• Proceedings of the KSR Conference
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• 2010.06a
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• pp.18-24
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• 2010

Conventional methods for railway vehicle dynamic analysis have mostly relied on the approximate method based on 2-dimensional contact analysis. Recently, 3-dimensional approaches to achieve an accurate solution for wheel-rail contact analysis have been proposed, but are not practical to apply to actual simulation due to time-consuming processes. The main focus of this study is to present a new method of railway vehicle dynamic analysis by calculating wheel-rail contact forces based on efficient 3-dimensional wheel-rail contact analysis. A 3-dimensional wheel-rail contact analysis and numerical analysis of wheelset dynamic equations will be presented.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.72-83
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• 2009

The purpose of this study is to examine the effects of a degree of discretization in the direction of longitudinal dam axis on the results of three dimensional fill dam dynamic analysis. In this study, the three dimensional dynamic analyses of the existing 'H' dam which is modeled with a different degree of discretization were carried out. From these results, the fundamental frequency of the dam and the responses at the dam crest such as acceleration and settlement were compared and analyzed. It was concluded that the size of finite element discretized in the direction of the longitudinal axis mush be smaller than 1/8 of dam length in order to obtain the reasonable fundamental frequency and response of acceleration and mush be smaller than 1/10 in order to obtain the reasonable settlement behaviors from the three dimensional dynamic analysis of the fill dam.

• Computational Structural Engineering
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• v.10 no.2
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• pp.171-178
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• 1997

Three-dimensional dynamic analyses of underground openings subjected to explosive loadings are carried out. Dynamic analyses consist of two steps; one-dimensional source calculation and three-dimensional tunnel analysis. One-dimensional source calculation includes explosive charge and the free field surrounding rock. The input pressure time history for three-dimensional tunnel analysis is obtained from the companion one-dimensional source calculation. The computer program MPDAP-3D incorporated this analysis capability. It is shown that the computer program is a useful tool for the analysis of the structural safety evaluation of underground openings during construction by drill and blasting method.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.759-764
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• 2010

In this study, from the comparison of the results obtained by 3 dimensional dynamic analyses using the inverse-calculated properties and those by calculating using the real earthquake records, the inverse calculation method for obtaining the dynamic properties of rockfill materials was verified. The fundamental frequency of the dam was determined by analyzing the response spectrum of observed records. By repeated dynamic analyses for various shear moduli of rockfill material, the shear moduli in the rockfill zone that satisfy the relationship between the fundamental frequency obtained by analysis of the observed records and that by numerical analyses were determined. Using the determined shear moduli, the 3 dimensional dynamic analyses for the dam were carried out and the result were compared with the real response characteristics on the crest of the dam.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.637-642
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• 2000

This paper suggests new analysis algorithm for tile dynamic response of three dimensional structure which is frequently found in pipe line system of plant by the combination of the transfer stiffness coefficient method(TSCM) and Newmark method. Presented analysis algorithm for dynamic response can improve the computational accuracy remarkably owing to advantages of tile TSCM in comparison of transfer matrix method(TMM). Analysis system was modeled as a lumped mass system in this mettled. The analysis algorithm for dynamic response was formulated for the three dimensional structure. The validity of the this method is demonstrated through the results of numerical experiment for simple computational model by the TSCM and TMM.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.21 no.3
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• pp.125-142
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• 2017

In this paper, development of the three-dimensional structural analysis is performed by applying FETI-local method. In the FETI-local method, the penalty term is added as a preconditioner. The OPT-DKT shell element is used in the present structural analysis. Newmark-${\beta}$ method is employed to conduct the dynamic analysis. The three-dimensional FETI-local static structural analysis is conducted. The contour and the displacement of the results are compared following the different number of sub-domains. The computational time and memory usage are compared with respect to the number of CPUs used. The three-dimensional dynamic structural analysis is conducted while applying FETI-local method. The present results show appropriate scalability in terms of the computational time and memory usage. It is expected to improve the computational efficiency by combining the advantages of the original FETI method, i.e., FETI-mixed using the mixed local-global Lagrange multiplier.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1851-1855
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• 2011

The accuracy of wheel-rail contact analysis is mainly determined by the methods to find wheel-rail contact points and to calculate contact forces. The 2-dimensional approach which calculates contact points based on the profile curves of the wheel and rail has advantage of reducing calculation time but shortage of approximating the solutions when comparing with 3-dimensional analysis In this analysis, wheelset dynamic behaviors calculated by the approach based on the 2-dimensional wheel-rail curves are compared with those by the 3-dimensional wheel-rail surfaces. Yaw angle and lateral displacement of wheelset center are compared when negotiating a curve.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3A
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• pp.465-471
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• 2006

To describe hysteretic behavior of steel structures under dynamic loading such as earthquake, the dynamic cyclic plasticity model considering stress-strain relationship and characteristics of used steel materials under static-dynamic deforming is required. In this paper, mechanical characteristics and stress-strain relationship of SM490 was clarified by carrying out static-dynamic monotonic and cyclic loading test. A dynamic cyclic plasticity model of SM490 was proposed based on the test results and applied 3-dimensional finite element analysis using finite deformation theory. An analytical method developed by the authors was verified validity and accuracy by comparing both analysis and test results. The comparison result shows that the analytical method developed by the authors can predict static-dynamic hysteretic behavior of steel structures with accuracy.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.8
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• pp.2043-2050
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• 1993

This paper presents a three dimensional modeling and dynamic analysis of a hydraulic excavator. An excavator composed of a boom, a bucket, two boom cylinders, an arm cylinder, and a bucket cylinder is used for the analysis. Each cylinder is modeled to two separate bodies linked by a translational joint. Judging from the actual degrees of freedom of the excavator, proper kinematic joints are selected to exclude redundant constraints in the modeling. In order to find the reaction forces at kinematic joints during operations, inverse dynamic analysis is carried out. Dynamic analysis is also carried out to verify the results from inverse dynamic analysis. The DADS program is used for analysis, with proper modification of the DADS user routine according to various motions.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.10a
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• pp.307-314
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• 2000

A parallel condensation algorithm for efficient dynamic analysis of three-dimensional large-scale structures is presented. The algorithm is developed for a user-friendly and cost effective high-performance computing system on a collection of Pentium processors connected via a 100 Mb/s Ethernet LAN. To harness the parallelism in the computing system effectively, a large-scale structure is partitioned into a number of substructures equal to the number of computers in the computing system Then, for reduction in the size of an eigenvalue problem the computations required for static condensation of each substructure is processed concurrently on each slave computer. The performance of th proposed parallel algorithm is demonstrated by applying to dynamic analysis of a three dimensional structure. The results show that how the parallel algorithm facilitates the efficient use of a small number of low-cost personal computers for dynamic analysis of large-scale structures.