• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.04a
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• pp.50-57
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• 1999

Structural analysis of large-scale structures involving large amount of computational load and data storage requires high-performance computing resources. We have previously developed PC-level distributed structural analysis algorithms based on substructuring technique where each personal computer assigned to a slave node has been involved in the computations for single substructures. Recently, it has been proved by the authors that the performance of distributed structural analysis algorithm can be further enhanced by changing substructuring schemes. Therefore a new distributed structural analysis algorithm with one PC to multiple substructures scheme is presented in this paper. The algorithm is implemented on the network of multiple personal computers and applied to structural analysis of two dimensional frame structures.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.12 no.3
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• pp.385-396
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• 1999

In the process of structural design for large-scale structures with several thousands of degrees of freedom, a plethora of structural calculations with large amount of data storage are required to obtain the forces and displacements of the members. However, current computational environment with single microprocessor such as a personal computer or a workstation is not capable of generating a high-level of efficiency in structural analysis and design process for large-scale structures. In this paper, a high-performance parallel computing system interconnected by a network of personal computers is proposed for an efficient structural analysis. Two distributed structural analysis algorithms are developed in the form of distributed or parallel preconditioned conjugate gradient (DPCG) method. To enhance the performance of the developed distributed structural analysis algorithms, the number of communications and the size of data to be communicated are minimized. These algorithms are applied to the structural analyses of three large space structures as well as a 144-story tube-in-tube framed structure.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.10a
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• pp.53-60
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• 1998

Efficiency of design process for large scale structures highly depends on the development of efficient structural analysis and structural response control algorithms because a successful design involves a number of structural analysis based on iterative structural response control process. In this paper, distributed structural analysis model on multiple personal computers connected by ethernet network is presented. To reduce communication cost required in the process of analysis, substructuring techniques are adopted to evenly distribute computational loads on each processor. With its applications on structural analysis of plane frame structures, performance of the proposed computational model are presented in detail.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.4
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• pp.317-324
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• 2008

Optimum design for general or complex structures are required to the need of many numbers of structural analyses. However, current computational environment with single processor is not capable of generating a high-level efficiency in structural analysis and design process for complex structures. In this paper, a virtual parallel computing system communicated by an internet of personal computers and workstation is constructed. In addition, a routine executing Pro/E, ANSYS and optimization algorithm automatically are adopted in the distributed process technique of sequential approximate optimization for the purpose of enhancing the flexibility of application to general structures. By employing the distributed processing technique during structural analysis using commercial application, total calculation time could be reduced, which will enhance the applicability of the proposed technique to the general complex structures.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.10a
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• pp.124-132
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• 2000

Distributed processing approach for structural optimization is presented in this study. It is implemented on network of personal computers. The validity and efficiency of this approach are demonstrated and verified by test model of truss. Repeated structural analysis algorithm, which spend a lot of overall structural optimization processes, are based on substructuring scheme with domain-wise parallelism and converted to be adapted to hardware and software environments. The design information data are modularized and assigned to each computer in order to minize the communication cost. The communications between nodes are limited to static condensation and constraint-related data collection.

• Structural Engineering and Mechanics
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• v.30 no.3
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• pp.331-350
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• 2008

A framework for multi-platform analytical and multi-component hybrid (testing-analysis) simulations is described in this paper and illustrated with several application examples. The framework allows the integration of various analytical platforms and geographically distributed experimental facilities into a comprehensive pseudo-dynamic hybrid simulation. The object-oriented architecture of the framework enables easy inclusion of new analysis platforms or experimental models, and the addition of a multitude of auxiliary components, such as data acquisition and camera control. Four application examples are given, namely; (i) multi-platform analysis of a bridge with soil and structural models, (ii) multiplatform, multi-resolution analysis of a high-rise building, (iii) three-site small scale frame hybrid simulation, and (iv) three-site large scale bridge hybrid simulation. These simulations serve as illustrative examples of collaborative research among geographically distributed researchers employing different analysis platforms and testing equipment. The versatility of the framework, ease of including additional modules and the wide application potential demonstrated in the paper provide a rich research environment for structural and geotechnical engineering.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.291-298
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• 2006

A parallelized topology design optimization method is developed on a distributed memory system. The parallelization is based on a domain decomposition method and a boundary communication scheme. For the finite element analysis of structural responses and design sensitivities, the PCG method based on a Krylov iterative scheme is employed. Also a parallelized optimization method of optimality criteria is used to solve large-scale topology optimization problems. Through several numerical examples, the developed method shows efficient and acceptable topology optimization results for the large-scale problems.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.2
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• pp.211-215
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• 2010

Continuous contraction and expansion of disk brake can be due to friction and temperature difference at repeated sudden braking. As serious vibration at disk is produced, the braking force will be changed ununiformly and braking system can not be stabilized. Temperature and heat flux at disk brake are investigated by structural and thermal analysis in this study. The maximum equivalent stress and displacement are shown respectively at the ventilated hole and the lower part of disk plate. At thermal analysis of initial state, temperature on disk plate is distributed from $95.9^{\circ}C$ to $100^{\circ}C$. The maximum heat flux of $0.0168W/mm^2$ is shown at the inner friction part between disk plate and pad. At thermal analysis of transient state, temperature on disk plate is distributed from $95^{\circ}C$ to $96.5^{\circ}C$ after 100 second. The maximum heat flux of $0.0024W/mm^2$ is also shown at the inner friction part between disk plate and pad. By comparing with initial state, the temperature on disk plate is more uniformly distributed and heat flux is more decreased by 7 times at transient state.

• Structural Engineering and Mechanics
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• v.56 no.2
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• pp.169-188
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• 2015

There are two types of nonlinear analysis methods for building frameworks depending on the method of modeling the plastification of members including lumped plasticity and distributed plasticity. The lumped plasticity method assumes that plasticity is concentrated at a zero-length plastic hinge section at the ends of the elements. The distributed plasticity method discretizes the structural members into many line segments, and further subdivides the cross-section of each segment into a number of finite elements. When a reinforced concrete member experiences inelastic deformations, cracks tend to spread form the joint interface resulting in a curvature distribution. The program IDARC includes a spread plasticity formulation to capture the variation of the section flexibility, and combine them to determine the element stiffness matrix. In this formulation, the flexibility distribution in the structural elements is assumed to be the linear. The main objective of this study is to evaluate the accuracy of linear flexibility distribution assumed in the spread inelasticity model. For this purpose, nonlinear analysis of two reinforced concrete frames is carried out and the linear flexibility models used in the elements are compared with the real ones. It is shown that the linear flexibility distribution is incorrect assumption in cases of significant gravity load effects and can be lead to incorrect nonlinear responses in some situations.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.505-510
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• 2002

We have focused on the development of a fiber optic BOTDA (Brillouin Optical Time Domain Analysis) sensor system in order to measure temperature distributed on large structures. Also, we present a feasibility study of the fiber optic sensor to monitor the distributed temperature on a building construction. A fiber optic BOTDA sensor system, which has a capability of measuring the temperature distribution, attempted over several kilometers of long fiber paths. This simple fiber optic sensor system employs a laser diode and two electro-optic modulators. The optical fiber of the length of 1400 m was installed on the surfaces of the building. The change of the distributed temperature on the building construction was well measured by this fiber optic sensor. The temperature changed normally up to 4℃ through one day.