• 제목/요약/키워드: Dynamic response model

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Evaluation on bridge dynamic properties and VIV performance based on wind tunnel test and field measurement

  • Yang, Yongxin;Ma, Tingting;Ge, Yaojun
    • Wind and Structures
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    • 제20권6호
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    • pp.719-737
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    • 2015
  • Full scale measurement on the structural dynamic characteristics and Vortex-induced Vibrations (VIV) of a long-span suspension bridge with a central span of 1650 m were conducted. Different Finite Element (FE) modeling principles for the separated twin-box girder were compared and evaluated with the field vibration test results, and the double-spine model was determined to be the best simulation model, but certain modification still needs to be made which will affect the basic modeling parameters and the dynamic response prediction values of corresponding wind tunnel tests. Based on the FE modal analysis results, small-scaled and large-scaled sectional model tests were both carried out to investigate the VIV responses, and probable Reynolds Number effects or scale effect on VIV responses were presented. Based on the observed VIV modes in the field measurement, the VIV results obtained from sectional model tests were converted into those of the three-dimensional (3D) full-scale bridge and subsequently compared with field measurement results. It is indicated that the large-scaled sectional model test can probably provide a reasonable and effective prediction on VIV response.

하드디스크 드라이브 액추에이터 시스템의 수학적 모델 (Mathematical Model of Hard Disk Drive Actuator System)

  • 권순억;박노열;김준오;정태건
    • 대한기계학회논문집A
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    • 제24권12호
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    • pp.3080-3087
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    • 2000
  • We obtain the mathematical model of the hard disk drive actuator system the system response data of the finite element analysis or experimental results. The model is base on the Rayleigh-Ritz method to approximate the dynamic response of the actuator system. The basic idea is to use the curve-fit technique to obtain the approximation coefficients. It allows the dynamic analysis of the actuator system without resort to the repetitive finite element modeling work. Even though the dynamic characteristics of the system of the system are affected somewhat by the structural modification and the change of the material properties, we can use the modified size and dynamic properties of the actuator system in the mathematical model to some extent. In this study, we express the mathematical model of the simplified rectangular plate first and then proceed to the actual hard disk drive actuator system.

운전자-자동차모델을 이용한 4륜조향자동차의 주행특성 해석 (Dynamic Characteristics Analysis of a Four-Wheel Steering Vehicle Using a Driver-Vehicle Model)

  • 이영화;김석일;서명원;김대영;김동룡
    • 한국자동차공학회논문집
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    • 제3권3호
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    • pp.119-128
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    • 1995
  • A driver-vehicle model means the integrated dynamic model that is able to estimate the steering wheel angle from the driver's desired path based on the dynamic characteristics of the driver and vehicle. In this paper, the dynamic characteristics of several four-wheel steering systems with the simultaneously steerable front and rear wheels are investigated and compared by means of the driver-vehicle model. Especially, the presented analysis results are obtained by using the ISO test codes such as lane change, double lane change and slalom, and the effects of the driver's steering response time and vehicle speed are examined on the responsiveness and stability of vehicle.

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액츄에이터 시스템의 수학적 모델을 이용한 HDD 공기 베어링 슬라이더의 동특성 해석 (Dynamic Analysis of HDD Air Bearing Sliders using the Mathematical Model of Actuator System)

  • 권순억;박노열;김준오;정태건
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2000년도 춘계학술대회논문집
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    • pp.485-491
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    • 2000
  • We obtain the mathematical model of the hard disk drive actuator system from the system response data of the finite element analysis or experimental results. System response data including the dynamics of the considered system are expressed as the mathematical model. It allows the dynamic analysis of the actuator system without resort to the repetitive finite element modeling work. Even though the dynamic characteristics of the system are affected somewhat by the structural modification and the change of the dynamic properties, we can use the modified size and material properties of the actuator system in the mathematical model to some extent. In this study, we express the mathematical model of the simplified rectangular plate first and then proceed to the actual hard disk drive actuator system.

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Dynamic response of an overhead transmission tower-line system to high-speed train-induced wind

  • Zhang, Meng;Liu, Ying;Liu, Hao;Zhao, Guifeng
    • Wind and Structures
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    • 제34권4호
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    • pp.335-353
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    • 2022
  • The current work numerically investigates the transient force and dynamic response of an overhead transmission tower-line structure caused by the passage of a high-speed train (HST). Taking the CRH2C HST and an overhead transmission tower-line structure as the research objects, both an HST-transmission line fluid numerical model and a transmission tower-line structure finite element model are established and validated through comparison with experimental and theoretical data. The transient force and typical dynamic response of the overhead transmission tower-line structure due to HST-induced wind are analyzed. The results show that when the train passes through the overhead transmission tower-line structure, the extreme force on the transmission line is related to the train speed with a significant quadratic function relationship. Once the relative distance from the track is more than 15 m, the train-induced force is small enough to be ignored. The extreme value of the mid-span dynamic response of the transmission line is related to the train speed and span length with a significant linear functional relationship.

