The methods that need to be employed to develop the better vibration guidelines to assess the integrity of a reciprocating compressor system are discussed. An R&D project of the European Forum of Reciprocating Compressors (EFRC) has been initiated to develop guidelines for vibrations in reciprocatin

  1. Hydroelastic Vibrations of Ships

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher; Folsø, Rasmus

    2002-01-01

    A formula for the necessary hull girder bending stiffness required to avoid serious springing vibrations is derived. The expression takes into account the zero crossing period of the waves, the ship speed and main dimensions. For whipping vibrations the probability of exceedance for the combined ...

  2. Vibration Theory, Vol. 3

    DEFF Research Database (Denmark)

    Nielsen, Søren R. K.

    The present textbook has been written based on previous lecture notes 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 4th edition of this textbook on linear stochastic vibration...

  3. Vibration Theory, Vol. 3

    DEFF Research Database (Denmark)

    Nielsen, Søren R. K.

    The present textbook has been written based on previous lecture notes 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 2nd edition of this textbook on linear stochastic vibration...

  4. Estudio de la deformabilidad a temperatura ambiente de aceros de alto silicio (≥ 4 wt % Si mediante test de compresión

    Directory of Open Access Journals (Sweden)

    Houbaert, Y.

    2005-12-01

    Full Text Available Series of silicon alloys (from 3.3 to 6.3% wt Si were produced to study their workability at room temperature. Cast samples, machined into cylinders, were compressed with a servohydraulic computer driven machine at a constant strain rate. The results supplied information about the strengthening, phenomena and confirmed that the workability decreases with the higher silicon content. In addition constitutive equations were fitted from the stress-strain data. Metallographic examination showed twins which density increased with the percentage of Si.Cuatro aleaciones Fe-Si en el rango de concentraciones 3,3-6,3 wt. % Si se fabricaron para estudiar su deformabilidad en frío. A partir del material colado se prepararon probetas cilíndricas que fueron ensayadas por compresión en una máquina servo-hidraúlica diseñada para mantener constante la velocidad de deformación durante el test. Los resultados proporcionaron información sobre el endurecimiento del material y confirmaron que la deformabilidad disminuye al aumentar el contenido en silicio. A partir de las curvas esfuerzo-deformación se dedujeron ecuaciones constitutivas, cuyos parámetros resultaron ser función de la concentración de silicio. El material deformado presentó un fuerte maclaje, mayor para las aleaciones más ricas en silicio.

  5. Design of Engine Vibration Testing Signal Processing and Analyzing Software%发动机振动测试信号处理及分析软件设计

    Institute of Scientific and Technical Information of China (English)

    王银惠

    2014-01-01

    The vibration testing signal processing and analyzing software was designed based on Matlab GUI, which can batch and analyze lots of data. The software functions of signal preprocessing, signal time domain analysis, frequency domain analysis were verified by the engine suspension vibration sig-nals. It was obtained through the visualization output that the suspension vibration signal energy of the X direction was mainly concentrated in the frequency of 50 Hz,75 Hz,160 Hz, the energy of Y direction mainly in the frequency 50 Hz,160 Hz, the energy of Z direction mainly in the frequency 50 Hz,160 Hz. The coherence analysis results were greater than 0.8, which can determine that the frequency response analysis is reliable, and the amplitude frequency curve of the frequency response function can testify the engine suspension’s damping effect. The software can quickly analyze the vibration signals.%基于Matlab GUI平台设计了振动测试信号处理与分析软件,其可以快速地处理分析数据。通过某发动机悬置系统振动信号实例验证了软件的信号预处理、信号时域分析、信号频域分析功能,其可视化输出得出悬置振动信号能量在X方向主要集中在频率50 Hz、75 Hz和160 Hz左右,Y方向主要集中在频率50 Hz和160 Hz左右,Z方向主要集中在频率50 Hz和160 Hz左右。相干分析结果基本都大于0.8,判定频响分析可靠,进而通过判断悬置上下所测信号幅值大小,判定该发动机悬置减震效果。该软件能有效快速地处理分析振动信号。

  6. Development of S-wave portable vibrator; S ha potable vibrator shingen no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Kaida, Y.; Matsubara, Y. [OYO Corp., Tokyo (Japan); Nijhof, V.; Brouwer, J.

    1996-05-01

    An S-wave portable vibrator to serve as a seismic source has been developed for the purpose of applying the shallow-layer reflection method to the study of the soil ground. The author, et al., who previously developed a P-wave portable vibrator has now developed an S-wave version, considering the advantage of the S-wave over the P-wave in that, for example, the S-wave velocity may be directly compared with the N-value representing ground strength and that the S-wave travels more slowly than the P-wave through sticky soil promising a higher-resolution exploration. The experimentally constructed S-wave vibrator consists of a conventional P-wave vibrator and an L-type wooden base plate combined therewith. Serving as the monitor for vibration is a conventional accelerometer without any modification. The applicability test was carried out at a location where a plank hammering test was once conducted for reflection aided exploration, and the result was compared with that of the plank hammering test. As the result, it was found that after some preliminary treatment the results of the two tests were roughly the same but that both reflected waves were a little sharper in the S-wave vibrator test than in the plank hammering test. 4 refs., 9 figs., 1 tab.

  7. Vibrational Spectroscopy of Biomembranes

    Science.gov (United States)

    Schultz, Zachary D.; Levin, Ira W.

    2011-07-01

    Vibrational spectroscopy, commonly associated with IR absorption and Raman scattering, has provided a powerful approach for investigating interactions between biomolecules that make up cellular membranes. Because the IR and Raman signals arise from the intrinsic properties of these molecules, vibrational spectroscopy probes the delicate interactions that regulate biomembranes with minimal perturbation. Numerous innovative measurements, including nonlinear optical processes and confined bilayer assemblies, have provided new insights into membrane behavior. In this review, we highlight the use of vibrational spectroscopy to study lipid-lipid interactions. We also examine recent work in which vibrational measurements have been used to investigate the incorporation of peptides and proteins into lipid bilayers, and we discuss the interactions of small molecules and drugs with membrane structures. Emerging techniques and measurements on intact cellular membranes provide a prospective on the future of vibrational spectroscopic studies of biomembranes.

  8. Fast Bayesian approach for modal identification using free vibration data, Part I - Most probable value

    Science.gov (United States)

    Zhang, Feng-Liang; Ni, Yan-Chun; Au, Siu-Kui; Lam, Heung-Fai

    2016-03-01

    The identification of modal properties from field testing of civil engineering structures is becoming economically viable, thanks to the advent of modern sensor and data acquisition technology. Its demand is driven by innovative structural designs and increased performance requirements of dynamic-prone structures that call for a close cross-checking or monitoring of their dynamic properties and responses. Existing instrumentation capabilities and modal identification techniques allow structures to be tested under free vibration, forced vibration (known input) or ambient vibration (unknown broadband loading). These tests can be considered complementary rather than competing as they are based on different modeling assumptions in the identification model and have different implications on costs and benefits. Uncertainty arises naturally in the dynamic testing of structures due to measurement noise, sensor alignment error, modeling error, etc. This is especially relevant in field vibration tests because the test condition in the field environment can hardly be controlled. In this work, a Bayesian statistical approach is developed for modal identification using the free vibration response of structures. A frequency domain formulation is proposed that makes statistical inference based on the Fast Fourier Transform (FFT) of the data in a selected frequency band. This significantly simplifies the identification model because only the modes dominating the frequency band need to be included. It also legitimately ignores the information in the excluded frequency bands that are either irrelevant or difficult to model, thereby significantly reducing modeling error risk. The posterior probability density function (PDF) of the modal parameters is derived rigorously from modeling assumptions and Bayesian probability logic. Computational difficulties associated with calculating the posterior statistics, including the most probable value (MPV) and the posterior covariance matrix

  9. Adding steel fibres to improve shock vibration resistance of concrete

    OpenAIRE

    Kwan, AKH; Ng, IYT

    2007-01-01

    A newly developed shock vibration test method was employed to study the effects of shock vibration on steel-fibrereinforced concrete so as to explore the possibility of improving the shock vibration resistance of concrete. In total, 21 batches of concrete with steel fibre contents ranging from 0 to 4% were cast and subjected to the shock vibration test at ages of 12 h, 1 day and 7 days. The results revealed that the effectiveness of adding steel fibres to alleviate the short-term damage cause...

  10. Active vibration control of lightweight floor systems

    Science.gov (United States)

    Baader, J.; Fontana, M.

    2016-04-01

    Wide-span and lightweight floors are often prone to structural vibrations due to their low resonance frequency and poor material damping. Their dynamic behaviour can be improved using passive, semi-active or active vibration control devices. The following article proposes a novel method for the controller synthesis for active vibration control. An existing passive TMD (tuned mass damper) is modelled and equipped with an actuator in order to provide more efficient damping. Using an iterative optimization approach under constraints, an optimal controller is found which minimizes a quadratic cost function in frequency domain. A simulation of an existing test bench shows that the active vibration control device is able to provide increased damping compared to the passive TMD.

  11. Geometry determination of complexes in a molecular liquid mixture using Electron-Vibration-Vibration two-dimensional infrared spectroscopy with a vibrational transition density cube method

    OpenAIRE

    Guo, Rui; Mukamel, Shaul; Klug, David R.

    2012-01-01

    We demonstrate the use of a new vibrational transition density cube (VTDC) method for determining the geometry of complexes in a molecular liquid mixture from electron-vibration-vibration two-dimensional infrared (EVV 2DIR) spectra. The VTDC method was used to calculate the electrically-mediated intermolecular vibrational coupling and thereby the EVV 2DIR spectra. Using the 1:1 benzonitrile-phenylacetylene liquid mixture as a test case, the new method leads to a distance of 3.60 Å between the...

  12. Ambient Vibration Test and Modal Analysis for MW-class Wind Tubine Tower%兆瓦级风电机组塔筒环境脉动实测与模态分析

    Institute of Scientific and Technical Information of China (English)

    刘香; 罗桂鑫; 苗占元

    2012-01-01

      through the environmental pulsating measure in a 1.5 MW wind generator tower drum in Inner Mongolia wind farm , modeling and modal analysis of tower drum are fnished with the ANSYS fnite element software, and compared with the feld measured results, the difference is in the allowed ranged. Proper interval exists between numerical simulation and data obtained from the wind generator tower drum inherent frequencies and blade rotation excitation frequency , which meets the standard design requirements of Wind Power Generation Unit Tower.%  通过对内蒙古辉腾锡勒风电场中某1.5MW风电机组塔筒进行环境脉动实测,利用ANSYS有限元软件完成对塔筒的建模和模态分析,并与现场实测分析得到的数值进行对比,其差值在允许范围.数值模拟与实测得到的风电机组塔筒固有频率均与桨叶旋转产生的激励频率有适当的间隔,满足我国标准《风力发电机组塔架》避免共振的规定.

  13. Study on the experiments of the relationship between the geometric dimensions of flexural vibration disk and its vibration characteristics

    Directory of Open Access Journals (Sweden)

    Y. Yuan

    2006-08-01

    Full Text Available Purpose: The vibration characteristics of flexural vibration disk in ultrasonic honing system were studiedsystematically through experiments.Design/methodology/approach: The vibration of flexural vibration disk was tested using the acoustic systemof ultrasonic honing.Findings: The results showed that the amplitude of vibration disk increases with the reducing of its thickness,when the disk was thin disk (the ratio between the thickness and radius was less than or equal to one fifths thevibration of disk was flexural vibration, the good vibration effect could be obtained. The maximal amplitudecould reach 20.5μm,at the same time, the number of the wave crests and size could be obtained. There existamplifying characteristics in the vibration of the disk. When the diameter of disk was not changed, the resonantfrequency would decrease with the reducing of the thickness of disk. The resonance could be excited at differentfrequencies. The corresponding maximal amplitude value provides certain reference value for the dimensionaldesign and application of flexural vibration disk.Research limitations/implications: From analysis, the ratio between diameter and thickness of flexuralvibration disk has direct effect on amplitude. The rational diameter and thickness of flexural vibration diskshould be selected according to specific machining conditions and the size requirements of the whole honingequipment during the course of design of ultrasonic honing acoustic system.Originality/value: The studied on relationship between geometric dimensions of flexural vibration disk and itsvibration characteristics were made.

  14. Internal Temperature Control For Vibration Testers

    Science.gov (United States)

    Dean, Richard J.

    1996-01-01

    Vibration test fixtures with internal thermal-transfer capabilities developed. Made of aluminum for rapid thermal transfer. Small size gives rapid response to changing temperatures, with better thermal control. Setup quicker and internal ducting facilitates access to parts being tested. In addition, internal flows smaller, so less energy consumed in maintaining desired temperature settings.

  15. DOWNHOLE VIBRATION MONITORING & CONTROL SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Martin E. Cobern

    2004-10-29

    The objective of this program is to develop a system to both monitor the vibration of a bottomhole assembly, and to adjust the properties of an active damper in response to these measured vibrations. Phase I of this program, which entailed modeling and design of the necessary subsystems and design, manufacture and test of a full laboratory prototype, was completed on May 31, 2004. Phase II began on June 1, and the first month's effort were reported in the seventh quarterly report on the project.1 The principal objectives of Phase II are: more extensive laboratory testing, including the evaluation of different feedback algorithms for control of the damper; design and manufacture of a field prototype system; and, testing of the field prototype in drilling laboratories and test wells. The redesign and upgrade of the laboratory prototype was completed on schedule during this period, and assembly was complete at the end of this period. Testing will begin during the first week of October. This aspect of the project is thus approximately six weeks behind schedule. Design of the field prototype is progressing per schedule.

  16. Ambiente il nostro futuro

    OpenAIRE

    Canigiani, Franca

    2016-01-01

    L’ambiente è il quadro di vita, la casa comune, il patrimonio di base delle società umane – scriveva un indimenticabile maestro della geografia italiana: Giuseppe Barbieri. Due gli avvenimenti che nel 2015 hanno segnato il passo dell’umanità sulla strada di una più matura coscienza ambientale, fino a comprendere che è necessario e urgente prendersi cura della Terra: primo, la pubblicazione della lettera enciclica di papa Francesco, Laudato si’ sulla cura della casa comune, straordinario saggi...

  17. AOX y medio ambiente.

    OpenAIRE

    Riva Juan, Mª del Carmen; López Ribas, David

    1996-01-01

    Los productos organohalogenados son muy utilizados por la industria y su presencia en el medio ambiente está siendo controlada. En los últimos años se han desarrollado varias técnicas de detección, siendo desde finales de los 80 los AOX (adsorbable organic halogens) uno de los parámetros sobre los que se han realizado más estudios. En muchos paises de la Unión Europea y en E.E.U.U. de América, la presencia de compuestos organohalogenados en aguas continentales y suelos está legislada indicand...

  18. Arquitectura y medio ambiente

    OpenAIRE

    Saura Carulla, Magdalena

    2003-01-01

    La arquitectura y la planificación son el resultado de una integración ponderada de conocimientos técnicos y una multiplicidad de aspectos relacionados con el conocimiento natural y social. En este trabajo el autor propone, desde el ámbito de las ciencias del medio ambiente, diversos planteamientos teóricos y prácticos relacionados con la arquitectura y el urbanismo. El conocimiento de la naturaleza de los sistemas naturales y de los sistemas ecosociales permite al diseñador aplicar un marco ...

  19. An evaluation on low-level vibration energy harvesting using piezoelectret foam

    Science.gov (United States)

    Anton, S. R.; Farinholt, K. M.

    2012-04-01

    Energy harvesting technology is critical in the development of self-powered electronic devices. Over the past few decades, several transduction mechanisms have been investigated for harvesting various forms of ambient energy. This paper provides an investigation of a novel transducer material for vibration energy harvesting; piezoelectret foam. Piezoelectrets are cellular ferroelectret foams, which are thin, flexible polymeric materials that exhibit piezoelectric properties. The basic operational principle behind cellular ferroelectrets involves the deformation of internally charged voids in the polymer, which can be represented as macroscopic dipoles, resulting in a potential developed across the material. Both the mechanical and electromechanical properties of this material are investigated in this work. Mechanical testing is performed using traditional tensile testing techniques to obtain experimental measures of the stiffness and strength of the materials. Electromechanical testing is performed in order to establish a relationship between input mechanical energy and output electrical energy by dynamically measuring the piezoelectric constant, d33. Additionally, the properties of ferroelectret foams are compared to those of polyvinylidene fluoride (PVDF), a conventional polymer-based piezoelectric material whose crystalline phase exhibits piezoelectricity through dipole orientation. Finally, the feasibility of vibration energy harvesting using piezoelectret materials is investigated.

  20. Coherent vibrational dynamics

    CERN Document Server

    Lanzani, Guglielmo; De Silvestri, Sandro

    2007-01-01

    Vibrational spectroscopy is a powerful investigation tool for a wide class of materials covering diverse areas in physics, chemistry and biology. The continuous development in the laser field regarding ultrashort pulse generation has led to the possibility of producing light pulses that can follow vibrational motion coupled to the electronic transitions in molecules and solids in real time. Aimed at researchers and graduate students using vibrational spectroscopy, this book provides both introductory chapters as well as more advanced contents reporting on recent progress. It also provides a good starting point for scientists seeking a sound introduction to ultrafast optics and spectroscopic techniques.

  1. Implementation of large-scale shaking table test on vibration sinking pipe stone pile%振动沉管碎石桩大型振动台试验的实现

    Institute of Scientific and Technical Information of China (English)

    高博; 张鸿儒; 施烨辉

    2012-01-01

    目前有关碎石桩复合地基在动荷载作用下的研究主要是针对其排水作用,而对其密实作用的研究很少,碎石桩复合地基在动荷载作用下沉降计算理论落后于工程实践.为了在碎石桩复合地基的动力模拟试验中模拟碎石桩的密实作用,设计了大型堆叠式剪切模型箱,并采用振动沉管法在振动台模型箱中进行了碎石桩的震后沉降试验研究,结果表明其能较好地模拟碎石桩振动沉管施工工艺.%The research of stone pile composite foundation under dynamic load concentrates mainly on its drainage but not on its compactness effects. This makes that research of composite foundation settlement by dynamic load is behind its engineering practice. We designed a laminar shear model box for simulating the compactness of stone pile composite foundation, and through vibration sinking pipe stone pile technology, carried out a large-scale shaking table test to research post-earthquake settlement behaviors of stone pile composite foundation. The results show that the test is succesful in simulating construction technology of vibration sinking pipe of stone pile.

