• Title, Summary, Keyword: Dynamic response model

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Blast load induced response and the associated damage of buildings considering SSI

  • Mahmoud, Sayed
    • Earthquakes and Structures
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    • v.7 no.3
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    • pp.349-365
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    • 2014
  • The dynamic response of structures under extremely short duration dynamic loads is of great concern nowadays. This paper investigates structures' response as well as the associated structural damage to explosive loads considering and ignoring the supporting soil flexibility effect. In the analysis, buildings are modeled by two alternate approaches namely, (1) building with fixed supports, (2) building with supports accounting for soil-flexibility. A lumped parameter model with spring-dashpot elements is incorporated at the base of the building model to simulate the horizontal and rotational movements of supporting soil. The soil flexibility for various shear wave velocities has been considered in the investigation. In addition, the influence of variation of lateral natural periods of building models on the obtained response and peak response time-histories besides damage indices has also been investigated under blast loads with different peak over static pressures. The Dynamic response is obtained by solving the governing equations of motion of the considered building model using a developed Matlab code based on the finite element toolbox CALFEM. The predicted results expressed in time-domain by the building model incorporating SSI effect are compared with the corresponding model results ignoring soil flexibility effect. The results show that the effect of surrounding soil medium leads to significant changes in the obtained dynamic response of the considered systems and hence cannot be simply ignored in damage assessment and response time-histories of structures where it increases response and amplifies damage of structures subjected to blast loads. Moreover, the numerical results provide an understanding of level of damage of structure through the computed damage indices.

Dynamic response characteristics of crossing tunnels under heavy-haul train loads

  • Dong, Jie;Zhong, Shuai;Wang, Hai-long;Wu, Zhi-hui
    • Geomechanics and Engineering
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    • v.20 no.2
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    • pp.103-112
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    • 2020
  • The dynamic response of crossing tunnels under heavy-haul train loads is still not fully understood. In this study, based on the case of a high-speed tunnel underneath an existing heavy-haul railway tunnel, a model experiment was performed to research the dynamic response characteristics of crossing tunnels. It is found that the under-crossing changes the dynamic response of the existing tunnel and surrounding rock. The acceleration response of the existing tunnel enhances, and the dynamic stress of rock mass between crossing tunnels decreases after the excavation. Both tunneling and the excitation of heavy-haul train loads stretch the tunnel base, and the maximum tensile strain is 18.35 µε in this model test. Then, the measured results were validated by numerical simulation. Also, a parametric study was performed to discuss the influence of the relative position between crossing tunnels and the advanced support on the dynamic behavior of the existing tunnel, where an amplifying coefficient of tunnel vibration was introduced to describe the change in acceleration due to tunneling. These results reveal the dynamic amplifying phenomenon of the existing tunnel during the new tunnel construction, which can be referred in the dynamic design of crossing tunnels.

A Study on the Step Response Model Development of a Dynamic Matrix Control(DMC) For Boiler-Turbine Systems in a Fossil Power Plant (화력발전 보일러-터빈 시스템을 위한 Dynamic Matrix Control(DMC)의 계단응답모델 선정에 관한 연구)

  • Moon, Un-Chul
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.20 no.5
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    • pp.125-133
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    • 2006
  • This paper presents comparison results of Step Response Model of Dynamic Matrix Control(DMC) for a drum-type boiler-turbine system of a fossil power plant. Two possible kinds of step response models are investigated in designing the DMC, one is developed with the linearization of theoretical model and the other is developed with the process step-test data. Then, the control performances of each model-based DMC are simulated and evaluated. It is observed that the simulation results with the step-response model based on the test data show satisfactory results, while the linearized model is not suitable for the control of boiler-turbine system.

Dynamic torsional response measurement model using motion capture system

  • Park, Hyo Seon;Kim, Doyoung;Lim, Su Ah;Oh, Byung Kwan
    • Smart Structures and Systems
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    • v.19 no.6
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    • pp.679-694
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    • 2017
  • The complexity, enlargement and irregularity of structures and multi-directional dynamic loads acting on the structures can lead to unexpected structural behavior, such as torsion. Continuous torsion of the structure causes unexpected changes in the structure's stress distribution, reduces the performance of the structural members, and shortens the structure's lifespan. Therefore, a method of monitoring the torsional behavior is required to ensure structural safety. Structural torsion typically occurs accompanied by displacement, but no model has yet been developed to measure this type of structural response. This research proposes a model for measuring dynamic torsional response of structure accompanied by displacement and for identifying the torsional modal parameter using vision-based displacement measurement equipment, a motion capture system (MCS). In the present model, dynamic torsional responses including pure rotation and translation displacements are measured and used to calculate the torsional angle and displacements. To apply the proposed model, vibration tests for a shear-type structure were performed. The torsional responses were obtained from measured dynamic displacements. The torsional angle and displacements obtained by the proposed model using MCS were compared with the torsional response measured using laser displacement sensors (LDSs), which have been widely used for displacement measurement. In addition, torsional modal parameters were obtained using the dynamic torsional angle and displacements obtained from the tests.

Dynamic Response Control of a Flexible Wing using Sliding Mode Control (슬라이딩 모드 제어기법을 이용한 유연날개 동적 응답 제어)

  • Lee, Sang-Wook;Suk, Jinyoung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.522-527
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    • 2013
  • In this study, dynamic response control of a flexible wing such as gust loads alleviation using sliding mode control method is presented. To achieve this purpose, trailing edge control surface of a flexible wing is used as control means generating the aerodynamic control force. Aeroservoelastic CASE) model consisting of aeroelastic plant, control surface actuator model, and gust model depicting the atmospheric turbulence is formulated in the state space. A sliding mode controller based on the estimated state vector is designed for active dynamic response control of flexible wing aeroservoelastic model. The performance of the controller designed is demonstrated via numerical simulation for the representative flexible wing model under atmospheric turbulence loading.