Seismic response and damage development analyses of an RC structural wall building using macro-element

  • Hemsas, Miloud;Elachachi, Sidi-Mohammed;Breysse, Denys
    • Structural Engineering and Mechanics
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    • 제51권3호
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    • pp.447-470
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    • 2014
  • Numerical simulation of the non-linear behavior of (RC) structural walls subjected to severe earthquake ground motions requires a reliable modeling approach that includes important material characteristics and behavioral response features. The objective of this paper is to optimize a simplified method for the assessment of the seismic response and damage development analyses of an RC structural wall building using macro-element model. The first stage of this study investigates effectiveness and ability of the macro-element model in predicting the flexural nonlinear response of the specimen based on previous experimental test results conducted in UCLA. The sensitivity of the predicted wall responses to changes in model parameters is also assessed. The macro-element model is next used to examine the dynamic behavior of the structural wall building-all the way from elastic behavior to global instability, by applying an approximate Incremental Dynamic Analysis (IDA), based on Uncoupled Modal Response History Analysis (UMRHA), setting up nonlinear single degree of freedom systems. Finally, the identification of the global stiffness decrease as a function of a damage variable is carried out by means of this simplified methodology. Responses are compared at various locations on the structural wall by conducting static and dynamic pushover analyses for accurate estimation of seismic performance of the structure using macro-element model. Results obtained with the numerical model for rectangular wall cross sections compare favorably with experimental responses for flexural capacity, stiffness, and deformability. Overall, the model is qualified for safety assessment and design of earthquake resistant structures with structural walls.

열해석 모델 간략화 및 동적특성에 관한 연구 (A STUDY ON THERMAL MODEL REDUCTION AND DYNAMIC RESPONSE)

  • 전형열;김정훈
    • 한국전산유체공학회지
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    • 제19권4호
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    • pp.37-44
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    • 2014
  • A detailed satellite panel thermal model composed of more than thousands nodes can not be directly integrated into a spacecraft thermal model due to its node size and the limitation of commercial satellite thermal analysis programs. For the integration of the panel into the satellite thermal model, a reduced thermal model having proper accuracy is required. A thermal model reduction method was developed and validated by using a geostationary satellite panel. The temperature differences of main components between the detailed and the reduced thermal model were less than $1^{\circ}C$ in steady state analysis. Also, the dynamic responses of the detailed and the reduced thermal model show very similar trends. Thus, the developed reduction method can be applicable to actual satellite thermal design and analysis with resonable accuracy and convenience.

수중폭발 충격파와 가스구체 압력파를 함께 고려한 구조물의 동적응답해석 (Integrated Structural Dynamic Response Analysis considering the UNDEX Shock Wave and Gas Bubble Pulse)

  • 이상갑;권정일;정정훈
    • 대한조선학회논문집
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    • 제44권2호
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    • pp.148-153
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    • 2007
  • Two typical impact loadings, shock wave and gas bubble pulse, due to UNDEX(UNDerwater EXplosion), should be considered together for the closest response analysis of structure subjected to UNDEX to a reality. Since these two impact loadings have different response time bands, however, their response characteristics of structure are different from each other. It is impossible to consider these effectively under the current computational environment and the mathematical model has not yet been developed. Whereas Hicks model approximates the fluid-structure interaction due to gas bubble pulse as virtual mass effect, treating the flow by the response of gas bubble after shock wave as incompressible ideal fluid contrary to the compressible flow due to shock wave, Geers-Hunter model could make the closest response analysis of structure under UNDEX to a real one as a mathematical model considering the fluid-structure interaction due to shock wave and gas bubble pulse together using acoustic wave theory and DAA(Doubly Asymptotic Approximation). In this study, the application and effectiveness of integrated dynamic response analysis of submerged structure was examined with the analysis of the shock wave and gas bubble pulse together.

가진력과 단면형상 변화에 따른 외팔보 감쇠 진동의 민감도 해석 (Sensitivity Analysis of Dynamic Response by Change in Excitation Force and Cross-sectional Shape for Damped Vibration of Cantilever Beam)

  • 윤성호
    • 한국기계가공학회지
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    • 제20권8호
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    • pp.11-17
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    • 2021
  • This paper describes the time rate of change of dynamic response of a cantilever beam inserted with a damping element, such as bonding, which is excited under a general force at various locations. A sensitivity analysis was performed in a finite element model to show that two types of second-order algebraic governing equations were used to predict the rate of change of dynamic displacement: one is related to the modal coordinate linked to a physical coordinate, and the other to the design parameter of the time rate of change of displacement. The sensitivity differential equation formulation includes more complicated terms compared with that of the undamped cantilever beam. The sensitivities of the dynamic response were observed by changing the location of the excitation force, displacement extraction, and cross-sectional area of the beam. The analytical results obtained by this suggested theory showed a relatively good agreement when compared with those obtained using the commercial finite element program. The suggested analysis procedure enables the prediction of the response sensitivity for any finite element model of the dynamic system.

유리 섬유 강화 폴리우레탄 폼의 온도 및 변형률 속도 의존 재료 거동 모델링 (Modeling of the Temperature-Dependent and Strain Rate-Dependent Dynamic Behavior of Glass Fiber-Reinforced Polyurethane Foams)

  • 이동주;신상범;김명현
    • 한국해양공학회지
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    • 제33권6호
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    • pp.547-555
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    • 2019
  • The purpose of this study was to establish a numerical model of polyurethane foam (PUF) to simulate the dynamic response and strength of membrane-type Liquefied natural gas (LNG) Cargo containment system (CCS) under the impact load. To do this, initially, the visco-plastic behavior of PUF was characterized by testing the response of the PUF to the impact loads with various strain rates as well as PUF densities at room temperature and at cryogenic conditions. A PUF material model was established using the test results of the material and the FE analysis. To verify the validation of the established material model, simulations were performed for experimental applications, e.g., the dry drop test, and the results of FEA were compared to the experimental results. Based on this comparison, it was found that the dynamic response of PUF in dry drop tests, such as the reaction force and fracture behaviors, could be simulated successfully by the material model proposed in this study.