  2. Crisis ambiental y cristianismo

    Directory of Open Access Journals (Sweden)

    Felipe Cárdenas

    2008-01-01

    Full Text Available En el artículo se identifican y reconocen algunas opciones que se pueden desarrollar en el cristianismo en relación con la problemática ambiental. Se aborda el dilema bíblico suscitado por interpretaciones antiecológicas y ecológicas. Con base en una lectura de la Biblia, de testimonios cristianos, y en una rememoria de estructuras institucionales, como la parroquia, se analiza el valor que tiene el mensaje cristiano en lo referido a la mitigación de la crisis ambiental.This article identifies and recognizes some options that can be developed in Christianity in relation to the environmental problem. It starts by analyzing the biblical dilemma provoked by both ecological and antiecological interpretations. Based on a reading of the Bible, testimonies from Christians and with a rememory of institutional structures, like the parish, the valué of the Christian message for mitigating the environmental crisis is analyzed.

  3. Damping Vibration at an Impeller

    Science.gov (United States)

    Hager, J. A.; Rowan, B. F.

    1982-01-01

    Vibration of pump shaft is damped at impeller--where vibration-induced deflections are greatest--by shroud and seal. Damping reduces vibrational motion of shaft at bearings and load shaft places on them. Flow through clearance channel absorbs vibration energy.

  4. Behavior of Cell on Vibrating Micro Ridges

    Directory of Open Access Journals (Sweden)

    Haruka Hino

    2015-06-01

    Full Text Available The effect of micro ridges on cells cultured at a vibrating scaffold has been studied in vitro. Several parallel lines of micro ridges have been made on a disk of transparent polydimethylsiloxane for a scaffold. To apply the vibration on the cultured cells, a piezoelectric element was attached on the outside surface of the bottom of the scaffold. The piezoelectric element was vibrated by the sinusoidal alternating voltage (Vp-p < 16 V at 1.0 MHz generated by a function generator. Four kinds of cells were used in the test: L929 (fibroblast connective tissue of C3H mouse, Hepa1-6 (mouse hepatoma, C2C12 (mouse myoblast, 3T3-L1 (mouse fat precursor cells. The cells were seeded on the micro pattern at the density of 2000 cells/cm2 in the medium containing 10% FBS (fetal bovine serum and 1% penicillin/ streptomycin. After the adhesion of cells in several hours, the cells are exposed to the ultrasonic vibration for several hours. The cells were observed with a phase contrast microscope. The experimental results show that the cells adhere, deform and migrate on the scaffold with micro patterns regardless of the ultrasonic vibration. The effects of the vibration and the micro pattern depend on the kind of cells.

  5. Vibration enhanced quantum transport

    CERN Document Server

    Semião, F L; Milburn, G J

    2009-01-01

    In this paper, we study the role of a collective vibrational motion in the phenomenon of electronic energy transfer (EET) between chromophores with different electronic transition frequencies. Previous experimental work on EET in conjugated polymer samples has suggested that the common structural framework of the macromolecule introduce correlations in the energy gap fluctuations which cause coherent EET. We present a simple model describing the coupling between the chromophores and a common vibrational mode, and find that vibration can indeed lead to an enhancement in the transport of excitations across the quantum network. Furthermore, in our model phase information is partially retained in the transfer process from a donor to an acceptor, as experimentally demonstrated in the conjugated polymer system. Consequently, this mechanism of vibration enhanced quantum transport might find applications in quantum information transfer of qubit states or entanglement.

  6. 2008 Vibrational Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Philip J. Reid

    2009-09-21

    The conference focuses on using vibrational spectroscopy to probe structure and dynamics of molecules in gases, liquids, and interfaces. The goal is to bring together a collection of researchers who share common interests and who will gain from discussing work at the forefront of several connected areas. The intent is to emphasize the insights and understanding that studies of vibrations provide about a variety of systems.

  7. An energy harvesting system using the wind-induced vibration of a stay cable for powering a wireless sensor node

    International Nuclear Information System (INIS)

    This paper proposes an electromagnetic energy harvesting system, which utilizes the wind-induced vibration of a stay cable, and investigates its feasibility for powering a wireless sensor node on the cable through numerical simulations as well as experimental tests. To this end, the ambient acceleration responses of a stay cable installed in an in-service cable-stayed bridge are measured, and then they are used as input excitations in cases of both numerical simulations and experimental tests to evaluate the performance of the proposed energy harvesting system. The results of the feasibility test demonstrate that the proposed system generates sufficient electricity for operation of a wireless sensor node attached on the cable under the moderate wind conditions

  8. Types for BioAmbients

    Directory of Open Access Journals (Sweden)

    Sara Capecchi

    2010-02-01

    Full Text Available The BioAmbients calculus is a process algebra suitable for representing compartmentalization, molecular localization and movements between compartments. In this paper we enrich this calculus with a static type system classifying each ambient with group types specifying the kind of compartments in which the ambient can stay. The type system ensures that, in a well-typed process, ambients cannot be nested in a way that violates the type hierarchy. Exploiting the information given by the group types, we also extend the operational semantics of BioAmbients with rules signalling errors that may derive from undesired ambients' moves (i.e. merging incompatible tissues. Thus, the signal of errors can help the modeller to detect and locate unwanted situations that may arise in a biological system, and give practical hints on how to avoid the undesired behaviour.

  9. Types for BioAmbients

    CERN Document Server

    Capecchi, Sara; 10.4204/EPTCS.19.7

    2010-01-01

    The BioAmbients calculus is a process algebra suitable for representing compartmentalization, molecular localization and movements between compartments. In this paper we enrich this calculus with a static type system classifying each ambient with group types specifying the kind of compartments in which the ambient can stay. The type system ensures that, in a well-typed process, ambients cannot be nested in a way that violates the type hierarchy. Exploiting the information given by the group types, we also extend the operational semantics of BioAmbients with rules signalling errors that may derive from undesired ambients' moves (i.e. merging incompatible tissues). Thus, the signal of errors can help the modeller to detect and locate unwanted situations that may arise in a biological system, and give practical hints on how to avoid the undesired behaviour.

  10. Acoustic sensor engineering evaluation test report. [microphones for monitoring inside the space shuttle orbiter

    Science.gov (United States)

    Phillips, E. L., Jr.; Bronson, R. D.

    1976-01-01

    Two types of one-inch diameter sound pressure level sensors, which are candidates for monitoring ambient noise in the shuttle orbiter crew compartment during rest periods, were exposed to temperature, passive humidity, and vibration. One unexposed sensor of each type served as a reference unit. Except for the humidity exposures, each of the three capacitive microphones was individually tested in sequence with the essential voltage power supply and preamplifier. One unit exibited anomalous characteristics after the humidity exposure but returned to normal after being dried in an oven at 115 deg for two hours. Except for the humidity exposures, each of the three piezoelectric microphones was individually tested with a laboratory type amplifier. Two apparent failures occurred during these tests. The diaphragm on one was found ruptured after the fourth cycle of the humidity test. A second sensor showed an anomaly after the random vibration tests at which time its sensitivity was consistent at about one-half its former value.

  11. Effective harmonic oscillator description of anharmonic molecular vibrations

    Indian Academy of Sciences (India)

    Tapta Kanchan Roy; M Durga Prasad

    2009-09-01

    The validity of an effective harmonic oscillator approximation for anharmonic molecular vibrations is tested and compared with vibrational self consistent field and vibrational configurational interaction results. The effective harmonic oscillator is constructed variationally, by taking the trial wave function as a harmonic oscillator eigenfunction with the centroid and width parameter as variational paraeters. It is found that the effective harmonic oscillator approximation provides a description of the anharmonic eigenstates very similar to the vibrational self consistent field results. Coriolis coupling is also included in these studies.

  12. Vibration Analysis of Digital Radiography System for Large Container Inspection

    Institute of Scientific and Technical Information of China (English)

    黄松岭; 李路明; 周立业; 向新程; 安继刚

    2003-01-01

    The cantilever vibration characteristics of a digital radiography system were analyzed to predict the effect of vibration on the performance of a mobile container inspection system. The static deformation,vibration mode and natural frequency of the cantilever of the digital radiography system were calculated with the ALGOR Finite Element System to verify the strength and rigidity of the cantilever. The maximum amplitude of the cantilever vibration occurs as it starts accelerating. The predictions show good agreement with test results, indicating that the finite element model of the cantilever structure accurately models the mechanical characteristics.

  13. MECHANISM OF ORIGIN OF STRUCTURAL VIBRATIONS IN CONICAL ROLLER BEARINGS

    Directory of Open Access Journals (Sweden)

    V.І. Marchuk

    2014-09-01

    Full Text Available This paper investigates the mechanism of origin of structural, structural and technological defects of rollers. The technique for integrated indicator of vibration working surfaces of the rings to determine the level of life of the finished part to the operation as part of the bearing and predict the vibroacoustic characteristics of rolling bearings. It was established that technological defects cause low-frequency and high-frequency vibrations. The question about the extent to which it is necessary to strengthen the tolerances on the parameters of bearings on which vibration level is determined not errors bearing parts and their structural properties. Calculated values of the amplitudes vibroacceleration due to the rigidity of the bearing vibrations are so small that in some cases adopted precision calculations turned enough to detect such vibrations. Thus, when tested on the vibro-acoustic installations structural vibration does not play an important role.

  14. Characteristics of ultrasonic vibration transmission in bonding process

    Institute of Scientific and Technical Information of China (English)

    LI Jun-hui; MIN Si-zong; HAN Lei; ZHONG Jue

    2005-01-01

    The transmitting models of ultrasonic vibration in ultrasonic transducer and capillary were presented according to the propagating mechanism of ultrasonic wave in elastic body. The coupling characteristics of ultrasonic longitudinal-complex transverse vibration system were simulated by Matlab software. The ultrasonic vibration displacement and the velocity of high frequency were measured by using the PSV-400-M2(1.5 MHz) laser Doppler vibrometer. The vibration locus shapes driven by the same frequency and different frequencies were tested by using GDS-820S dual channel digital oscilloscope. The microstructures at bonding interface were observed by means of KYKY2800 scanning electron microscope. The results show that ultrasonic vibration displacement or velocity and energy density increase with the decrease of section area in the transmitting process. The vibration locus shapes driven simultaneously by the same frequency and different frequencies are elliptical (or circular) loci and rectangular (or square) loci, respectively. And the characteristics at bonding interface are improved by coupling loci.

  15. Natural vibration dynamics of Rainbow Bridge, Utah

    Science.gov (United States)

    Moore, J. R.; Thorne, M. S.; Wood, J. R.; Doyle, S.; Stanfield, E.; White, B.

    2015-12-01

    We measured resonant frequencies of Rainbow Bridge, Utah, one of the world's longest rock spans, during a field experiment recording ambient vibration data. Measurements were generated over 20 hours on March 23-24, 2015 using two broadband three-component seismometers placed on the bridge, and compared to concurrent data from nearby reference stations 20 and 220 m distant. We identified seven distinct modes of vibration for Rainbow Bridge between 1 and 6 Hz. Data for each resonant frequency was then analyzed to determine the frequency-dependent polarization vector in an attempt to clarify mode shapes; e.g. the fundamental mode represents out-of-plane horizontal flexure. We compared experimental data to results of 3D numerical modal analysis, using a new photogrammetric model of Rainbow Bridge generated in this study imported into COMSOL Multiphysics. Results compare well with measured data for seven of the first eight modeled modes, matching vibrational frequencies and polarization orientations generally within 10%. Only predicted mode 6 was not explicitly apparent in our experimental data. Large site-to-reference spectral ratios resolved from experimental data indicate high amplification on the bridge as compared to nearby bedrock.

  16. Vibrational Spectroscopy and Dynamics of Water.

    Science.gov (United States)

    Perakis, Fivos; Marco, Luigi De; Shalit, Andrey; Tang, Fujie; Kann, Zachary R; Kühne, Thomas D; Torre, Renato; Bonn, Mischa; Nagata, Yuki

    2016-07-13

    We present an overview of recent static and time-resolved vibrational spectroscopic studies of liquid water from ambient conditions to the supercooled state, as well as of crystalline and amorphous ice forms. The structure and dynamics of the complex hydrogen-bond network formed by water molecules in the bulk and interphases are discussed, as well as the dissipation mechanism of vibrational energy throughout this network. A broad range of water investigations are addressed, from conventional infrared and Raman spectroscopy to femtosecond pump-probe, photon-echo, optical Kerr effect, sum-frequency generation, and two-dimensional infrared spectroscopic studies. Additionally, we discuss novel approaches, such as two-dimensional sum-frequency generation, three-dimensional infrared, and two-dimensional Raman terahertz spectroscopy. By comparison of the complementary aspects probed by various linear and nonlinear spectroscopic techniques, a coherent picture of water dynamics and energetics emerges. Furthermore, we outline future perspectives of vibrational spectroscopy for water researches. PMID:27096701

  17. Bubble oscillations and motion under vibration

    CERN Document Server

    O'Hern, Tim; Torczynski, John

    2011-01-01

    Bubbles under vibration can behave in unusual ways, e.g., moving downward against the force of buoyancy. While the bubble downward motion due to the Bjerknes force is well known at acoustic frequencies close to the bubble resonant frequency, these experiments demonstrate that these effects can be observed at relatively low frequencies as well. Experiments were performed in a thin, quasi-two-dimensional rectangular acrylic box partially filled with 20-cSt PDMS silicone oil with overlying ambient air. The apparatus was subjected to sinusoidal axial vibration that produced breakup of the gas-liquid free surface, producing liquid jets into the air, droplets pinching off from these jets, gas cavities in the liquid from impacts of these droplets, and bubble transport below the interface. Vibration conditions for the attached videos are 280 Hz frequency, 15 g acceleration, and 94 micron peak-to-peak displacement. Behaviors shown in the videos include the following. 1. Free surface breakup into jets and droplets, and...

  18. VLTI-UT vibrations effort and performances

    Science.gov (United States)

    Poupar, Sébastien; Haguenauer, Pierre; Alonso, Jaime; Schuhler, Nicolas; Henriquez, Juan-Pablo; Berger, Jean-Philippe; Bourget, Pierre; Brillant, Stephane; Castillo, Roberto; Gitton, Philippe; Gonte, Frederic; Di Lieto, Nicola; Lizon, Jean-Louis; Merand, Antoine; Woillez, Julien

    2014-07-01

    The ESO Very Large Telescope Interferometer (VLTI) using the Unit Telescope (UT) was strongly affected by vibrations since the first observations. Investigation by ESO on that subject had started in 2007, with a considerable effort since mid 2008. An important number of investigations on various sub-systems (On telescope: Guiding, Passive supports, Train Coude, insulation of electronics cabinets; On Instruments: dedicated campaign on each instruments with a special attention on the ones equipped with Close Cycle Cooler) were realized. Vibrations were not only recorded and analyzed using the usual accelerometers but also using on use sub-systems as InfRared Image Sensor (IRIS) and Multiple Applications Curvature Adaptive Optics (MACAO) and using a specific tool developed for vibrations measurements Mirror vibrAtion Metrology systeM for the Unit Telescope (MAMMUT). Those tools and systems have been used in order to improve the knowledge on telescope by finding sources. The sources whenever it was possible were damped. As known for years, instruments are still the principal sources of vibrations, for the majority of the UT. A special test in which 2 UTs instruments were completely shut down was realized to determine the minimum Optical Path Length (OPL) achievable. Vibrations is now a part of the instruments interface document and during the installation of any new instrument (KMOS) or system (AOF) a test campaign is realized. As a result some modifications (damping of CCC) can be asked in case of non-compliance. To ensure good operational conditions, levels of vibrations are regularly recorded to control any environmental change.

  19. Body temperature of the parasitic wasp Pimpla turionellae (Hymenoptera) during host location by vibrational sounding.

    Science.gov (United States)

    Kroder, Stefan; Samietz, Jörg; Stabentheiner, Anton; Dorn, Silvia

    2008-03-01

    The pupal parasitoid Pimpla turionellae (L.) uses self-produced vibrations transmitted on the plant substrate, so-called vibrational sounding, to locate immobile concealed pupal hosts. The wasps are able to use vibrational sounding reliably over a broad range of ambient temperatures and even show an increased signal frequency and intensity at low temperatures. The present study investigates how control of body temperature in the wasps by endothermic mechanisms may facilitate host location under changing thermal environments. Insect body temperature is measured with real-time IR thermography on plant-stem models at temperature treatments of 10, 18, 26 and 30 °C, whereas behaviour is recorded with respect to vibrational host location. The results reveal a low-level endothermy that likely interferes with vibrational sound production because it occurs only in nonsearching females. At the lowest temperature of 10 °C, the thoracic temperature is 1.15 °C warmer than the ambient surface temperature whereas, at the high temperatures of 26 and 30 ° C, the wasps cool down their thorax by 0.29 and 0.47 °C, respectively, and their head by 0.45 and 0.61 °C below ambient surface temperature. By contrast, regardless of ambient temperature, searching females always have a slightly elevated body temperature of at most 0.30 °C above the ambient surface temperature. Behavioural observations indicate that searching females interrupt host location more frequently at suboptimal temperatures, presumably due to the requirements of thermoregulation. It is assumed that both mechanisms, producing vibrations for host location and low-level endothermy, are located in the thorax. Endothermy by thoracic muscle work probably disturbs signal structure of vibrational sounding, so the processes cannot be used at the same time. PMID:22140295

  20. Vibration analysis using moire interferometry

    Science.gov (United States)

    Asundi, A.; Cheung, M. T.

    The present use of moire interferometry for low amplitude vibration and analysis demonstrates the possibility of obtaining out-of-plane displacement contours whose sensitivity is comparable to that of holographic methods. A major advantage of the present system, is the obviation of prior knowledge of resonant frequencies, as called for in time-average holography. The experimental apparatus employed encompasses a laser beam, a parabolic mirror, a high frequency (600 line/mm) grating, and a camera, in addition to the test model.

  1. Ambient mass spectrometry imaging

    DEFF Research Database (Denmark)

    Janfelt, Christian; Nørgaard, Asger W

    2012-01-01

    Easy ambient sonic spray ionization (EASI) and desorption electrospray ionization (DESI) were used for imaging of a number of samples, including sections of rat brain and imprints of plant material on porous Teflon. A novel approach termed Displaced Dual-mode Imaging was utilized for the direct...... comparison of the two methods: Images were recorded with the individual rows alternating between EASI and DESI, yielding a separate image for each technique recorded under perfectly similar conditions on the same sample. EASI works reliably for imaging of all samples, but the choice of spray solvent and flow...... rate is more critical in tissue imaging with EASI than with DESI. The overall sensitivity of EASI is, in general, slightly lower than that of DESI, and the representation of the dynamic range is different in images of the two techniques for some samples. However, for abundant compounds, EASI works well...

