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김찬묵(C.M.Kim),정승원(S.W.Chung) 한국자동차공학회 1993 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
The purpose of this paper is to investigate the natural frequencies of stiffened plates due to transformation of stiffener shape and existence of viscoelastic resin. To verify vibration characteristics, local stiffness matrix and local mass matrix are calculated by using F.E.M including plate and beam theory.<br/> In case of stiffened plate with viscoelastic resin, the natural frequency of each mode is decreased about 10 ~50 percent at quadrilateral form stiffener and about 10 ~ 40 percent at triangular form stiffener. In case of viscoelastic resin of quadrilateral and triangular form, the higher the height of stiffener is, the higher the natural frequency is at the first mode. But the natural frequencies beyond the second mode are known to unrelate to the height of stiffener.<br/> In case of stiffened plate with quadrilateral form stiffener and without resin the numerical values by using F.EM are about 5 ~ 10 percent higher than those of experiment.<br/>
김성래(S. R. Kim),이채욱(C. W. Lee),김문영,김찬묵(C. M. Kim),임홍재(H. J. Yim) 한국소음진동공학회 2012 한국소음진동공학회 학술대회논문집 Vol.2012 No.4
In this paper, we propose the efficient technique that reduces the number of spot-welds and increases the structural rigidity by using the topology optimization technique. Eigen value analysis is used to evaluate the rigidity of the optimized model. As a first step, the topology optimization is performed to find optimal spot-weld distributions. In this study, the design objective is to maximize the weighted frequencies. The volume fractions of the weld components are used as design constraints, and also the densities of each element in the individual design space are used as design variables. And then, to consider the possibility of spot-weld failure, the contribution rate analysis was performed by using the orthogonal array method of DOE. The spot-welds in the rear panel part are reinforced according to estimation results of the contribution rate analysis. Finally, we obtained optimized spot-weld layout model which has the reduced number of spot-welds and the improved dynamic stiffness.