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Statistical Analysis and Prediction for Behaviors of Tracked Vehicle Traveling on Soft Soil Using Response Surface Methodology (반응표면법에 의한 연약지반 차량 거동의 통계적 분석 및 예측)

  • Lee Tae-Hee;Jung Jae-Jun;Hong Sup;Km Hyung-Woo;Choi Jong-Su
    • Journal of Ocean Engineering and Technology
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    • v.20 no.3
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    • pp.54-60
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    • 2006
  • For optimal design of a deep-sea ocean mining collector system, based on self-propelled mining vehicle, it is imperative to develop and validate the dynamic model of a tracked vehicle traveling on soft deep seabed. The purpose of this paper is to evaluate the fidelity of the dynamic simulation model by means of response surface methodology. Various statistical techniques related to response surface methodology, such as outlier analysis, detection of interaction effect, analysis of variance, inference of the significance of design variables, and global sensitivity analysis, are examined. To obtain a plausible response surface model, maximum entropy sampling is adopted. From statistical analysis and prediction for dynamic responses of the tracked vehicle, conclusions will be drawn about the accuracy of the dynamic model and the performance of the response surface model.

Response Characteristics for Low Voltage Liquid Crystal Display Employing a Constant Charge Model

  • Kim, Mi-Soon;Huh, Su-Jung;Suh, Duck-Jong;Ahn, Yi-Joon;Lee, Kyung-Jin;Ahn, Seon-Hong;Kim, Kyeong-Hyeon;Kim, Sang-Soo
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.228-230
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    • 2008
  • The response time characteristic of low voltage liquid crystals (LCs) is investigated and a new simulator for low voltage LCs is proposed. In order to enable low voltage operation, it is important to minimize Vth of LCs and variation of pixel voltage caused by dynamic capacitance operation of LC Display. Because dynamic capacitance variation is much larger for low voltage LC operation compared to that of conventional LC material, it is necessary to make a better model for dynamic capacitance operation. A proposed minimizing Vth of LCs and variation of pixel voltage study results through a new constant charge model improve response characteristics for low voltage LCs operation.

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Effects of Design on the Dynamic Response of Reinforced Concrete Slabs (철근 콘크리트 슬래브의 디자인이 동적 거동에 미치는 영향)

  • Oh, Kyung-Yoon;Cho, Jin-Goo;Choi, Soo-Myung;Hong, Chong-Hyun
    • Journal of The Korean Society of Agricultural Engineers
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    • v.49 no.6
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    • pp.47-54
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    • 2007
  • This paper is on the research of the special character of the dynamic response according to a design of the clamped reinforced concrete slab. In this study, the 20-node solid element has been used to analyze the dynamic characteristics of RC slabs with clamped edges. The elasto-visco plastic model for material non-linearity and the smeared crack model have been adopted in the finite element formulation. The design factor, which affect the dynamic response of the reinforced concrete slab, are the steel layer thickness, steel layer depth, steel layout method, steel layout angle and the slab thickness and span ratio. The main purpose of this study was to find out the dynamic response of the reinforced concrete slab according to above variables. The reduction of deflection/thickness ratio appeared less than 2% when the slab thickness between 20 and 21cm. It is desirable that the slab thickness must be above 20-21cm. The reduction ratio of deflection is appeared greatly when the value of the span/thickness ratio is between 25 and 30. In conclusion, the steel layer depth and thickness had a little effect on deflection of the dynamic response, but had no effect on the steel layout angle.

A Study on the Dynamic Load Model of Truss Bridge subjected to Moving Train Loads (열차하중을 받는 트러스교의 동적하중모형 연구)

  • 안주옥;박상준
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.111-118
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    • 1996
  • Dynamic load models which show the practical behavior of truss bridge subjected to moving train load are presented. Three basically approaches are available for evaluating structural response to dynamic effects : moving force, moving mass, and influence moving force and mass. Simple warren truss bridge model is selected in this research, and idealized lumped mass system, modelled as a planar structure. In the process of dynamic analysis, the uncoupled equation of motion is derived from simultaneous equation of the motion of truss bridge and moving train load. The solution of the uncoupled equations of motion is solved by Newmark-$\beta$ method. The results show that dynamic response of moving mass and static analysis considering the impact factor specified in the present railway bridge code was nearly the same. Generally, the dynamic response of moving force is somewhat greater than that of moving mass. The dynamic load models which are presented by this study are obtained relatively adequate load model when apply to a truss bridge.

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Dynamic Response Characteristics of Embankment Model for Various Slope Angles (다양한 경사를 가지는 제방모형의 지반 증폭 특성)

  • Kim, Hoyeon;Jin, Yong;Lee, Yonghee;Kim, Hak-sung;Kim, Daehyeon
    • Journal of the Korean Geosynthetics Society
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    • v.19 no.2
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    • pp.35-46
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    • 2020
  • In this study, the dynamic response characteristics of the embankment model were analyzed using shaking table experiments. Laminar shear box was used to minimize the boundary effect of the model. The ratio of the vertical length to horizontal length of the slopes were 1:1, 1:1.5, and 1:2. The sensor array which is consist of 12 accelerometers was used to measure acceleration time-histories at each location of the slope model. The dynamic response characteristics of the models were analyzed for sine wave, sinesweep wave, and artificial earthquake wave in this study. The experimental results show that the dynamic response of the embankment model is increased with the slope angle. Furthermore, the experimental setup used in this study was verified with the comparative analysis between experimental results and 1-D analytical simulation on the flat ground model.