  2. MEIO AMBIENTE E DESENVOLVIMENTO

    OpenAIRE

    Suely Salgueiro Chacon; Daniel Rodriguez de Carvalho Pinheiro; Francisco Correia de Oliveira; Elizabeth Castelo Branco de Souza

    2009-01-01

    O objetivo deste artigo é resgatar elementos para subsidiar uma reflexão crítica sobre o modelo de desenvolvimento econômico prevalente na sociedade e as relações com o meio ambiente, sob a ameaça que ronda o destino da espécie humana, conforme afirmação de Lovelock (2006, p. 20) sobre o conceito de desenvolvimento sustentável: “uma ideia adorável se a tivéssemos aplicado 200 anos atrás, quando havia um bilhão de pessoas no mundo. Agora é tarde demais. Não há mais espaço para nenhum tipo de d...

  3. Reforma constitucional y ambiente

    Directory of Open Access Journals (Sweden)

    Teodoro Bustamante

    2013-09-01

    Full Text Available América Latina está atravesada por una ola de reformas constitucionales. Sus causas, las expectativas que ellas despiertan, los riesgos que se han asociado al proceso de lucha política en su entorno, son temas de un análisis fundamentalmente político; pero hay algunos aspectos en los cuales ese debate tiene una directa repercusión sobre el tema ambiental. En el caso del Ecuador, esto se refleja en el hecho de que una de las innovaciones que se proponen, se refieren a una nueva forma de abordar los temas ambientales, básicamente se establecen Derechos de la Naturaleza.

  4. Resolve of a Hydro-power Plant Full Load Abnormal Vibration Based on Model Turbine Test Investigation%基于模型试验解决某电站满负荷工况异常振动问题

    Institute of Scientific and Technical Information of China (English)

    徐用良; 刘智良; 刘文杰; 王洪杰

    2016-01-01

    本文介绍了混流式水轮机满负荷工况异常振动的一种处理方法。相比传统的优化泄水锥方案,本文基于模型试验和模型转轮修型以及原型机现场测量对混流式水轮机满负荷工况稳定性迚行研究。通过对比模型及相似原型机尾水管压力脉动幅值,模型和原型在满负荷区域相似性较好,为本方法的使用奠定基础。通过不同方案结果的比较,尾水管压力脉动陡升可能是导致原型机满负荷工况异常振动的一个重要原因,优化转轮叶片出口靠上冠区域的型线是解决该问题的一个重要手段。%In this paper, it presents a method about dealing with full load abnormal vibration of Francis turbine. Comparing with the traditional method concerning with optimization of runner cone, it investigates the full load stability by model test and model runner outlet profile modification as well as prototype site measurement. As pressure pulsation of draft tube of the model and homogenous prototype shown well agreement, it makes foundation of this method. By contrast results from different methods, conclusion can be drawn that the sharply increasing of draft tube pressure pulsation is the main reason of full load abnormal vibration. And optimization of runner outlet profile close to the crown is a good method to resolve this problem.

  5. Vibration Analysis of Air Condition Unit on Subway

    Directory of Open Access Journals (Sweden)

    Yan Liu

    2013-06-01

    Full Text Available Subway system has many merits including large passenger carrying ability, high speed, strong controllability and reliability of driving. Nevertheless, subways also have brought many disadvantages for human. In many subway systems, noisy environments are clearly observed and passengers are exposed to higher noise levels than permissible limit. This study presents a study of noise and vibration of subway air condition system, so as to grasp the vibration distribution laws of the air condition system. By the tested of noise and vibration, the researcher find the sound distribution rule of air condition is very important Based on the consequence of the testing, the acceleration of air condition has little to do with the subway speed and more to do with the vibration of fan; When the train driving on the viaduct bridge, the acceleration of air condition is biggish in 125 Hz and In 50-1000 Hz the vibration of air condition is obviously. When the train running underground line, as a result of the resonance of body, air condition’s vibration is biggish in 630 Hz and the vibration is obviously in 125-1250 Hz. With the increase of the speed, the influence of the ground’s second radiation on body vibration is enhanced. The superfine gross wool which is used to air condition can achieve good results for noise reduction. This research has higher reference for the vibration and noise reduction of the subway air condition system.

  6. Downhole Vibration Monitoring and Control System

    Energy Technology Data Exchange (ETDEWEB)

    Martin E. Cobern

    2007-09-30

    The objective of this program is to develop a system to both monitor the vibration of a bottomhole assembly, and to adjust the properties of an active damper in response to these measured vibrations. The key feature of this system is its use of a magnetorheological fluid (MRF) to allow the damping coefficient to be changed extensively, rapidly and reversibly without the use of mechanical valves, but only by the application of a current. Phase I of this program, which entailed modeling and design of the necessary subsystems and design, manufacture and test of a full laboratory prototype, was completed on May 31, 2004. Much of the effort was devoted to the design and testing of the MRF damper, itself. The principal objectives of Phase II were: more extensive laboratory testing, including the evaluation of different feedback algorithms for control of the damper; design and manufacture of a field prototype system; and, testing of the field prototype in a drilling laboratory. Phase II concluded on January 31, 2006, and a final report was issued. Work on Phase III of the project began during the first quarter, 2006, with the objectives of building precommercial prototypes, testing them in a drilling laboratory and the field; developing and implementing a commercialization plan. All of these have been accomplished. The Downhole Vibration Monitoring & Control System (DVMCS) prototypes have been successfully proven in testing at the TerraTek drilling facility and at the Rocky Mountain Oilfield Test Center (RMOTC.) Based on the results of these tests, we have signed a definitive development and distribution agreement with Smith, and commercial deployment is underway. This current version of the DVMCS monitors and controls axial vibrations. Due to time and budget constraints of this program, it was not possible to complete a system that would also deal with lateral and torsional (stick-slip) vibrations as originally planned; however, this effort is continuing without DOE

  7. Experimental study of modal parameter identification in a simulated ambient-excited structure

    Institute of Scientific and Technical Information of China (English)

    JI Xiaodong; QIAN Jiaru; XU Longhe

    2007-01-01

    Structure modal parameter online identification was used to monitor the structural health as evidenced by changes in the vibration characteristics.The natural excitation technique and the eigensystem realization algorithm were combined to identify the modal parameters in the time domain of a structure excited by simulated ambient vibrations.The mass-normalized mode shapes were obtained from the eigen-sensitivity analysis.The experimental modal analysis was performed on a two-story steel braced frame model excited by simulated ambient vibrations and hammer impacts.The mass-normalized mode shapes were acquired by changing the structural mass and by eigen-sensitivity analysis.From finite element analysis results and the experimental data,it is shown that this method is effective.

  8. CCN activation of ambient and "synthetic ambient" urban aerosol

    Science.gov (United States)

    Burkart, Julia; Reischl, Georg; Steiner, Gerhard; Bauer, Heidi; Leder, Klaus; Kistler, Magda; Puxbaum, Hans; Hitzenberger, R.

    2013-05-01

    In this study, the Cloud Condensation Nuclei (CCN) activation properties of the urban aerosol in Vienna, Austria, were investigated in a long term (11 month) field study. Filter samples of the aerosol below 100 nm were taken in parallel to these measurements, and later used to generate "synthetic ambient" aerosols. Activation parameters of this "synthetic ambient" aerosol were also obtained. Hygroscopicity parameters κ [1] were calculated both for the urban and the "synthetic ambient" aerosol and also from the chemical composition. Average κ for the "synthetic ambient" aerosol ranged from 0.20 to 0.30 with an average value of 0.24, while the κ from the chemical composition of this "synthetic ambient" aerosol was significantly higher (average 0.43). The full results of the study are given elsewhere [2,3].

  9. Research on vibration testing of a masonry building model based on stereovision%基于立体视觉的砌体房屋模型振动试验研究

    Institute of Scientific and Technical Information of China (English)

    单宝华; 申宇

    2013-01-01

    To meet the monitoring requirement of three-dimensional deformations for structural dynamic responses,a 3 D deformation measurement algorithm based on stereovision is proposed in this paper.The world coordinate system is established on the measurement surface of the structure,and 3D displacement equations of structural vibration responses are acquired.The algorithms of edge detection,center fitting and matching constraint are developed for circle identifying point,and the structural vibration analysis software of stereovision is compiled on the basis of above imaging processing algorithms with MATLAB.A shaking table test of masonry building model is performed under Taft and El Centro ground motions for different accelerations with the stereovision measurement system integrated in this paper.The out-of-plane and in-plane displacement time histories are obtained simultaneously.In-plane displacement curves show good agreement between stereovision method and displacement meter,and demonstrating that the former is valid for measuring structural vibration.Out-of-plane displacement curves indicate that the masonry building model twists under earthquake ground motions and the twist responses become stronger,when the peak acceleration of earthquake ground motion increases.The experimental results fully prove that the proposed approach in this paper is reliable and useful for monitoring the structural 3 D vibration responses.%针对结构动态响应监测三维变形的需求,研究立体视觉三维测量算法,建立基于结构测面的世界坐标系,得到结构振动响应三维位移公式.研究圆形标识点边缘检测、中心拟合及匹配约束算法,编译基于MATLAB平台的立体视觉结构振动测试分析软件.使用本文集成的立体视觉测量系统完成不同加速度峰值Taft波及El Centro波作用下砌体房屋模型振动台试验,同时测得结构三维位移时程曲线.面内位移时程曲线表明立体视觉方法与位移计数

  10. Nonlinear vibration caused by fatigue

    Science.gov (United States)

    Foong, Chee-Hoe; Wiercigroch, Marian; Pavlovskaia, Ekaterina; Deans, William F.

    2007-06-01

    The main aim of this work is to study the interactions between vibration and fatigue crack growth. In this paper, a detailed mathematical modelling of a newly designed fatigue-testing rig, description of the rig, experimental set-up and procedures, and sensor calibrations are presented. The test rig consists of two base-excited oscillators, one positioned above and the other below a single-edge-notched beam sample. The inertial forces of the oscillators act on the sample causing its bending and fatigue. Mathematically the fatigue crack sample is modelled as a discrete spring with piecewise nonlinear stiffness which is assumed to be constant when the crack closes and to decrease with crack length when it opens. The results from the modelling correlate well with the experimental tests.

  11. Validating Firewalls in Mobile Ambients

    DEFF Research Database (Denmark)

    Nielson, Flemming; Nielson, Hanne Riis; Hansen, René Rydhof;

    1999-01-01

    The ambient calculus is a calculus of computation that allows active processes (mobile ambients) to move between sites. A firewall is said to be protective whenever it denies entry to attackers not possessing the required passwords. We devise a polynomial time algorithm for rejecting proposed...

  12. Foro Ambiental : CEDENMA, Asamblea Constituyente

    Directory of Open Access Journals (Sweden)

    Anne-Lise Naizot

    2013-09-01

    Full Text Available Resumen de la Mesa redonda: Orientaciones de la nueva Constitución ecuatoriana en materia ambiental: ¿avances o retrocesos en relación con el marco político y filosófico ambiental vigente en algunos países de la región?

  13. DOWNHOLE VIBRATION MONITORING & CONTROL SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Martin E. Cobern

    2005-04-27

    The objective of this program is to develop a system to both monitor the vibration of a bottomhole assembly, and to adjust the properties of an active damper in response to these measured vibrations. Phase I of this program, which entailed modeling and design of the necessary subsystems and design, manufacture and test of a full laboratory prototype, was completed on May 31, 2004. The principal objectives of Phase II are: more extensive laboratory testing, including the evaluation of different feedback algorithms for control of the damper; design and manufacture of a field prototype system; and, testing of the field prototype in drilling laboratories and test wells. As a result of the lower than expected performance of the MR damper noted last quarter, several additional tests were conducted. These dealt with possible causes of the lack of dynamic range observed in the testing: additional damping from the oil in the Belleville springs; changes in properties of the MR fluid; and, residual magnetization of the valve components. Of these, only the last was found to be significant. By using a laboratory demagnetization apparatus between runs, a dynamic range of 10:1 was achieved for the damper, more than adequate to produce the needed improvements in drilling. Additional modeling was also performed to identify a method of increasing the magnetic field in the damper. As a result of the above, several changes were made in the design. Additional circuitry was added to demagnetize the valve as the field is lowered. The valve was located to above the Belleville springs to reduce the load placed upon it and offer a greater range of materials for its construction. In addition, to further increase the field strength, the coils were relocated from the mandrel to the outer housing. At the end of the quarter, the redesign was complete and new parts were on order. The project is approximately three months behind schedule at this time.

  14. Two degrees of freedom piezoelectric vibration energy harvester

    Science.gov (United States)

    Wang, Wei; Liu, Shengsheng; Cao, Junyi; Zhou, Shengxi; Lin, Jing

    2016-04-01

    Recently, vibration energy harvesting from surrounding environments to power wearable devices and wireless sensors in structure health monitoring has received considerable interest. Piezoelectric conversion mechanism has been employed to develop many successful energy harvesting devices due to its simple structure, long life span, high harvesting efficiency and so on. However, there are many difficulties of microscale cantilever configurations in energy harvesting from low frequency ambient. In order to improve the adaptability of energy harvesting from ambient vibrations, a two degrees of freedom (2-DOF) magnetic-coupled piezoelectric energy harvester is proposed in this paper. The electromechanical governing models of the cantilever and clamped hybrid energy harvester are derived to describe the dynamic characteristics for 2-DOF magnetic-coupled piezoelectric vibration energy harvester. Numerical simulations based on Matlab and ANSYS software show that the proposed magnetically coupled energy harvester can enhance the effective operating frequency bandwidth and increase the energy density. The experimental voltage responses of 2-DOF harvester under different structure parameters are acquired to demonstrate the effectiveness of the lumped parameter model for low frequency excitations. Moreover, the proposed energy harvester can enhance the energy harvesting performance over a wider bandwidth of low frequencies and has a great potential for broadband vibration energy harvesting.

  15. Vibration Characteristics of Roundabout Swing of HAWT Wind Wheel

    Directory of Open Access Journals (Sweden)

    Jian-long Ma

    2016-01-01

    Full Text Available Modal testing was used to show that the roundabout swing was a natural vibration mode of the wind wheel of a horizontal-axis wind turbine (HAWT. During the vibration, the blade root was simultaneously subjected to bending and rotary shear stresses. A method for indirect testing and determination of the dynamic frequencies of the typical vibrations of the wind wheel was developed, based on the frequency-holding characteristic of each subsignal during the transmission of the multiple mixed-vibration signals. The developed method enabled simple and accurate acquisition of the dynamic frequencies without destruction of the flow and structural fields. The dynamic vibration stress of the roundabout swing was found to be significantly stronger than those of the first- and second-order flexural vibrations of the blades. By a combination of numerical simulations and tests, it was determined that the pneumatic circumferential force was the primary determinant of the roundabout swing vibration frequencies, the relationship being quadratic. The roundabout swing vibration potentially offers new explanations and analytical pathways regarding the behavior of horizontal-axis wind turbines, which have been found to be frequently involved in fatigue-damage accidents within periods shorter than their design lives.

  16. Discussion about Two Different Mechanical Ways of Vibration Loading for Test Plateform of Shock Absorber%减震器测试台两种不同机械加振方式的讨论

    Institute of Scientific and Technical Information of China (English)

    曲承童; 姜涛

    2013-01-01

    Test platform of mechanical shock absorber is suitable for automatic detection on production lines because of its simple operation,high efficiency,good stability and compact structure. For test platform of shock absorber,two me-chanical ways of vibration loading wre discussed:the crank slide block guiding mechanism and the crank connecting rod slide block mechanism. Using the mathematical formula,the laws of displacement are worked out,velocity and acceler-ation, and draw and compare the curves of these laws by MATLAB. Then the advantages and disadvantages of the two structures are discussed.%  机械式减振器性能测试台操作简单、效率高、稳定性好、机构紧凑,故十分适合生产线的自动检测。针对目前机械激振式减震器性能测试台的两种减振方式曲柄滑块导轨机构和曲柄连杆滑块机构予以讨论,运用数学公式给出其位移、速度、加速度运动规律,并利用MATLAB给出各自运动规律曲线加以比较,讨论两种机构的优缺点。

  17. 基于动态特性的大型减速齿轮装置试验系统的振动控制研究%Vibration Analysis of a Large-size Reduction Gearbox Test System Based on Its Dynamic Characteristics

    Institute of Scientific and Technical Information of China (English)

    陈雪华; 冯健

    2013-01-01

    In testing process of a large-size reduction gearbox test system,its vibration and noise are the key parameters used to estimate its performance,which are caused by the vibration of the test gearbox and the support saddles.In this paper,a new simulation method is proposed to analyze vibrations of a large-size reduction gearbox test system,which consists of a finite ele-ment (FE)method and a torsional vibration analysis method.In this method,the natural fre-quencies,the mode shape and the vibration response of the large-size reduction gearbox test system are studied using the FE method,and the factors of the resonance of the system are dis-cussed.Furthermore,a torsional vibration model of the large-size reduction gearbox test system is proposed to study the torsional vibration of the gearbox test system.Also,the factors of the torsional vibration are discussed.The simulation results show that the vibration analysis and the optimization design of the gearbox test system should be considered at the beginning of its design stage.The results also show that the proposed method can be used to improve the vibration and noise level of a large-size reduction gearbox test system.%在大型减速齿轮装置的试验过程中,振动与噪声是试验过程的控制关键因素,其受到被测产品、陪试产品及试验台架振动指标影响。针对这个问题,采用有限元方法,对试验台系统进行了模态分析和谐响应分析,研究了试验系统各部套的模态频率和振型,分析了发生共振的可能性,并建立了试验台系统的扭转振动模型,对试验台的扭转振动特性进行了研究,分析了可能引起试验台系统发生扭转振动的因素,找到了试验台系统振动控制的最佳方案。研究表明:在设计初期就应用仿真技术对大型减速齿轮装置试验系统的振动进行分析与优化设计,能解决大型减速齿轮装置在实际运转中的振动与噪音问题,从而加

  18. Research on Vibration Isolation Systems Used in Laser and Nanotechnologies

    Directory of Open Access Journals (Sweden)

    Justinas Kuncė

    2012-12-01

    Full Text Available The paper discusses the efficiency of a vibration isolation system made of the optical table and two negative-stiffness tables and considers excitation referring to harmonic and nonharmonic methods in the frequency range of 0,2–110 Hz. The article reviews the types and sources of vibrations and types of vibration isolation systems, including those of negative-stiffness. The paper also presents the methodology of experimental tests and proposes research on vibration transmissibility. A composite system consisting of two vibration isolation table having negative stiffness and an air table has been tested. The results and conclusions of experimental analysis are suggested at the end of the article.Article in Lithuanian

  19. Frictional effect of ultrasonic-vibration on upsetting.

    Science.gov (United States)

    Hung, Jung-Chung; Tsai, Yu-Chung; Hung, Chinghua

    2007-06-01

    The ultrasonic-vibration ring compression test and finite element analysis were performed on aluminum alloy specimens to explore the frictional effect of superimposing ultrasonic-vibration during upsetting. The extrapolated compression test was first adopted to obtain the frictionless material properties for finite element analysis. Experimental results of extrapolated compression test also indicate that ultrasonic-vibration can reduce the compressive force when friction is eliminated and can increase the temperatures of a material at the same time. The following results of the hot extrapolated compression test and the hot ring compression test reveal that increasing temperature by ultrasonic-vibration may reduce the flow stress and increase the interfacial friction. Finally, finite element analysis was conducted to derive the friction calibration curves and to evaluate the friction factor.

