• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1999년도 봄 학술발표회 논문집
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• pp.260-267
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• 1999

In this paper, We propose the initial shape finding and dynamic analysis of cable dome structure are presented. Cable dome that is consist of three component such as cable, strut and fabric membrane have complex structural characteristics. Main structural system of cable dome is cable-strut tensegric system, and fabric membrane element Is conceived as cladding roof material. One of the important problem of cable dome is shape finding of those subjected to cable and membrane forces, which stabilize the structures. And the other is structural response from external load effect such as snow and wind When cable dome are subjected to dynamic load such as wind load each structural component has many important problem because of their special structural characteristics. One problem is that geometrical nonlinearity should be considered in the dynamic analysis because large deformation is occurred from their flexible characteristic. The other problem is that wrinkling occurs occasionally because cable and membrane elements can not transmit compressive forces. So this paper describe the physical structural response of cable dome structure.

• 한국전산구조공학회논문집
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• 제15권1호
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• pp.21-32
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• 2002

일반적으로 응답스펙트럼 해석법은 건물의 지진해석에 널리 사용되고 있지만 기계하중이나 이동하중 등에 의하여 발생하는 진동에 대한 해석에는 시간이력해석이 주로 사용되고 있다. 그런데, 시간이력해석법은 정확한 반면 매우 복잡하고 어려우며 많은 시간을 필요로 한다. 따라서, 본 논문에서는 동적하중을 받는 구조물의 최대응답을 응답스펙트럼해석법을 이용하여 간편하게 계산하는 방법을 제시하고자 한다. 우선, 이 해석법의 해석과정에 대하여 알아보았으며, 복수절점에 동적 하중을 받는 경우에 대해서 해석시간 및 메모리를 줄이는 방법을 제시하였다. 다음으로는 이동하중을 받는 경우에 대하여 구조물의 최대응답을 구하는 방법에 대하여 알아보았다. 마지막으로 예제를 통하여 시간이력해석을 수행하여 얻은 최대응답과 응답스펙트럼해석에 의한 최대응답을 비교하여 제시한 해석법의 정확성을 확인하였다.

• 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.

• 동력기계공학회지
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• 제16권1호
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• pp.65-71
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• 2012

A numerical procedure is described for predicting the dynamic structural responses of tension leg platforms(TLPs) in current and waves. The developed numerical approach is based on a combination of the three dimensional source distribution method and the dynamic structural analysis method, in which the superstructure of the TLPs is assumed to be flexible instead of rigid. The hydrodynamic interactions among TLP members, such as columns and pontoons, and the structural damping are included in the dynamic structural analysis. The equations of motion of a whole structure are formulated using element-fixed coordinate systems which have the origin at the nodes of the each hull element and move parallel to a space-fixed coordinate system. The dynamic structural responses of a TLP were analyzed in the case of including the current or not including the one in waves and the effects of current on the TLP were investigated.

• Earthquakes and Structures
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• 제6권4호
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• pp.351-373
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• 2014

This paper investigates the seismic response of lightweight acceleration-sensitive non-structural components (NSCs) mounted on irregular reinforced concrete (RC) primary structures (P-structures) using non-linear dynamic finite element (FE) analysis. The aim of this paper is to study the influence of NSC to P-structure vibration period ratio, peak ground acceleration, NSC to P-structure height ratio, and P-structure torsional behaviour on the seismic response of the NSCs. Representative constitutive models were used to simulate the behaviour of the RC P-structures. The NSCs were modelled as vertical cantilevers fixed at their bases with masses on the free ends and varying lengths so as to match the frequencies of the P-structures. Full dynamic interaction is considered between the NSCs and P-structures. A set of 21 natural and artificial earthquake records were used to evaluate the seismic response of the NSCs. The numerical results indicate that the behaviour of the NSCs is significantly influenced by the investigated parameters. Comparison between the FE results and Eurocode (EC8) predictions suggests that EC8 underestimates the response of NSCs mounted on the flexible sides of irregular RC P-structures when the fundamental periods and heights of the NSCs match those of the P-structures. The perceived cause of this discrepancy is that EC8 does not take into account the amplification in the dynamic response of NSCs induced by the torsional behaviour of RC P-structures.

