• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.5 s.176
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• pp.1271-1280
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• 2000

A sensor placement technique to identify structural parameter was developed. Experimental results must be acquired to identify unknown dynamic characteristics of a targeting structure for the comparison between analytical model and real structure. If the experimental environment was not equipped itself properly, it can be happened that some valuable information are distorted or ill-condition can be occurred. In this work the index to determine exciting points was derived from the criterion of maximizing parameter sensitivity matrix and that to choose measurement points was from that of preserving the invariant of sensitivity matrix. This idea was applied to a compressor hull structure to verify its performance. The result shows that the selection of measurement and excitation points using suggested criteria improve the ill-conditioning problem of inverse type problems such , as model updating.

• Journal of KSNVE
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• v.6 no.4
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• pp.431-438
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• 1996

The channel type structure which has large openings is frail with respect to torsional strength, and the horizontal-torsional motion is highly coupled, because of the large difference between the centroil and the shear center. Also, a discontinuous boundary phase is came from tansition section between the opened section and the closed section. To analyze the Bending- Torsional coupled mode parameters for the channel type structure, the Transfer Matrix Method was used. Comparing the result of F.D.M.T.M.M yields good results in relatively low frequency region.

• Journal of the Korean Chemical Society
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• v.25 no.3
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• pp.140-144
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• 1981

The structure and reactivity of isophorone diisocyanate, which is used as a curing agent in propellants casting, were investigated using the EHT, CNDO/2 and STO-3G MO methods. The results showed that the reactivity can be assessed by the positive charge on C atom of -NCO group. The structure of this compound was found to be such that it has slow polymerization rate but provides homogenous matrix for explosives.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.873-880
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• 2006

Since the mega frame structure has significant numbers of elements and nodes, it takes tremendous times and computer memories to analyze and design the structures. Therefore, the exclusive structural analysis program for mega frame system is developed to reduce the efforts and time required for the analysis and design of mega frame structure. To this end, an efficient modelling technique using the characteristics of mega frame structures and an efficient analytical model, which uses a few DOFs selected by the user using the matrix condensation method. are developed in tins study. Static and dynamic analyses are conducted using an example structure.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.04a
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• pp.220-223
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• 2003

The methodology of micromechanical finite element method (MFEM) is proposed to calculate the micromechanical strains on fiber and matrix under mechanical and thermal loadings. For micromechanical analysis, composite structure is idealized the square and hexagonal unit cells. Boundary conditions are determined to calculate the effective material properties of composites and the strain magnification matrix. And they are verified by comparing with the results from multi cells, and the strain distributions of the unit cells are in accordance with those of the multi cells. Finally, the effective material properties of composite structure are obtained with respect to its fiber volume fraction and compared with results from rules-of-mixture.

• Journal of Advanced Marine Engineering and Technology
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• v.26 no.1
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• pp.108-115
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• 2002

This paper suggests a new analysis algorithm for the time historical response of three dimensional rectilinear structure which is frequently found in a pipe line system of plant by the combination of the transfer stiffness coefficient method(TSCM) and the Newmark method. The present analysis algorithm for a time historical response can improve the computational accuracy and time remarkably owing to advantages of the TSCM in comparison with transfer matrix method(TMM). The structural system is modeled as a lumped mass system in this method. The analysis algorithm was formulated far the three dimensional rectilinear structure. We confirmed the validity of the present algorithm by comparing the numerical computation results of TSCM with those of TMM.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.9 s.180
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• pp.2334-2343
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• 2000

This paper proposes an efficient beam-shell modeling technique for the free vibration analysis of a T-joint thin-walled beam structure. Except a small portion of a T-joint which is modeled by shell elements, the structure is modeled by thin-walled beam elements that can describe warping and distortion. In order to match the shell and thin-walled beam elements at the interface of the dissimilar elements, a technique based on a pseudo inverse matrix is formulated. This paper also examines the role of the thin-walled element taking into account the distortion and warping deformation degrees of freedom in predicting accurately the dynamic characteristics of a T-joint thin-walled structure.

• 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.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.12
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• pp.655-660
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• 2004

This paper deals with the design of a fixed-structure $H_\infty$ power system stabilizer (PSS) by using an iterative linear matrix inequality (LMI) method. The fixed-structure $H_\infty$ controller is represented in terms of LMIs with a rank condition. To solve the non-convex rank-constrained LMI problem, a linear penalty function is incorporated into the objective function so that minimizing the penalized objective function subject to LMIs amounts to a convex optimization problem. With an increasing sequence of the penalty parameter, the solution of the penalized optimization problem moves towards the feasible region of the original non-convex problem. The proposed algorithm is, therefore, convergent. Numerical experiments show the practical applicability of the proposed algorithm.

• Journal of Powder Materials
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• v.24 no.1
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• pp.17-23
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• 2017

In this study, a finite element analysis approach is proposed to predict the fluid-structure interaction behavior of active materials for lithium-ion batteries (LIBs), which are mainly composed of graphite powder. The porous matrix of graphite powder saturated with fluid electrolyte is considered a representative volume element (RVE) model. Three different RVE models are proposed to consider the uncertainty of the powder shape and the porosity. P-wave modulus from RVE solutions are analyzed based on the microstructure and the interaction between the fluid and the graphite powder matrix. From the results, it is found that the large surface area of the active material results in low mechanical properties of LIB, which leads to poor structural durability when subjected to dynamic loads. The results obtained in this study provide useful information for predicting the mechanical safety of a battery pack.