  20. Multiaxis Rainflow Fatigue Methods for Nonstationary Vibration

    Science.gov (United States)

    Irvine, T.

    2016-01-01

    Mechanical structures and components may be subjected to cyclical loading conditions, including sine and random vibration. Such systems must be designed and tested accordingly. Rainflow cycle counting is the standard method for reducing a stress time history to a table of amplitude-cycle pairings prior to the Palmgren-Miner cumulative damage calculation. The damage calculation is straightforward for sinusoidal stress but very complicated for random stress, particularly for nonstationary vibration. This paper evaluates candidate methods and makes a recommendation for further study of a hybrid technique.

  1. FY 2013 Summary Report: Post-Irradiation Examination of Zircaloy-4 Samples in Target Capsules and Initiation of Bending Fatigue Testing for Used Nuclear Fuel Vibration Integrity Investigations

    Energy Technology Data Exchange (ETDEWEB)

    Howard, Richard H [ORNL; Yan, Yong [ORNL; Wang, Jy-An John [ORNL; Ott, Larry J [ORNL; Howard, Rob L [ORNL

    2013-10-01

    This report documents ongoing work performed at Oak Ridge National Laboratory (ORNL) for the Department of Energy, Office of Fuel Cycle Technology Used Fuel Disposition Campaign (UFDC), and satisfies the deliverable for milestone M2FT-13OR0805041, “Data Report on Hydrogen Doping and Irradiation in HFIR.” This work is conducted under WBS 1.02.08.05, Work Package FT-13OR080504 ST “Storage and Transportation-Experiments – ORNL.” The objectives of work packages that make up the S&T Experiments Control Account are to conduct the separate effects tests (SET) and small-scale tests that have been identified in the Used Nuclear Fuel Storage and Transportation Data Gap Prioritization (FCRD-USED-2012-000109). In FY 2013, the R&D focused on cladding and container issues and small-scale tests as identified in Sections A-2.9 and A-2.12 of the prioritization report.

  2. Vibrations and waves

    CERN Document Server

    Kaliski, S

    2013-01-01

    This book gives a comprehensive overview of wave phenomena in different media with interacting mechanical, electromagnetic and other fields. Equations describing wave propagation in linear and non-linear elastic media are followed by equations of rheological models, models with internal rotational degrees of freedom and non-local interactions. Equations for coupled fields: thermal, elastic, electromagnetic, piezoelectric, and magneto-spin with adequate boundary conditions are also included. Together with its companion volume Vibrations and Waves. Part A: Vibrations this work provides a wealth

  3. Vibrational spectroscopy of resveratrol

    Science.gov (United States)

    Billes, Ferenc; Mohammed-Ziegler, Ildikó; Mikosch, Hans; Tyihák, Ernő

    2007-11-01

    In this article the authors deal with the experimental and theoretical interpretation of the vibrational spectra of trans-resveratrol (3,5,4'-trihydroxy- trans-stilbene) of diverse beneficial biological activity. Infrared and Raman spectra of the compound were recorded; density functional calculations were carried out resulting in the optimized geometry and several properties of the molecule. Based on the calculated force constants, a normal coordinate analysis yielded the character of the vibrational modes and the assignment of the measured spectral bands.

  4. Man-Induced Vibrations

    DEFF Research Database (Denmark)

    Jönsson, Jeppe; Hansen, Lars Pilegaard

    1994-01-01

    work has been done on the measurement of the exact load functions and related reponse analysis. A recent work using a spectral description has been performed by Per-Erik Erikson and includes a good literature survey. Bachmann and Ammann give a good overview of vibrations caused by human activity. Other...... concerned with spectator-induced vertical vibrations on grandstands. The idea is to use impulse response analysis and base the load description on the load impulse. If the method is feasable, it could be used in connection with the formulation of requirements in building codes. During the last two decades...

  5. Vibration detection of component health and operability

    Science.gov (United States)

    Baird, B. C.

    1975-01-01

    In order to prevent catastrophic failure and eliminate unnecessary periodic maintenance in the shuttle orbiter program environmental control system components, some means of detecting incipient failure in these components is required. The utilization was investigated of vibrational/acoustic phenomena as one of the principal physical parameters on which to base the design of this instrumentation. Baseline vibration/acoustic data was collected from three aircraft type fans and two aircraft type pumps over a frequency range from a few hertz to greater than 3000 kHz. The baseline data included spectrum analysis of the baseband vibration signal, spectrum analysis of the detected high frequency bandpass acoustic signal, and amplitude distribution of the high frequency bandpass acoustic signal. A total of eight bearing defects and two unbalancings was introduced into the five test items. All defects were detected by at least one of a set of vibration/acoustic parameters with a margin of at least 2:1 over the worst case baseline. The design of a portable instrument using this set of vibration/acoustic parameters for detecting incipient failures in environmental control system components is described.

  6. Flow induced vibration in pump impellers

    International Nuclear Information System (INIS)

    The complex nature of flow-induced vibration (FIV) has led prominent researchers in the field to conclude that it is extremely important to understand the flow-induced vibration mechanism in order to design out of the problem (DOP), rather than to attempt to design the problem area on the basis of analysis with a high degree of certitude (i.e., predicting system response). Designing out of the problem may not be affected by addressing one parameter but rather several: structural contour, material selection, flow properties, structural stiffness, damping, and fluid-structure coupling In this paper the mechanism of flow induced vibration fatigue failure of large circulating water pumps is discussed. This paper provides an overview of the inter-relationship of finite element and theoretical analysis, component and material testing, operational data, fabrication, and repair practices

  7. A membrane disdrometer based on membrane vibration

    International Nuclear Information System (INIS)

    Raindrop sizes were indirectly determined through the distinctive vibrations and sounds that occur when raindrops of different sizes impact on a membrane. The relationships between diameter, raindrop kinetic momentum, membrane deflection, and impact force were analyzed. Membrane deflection and vibration models were created, and the optimum membrane diameter and thickness were identified. A prototype membrane disdrometer was developed on the basis of these findings. The relationship between raindrop size and membrane vibration sound pressure was determined experimentally. The fundamental parameter of raindrop size recognition was used. The test results indicate that raindrops 0.4–2.0 mm in diameter can be detected by the proposed membrane disdrometer, and 50 raindrops per second in a zone area of 28.3 cm2 can be detected in natural rain. (paper)

  8. Active structures to reduce torsional vibrations

    Science.gov (United States)

    Matthias, M.; Schlote, D.; Atzrodt, H.

    2013-03-01

    This paper describes the development of different active measures to reduce torsional vibrations in power trains. The measures are based on concepts developed for active mounts to reduce the transmission of structure-borne sound. To show the potential of these active measures and investigate their mode of operation to influence torsional vibrations, numerical simulations of powertrains with different active measures were done. First experimental results from tests on an experimental (reduced size) power train were used to align the numerical models. The work was done within the project 'LOEWE-Zentrum AdRIA: Adaptronik - Research, Innovation, Application' funded by the German federal state of Hessen, and the Project AKTos: 'Active control of torsional vibrations by coupling elements' placed in the research Framework program 'Navigation and Maritime Technology for the 21st Century' funded by the German Federal Ministry of Economics and Technology.

  9. Vibration Propagation in Spider Webs

    Science.gov (United States)

    Hatton, Ross; Otto, Andrew; Elias, Damian

    Due to their poor eyesight, spiders rely on web vibrations for situational awareness. Web-borne vibrations are used to determine the location of prey, predators, and potential mates. The influence of web geometry and composition on web vibrations is important for understanding spider's behavior and ecology. Past studies on web vibrations have experimentally measured the frequency response of web geometries by removing threads from existing webs. The full influence of web structure and tension distribution on vibration transmission; however, has not been addressed in prior work. We have constructed physical artificial webs and computer models to better understand the effect of web structure on vibration transmission. These models provide insight into the propagation of vibrations through the webs, the frequency response of the bare web, and the influence of the spider's mass and stiffness on the vibration transmission patterns. Funded by NSF-1504428.

  10. Nonlinear Dynamics of an Ambient Noise Driven Array of Coupled Graphene Nanostructured Devices for Energy Harvesting

    Directory of Open Access Journals (Sweden)

    El Aroudi A.

    2014-01-01

    Full Text Available Nonlinearities have been shown to play an important role in increasing the extracted energy of energy harvesting devices at the macro and micro scales. Vibration-based energy harvesting on the nano scale has also received attention. In this paper, we characterize the nonlinear dynamical behavior of an array of three coupled strained nanostructured graphene for its potential use in energy harvesting applications. The array is formed by three compressed vibrating membrane graphene sheet subject to external vibrational noise excitation. We present the continuous time dynamical model of the system in the form of a double-well three degree of freedom system. Random vibrations are considered as the main ambient energy source for the system and its performances in terms of the probability density function, RMS or amplitude value of the position, FFT spectra and state plane trajectories are presented in the steady state non-equilibrium regime when the noise level is considered as a control parameter.

  11. Aspectos computacionais do ambiente IMAGUS

    OpenAIRE

    Raabe, André Luís Alice; Giraffa, Lúcia Maria Martins

    2000-01-01

    Este artigo apresenta a descrição do ambiente IMAGUS enfatizando aspectos da implementação do protótipo do ambiente. O IMAGUS permite a construção de materiais com fins pedagógicos que se utilizam de vídeos acessado via Internet. O protótipo foi desenvolvido para validar a arquitetura proposta para o ambiente. São apresentadas as soluções a nível de modelagem e a implementação do protótipo baseada na utilização da interface Java Media Framework

  12. Development of vibrating insoles

    NARCIS (Netherlands)

    Hijmans, J.M.; Geertzen, J.H.B.; Schokker, B.; Postema, K.

    2007-01-01

    The objective of this study was to describe the development of vibrating insoles. Insoles, providing a subsensory mechanical noise signal to the plantar side of the feet, may improve balance in healthy young and older people and in patients with stroke or diabetic neuropathy. This study describes th

  13. High-Temperature Vibration Damper

    Science.gov (United States)

    Clarke, Alan; Litwin, Joel; Krauss, Harold

    1987-01-01

    Device for damping vibrations functions at temperatures up to 400 degrees F. Dampens vibrational torque loads as high as 1,000 lb-in. but compact enough to be part of helicopter rotor hub. Rotary damper absorbs energy from vibrating rod, dissipating it in turbulent motion of viscous hydraulic fluid forced by moving vanes through small orifices.

  14. CHECKING OF TECHNICAL BRIDGES’ STATE BY PASSIVE VIBRATIONAL DYNAMICS METHODS

    Directory of Open Access Journals (Sweden)

    V. P. Redchenko

    2010-03-01

    Full Text Available In the article the results of studies of the passive vibration test methods and the possibilities of using them for determining and monitoring of technical condition of bridges are presented.

  15. Study on the Ultra High Cycle Bending Vibration Fatigue Test of Titanium Alloys%钛合金超高周弯曲振动疲劳性能试验

    Institute of Scientific and Technical Information of China (English)

    申景生; 李全通; 吴晓峰; 高潮; 刘青川

    2011-01-01

    Based on the three-point bending method, an ultra high cycle bending vibration fatigue system is developed and the design method of fatigue test specimens is introduced too. The S - N curve of titanium alloy TC17 is determined by the ultra high cycle dissymmetrical bending fatigue system (20 kHz). The result shows that when stress ratio(R) is -1, the S - N curve of titanium alloy TC17 is a continuously declining curve, The specimens continue to fail over 107 stress cycles. In 107 weeks time, the samples don' t happen the fatigue damage, so it does not exist in the traditional sense fatigue limit.%在三点弯曲超高周疲劳试验的基础上,开发了悬臂梁式弯曲振动超高周疲劳试验系统,并介绍了疲劳试验试片的设计方法.利用超高周弯曲疲劳试验系统(20 kHz)测定了钛合金TC17的S-N曲线,结果表明,当应力比R=-1时TC17钛合金的S-N曲线是一条连续下降型曲线,在107周次以后,试样仍未发生疲劳破坏,不存在传统意义上的疲劳极限.

  16. Analysis of vibration test for the skew box girder bridge under human-induced excitation%人群荷载作用下斜箱梁桥振动试验分析

    Institute of Scientific and Technical Information of China (English)

    赵学; 王介修; 勾志硕; 贾艳敏

    2014-01-01

    By the actual test and theoretical analysis for vibration of the skew box girder bridge under human-induced excitation,the determina-tion of dynamic characteristic and the dynamic reaction under the effect of moving pedestrian,actual working state of the bridge under moving load have been studied,with safe bearing capacity and use condition of the whole structure determined.%通过对三跨预应力连续斜箱梁桥在人群荷载作用下的振动问题进行实桥测试和理论分析,测定其动态特性及在跑动的人群荷载作用下的动态响应,了解了该桥在动荷载作用下的实际工作状态,从而判断该桥整体结构的安全承载能力和使用条件。

  17. Dynamics analysis of vibration process in Particle Impact Noise Detection

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hui; ZHOU Chang-lei; WANG Shu-juan; ZHAI Guo-fu

    2007-01-01

    Particle Impact Noise Detection (PIND) test is a reliability screening technique for hermetic device that is prescribed by MIL-PRF-39016E. Some test conditions are specified, although MIL-PRF-39016E did not specify how to obtain these conditions. This paper establishes the dynamics model of vibration process based on first order mass-spring system. The corresponding Simulink model is also established to simulate vibration process in optional input excitations. The response equations are derived in sinusoidal excitations and the required electromagnetic force waves are computed in order to obtain a given vibration and shock accelerations. Last, some simulation results are given.

  18. 一种应变式超低频微振动测试台%An ultra-low frequency micro-vibration testing platform based on strain-resistance effect

    Institute of Scientific and Technical Information of China (English)

    陈江攀; 程伟; 夏明一

    2014-01-01

    In order to measure micro-vibration of a SADA (solar array drive assembly ) in low and ultra-low frequency zone caused by electromechanical coupling,a six-component testing platform based on strain-resistance effect was developed.Its response characteristic in low frequency zone was outstanding and its installation interface was flexible. The working principle and dynamic calibration method of this platform were introduced in detail.In order to assess the performance of this testing platform,linearity examination,natural frequencies measurement and dynamic testing error examination for it were done.The results showed that linearity errors of eight force sensors are within 3.4% under the action of external force within 1 00N;there are no natural frequencies within 1 00Hz,so that the micro-vibration signals can not be modulated through structural coupling in frequency domain of (0 -1 00Hz );dynamic testing errors of six components are within ±9.6% in frequency domain of (0 -1 00Hz),testing resolutions of three forces and three moments can reach 0.0lN and 0.001 N.m,respectively.%为了测试卫星太阳翼驱动机构低频、超低频区由机电耦合产生的微振动,发明了一种应变式超低频微振动六分量测试台,该测试台低频响应特性好,安装接口灵活。介绍该测试台的工作原理和动态标定方法,并对该测试台进行了线性度检验、固有频率测试以及动态测试误差检验。通过线性度检验可得:在100 N范围内的外力作用下,组成该测试台的八个双孔梁应变式力传感器的线性度相对误差在±3.4%以内;通过固有频率测试可得:该测试台在100 Hz内没有固有频率,不会通过结构耦合对被测微振动信号进行调制;通过动态测试误差检验可得:在频域上0!100 Hz范围内,该测试台对六个分量动态测试的相对误差在±9.6%以内,同时还可以得出该测试台对三个力分量和三个力矩分量

  19. Multivariate Analysis of Ladle Vibration

    Science.gov (United States)

    Yenus, Jaefer; Brooks, Geoffrey; Dunn, Michelle

    2016-08-01

    The homogeneity of composition and uniformity of temperature of the steel melt before it is transferred to the tundish are crucial in making high-quality steel product. The homogenization process is performed by stirring the melt using inert gas in ladles. Continuous monitoring of this process is important to make sure the action of stirring is constant throughout the ladle. Currently, the stirring process is monitored by process operators who largely rely on visual and acoustic phenomena from the ladle. However, due to lack of measurable signals, the accuracy and suitability of this manual monitoring are problematic. The actual flow of argon gas to the ladle may not be same as the flow gage reading due to leakage along the gas line components. As a result, the actual degree of stirring may not be correctly known. Various researchers have used one-dimensional vibration, and sound and image signals measured from the ladle to predict the degree of stirring inside. They developed online sensors which are indeed to monitor the online stirring phenomena. In this investigation, triaxial vibration signals have been measured from a cold water model which is a model of an industrial ladle. Three flow rate ranges and varying bath heights were used to collect vibration signals. The Fast Fourier Transform was applied to the dataset before it has been analyzed using principal component analysis (PCA) and partial least squares (PLS). PCA was used to unveil the structure in the experimental data. PLS was mainly applied to predict the stirring from the vibration response. It was found that for each flow rate range considered in this study, the informative signals reside in different frequency ranges. The first latent variables in these frequency ranges explain more than 95 pct of the variation in the stirring process for the entire single layer and the double layer data collected from the cold model. PLS analysis in these identified frequency ranges demonstrated that the latent

  20. Vibrational Conical Intersections: Implications for Ultrafast Vibrational Dynamics

    Science.gov (United States)

    Dawadi, Mahesh; Prasad Thapaliya, Bishnu; Bhatta, Ram; Perry, David

    2015-03-01

    The presence of conical intersections (CIs) between electronic potential energy surfaces is known to play a key role in ultrafast electronic relaxation in diverse circumstances. Recent reports have documented the existence of vibrational CIs connecting vibrationally adiabatic surfaces. Just as electronic CIs are now appreciated to be ubiquitous, controlling the rates of many photochemical processes, the present work on methanol and methyl mercaptan suggests that vibrational CIs may also be widespread, possibly controlling the outcome of some high-energy processes where vibrationally excited species are present. Other examples of vibrational CIs include the vibrational Jahn-Teller effect in C3V organic molecules and transition metal complexes. While the present work addresses only the couplings within bound molecules, the concept of vibrational CIs providing pathways for ultrafast relaxation also applies to molecular collisions. This work is supported by DOE (DEFG02-90ER14151).