• Geomechanics and Engineering
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• 제1권2호
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• pp.121-142
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• 2009

The paper deals with the applications of spectral finite element method to the dynamic analysis of framed foundations supporting high speed machines. Comparative performance of approximate dynamic stiffness methods formulated using static stiffness and lumped or consistent or average mass matrices with the exact spectral finite element for a three dimensional Euler-Bernoulli beam element is presented. The convergence of response computed using mode superposition method with the appropriate dynamic stiffness method as the number of modes increase is illustrated. Frequency proportional discretisation level required for mode superposition and approximate dynamic stiffness methods is outlined. It is reiterated that the results of exact dynamic stiffness method are invariant with reference to the discretisation level. The Eigen-frequencies of the system are evaluated using William-Wittrick algorithm and Sturm number generation in the $LDL^T$ decomposition of the real part of the dynamic stiffness matrix, as they cannot be explicitly evaluated. Major's method for dynamic analysis of machine supporting structures is modified and the plane frames are replaced with springs of exact dynamic stiffness and dynamically flexible longitudinal frames. Results of the analysis are compared with exact values. The possible simplifications that could be introduced for a typical machine induced excitation on a framed structure are illustrated and the developed program is modified to account for dynamic constraint equations with a master slave degree of freedom (DOF) option.

• 대한조선학회논문집
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• 제48권5호
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• pp.451-456
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• 2011

To ensure structural integrity of membrane type LNG tank, the rational assessment of the sloshing impact responses of tank structures should be preceded. The sloshing impact pressures acting on the insulation system of LNG tank are typical irregular loads and the resulting structural responses show very complex behaviors accompanied with fluid structure interaction. So it is not easy to estimate them accurately and immense time consuming calculation process would be necessary. In this research, a simplified method to analyse the dynamic structural responses of LNG tank insulation system under pressure time histories obtained by sloshing model test or numerical analysis was studied. The proposed technique based on the concept of linear combination of the triangular response functions which are the transient responses of structures under the unit triangular impact pressure acting on structures. The validity of suggested method was verified through the example calculations and applied to the dynamic structural response analysis of a real Mark III membrane type insulation system using the sloshing impact pressure time histories obtained by model test.

• Smart Structures and Systems
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• 제8권2호
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• pp.157-172
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• 2011

A new method for both local damage(s) identification and input excitation force identification of beam structures is presented using the dynamic response sensitivity-based finite element model updating method. The state-space approach is used to calculate both the structural dynamic responses and the responses sensitivities with respect to structural physical parameters such as elemental flexural rigidity and with respect to the force parameters as well. The sensitivities of displacement and acceleration responses with respect to structural physical parameters are calculated in time domain and compared to those by using Newmark method in the forward analysis. In the inverse analysis, both the input excitation force and the local damage are identified from only several acceleration measurements. Local damages and the input excitation force are identified in a gradient-based model updating method based on dynamic response sensitivity. Both computation simulations and the laboratory work illustrate the effectiveness and robustness of the proposed method.

• Structural Engineering and Mechanics
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• 제38권4호
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• pp.429-441
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• 2011

In large-scale problem, a huge size of computational resources is needed for a reliable solution which represents the detailed description of dynamic behavior. Recently, eigenvalue reduction schemes have been considered as important technique to resolve computational resource problems. In addition, the efforts to advance an efficiency of reduction scheme leads to the development of the multi-level system condensation (MLSC) which is initially based on the two-level condensation scheme (TLCS). This scheme was proposed for approximating the lower eigenmodes which represent the global behavior of the structures through the element-level energy estimation. The MLSC combines the multi-level sub-structuring scheme with the previous TLCS for enhancement of efficiency which is related to computer memory and computing time. The present study focuses on the implementation of the MLSC on the direct time response analysis and the frequency response analysis of structural dynamic problems. For the transient time response analysis, the MLSC is combined with the Newmark's time integration scheme. Numerical examples demonstrate the efficiency of the proposed method.

• Smart Structures and Systems
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• 제6권5_6호
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• pp.579-593
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• 2010

Low-power radio frequency (RF) chip transceiver technology and the associated structural health monitoring platforms have matured recently to enable high-rate, lossless transmission of measurement data across large-scale sensor networks. The intrinsic value of these advanced capabilities is the allowance for high-quality, rapid operational modal analysis of in-service structures using distributed accelerometers to experimentally characterize the dynamic response. From the analysis afforded through these dynamic data sets, structural identification techniques can then be utilized to develop a well calibrated finite element (FE) model of the structure for baseline development, extended analytical structural evaluation, and load response assessment. This paper presents a case study in which operational modal analysis is performed on a three-span prestressed reinforced concrete bridge using a wireless sensor network. The low-power wireless platform deployed supported a high-rate, lossless transmission protocol enabling real-time remote acquisition of the vibration response as recorded by twenty-nine accelerometers at a 256 Sps sampling rate. Several instrumentation layouts were utilized to assess the global multi-span response using a stationary sensor array as well as the spatially refined response of a single span using roving sensors and reference-based techniques. Subsequent structural identification using FE modeling and iterative updating through comparison with the experimental analysis is then documented to demonstrate the inherent value in dynamic response measurement across structural systems using high-rate wireless sensor networks.