  1. The effects of ambient impurities on the surface tension

    OpenAIRE

    Ponce-Torres A.; Vega E. J.

    2016-01-01

    A liquid bridge is a liquid column held captive between two coaxial and parallel solid disks. It is an excellent test bench where measuring the surface tension. In this paper, we used this fluid configuration to examine experimentally the effects of ambient impurities on the surface tension over time. For this purpose, the liquid bridge equilibrium shape was analyzed when the liquid bridge was surrounded by three environments: the uncontrolled ambient, and both air and argon encapsulated in a...

  2. Nonlinear vibration with control for flexible and adaptive structures

    CERN Document Server

    Wagg, David

    2015-01-01

    This book provides a comprehensive discussion of nonlinear multi-modal structural vibration problems, and shows how vibration suppression can be applied to such systems by considering a sample set of relevant control techniques. It covers the basic principles of nonlinear vibrations that occur in flexible and/or adaptive structures, with an emphasis on engineering analysis and relevant control techniques. Understanding nonlinear vibrations is becoming increasingly important in a range of engineering applications, particularly in the design of flexible structures such as aircraft, satellites, bridges, and sports stadia. There is an increasing trend towards lighter structures, with increased slenderness, often made of new composite materials and requiring some form of deployment and/or active vibration control. There are also applications in the areas of robotics, mechatronics, micro electrical mechanical systems, non-destructive testing and related disciplines such as structural health monitoring. Two broader ...

  3. Researches Concerning to Minimize Vibrations when Processing Normal Lathe

    Directory of Open Access Journals (Sweden)

    Lenuța Cîndea

    2015-09-01

    Full Text Available In the cutting process, vibration is inevitable appearance, and in situations where the amplitude exceeds the limits of precision dimensional and shape of the surfaces generated vibrator phenomenon is detrimental.Field vibration is an issue of increasingly developed, so the futures will a better understanding of them and their use even in other sectors.The paper developed experimental measurement of vibrations at the lathe machining normal. The scheme described kinematical machine tool, cutting tool, cutting conditions, presenting experimental facility for measuring vibration occurring at turning. Experimental results have followed measurement of amplitude, which occurs during interior turning the knife without silencer incorporated. The tests were performed continuously for different speed, feed and depth of cut.

  4. Vortex-induced vibration of a suspension bridge with central-slotted box section and its control test study%桥面中央开口悬索桥涡激共振与制涡试验研究

    Institute of Scientific and Technical Information of China (English)

    欧阳克俭; 陈政清; 韩艳; 李红利

    2009-01-01

    Vortex-induced vibration (VIV) of a suspension bridge with central-slottod box section and its control was studied by use of wind tunnel test. The conversion relationships between the resonant amplitudes of the model and those of the prototype bridge were considered. And the correction coefficients of modal shapes were also presented. Two methods were proposed to control VIV successfully. The second method was able to control VIV effectively under the condition that the section shape was not altered and it could meet the requirements of engineering practice. The test al- so indicated that damping could suppress the amplitudes of VIV notably.%研究了中央开口断面悬索桥涡振及其控制风洞试验.考虑了模型涡振幅值和和实桥涡振幅值之间换算的修正系数,风洞试验表明中央开口是导致该种断面形式涡激振动发生的主要原因.所设计的两种制涡方案都能达到控制涡振的目的,在不改变断面形式等因素的前提下,设计的制涡方案二能有效控制涡振,符合工程实际要求.同时试验也表明,阻尼能大幅降低涡振幅值.

  5. Numerical Simulation of Shock and Vibration Tests for Converter Cabinet%变流器柜体冲击和随机振动试验的数值模拟

    Institute of Scientific and Technical Information of China (English)

    丁杰; 忻力; 荣智林; 陈燕平

    2012-01-01

    According to the standard GB/T 21563-2008 'Railway applications- Rolling stock equipment- Shock and vibration tests', the responses of the structure under random loading were computed by the finite-element analysis software ANSYS. From the results, the maximum of the 1σ 2σ and 3σ Von Mises stress was obtained. Utilizing the S-N curve of the materials, and according to Steinberg's Gaussian distribution of responses under random loading and Miner's linear fatigue accumulation rule, the life prediction of the structure under random loading was carried out. The transient dynamics analysis was also performed for shock tests.%根据标准GB/T 21563-2008《轨道交通机车车辆设备冲击和振动试验》,采用ANSYS有限元分析软件计算了随机振动环境下的响应,得到了结构的1σ、2σ、3σVonMises最大应力.利用材料的S-N曲线,并根据Steinberg提出结构在随机载荷作用下的响应是基于高斯分布和Miner提出的线性疲劳累计损伤理论,对设计的结构在给定随机振动环境下的疲劳寿命进行了预估.运用瞬态动力学分析方法模拟了冲击试验过程中的受力情况.

  6. 基于振动法的磁记忆检测系统研究与设计%Research and design of magnetic memory testing system based on vibration method

    Institute of Scientific and Technical Information of China (English)

    王嘉明; 姚恩涛

    2016-01-01

    This paper proposed a method of measuring metal magnetic memory signal based on vibration method.A metal magnetic memory testing system was designed,including a sensor probe structure with a magnetic field shielding shell,a preprocessing module of magnetic memory signal and an orthogonal vector phase locked amplifying module. And the lower machine module was designed based on STM32F107VCT6 chip.The system is used to test the processed standard specimen.The stress concentration region of the specimen can be detected by the method of measuring the magnetic field gradient,and the relationship between the magnetic field gradient and the stress concentration factor is verified.%提出基于振动法的金属磁记忆信号检测方法。设计相应的金属磁记忆检测系统,包括带有磁场屏蔽外壳的传感器探头结构、磁记忆信号预处理模块和正交矢量锁相放大模块,并基于 STM32F107VCT6芯片设计下位机模块。利用研制的系统对经过加工的标准试件进行检测,通过测量法向磁场梯度的方法可以检测出试件应力集中区域,验证法向磁场梯度和应力集中系数的关系。

  7. Improved Active Vibration Isolation Systems

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The control force, feedback gain, and actuator stroke of several active vibration isolation systems were analyzed based on a single-layer active vibration isolation system. The analysis shows that the feedback gain and actuator stroke cannot be selected independently and the active isolation system design must make a compromise between the feedback gain and actuator stroke. The performance of active isolation systems can be improved by the joint vibration reduction using an active vibration isolation system with an adaptive dynamic vibration absorber. The results show that the joint vibration reduction method can successfully avoid the compromise between the feedback gain and actuator stroke. The control force and the object vibration amplitude are also greatly reduced.

  8. Self-suspended vibration-driven energy harvesting chip for power density maximization

    Science.gov (United States)

    Murillo, Gonzalo; Agustí, Jordi; Abadal, Gabriel

    2015-11-01

    This work introduces a new concept to integrate energy-harvesting devices with the aim of improving their throughput, mainly in terms of scavenged energy density and frequency tunability. This concept, named energy harvester in package (EHiP), is focused on the heterogeneous integration of a MEMS die, dedicated to scavenging energy, with an auxiliary chip, which can include the control and power management circuitry, sensors and RF transmission capabilities. The main advantages are that the whole die can be used as an inertial mass and the chip area usage is optimized. Based on this concept, in this paper we describe the development and characterization of a MEMS die fully dedicated to harvesting mechanical energy from ambient vibrations through an electrostatic transduction. A test PCB has been fabricated to perform the assembly that allows measurement of the resonance motion of the whole system at 289 Hz. An estimated maximum generated power of around 11 μW has been obtained for an input vibration acceleration of ˜10 m s-2 when the energy harvester operates in a constant-charge cycle for the best-case scenario. Therefore, a maximum scavenged power density of 0.85 mW cm-3 is theoretically expected for the assembled system. These results demonstrate that the generated power density of any vibration-based energy harvester can be significantly increased by applying the EHiP concept, which could become an industrial standard for manufacturing this kind of system, independently of the transduction type, fabrication technology or application.

  9. Nonlinear vibration energy harvesting based on variable double well potential function

    Science.gov (United States)

    Yang, Wei; Towfighian, Shahrzad

    2016-04-01

    Converting ambient mechanical energy to electricity, vibration energy harvesting, enables powering of the low-power remote sensors. Nonlinear energy harvesters have the advantage of a wider frequency spectrum compared to linear resonators making them more efficient in scavenging the broadband frequency of ambient vibrations. To increase the output power of the nonlinear resonators, we propose an energy harvester composed of a cantilever piezoelectric beam carrying a movable magnet facing a fixed magnet at a distance. The movable magnet on the beam is attached to a spring at the base of the beam. The spring-magnet system on the cantilever beam creates the variable double well potential function. The spring attached to the magnet is in its compressed position when the beam is not deflected, as the beam oscillates, the spring energy gradually releases and further increases the amplitude of vibration. To describe the motion of the cantilever beam, we obtained two coupled partial differential equations by assuming the cantilever beam as Euler-Bernoulli beam considering the effect of the moving magnet. Method of multiple scales is used to solve the coupled equations. The cantilever beam with the two magnets is a bi-stable system. Making one magnet movable can create internal resonance that is explored as a mechanism to increase the frequency bandwidth. The effect of system parameters on the frequency bandwidth of the resonator is investigated through numerical solutions. This study benefits vibration energy harvesting to achieve a higher performance when excited by the wideband ambient vibrations.

  10. Evaluation of Bus Vibration Comfort Based on Passenger Crowdsourcing Mode

    Directory of Open Access Journals (Sweden)

    Hong Zhao

    2016-01-01

    Full Text Available Vibration comfort is an important factor affecting the quality of service (QoS of bus. In order to make people involved in supervising bus’s vibration comfort and improve passengers’ riding experience, a novel mode of passenger crowdsourcing is introduced. In this paper, comfort degree of bus vibration is calculated from bus’s vibration signals collected by passengers’ smartphones and sent through WiFi to the Boa web server which shows the vibration comfort on the LCD deployed in bus and maybe trigger alarm lamp when the vibration is beyond the threshold. Three challenges here have been overcome: firstly, space coordinate transformation algorithm is used to solve the constant drift of signals collected; secondly, a low-pass filter is designed to isolate gravity from signals real-timely via limited computing resources; thirdly, an embedded evaluation system is developed according to the calculation procedure specified by criterion ISO 2631-1997. Meanwhile, the model proposed is tested in a practical running environment, the vibration data in whole travel are recorded and analyzed offline. The results show that comfort degree of vibration obtained from the experimental system is identical with the truth, and this mode is proved to be effective.

  11. Molecular vibrational energy flow

    Science.gov (United States)

    Gruebele, M.; Bigwood, R.

    This article reviews some recent work in molecular vibrational energy flow (IVR), with emphasis on our own computational and experimental studies. We consider the problem in various representations, and use these to develop a family of simple models which combine specific molecular properties (e.g. size, vibrational frequencies) with statistical properties of the potential energy surface and wavefunctions. This marriage of molecular detail and statistical simplification captures trends of IVR mechanisms and survival probabilities beyond the abilities of purely statistical models or the computational limitations of full ab initio approaches. Of particular interest is IVR in the intermediate time regime, where heavy-atom skeletal modes take over the IVR process from hydrogenic motions even upon X H bond excitation. Experiments and calculations on prototype heavy-atom systems show that intermediate time IVR differs in many aspects from the early stages of hydrogenic mode IVR. As a result, IVR can be coherently frozen, with potential applications to selective chemistry.

  12. 基于复合疲劳试验的涡轮叶片振动应力反推法%Inverse method for estimating the vibration stress of turbine blades based on combined high-and-low cycle fatigue tests

    Institute of Scientific and Technical Information of China (English)

    孙瑞杰; 闫晓军; 聂景旭

    2012-01-01

    提出了一种利用复合疲劳试验和外场故障数据反推涡轮叶片实际振动应力的方法.该方法针对与故障叶片同批次的叶片,开展数个振动应力水平下的单件试验和某一特定振动应力水平下的成组试验,利用极大似然法推导出叶片的概率-应力一寿命曲线(P—S—N);最后基于99.87%存活率下的概率-应力-寿命曲线(P99.87%-S—N),结合叶片的外场故障统计结果,反推出叶片实际工作中振动应力的范围和可能的最大振动应力.%An inverse method based on combined high-and-low cycle fatigue (HCF/ LCF) tests and the outfield practical failure data was developed to estimate the vibration stress of the turbine blade in working condition. All the test specimens of the turbine blades owned the same production procedures as the outfield failure blades. Two groups of HCF/ LCF tests were performed, one was median life test at six vibration stress levels, and the other was life dispersion test at a given vibration stress level. Then, P-S-N curves were extrapolated with the maximum likelihood method. Finally, vibration stress of the turbine blade in working condition was determined by the P99.87%-S-N curve combined with the statistical life of the outfield practical failure data.

  13. The study of the determination of subjective vibration velocity rating of main transformer under operating in nuclear power plant

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Wook Ryun; Lee, Jun Shin; Kim, Byong Han; Lee, Sang Kil; Lee, Sang Guk [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    2005-07-01

    Main transformer's integrity assessment in nuclear power plant is estimated by the electrical test of electrical core and wire and the chemical analysis of insulating oil. Mechanical test or analysis has not been so far. So this study makes it with the vibration velocity rating. The vibration velocity ratings in main transformer that is based on the real data from vibration velocity measurement under operating and other machinery vibration code such as ISO code is renewed.

  14. Vibration of safety injection pump motors

    Energy Technology Data Exchange (ETDEWEB)

    Wattrelos, D.

    1996-12-01

    This paper covers a fault encountered in the safety injection pump motors of the French 900 MWe unit nuclear power stations. This fault was not revealed either during the low pressure safety injection and containment spray system pump qualification tests under accident conditions or during the special tests on a test bench carried out to attempt to replicate the fault and to identify ways of remedying it. This constitutes a potential common mode of failure of the safety injection system and the containment spray system pumps. The vibration phenomena illustrate the importance of carrying out tests in the plants under conditions as close as possible to those of actual accident situations.

  15. Piezoelectric energy harvesting from hybrid vibrations

    Science.gov (United States)

    Yan, Zhimiao; Abdelkefi, Abdessattar; Hajj, Muhammad R.

    2014-02-01

    The concept of harvesting energy from ambient and galloping vibrations of a bluff body with a triangular cross-section geometry is investigated. A piezoelectric transducer is attached to the transverse degree of freedom of the body in order to convert these vibrations to electrical energy. A coupled nonlinear distributed-parameter model is developed that takes into consideration the galloping force and moment nonlinearities and the base excitation effects. The aerodynamic loads are modeled using the quasi-steady approximation. Linear analysis is performed to determine the effects of the electrical load resistance and wind speed on the global damping and frequency of the harvester as well as on the onset of instability. Then, nonlinear analysis is performed to investigate the impact of the base acceleration, wind speed, and electrical load resistance on the performance of the harvester and the associated nonlinear phenomena that take place. The results show that, depending on the interaction between the base and galloping excitations, and the considered values of the wind speed, base acceleration, and electrical load resistance, different nonlinear phenomena arise while others disappear. Short- and open-circuit configurations for different wind speeds and base accelerations are assessed. The results show that the maximum levels of harvested power are accompanied by a minimum transverse displacement when varying the electrical load resistance.

  16. Pickin’ up good vibrations

    CERN Multimedia

    Katarina Anthony

    2015-01-01

    In preparation for the civil engineering work on the HL-LHC, vibration measurements were carried out at the LHC’s Point 1 last month. These measurements will help evaluate how civil engineering work could impact the beam, and will provide crucial details about the site’s geological make-up before construction begins.   A seismic truck at Point 1 generated wave-like vibrations measured by EN/MME. From carrying out R&D to produce state-of-the-art magnets to developing innovative, robust materials capable of withstanding beam impact, the HL-LHC is a multi-faceted project involving many groups and teams across CERN’s departments. It was in this framework that the project management mandated CERN's Mechanical and Materials Engineering (EN/MME) group to measure the propagation of vibrations around Point 1. Their question: can civil engineering work for the HL-LHC – the bulk of which is scheduled for LS2 – begin while the LHC is running? Alth...

  17. Vibrating Rays Theory

    CERN Document Server

    Bilbao, Luis; Minotti, Fernando

    2014-01-01

    The present work is aimed to explain why we started to consider Vibrating Rays Theory (VRT) as a viable representation of nature, and to elaborate some of its consequences. In 1846 Faraday introduced the concept of vibrating rays, in which an atom is conceived as having rays that extend to infinity and move with it. According to this point of view, electromagnetic radiative phenomena correspond to vibration of these rays, which propagate at speed c relative to the rays (and the atom). Although a discussion on this subject might seem to be out-of-date, there are many reasons that justified this debate. The first reason is based on the fact that the constancy of the speed of light, irrespective of the source movement, has not been demonstrated experimentally in a conclusive way. In fact, only ballistic emission theories can be discarded by the experimental results. The second reason is based on the fact that study of radiometric data from spacecrafts indicates the existence of different kinds of anomalous Doppl...

  18. Vibrational stability of graphene

    Directory of Open Access Journals (Sweden)

    Yangfan Hu

    2013-05-01

    Full Text Available The mechanical stability of graphene as temperature rises is analyzed based on three different self-consistent phonon (SCP models. Compared with three-dimensional (3-D materials, the critical temperature Ti at which instability occurs for graphene is much closer to its melting temperature Tm obtained from Monte Carlo simulation (Ti ≃ 2Tm, K. V. Zakharchenko, A. Fasolino, J. H. Los, and M. I. Katsnelson, J. Phys. Condens. Matter 23, 202202. This suggests that thermal vibration plays a significant role in melting of graphene while melting for 3-D materials is often dominated by topologic defects. This peculiar property of graphene derives from its high structural anisotropy, which is characterized by the vibrational anisotropic coefficient (VAC, defined upon its Lindermann ratios in different directions. For any carbon based material with a graphene-like structure, the VAC value must be smaller than 5.4 to maintain its stability. It is also found that the high VAC value of graphene is responsible for its negative thermal expansion coefficient at low temperature range. We believe that the VAC can be regarded as a new criterion concerning the vibrational stability of any low-dimensional (low-D materials.

  19. The effects of ambient impurities on the surface tension

    Directory of Open Access Journals (Sweden)

    Ponce-Torres A.

    2016-01-01

    Full Text Available A liquid bridge is a liquid column held captive between two coaxial and parallel solid disks. It is an excellent test bench where measuring the surface tension. In this paper, we used this fluid configuration to examine experimentally the effects of ambient impurities on the surface tension over time. For this purpose, the liquid bridge equilibrium shape was analyzed when the liquid bridge was surrounded by three environments: the uncontrolled ambient, and both air and argon encapsulated in a small glass cover. Ambient contamination produced a sharp decrease of the surface tension of ultra-pure water. The presence of an anionic surfactant in the free surface of an aqueous solution did not inhibit the action of impurities coming from the ambient. Impurities can influence the dynamical behavior of the free surface in flows dominated by the surface tension. Therefore, a careful control of that influence can be crucial in many applications of fluid mechanics.

  20. The effects of ambient impurities on the surface tension

    Science.gov (United States)

    Ponce-Torres, A.; Vega, E. J.

    2016-03-01

    A liquid bridge is a liquid column held captive between two coaxial and parallel solid disks. It is an excellent test bench where measuring the surface tension. In this paper, we used this fluid configuration to examine experimentally the effects of ambient impurities on the surface tension over time. For this purpose, the liquid bridge equilibrium shape was analyzed when the liquid bridge was surrounded by three environments: the uncontrolled ambient, and both air and argon encapsulated in a small glass cover. Ambient contamination produced a sharp decrease of the surface tension of ultra-pure water. The presence of an anionic surfactant in the free surface of an aqueous solution did not inhibit the action of impurities coming from the ambient. Impurities can influence the dynamical behavior of the free surface in flows dominated by the surface tension. Therefore, a careful control of that influence can be crucial in many applications of fluid mechanics.

  1. Ambiente juvenil: discurso ambiental entre jóvenes universitarios

    OpenAIRE

    Quinn-Anderson, William C.

    2008-01-01

    Esta tesis pretende hacer una aportación al conocimiento del medio ambiente del occidente de México, específicamente de la zona metropolitana de Guadalajara, a partir del estudio de la cultura ambiental manifestada en el discurso de los jóvenes universitarios del ITESO. La apuesta es que puede ser provechoso considerar dentro del concepto de “medio ambiente” no solamente componentes bióticos y abióticos, sino también elementos socioculturales como cultura y significado. Es evidente que hay in...

  2. Method of analyzing vibration characteristics of armature system of hermetically sealed electromagnetic relay

    Institute of Scientific and Technical Information of China (English)

    REN Wan-bin; CUI Li; LUO Fu-biao; ZHAI Guo-fu

    2007-01-01

    Published research is minimal on vibration characteristics of hermetically sealed electromagnetic relay (EMR) exposed to mechanical environment. The vibration characteristics of armature system, link contact system with electromagnetic system will cause EMR malfunction. The nonlinear dynamics model of armature systems was studied by considering electromagnetic attraction force and opposite mechanical force in this paper. Angular displacements of armature under different sinusoidal vibration conditions are solved in order to obtain the failure mode result from armature system. Vibration tests showed the presented analyzing method is suitable for EMR. The conclusions are instructive for increasing vibration resistance of armature systems of EMR, and are significant for reliability design of switch apparatus.

  3. Vibration reduction on automotive shafts using piezoceramics

    Science.gov (United States)

    Kunze, Holger; Riedel, Mathias; Schmidt, Knut; Bianchini, Emanuele

    2003-08-01

    This paper reports an experimental study on active vibration reduction for automotive shafts with the use of piezoelectric material. The work focuses on an axle of an Audi A2. The demand in the automobile sector for higher comfort in the vehicle is of a great importance alongside the requirements of lighter weight and low fuel consumption. These requirements are typically in conflict with each other. One solution is the use of intelligent materials instead of viscoelastic materials and proof mass absorbers. These solutions are quite heavy especially at low frequencies. Active vibration control and piezoelectric devices are advantageous in this application due to their low mass to performance ratio. Our research study explores the use of such piezoelectric devices for an axle. In conjunction with electronics it will reduce vibrations in the first natural bending mode of the axle. Laboratory tests simulated the condition present in the road. At first a stationary set up was used, then a simulated disturbance was input at the attachment points of the shaft. Finally, a test with rotating shaft was performed. Piezoelectric devices (custom QuickPacks from ACX, a Division of Cymer) were used as sensors and as actuators to properly control the axle during the different operating conditions. The power consumption of each actuator pair was less than 20W. The work described here details the test setup, the control strategy, the hardware implementation as well as the test results obtained.

  4. 破碎机引起的钢-混凝土混合结构工业厂房振动测试与治理%Vibration test and treatment for an industrial building with a steel-concrete hybrid structure induced by crushers

    Institute of Scientific and Technical Information of China (English)

    朱丽华; 白国良; 曾金盛; 姜孔毅

    2012-01-01

    A crushing and screening plant in a mining enterprise is a steel-concrete hybrid structure. There are nine crushers in the factory building, and the foundation of crushers is not separated from the main plant structure. The working disturbing force of crushers leads to serious structural vibration. The structural dynamic characteristic parameters are tested on site with the way of crane impact force and ground microtremor, and then the vibration linear displacement of the whole structure and machine foundation platform under different work states of crushers are measured. According to the test results the vibration safety of the factory building is evaluated. A finite element model is established by using ANSYS , and then modal analysis and harmonic response analysis are performed. The analysis results are compared with the test results in order to verify the accuracy of the finite element model, and then the magnitude of the structural vibration displacement after the reformation of crushers is predicted. The structural vibration is tested again after reformation of two crushers. The test results show that the structural vibration is significantly decreased and the test results show that they are agreeable to the predicted results. The vibration test method and treatment method presented by this paper can provide a reference for the similar industrial buildings with vibration overrun problem.%某工矿企业破碎筛分车间为钢-混凝土混合结构厂房,布置有9台破碎机,且破碎机基础与主厂房结构没有脱开.破碎机的工作扰力导致结构振动严重.利用吊车冲击和地脉动现场实测了结构动力特性参数,而后测试了破碎机不同开启工况下的结构整体和设备基础的振动线位移,根据实测值评估了厂房的振动安全性.采用ANSYS(R)程序建立有限元模型,进行模态分析和谐响应分析,并与实测结果进行对比分析,以验证有限元模型的准确性,再预测破碎机改造

  5. Airflow induced vibration of the Si-IT prototype

    CERN Document Server

    Dijkstra, H; De Aguiar, V; Rigo, V

    2014-01-01

    In this note we present the results of air-flow induced vibration tests performed on mechanical prototypes of the Si option of the Inner Tracker upgrade. We made a modal analyze where we observed the eigenfrequency of the Si-ladder structure at ∼30 Hz as previously measured at CERN. Flowing dry-air to cool the prototypes we do not observe a lock-in state of the vortex induced vibration (VIV). The maximum observed vibration amplitude is calculated. We conclude that the VIV excites the eigenfrequency almost independently from the air-flow speed, and with an amplitude which does not damage the structure.

  6. Ice induced vibrations of offshore structures

    Directory of Open Access Journals (Sweden)

    E.A. Salganik

    2014-06-01

    Full Text Available The aim of the article was to analyze the process of the dynamic interaction between ice and offshore structures and find conditions of vibration beginnings. The problems of creating a full-scale finite element model of ice and offshore structure interaction and comparison of the received results of vibration conditions with the field data were solved. Modeling was realized with the finite element analysis software ANSYS. The problems of modeling cracks formation, checking the multilateral model using basic ice strength tests and finding ice loads level on different types of structures were solved in order to create a destructible ice model. The object of the investigation is the role of elastic and inertial offshore structure parameters and geometrical and dynamical ice field parameters in the process of ice-induced structure vibrations. Molikpaq drilling and oil production platform in Canada and Norströmsgrund lighthouse in Sweden were chosen as objects for modeling. The research contains verification of the results, their comparison to field data, load magnitudes from ISO 19906 «Petroleum and natural gas industries – Arctic offshore structures» algorithm and results of discrete element modeling. The results are acceptable in comparison with the results of other ice-induced vibration research.

  7. Vibration isolation of automotive vehicle engine using periodic mounting systems

    Science.gov (United States)

    Asiri, S.

    2005-05-01

    mounting systems with plain and periodic mounts will be studied first. The dynamic characteristics of such systems will be obtained experimentally in both cases. The tests will be then carried out to study the performance characteristics of periodic mounts with geometrical and/or material periodicity. The effectiveness of the periodicity on the vibration levels of mounting systems will be demonstrated theoretically and experimentally. Finally, the experimental results will be compared with the theoretical predictions.

  8. Conhecimento, interdisciplinaridade e Psicologia Ambiental

    Directory of Open Access Journals (Sweden)

    Ombretta Romice

    2005-01-01

    Full Text Available Responde às questões - como os métodos da Psicologia Ambiental devem ser discutidos em um enquadramento interdisciplinar; a Psicologia Ambiental pede alguma abordagem metodológica especial; como a intervenção ambiental é determinada pela interdisciplinaridade; quais são estas disciplinas e como elas se relacionam entre si - baseando-se em experiências profissionais como orientador em um projeto com comunidade, com habitação popular e exclusão social em vários países da Europa, e como consultora. Conclui que as abordagens usadas pelas diferentes profissões são muito separadas, e que apenas metas comuns não são suficientes, sendo também necessários um treino conjunto e identidade de valores.

  9. VIBRATION ISOLATION SYSTEM PROBABILITY ANALYSIS

    Directory of Open Access Journals (Sweden)

    Smirnov Vladimir Alexandrovich

    2012-10-01

    Full Text Available The article deals with the probability analysis for a vibration isolation system of high-precision equipment, which is extremely sensitive to low-frequency oscillations even of submicron amplitude. The external sources of low-frequency vibrations may include the natural city background or internal low-frequency sources inside buildings (pedestrian activity, HVAC. Taking Gauss distribution into account, the author estimates the probability of the relative displacement of the isolated mass being still lower than the vibration criteria. This problem is being solved in the three dimensional space, evolved by the system parameters, including damping and natural frequency. According to this probability distribution, the chance of exceeding the vibration criteria for a vibration isolation system is evaluated. Optimal system parameters - damping and natural frequency - are being developed, thus the possibility of exceeding vibration criteria VC-E and VC-D is assumed to be less than 0.04.

  10. Report of workshop on vibration related to fluid in atomic energy field. 4

    International Nuclear Information System (INIS)

    This is the fourth workshop on the vibration related to fluid in atomic energy field of Yayoi research group. This time, two topics were taken up. One is edgetone phenomena and the liquid surface vibration phenomena due to flow. Another is the introduction of the experience in light water reactors. The workshop was held on August 30 and 31, 1993 at Nuclear Engineering Research Laboratory, University of Tokyo. At the workshop, lectures were given on the mechanism of occurrence of edgetone, the theoretical analysis of edgetone and edgenoise, the self-excited vibration of free liquid surface due to vertical plane jet and vertical cylindrical jet, the research on flow instability phenomena in parallel loop system, the irregular vibration behavior of U-shaped tubes excited by flow, the research on the vibration of cyclindrical weir due to fluid discharge, the examples of the vibration related to fluid in LWRs, the estimation of fatigue phenomena in bearing rings, the vibration of rotary vanes and verifying test, the analysis of flow in isolated phase bus plate vane and the measurement of velocity distribution, flow in piping and the behavior of valve vibration, the condition for the occurrence of flow vibration in the main steam separation valve of BWR, the vibration of piping due to orifice, the analysis of flow in two-dimensional vibrating cascade, and the subjects of fluid vibration assessment in atomic energy. (K.I.)

  11. Ambient cosmology and spacetime singularities

    CERN Document Server

    Antoniadis, Ignatios

    2015-01-01

    We present a new approach to the issues of spacetime singularities and cosmic censorship in general relativity. This is based on the idea that standard 4-dimensional spacetime is the conformal infinity of an ambient metric for the 5-dimensional Einstein equations with fluid sources. We then find that the existence of spacetime singularities in four dimensions is constrained by asymptotic properties of the ambient 5-metric, while the non-degeneracy of the latter crucially depends on cosmic censorship holding on the boundary.

  12. Ambient cosmology and spacetime singularities

    Energy Technology Data Exchange (ETDEWEB)

    Antoniadis, Ignatios [Bern University, Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, Bern (Switzerland); Ecole Polytechnique, Palaiseau (France); Cotsakis, Spiros [CERN, Theory Division, Department of Physics, Geneva 23 (Switzerland); National Technical University, School of Applied Mathematics and Physical Sciences, Athens (Greece)

    2015-01-01

    We present a new approach to the issues of spacetime singularities and cosmic censorship in general relativity. This is based on the idea that standard 4-dimensional spacetime is the conformal infinity of an ambient metric for the 5-dimensional Einstein equations with fluid sources. We then find that the existence of spacetime singularities in four dimensions is constrained by asymptotic properties of the ambient 5-metric, while the non-degeneracy of the latter crucially depends on cosmic censorship holding on the boundary. (orig.)

  13. Medio ambiente y responsabilidad social

    OpenAIRE

    Roa Buitrago, Rosa Isabel

    2012-01-01

    Las organizaciones, dentro de los procesos de responsabilidad social y con el fin de mejorar la calidad de vida de las comunidades que impactan, han optado por proteger y preservar el medio ambiente de acuerdo a ciertos protocolos y normas internacionales que generan una cultura al respecto. Este cuaderno de investigación aborda la norma ISO 26000, la cual asume el tema de la Responsabilidad Social Empresarial (RSE) en materia de medio ambiente y es una guía para ser implementada en las orga...

  14. Los estudios sobre el ambiente y la ciencia ambiental

    Directory of Open Access Journals (Sweden)

    Amelia Nancy Giannuzzo

    2010-03-01

    Full Text Available La existencia de la ciencia ambiental es reconocida en libros, revistas de publicación científica y carreras de grado y posgrado. Sin embargo, se desconoce su existencia en forma literal o indirecta, al no ser considerado su aporte, por ejemplo, en los planteos referidos sobre la ciencia y la tecnología de la sustentabilidad. En este trabajo se presentan estos antecedentes, relacionándolos con el objetivo del mismo, que es el de aportar a la dilucidación de la existencia y conformación de la ciencia ambiental. Para esto, se analiza la relación de las disciplinas con la dimensión compleja del ambiente como objeto de estudio y aspectos metodológicos derivados. A los fines de aportar al esclarecimiento conceptual, se identifican las distintas acepciones de ambiente comúnmente referidas en la bibliografía. Además, se discuten aspectos relacionados de multidisciplinariedad, interdisciplinariedad y transdisciplinariedad, y sobre el status epistémico de la ciencia ambiental. Se concluye que una mayor precisión conceptual embasada en un marco compartido por las disciplinas que estudian el ambiente, incluida la ciencia ambiental, y los distintos actores involucrados en las problemáticas ambientales, favorecerá el refinamiento de las metodologías tendientes a disminuir la fragmentación de las investigaciones concernientes y las aplicaciones para su resolución.The existence of an environmental science is recognized in books, journals of science as well as in undergraduate and graduate studies. Its existence, however, is unknown either literally or indirectly when, for instance, its contribution to topics connected to the science and technology of sustainability is not considered. This background is presented in this paper and connected to its objective, which is to elucidate the existence and structure of the environmental science. To this goal, I analyse the relationship of the disciplines with the complex dimension of the environment

  15. Computer analysis of railcar vibrations

    Science.gov (United States)

    Vlaminck, R. R.

    1975-01-01

    Computer models and techniques for calculating railcar vibrations are discussed along with criteria for vehicle ride optimization. The effect on vibration of car body structural dynamics, suspension system parameters, vehicle geometry, and wheel and rail excitation are presented. Ride quality vibration data collected on the state-of-the-art car and standard light rail vehicle is compared to computer predictions. The results show that computer analysis of the vehicle can be performed for relatively low cost in short periods of time. The analysis permits optimization of the design as it progresses and minimizes the possibility of excessive vibration on production vehicles.

  16. Radial Variations of Vibrational Properties of Three Tropical Woods

    OpenAIRE

    Zhang, Tian; Bai, Shu-Lin; Bardet, Sandrine; Alméras, Tancrède; Thibaut, Bernard; Beauchêne, Jacques

    2011-01-01

    International audience Radial trends of vibrational properties, including the specific dynamic modulus (E'/r) and damping coefficient (tand), were investigated for 3 tropical rainforest hardwood species, Simarouba amara, Carapa procera and Symphonia globulifera by free-free flexural vibration test. The microfibril angle (MFA) was estimated through X-Ray diffraction. Consistent patterns of radial variations were observed for all studied properties. E'/r was found to decrease from pith to ba...

  17. Vibrations of a delivery car excited by railway track crossing

    International Nuclear Information System (INIS)

    Vertical vibrations of a delivery car passing through railway tracks have been investigated in this paper. The application of recurrence plots allows to examine short time series of acceleration non-stationary courses. Recurrence quantification analysis and square deviations estimated in small windows have been used to monitor car vibrations and transient behaviour. Measuring acceleration on the 'sprung' and 'unsprung' masses of a vehicle has enabled also to test the quality of a car suspension.

  18. The effect of cooling water on magnet vibrations

    CERN Document Server

    Redaelli, S; Coosemans, Williame; Schnell, Wolfgang

    2002-01-01

    The quadrupole magnets in the CLIC Test Facility II (CTF2) incorporate a water cooling circuit. In the frame-work of the CLIC stability study, the mechanical vibrations of the magnets were measured for different flows of cool-ing water. We present the results and compare them with simple theoretical estimates. It is shown that the vibra-tion requirements of the Compact LInear Collider (CLIC) quadrupoles with cooling water can basically be met.

  19. Chaotic vortex induced vibrations

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, J.; Sheridan, J. [Fluids Laboratory for Aeronautical and Industrial Research (FLAIR), Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, Victoria 3800 (Australia); Leontini, J. S. [Department of Mechanical and Product Design Engineering, Swinburne University of Technology, Hawthorn, Victoria 3122 (Australia); Lo Jacono, D. [Institut de Mécanique des Fluides de Toulouse (IMFT), CNRS, UPS and Université de Toulouse, 31400 Toulouse (France)

    2014-12-15

    This study investigates the nature of the dynamic response of an elastically mounted cylinder immersed in a free stream. A novel method is utilized, where the motion of the body during a free vibration experiment is accurately recorded, and then a second experiment is conducted where the cylinder is externally forced to follow this recorded trajectory. Generally, the flow response during both experiments is identical. However, particular regimes exist where the flow response is significantly different. This is taken as evidence of chaos in these regimes.

  20. Lattice Vibrations in Chlorobenzenes:

    DEFF Research Database (Denmark)

    Reynolds, P. A.; Kjems, Jørgen; White, J. W.

    1974-01-01

    Lattice vibrational dispersion curves for the ``intermolecular'' modes in the triclinic, one molecule per unit cell β phase of p‐C6D4Cl2 and p‐C6H4Cl2 have been obtained by inelastic neutron scattering. The deuterated sample was investigated at 295 and at 90°K and a linear extrapolation to 0°K...... by consideration of electrostatic forces or by further anisotropy in the dispersion forces not described in the atom‐atom model. Anharmonic effects are shown to be large, but the dominant features in the temperature variation of frequencies are describable by a quasiharmonic model....

  1. Structural Acoustics and Vibrations

    Science.gov (United States)

    Chaigne, Antoine

    This structural chapter is devoted to vibrations of structures and to their coupling with the acoustic field. Depending on the context, the radiated sound can be judged as desirable, as is mostly the case for musical instruments, or undesirable, like noise generated by machinery. In architectural acoustics, one main goal is to limit the transmission of sound through walls. In the automobile industry, the engineers have to control the noise generated inside and outside the passenger compartment. This can be achieved by means of passive or active damping. In general, there is a strong need for quieter products and better sound quality generated by the structures in our daily environment.

  2. Nonlinear interferometric vibrational imaging

    CERN Document Server

    Marks, D L

    2003-01-01

    Coherent Anti-Stokes Raman Scattering (CARS) processes are ``coherent,'' but the phase of the anti-Stokes radiation is usually lost by most incoherent spectroscopic CARS measurements. We propose a novel Raman microscopy imaging method called Nonlinear Interferometric Vibrational Imaging, which measures Raman spectra by obtaining the temporal anti-Stokes signal through nonlinear interferometry. With a more complete knowledge of the anti-Stokes signal, we show through simulations that a high-resolution Raman spectrum can be obtained of a molecule in a single pulse using broadband radiation. This could be useful for identifying the three-dimensional spatial distribution of molecular species in tissue.

  3. Anharmonic vibrations in nuclei

    CERN Document Server

    Fallot, M; Andrés, M V; Catara, F; Lanza, E G; Scarpaci, J A; Chomaz, Ph.

    2003-01-01

    In this letter, we show that the non-linearitites of large amplitude motions in atomic nuclei induce giant quadrupole and monopole vibrations. As a consequence, the main source of anharmonicity is the coupling with configurations including one of these two giant resonances on top of any state. Two-phonon energies are often lowered by one or two MeV because of the large matrix elements with such three phonon configurations. These effects are studied in two nuclei, 40Ca and 208Pb.

  4. Spent Nuclear Fuel Vibration Integrity Study

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jy-An John [ORNL; Wang, Hong [ORNL; Jiang, Hao [ORNL; Yan, Yong [ORNL; Bevard, Bruce Balkcom [ORNL

    2016-01-01

    The objective of this research is to collect dynamic experimental data on spent nuclear fuel (SNF) under simulated transportation environments using the Cyclic Integrated Reversible-Bending Fatigue Tester (CIRFT), the hot-cell testing technology developed at Oak Ridge National Laboratory (ORNL). The collected CIRFT data will be utilized to support ongoing spent fuel modeling activities, and support SNF transportation related licensing issues. Recent testing to understand the effects of hydride reorientation on SNF vibration integrity is also being evaluated. CIRFT results have provided insight into the fuel/clad system response to transportation related loads. The major findings of CIRFT on the HBU SNF are as follows: SNF system interface bonding plays an important role in SNF vibration performance, Fuel structure contributes to the SNF system stiffness, There are significant variations in stress and curvature of SNF systems during vibration cycles resulting from segment pellets and clad interaction, and SNF failure initiates at the pellet-pellet interface region and appears to be spontaneous. Because of the non-homogeneous composite structure of the SNF system, finite element analyses (FEA) are needed to translate the global moment-curvature measurement into local stress-strain profiles. The detailed mechanisms of the pellet-pellet and pellet-clad interactions and the stress concentration effects at the pellet-pellet interface cannot be readily obtained directly from a CIRFT system measurement. Therefore, detailed FEA is used to understand the global test response, and that data will also be presented.

  5. Scale modeling flow-induced vibrations of reactor components

    International Nuclear Information System (INIS)

    Similitude relationships currently employed in the design of flow-induced vibration scale-model tests of nuclear reactor components are reviewed. Emphasis is given to understanding the origins of the similitude parameters as a basis for discussion of the inevitable distortions which occur in design verification testing of entire reactor systems and in feature testing of individual component designs for the existence of detrimental flow-induced vibration mechanisms. Distortions of similitude parameters made in current test practice are enumerated and selected example tests are described. Also, limitations in the use of specific distortions in model designs are evaluated based on the current understanding of flow-induced vibration mechanisms and structural response

  6. Principal Components Analysis of Triaxial Vibration Data From Helicopter Transmissions

    Science.gov (United States)

    Tumer, Irem Y.; Huff, Edward M.

    2001-01-01

    Research on the nature of the vibration data collected from helicopter transmissions during flight experiments has led to several crucial observations believed to be responsible for the high rates of false alarms and missed detections in aircraft vibration monitoring systems. This work focuses on one such finding, namely, the need to consider additional sources of information about system vibrations. In this light, helicopter transmission vibration data, collected using triaxial accelerometers, were explored in three different directions, analyzed for content, and then combined using Principal Components Analysis (PCA) to analyze changes in directionality. In this paper, the PCA transformation is applied to 176 test conditions/data sets collected from an OH58C helicopter to derive the overall experiment-wide covariance matrix and its principal eigenvectors. The experiment-wide eigenvectors. are then projected onto the individual test conditions to evaluate changes and similarities in their directionality based on the various experimental factors. The paper will present the foundations of the proposed approach, addressing the question of whether experiment-wide eigenvectors accurately model the vibration modes in individual test conditions. The results will further determine the value of using directionality and triaxial accelerometers for vibration monitoring and anomaly detection.

  7. TERCEIRO SETOR E MEIO AMBIENTE

    OpenAIRE

    Melo, Marina Félix de

    2012-01-01

    Objetivamos discutir, brevemente, como têm se dado as discussões sobre o Terceiro Setor brasileiro e, particularmente, sobre as ONGs que atuam em defesa do meio ambiente, levantando questionamentos acerca das limitações enfrentadas pelo Terceiro Setor neste contexto

  8. Shape analysis for mobile ambients

    DEFF Research Database (Denmark)

    Nielson, Hanne Riis; Nielson, Flemming

    2001-01-01

    The ambient calculus is a calculus of computation that allows active processes to move between sites. We present an analysis inspired by state-of-the-art pointer analyses that safely and accurately predicts which processes may turn up at what sites during the execution of a composite system...

  9. Abstract Interpretation of Mobile Ambients

    DEFF Research Database (Denmark)

    Hansen, René Rydhof; Jensen, J. G.; Nielson, Flemming;

    1999-01-01

    We demonstrate that abstract interpretation is useful for analysing calculi of computation such as the ambient calculus (which is based on the p-calculus); more importantly, we show that the entire development can be expressed in a constraint-based formalism that is becoming exceedingly popular...

  10. Shape analysis for Mobile Ambients

    DEFF Research Database (Denmark)

    Nielson, Hanne Riis; Nielson, Flemming

    2000-01-01

    The ambient calculus is a calculus of computation that allows active processes to move between sites. We present an analysis inspired by state-of-the-art pointer analyses that safety and accurately predicts which processes may turn up at what sites during the execution of a composite system...

  11. La crisis del medio ambiente

    Directory of Open Access Journals (Sweden)

    Juan Carlos Quintero Vélez

    2013-07-01

    Full Text Available Este artículo, introducción al tema del medio ambiente, pretende proporcionar conceptos básicos para analizar y dimensionar el impacto que genera el hombre sobre los sistemas que soportan la vida. Para entender estos problemas, es indispensable partir de un análisis básico de la relación entre el hombre actual, su medio ambiente, sus necesidades y sus actividades. El autor revisa los antecedentes, las causas y las consecuencias de la crisis ambiental internacional, e intenta dar explicación a la problemática nacionalen este campo, y establecer los puntos más críticos en Colombia. Finalmente, con base en los parámetros establecidos por el gobierno, se presenta el concepto de“desarrollo sostenible" como modelo que interrelaciona los procesos económicos, sociales y tecnológicos con el medio ambiente.

  12. Digital identity in ambient environments

    NARCIS (Netherlands)

    Schouten, Ben; Ambekar, Onkar

    2006-01-01

    Embedded systems and ambient technology enable users to interact at any time and anywhere. In the BASIS project for identity management, CWI investigates transparent biometrics in home environments. Possible application areas are user profiling for shopping , listening to one's favourite music and o

  13. Test

    DEFF Research Database (Denmark)

    Bendixen, Carsten

    2014-01-01

    Bidrag med en kortfattet, introducerende, perspektiverende og begrebsafklarende fremstilling af begrebet test i det pædagogiske univers.......Bidrag med en kortfattet, introducerende, perspektiverende og begrebsafklarende fremstilling af begrebet test i det pædagogiske univers....

  14. Vibrational spectra and DFT calculations of sonderianin diterpene

    Science.gov (United States)

    Oliveira, I. M. M.; Santos, H. S.; Sena, D. M.; Cruz, B. G.; Teixeira, A. M. R.; Freire, P. T. C.; Braz-Filho, R.; Sousa, J. W.; Albuquerque, M. R. J. R.; Bandeira, P. N.; Bernardino, A. C. S. S.; Gusmão, G. O. M.; Bento, R. R. F.

    2015-11-01

    In the present study, the natural product sonderianin diterpene (C21H26O4), a diterpenoid isolated from Croton blanchetianus, with potential application in the drug industry, was characterized by nuclear magnetic resonance, infrared and Raman spectroscopy. Vibrational spectra were supported by Density Functional Theory calculations. Infrared and Raman spectra of sonderianin were recorded at ambient temperature in the regions from 400 cm-1 to 3600 cm-1 and from 40 cm-1 to 3500 cm-1, respectively. DFT calculations with the hybrid functional B3LYP and the basis set 6-31 G(d,p) were performed with the purpose of obtaining information on the structural and vibrational properties of this organic compound. A comparison with experimental spectra allowed us to assign all of the normal modes of the crystal. The assignment of the normal modes was carried out by means of potential energy distribution.

  15. U-shape magnetostrictive vibration based power generator for universal use

    Science.gov (United States)

    Ueno, T.

    2016-04-01

    Vibrational power generator extracts electrical energy from ambient vibration. Author invented novel configuration using magnetostrictive material. The device is based on parallel beams of iron-gallium alloy and magnetic material, and features high efficiency, high robustness, and low electrical impedance. In this paper, author proposes U-shape generator for universal use. It consists of the parallel beams and fixed and free end beams forming U-shape frame flexibly modified for variety of mechanical input. Miniature U-shape prototype using Fe-Ga rod 6 by 0.5 by 13 mm3 exhibited average power of 3.7 mW under vibration of 166 Hz and 2.5 G. L-shape type was demonstrated to generate electromotive force by two directional vibrations. In switch type, maximum energy of 0.7 mJ was retrieved by one pushing force. The performances are sufficient to drive wireless module for heath monitoring and remote control.

  16. Attenuation of cryocooler induced vibration in spaceborne infrared payloads

    Science.gov (United States)

    Veprik, A.; Twitto, A.

    2014-01-01

    Recent advancement of operational responsive space programs calls for a development of compact, reliable, low power and vibration free cryogenic cooling for sophisticated infrared payloads. The refrigeration in a typical closed cycle split Stirling linear cryocooler is achieved by a cyclic compression and expansion of a gaseous working agent due to a synchronized reciprocation of electro-dynamically and pneumatically actuated compressor and expander pistons. Attenuation of the cryocooler induced vibration usually relies on the concept of actively assisted momentum cancellation. In a typical dual-piston compressor this objective is achieved by actively synchronizing the motion of oppositely moving piston assemblies; a typical single-piston expander may be counterbalanced by a motorized counter-balancer. The above approach produces complexity, weight, size, high incurred costs and affects reliability. The authors analyze the case of passive attenuation the vibration export induced by the split Stirling linear cryocooler comprised of inline mounted single-piston compressor and expander. Placement of all the moving components onto a common axis results in a single axis consolidation of vibration export and enables use of single tuned dynamic absorber and low frequency vibration mount. From theoretical analysis and full-scale testing, the performance of such vibration protection arrangement is similar to known systems of active vibration cancellation.

  17. Prediction of silo-vibrations using a modified lambdameter

    Science.gov (United States)

    Jäckel, Stefan; Schünemann, Ralf; Mütze, Thomas; Peuker, Urs A.

    2013-06-01

    Predicting silo-vibrations is not yet universally possible but only to a very limited extent. A mechanism of excitation of silo vibrations can be found in oscillating shear stresses between the bulk solid and the inner silo wall, the so-called "wall-stick-slip" effect. So if this wall-stick-slip occurs during shear experiments in shear testers, the probability of silo-vibrations in silos will be high. However if there is no slip-stick effect observed, this will not consequently exclude silo-vibrations. The influences on a stable stick-slip were studied in wall friction experiments with a rotational shear tester and in a specially developed silo model based on a lambdameter. The examined parameters are normal stress, shear velocity, wall roughness and particle shape. Plastic pellets which are known to honk (PET, PA) and plastic pellets that do not honk (PE) are considered [1]. It is shown that the silo model based on a lambdameter is more suitable for initiation and measurement of stable wall-stick-slip of granular media than the conventional rotational shear tester. The industrial experiences in respect of silo vibrations are proved in the silo model for all tested types of plastic pellets. So, if the origin of silo vibrations is wall-stick-slip, the silo model based on a lambdameter gives a better opportunity for predicting silo vibrations. This paper gives a summary on the results obtained with the new method.

  18. Vibration Disturbance Damping System Design to Protect Payload of the Rocket

    Directory of Open Access Journals (Sweden)

    Sutisno Sutisno

    2012-12-01

    Full Text Available Rocket motor generates vibrations acting on whole rocket body including its contents. Part of the body which is sensitive to disturbance is the rocket payload. The payload consists of various electronic instruments including: transmitter, various sensors, accelerometer, gyro, the embedded controller system, and others. This paper presents research on rocket vibration influence to the payload and the method to avoid disturbance. Avoiding influence of vibration disturbance can be done using silicone gel material whose typical damping factors are relatively high. The rocket vibration was simulated using electromagnetic motor, and the vibrations were measured using an accelerometer sensor. The measurement results were displayed in the form of curve, indicating the vibration level on some parts of the tested material. Some measurement results can be applied to determine the good material to attenuate vibration disturbance on the instruments of the payload.

  19. An improved filter-u least mean square vibration control algorithm for aircraft framework

    Science.gov (United States)

    Huang, Quanzhen; Luo, Jun; Gao, Zhiyuan; Zhu, Xiaojin; Li, Hengyu

    2014-09-01

    Active vibration control of aerospace vehicle structures is very a hot spot and in which filter-u least mean square (FULMS) algorithm is one of the key methods. But for practical reasons and technical limitations, vibration reference signal extraction is always a difficult problem for FULMS algorithm. To solve the vibration reference signal extraction problem, an improved FULMS vibration control algorithm is proposed in this paper. Reference signal is constructed based on the controller structure and the data in the algorithm process, using a vibration response residual signal extracted directly from the vibration structure. To test the proposed algorithm, an aircraft frame model is built and an experimental platform is constructed. The simulation and experimental results show that the proposed algorithm is more practical with a good vibration suppression performance.

  20. Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE): emissions of trace gases and light-absorbing carbon from wood and dung cooking fires, garbage and crop residue burning, brick kilns, and other sources

    Science.gov (United States)

    Stockwell, Chelsea E.; Christian, Ted J.; Goetz, J. Douglas; Jayarathne, Thilina; Bhave, Prakash V.; Praveen, Puppala S.; Adhikari, Sagar; Maharjan, Rashmi; DeCarlo, Peter F.; Stone, Elizabeth A.; Saikawa, Eri; Blake, Donald R.; Simpson, Isobel J.; Yokelson, Robert J.; Panday, Arnico K.

    2016-09-01

    The Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE) campaign took place in and around the Kathmandu Valley and in the Indo-Gangetic Plain (IGP) of southern Nepal during April 2015. The source characterization phase targeted numerous important but undersampled (and often inefficient) combustion sources that are widespread in the developing world such as cooking with a variety of stoves and solid fuels, brick kilns, open burning of municipal solid waste (a.k.a. trash or garbage burning), crop residue burning, generators, irrigation pumps, and motorcycles. NAMaSTE produced the first, or rare, measurements of aerosol optical properties, aerosol mass, and detailed trace gas chemistry for the emissions from many of the sources. This paper reports the trace gas and aerosol measurements obtained by Fourier transform infrared (FTIR) spectroscopy, whole-air sampling (WAS), and photoacoustic extinctiometers (PAX; 405 and 870 nm) based on field work with a moveable lab sampling authentic sources. The primary aerosol optical properties reported include emission factors (EFs) for scattering and absorption coefficients (EF Bscat, EF Babs, in m2 kg-1 fuel burned), single scattering albedos (SSAs), and absorption Ångström exponents (AAEs). From these data we estimate black and brown carbon (BC, BrC) emission factors (g kg-1 fuel burned). The trace gas measurements provide EFs (g kg-1) for CO2, CO, CH4, selected non-methane hydrocarbons up to C10, a large suite of oxygenated organic compounds, NH3, HCN, NOx, SO2, HCl, HF, etc. (up to ˜ 80 gases in all). The emissions varied significantly by source, and light absorption by both BrC and BC was important for many sources. The AAE for dung-fuel cooking fires (4.63 ± 0.68) was significantly higher than for wood-fuel cooking fires (3.01 ± 0.10). Dung-fuel cooking fires also emitted high levels of NH3 (3.00 ± 1.33 g kg-1), organic acids (7.66 ± 6.90 g kg-1), and HCN (2.01 ± 1.25 g kg-1), where the latter could

  1. Vibrations and Stability: Solved Problems

    DEFF Research Database (Denmark)

    Thomsen, Jon Juel

    Worked out solutions for exercise problems in J. J. Thomsen 'Vibrations and Stability: Advanced Theory, Analysis, and Tools', Springer, Berlin - Heidelberg, 2003.......Worked out solutions for exercise problems in J. J. Thomsen 'Vibrations and Stability: Advanced Theory, Analysis, and Tools', Springer, Berlin - Heidelberg, 2003....

  2. The study of eccentric vibrator

    International Nuclear Information System (INIS)

    The developed mathematical model of the motion of the eccentric vibrator allowed to define two own frequencies of oscillations of the mechanical system. To confirm the nominated theoretical positions, the motion of the eccentric vibrator is simulated with the aid of the ADAMS (Automated Dynamic Analysis of Mechanical Systems) software complex

  3. Prevalence of vibration-induced white finger and assessment of vibration exposure among travertine workers in Italy.

    Science.gov (United States)

    Bovenzi, M; Franzinelli, A; Strambi, F

    1988-01-01

    Among 76 stonedrillers and stonecutters/chippers working in the Rapolano travertine quarries (Tuscany, Italy), 27 subjects (35.5%) were affected with vibration-induced white finger (VWF). The median latent period for VWF was ten years (range 0.1-26 years). A VWF prevalence of 8% was found among 60 comparable controls (P less than 0.0001). Vibration measurements showed that the frequency-weighted accelerations for two rock-drills and two small chipping hammers ranged from 19.7 to 36.4 m/s2. Weighted accelerations between 2.4 and 4.1 m/s2 were measured on the handles of a vertical grinder and a hand cutter. Vibration data, daily exposure time and total duration of exposure period were used to calculate two indicators of vibration dose such as the four-hour, energy-equivalent, frequency-weighted acceleration (m/s2) and the vibration exposure level (dB). A significant association between the vibration exposure level and the severity of VWF stages was observed among the travertine operators. The dose-effect relationship proposed by ISO 5349 was not suitable for the data of the present study because it overestimates the risk due to hand-transmitted vibration in the travertine workers. Finally, the results of a cold test indicated that the rewarming time of fingertips to room temperature was more prolonged in the operators with VWF than in those without VWF and in the controls. PMID:3198281

  4. The statistical distributed source boundary point method to calculate the acoustic radiation from the random vibrating body

    Institute of Scientific and Technical Information of China (English)

    WANGXiufeng; CHENXinzhao; LIUZhao

    2003-01-01

    The statistical distributed source boundary point method (SDSBPM) put forward is applied to calculate the acoustic radiation from the random vibrating body. A detailed description of this method is presented. A test for the SDSBPM is carried out through the random vibrating sphere and the random vibrating cuboid. An experiment on the exterior acoustic radiation of a random vibrating simulation axial box of the lathe tool is performed in a semi-anechoic chamber.

  5. The origins of vibration theory

    Science.gov (United States)

    Dimarogonas, A. D.

    1990-07-01

    The Ionian School of natural philosophy introduced the scientific method of dealing with natural phenomena and the rigorous proofs for abstract propositions. Vibration theory was initiated by the Pythagoreans in the fifth century BC, in association with the theory of music and the theory of acoustics. They observed the natural frequency of vibrating systems and proved that it is a system property and that it does not depend on the excitation. Pythagoreans determined the fundamental natural frequencies of several simple systems, such as vibrating strings, pipes, vessels and circular plates. Aristoteles and the Peripatetic School founded mechanics and developed a fundamental understanding of statics and dynamics. In Alexandrian times there were substantial engineering developments in the field of vibration. The pendulum as a vibration, and probably time, measuring device was known in antiquity, and was further developed by the end of the first millennium AD.

  6. Adaptive-passive vibration control systems for industrial applications

    Science.gov (United States)

    Mayer, D.; Pfeiffer, T.; Vrbata, J.; Melz, T.

    2015-04-01

    Tuned vibration absorbers have become common for passive vibration reduction in many industrial applications. Lightly damped absorbers (also called neutralizers) can be used to suppress narrowband disturbances by tuning them to the excitation frequency. If the resonance is adapted in-operation, the performance of those devices can be significantly enhanced, or inertial mass can be decreased. However, the integration of actuators, sensors and control electronics into the system raises new design challenges. In this work, the development of adaptive-passive systems for vibration reduction at an industrial scale is presented. As an example, vibration reduction of a ship engine was studied in a full scale test. Simulations were used to study the feasibility and evaluate the system concept at an early stage. Several ways to adjust the resonance of the neutralizer were evaluated, including piezoelectric actuation and common mechatronic drives. Prototypes were implemented and tested. Since vibration absorbers suffer from high dynamic loads, reliability tests were used to assess the long-term behavior under operational conditions and to improve the components. It was proved that the adaptive systems are capable to withstand the mechanical loads in an industrial application. Also a control strategy had to be implemented in order to track the excitation frequency. The most mature concepts were integrated into the full scale test. An imbalance exciter was used to simulate the engine vibrations at a realistic level experimentally. The neutralizers were tested at varying excitation frequencies to evaluate the tracking capabilities of the control system. It was proved that a significant vibration reduction is possible.

  7. Cryo-vacuum testing of the JWST Integrated Science Instrument Module (SPIE)

    Science.gov (United States)

    Kimble, Randy A.; Vila, M. Begona; Van Campen, Julie; Birkmann, Stephan M.; Comber, Brian J.; Fatig, Curtis C.; Glasse, Alistair C. H.; Glazer, Stuart D.; Kelly, Douglas M.; Mann, Steven D.; Martel, Andre R.; Novo-Gradac, Kevin J.; Ohl, Raymond G.; Penanen, Konstantin; Rohrbach, Scott O.; Sullivan, Joseph F.; Zak, Dean; Zhou, Julia

    2016-01-01

    In late 2015/early 2016, a major cryo-vacuum test was carried out for the Integrated Science Instrument Module (ISIM) of the James Webb Space Telescope (JWST). This test comprised the final cryo-certification and calibration test of the ISIM, after its ambient environmental test program (vibration, acoustics, EMI/EMC), and before its delivery for integration with the rest of the JWST observatory. Over the 108-day period of the round-the-clock test program, the full complement of ISIM flight instruments, structure, harness radiator, and electronics were put through a comprehensive program of thermal, optical, electrical, and operational tests. The test verified the health and excellent performance of the instruments and ISIM systems, proving the ISIM element's readiness for integration with the telescope. We report here on the context, goals, setup, execution, and key results for this critical JWST milestone.

  8. Vibration Reduction System Using Magnetic Suspension Technology

    Directory of Open Access Journals (Sweden)

    Spychała Jarosław

    2015-01-01

    Full Text Available The article presents considerations concerning the construction of vibration reduction system using magnetic suspension technology. Presents the results of simulation, numerical and experimental the bearingless electric motor, for which successfully used this type of solution. Positive results of research and testing have become the basis for the development of the concept of building this type of active vibration reduction system , at the same time acting as a support for a technical object, which is a jet engine. Bearing failures are manifested by loss or distortion of their mass, which leads to a total destruction of the roller bearing, and thus reflected in the security. The article presents the concept of building active magnetic suspension to eliminate the bearing system of classical rolling bearing and replace it with magnetic bearing.

  9. Pedestrian-induced lateral vibrations of footbridges

    DEFF Research Database (Denmark)

    Ingólfsson, Einar Thór; Georgakis, Christos T.; Jönsson, Jeppe

    2012-01-01

    The earliest scientific descriptions of excessive pedestrian-induced lateral vibrations are dated back to the 1970s, but it was not until the beginning of the new millennium that bridge engineers fully comprehended the potential negative effect of pedestrian crowds on long-span footbridges...... of studies related to pedestrian-induced lateral vibrations of footbridges is provided, primarily focusing on studies published within the last decade. Research in this field can generally be split into three categories; (i) fullscale testing of existing bridges subject to crowd loading, (ii) laboratory...... studies on human-structure interaction between single pedestrians and laterally moving platforms and (iii) mathematical modelling of the pedestrian-induced load. It is shown herein, that a significant amount of research has been carried out within each of the three categories, but there is only limited...

  10. Detection of fuel element vibration at KNK II

    International Nuclear Information System (INIS)

    The reactivity signal of the KNK-II-plant shows almost harmonic oscillations of δrho <= 0.5 c. Very sensitive correlation measurements, made during the regular plant operation with the normal plant instrumentation, revealed, that these oscillations are associated with individual fuel elements. Auxiliary measurements under various operational conditions and theoretical considerations show, that this phenomenon is probably caused by flow-induced mechanical vibration. Similar characteristics with respect to the frequencies have obviously not yet been observed for fuel element vibration during tests in out-of-core loops and in other reactors. Therefore efforts have been made in order to classify the flow-induced vibration and to identify the particular excitation mechanism. Most likely seems a flow-induced vibration of whole fuel elements by vortex shedding or jet switching. This model can explain all observations without exception. (orig.)

  11. Random Vibration Analysis of the Electronic Equipment Cabinet

    Institute of Scientific and Technical Information of China (English)

    LIU Yanping; LIU Dongqing

    2006-01-01

    In order to understand the vibration characteristic of system structure of electronic equipment cabinet within the particular vibration frequency, the finite element analysis software- ANSYS is used to simulate the tests of random vibrations of the cabinet system and obtain the isopleths graph of deformation and stress of the cabinet. It can confirm maximum of deformation and stress of the cabinet and position happened. Through more analysis of the frequency response curve, which can confirm harmful consequences random vibrations caused and weak link of the cabinet structure. The numerical simulation results are in good agreement with the experimental results. It shows that this research provides an efficient method for the anti-seismic design and the dynamic optimization design.

  12. Experimental Vibration Study on the Healthy and Delaminated Composite Plates

    International Nuclear Information System (INIS)

    Vibration based damage, in particular delamination detection, in the composite structures is an active research area. The present study is also on the dynamics of the composite plates with and without delamination based on the experimental study. The test plate made of E-glass fibre and epoxy resins has been used here. A piezo-electric shaker has been used to excite the composite plate and the acceleration responses were measured using the number of accelerometers. The dynamics of the delaminated composite plates were then compared with a healthy composite plate when the vibration experiments have been conducted at the lower modes. The paper will discuss the observations made on the measured vibration responses from both the healthy and the delaminated plates and the possibility of the delamination detection from the experimental vibration data.

  13. Vibration sensing in smart machine rotors using internal MEMS accelerometers

    Science.gov (United States)

    Jiménez, Samuel; Cole, Matthew O. T.; Keogh, Patrick S.

    2016-09-01

    This paper presents a novel topology for enhanced vibration sensing in which wireless MEMS accelerometers embedded within a hollow rotor measure vibration in a synchronously rotating frame of reference. Theoretical relations between rotor-embedded accelerometer signals and the vibration of the rotor in an inertial reference frame are derived. It is thereby shown that functionality as a virtual stator-mounted displacement transducer can be achieved through appropriate signal processing. Experimental tests on a prototype rotor confirm that both magnitude and phase information of synchronous vibration can be measured directly without additional stator-mounted key-phasor sensors. Displacement amplitudes calculated from accelerometer signals will become erroneous at low rotational speeds due to accelerometer zero-g offsets, hence a corrective procedure is introduced. Impact tests are also undertaken to examine the ability of the internal accelerometers to measure transient vibration. A further capability is demonstrated, whereby the accelerometer signals are used to measure rotational speed of the rotor by analysing the signal component due to gravity. The study highlights the extended functionality afforded by internal accelerometers and demonstrates the feasibility of internal sensor topologies, which can provide improved observability of rotor vibration at externally inaccessible rotor locations.

  14. The acute effect of vibration applications on jumping performance

    Directory of Open Access Journals (Sweden)

    Suat Yıldız

    2012-12-01

    Full Text Available Recently, vibration has become very popular as a method of exercise and training and drawn attention of researchers. The aim of this study was to analyses the acute affect of vibration applications as a method of exercise and training on jumping performance.In this study experimental group consists of 25 subjects who are studying at Physical Education and Sports Department of Sakarya University (age 22.2±1.7 years, height 179.2±4.8 cm. body weight 71.5±9.0 kg. This study included a vibration at density of 35 Hz (3x30 sec. frequency that result from aerobic exercise that has low density and b just methods of aerobic exercise (without any vibration that has low density. Subjects have taken the tests of countermovement and squat jumping after 2 minutes of each application. All applications and tests have been done in nonconsecutive days in a random scheme. In statistical analysis Wilcoxon has been applied in nonparametric scheme.For counter movement jumping; height of jumping, the difference between before and after the application of vibration related to the point of peak power and average power has been found significiant (respectively, p0.05; p>0.05; p>0.05.As a result, it is concluded that vibration that is applied at the range of 35 Hz frequency could increase the performance of acute countermovement jumping.

  15. Application of wavelet analysis in laser Doppler vibration signal denoising

    Science.gov (United States)

    Lan, Yu-fei; Xue, Hui-feng; Li, Xin-liang; Liu, Dan

    2010-10-01

    Large number of experiments show that, due to external disturbances, the measured surface is too rough and other factors make use of laser Doppler technique to detect the vibration signal contained complex information, low SNR, resulting in Doppler frequency shift signals unmeasured, can not be demodulated Doppler phase and so on. This paper first analyzes the laser Doppler signal model and feature in the vibration test, and studies the most commonly used three ways of wavelet denoising techniques: the modulus maxima wavelet denoising method, the spatial correlation denoising method and wavelet threshold denoising method. Here we experiment with the vibration signals and achieve three ways by MATLAB simulation. Processing results show that the wavelet modulus maxima denoising method at low laser Doppler vibration SNR, has an advantage for the signal which mixed with white noise and contained more singularities; the spatial correlation denoising method is more suitable for denoising the laser Doppler vibration signal which noise level is not very high, and has a better edge reconstruction capacity; wavelet threshold denoising method has a wide range of adaptability, computational efficiency, and good denoising effect. Specifically, in the wavelet threshold denoising method, we estimate the original noise variance by spatial correlation method, using an adaptive threshold denoising method, and make some certain amendments in practice. Test can be shown that, compared with conventional threshold denoising, this method is more effective to extract the feature of laser Doppler vibration signal.

  16. Piezoelectric Vibration Damping Study for Rotating Composite Fan Blades

    Science.gov (United States)

    Min, James B.; Duffy, Kirsten P.; Choi, Benjamin B.; Provenza, Andrew J.; Kray, Nicholas

    2012-01-01

    Resonant vibrations of aircraft engine blades cause blade fatigue problems in engines, which can lead to thicker and aerodynamically lower performing blade designs, increasing engine weight, fuel burn, and maintenance costs. In order to mitigate undesirable blade vibration levels, active piezoelectric vibration control has been investigated, potentially enabling thinner blade designs for higher performing blades and minimizing blade fatigue problems. While the piezoelectric damping idea has been investigated by other researchers over the years, very little study has been done including rotational effects. The present study attempts to fill this void. The particular objectives of this study were: (a) to develop and analyze a multiphysics piezoelectric finite element composite blade model for harmonic forced vibration response analysis coupled with a tuned RLC circuit for rotating engine blade conditions, (b) to validate a numerical model with experimental test data, and (c) to achieve a cost-effective numerical modeling capability which enables simulation of rotating blades within the NASA Glenn Research Center (GRC) Dynamic Spin Rig Facility. A numerical and experimental study for rotating piezoelectric composite subscale fan blades was performed. It was also proved that the proposed numerical method is feasible and effective when applied to the rotating blade base excitation model. The experimental test and multiphysics finite element modeling technique described in this paper show that piezoelectric vibration damping can significantly reduce vibrations of aircraft engine composite fan blades.

  17. Historical Ambient Air Quality Data Inventory

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Historical Ambient Air Quality Data Inventory contains measured and estimated data on ambient air pollution for use in assessing air quality, assisting in...

  18. Structural lubricity under ambient conditions

    Science.gov (United States)

    Cihan, Ebru; İpek, Semran; Durgun, Engin; Baykara, Mehmet Z.

    2016-01-01

    Despite its fundamental importance, physical mechanisms that govern friction are poorly understood. While a state of ultra-low friction, termed structural lubricity, is expected for any clean, atomically flat interface consisting of two different materials with incommensurate structures, some associated predictions could only be quantitatively confirmed under ultra-high vacuum (UHV) conditions so far. Here, we report structurally lubric sliding under ambient conditions at mesoscopic (∼4,000–130,000 nm2) interfaces formed by gold islands on graphite. Ab initio calculations reveal that the gold–graphite interface is expected to remain largely free from contaminant molecules, leading to structurally lubric sliding. The experiments reported here demonstrate the potential for practical lubrication schemes for micro- and nano-electromechanical systems, which would mainly rely on an atomic-scale structural mismatch between the slider and substrate components, via the utilization of material systems featuring clean, atomically flat interfaces under ambient conditions. PMID:27350035

  19. Fiscalidad ambiental (curso 2011-2012)

    OpenAIRE

    Gil Maciá, Lorenzo

    2012-01-01

    Tema fiscalidad ambiental. 1. Necesidad económica y jurídica de la protección del medio ambiente. 2. Características, naturaleza y clasificación de los tributos ambientales. 3. Competencias tributarias en el ámbito estatal, autonómico y local. 4. La fiscalidad ambiental en la legislación fiscal española. 5. Perspectivas de futuro en materia de imposición ambiental.

  20. Design and performance analysis of a rotary traveling wave ultrasonic motor with double vibrators.

    Science.gov (United States)

    Dong, Zhaopeng; Yang, Ming; Chen, Zhangqi; Xu, Liang; Meng, Fan; Ou, Wenchu

    2016-09-01

    This paper presents the development of a rotary traveling wave ultrasonic motor, in which a vibrating stator and vibrating rotor are combined in one motor. The stator and rotor are designed as similar structures an elastic body and a piezoelectric ceramic ring. In exciting of the piezoelectric ceramics, the elastic body of the stator and rotor will generate respective traveling waves, which force each other forward in the contact zone. Based on the elliptical rule of particle motion and matching principle of vibration, the design rules of two vibrators are determined. The finite element method is used to design the sizes of vibrators to ensure that they operate in resonance, and the simulation is verified by measuring the vibration with an impedance analyzer. It is found out that to maintain an appropriate contact between the stator and rotor, two vibrators need to be designed with close resonance frequencies, different vibration amplitudes, and be driven by an identical driving frequency. To analyze this innovative contact mechanism, particle velocity synthesis theory and contact force analysis using Hertz contact model are carried out. Finally, a prototype is fabricated and tested to verify the theoretical results. The test results show that the output performance of the motor driven by the two vibrators is significantly improved compared to the motor driven by a sole stator or rotor, which confirms the validity of the double-vibrator motor concept. PMID:27336793