• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1362-1365
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• 2003

On this study. we improved the efficiency applying algorithm that is repeatedly using orthogonal array in discrete design space and filling a defect of gradient method in continuous design space. we showed optimal ply angle that maximized buckling strength of CFRP laminated composite plate without a hole and with a hole by each aspect ratio. In the case of CFRP laminated composite plate without a hole, we confirmed the reliance and efficiency of algorithm in comparison with the result optimization achievement repeatedly using statistical orthogonal array of experimental design.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1660-1665
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• 2003

On this study, we improved the efficiency applying algorithm that is repeatedly using orthogonal array in discrete design space and filling a defect of gradient method in continuous design space. we showed optimal ply angle that maximized 1st natural frequency of CFRP laminated composite cantilever plate by each aspect ratio. A finite element analysis on the CFRP laminated composite cantilever plate using orthogonal array is carried out, and the results are compared with those obtained by modal testing.

• 한국소음진동공학회논문집
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• 제13권6호
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• pp.423-429
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• 2003

On this study. we improved the efficiency applying algorithm that is repeatedly using table of orthogonal array in discrete design space and filling a defect of gradient method in continuous design space. we showed optimal ply angle that maximized 1st natural frequency of CFRP laminated composite plate without a hole and with a hole by each aspect ratio. In the case of CFRP laminated composite plate without a hole, we confirmed the reliance and efficiency of algorithm in comparison with the result of optimization achievement repeatedly using statistical table of orthogonal array of experimental design and the BFGS optimal design method.

• 한국공간구조학회논문집
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• 제10권4호
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• pp.75-83
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• 2010

복합적층판은 다른 금속재료에 비해 높은 비강도, 비강성 등의 우수한 역학적 특성을 지니므로, 최근 다양한 분야에서 사용하고 있다. 그러나 이러한 복합적층판은 충격에 약하다는 단점이 있다. 그리하여 복합적층판의 충격거동에 대한 많은 연구가 이루어지고 있다. 충격거동을 조사하기 위해서는 우선 충격체와 복합적층판사이의 접촉력을 계산하여야 한다. 접촉력을 알기 위해서는 운동방정식, 복합적층판의 운동방정식 그리고 압입량에 관한 관계식을 동시에 풀어야 한다. 본 연구에서는 고전적인 헤르츠식, 썬식, 썬&양식 그리고 썬&탄식을 포함한 유한요소프로그램을 이용하여 복합적층판의 저속충격거동을 조사한다.

• Structural Engineering and Mechanics
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• 제57권4호
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• pp.603-616
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• 2016

In this study, a convenient formulation for the bending of laminated composite plates that hold non-homogeneous properties is examined. The constitutive equations of first order shear deformation plate theory are obtained using Hamilton Principle. The effect of non-homogeneity, lamination schemes and aspect ratio on the deflections and stresses is analysed. It is understood from the study that economical and optimum designs for laminated composite plates can be achieved by changing lamination scheme and by considering non-homogeneity response of composite plate.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.331-336
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• 2004

This paper is concerned with numerical simulation of hypervelocity impacts(HVIs) of a projectile on laminated composite plate targets using SPH method. A one-parameter visco-plasticity model and damage model is used to describe the HVIs response of composite materials. The numerical simulation was carried out for a steel projectile striking to aluminum plate targets and for an aluminum projectile striking to laminated graphite/epoxy (Gr/Ep) composite plate targets. Through the numerical simulation, comparison with the HVIs response of isotropic materials and composite materials is discussed.

• 항공우주시스템공학회지
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• 제13권4호
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• pp.10-17
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• 2019

This study is concerned with a numerical analysis based on the finite element method to describe the effect of midplane delamination in smart laminated composite plate structures. A new finite element model for centrally located delamination and healthy section was developed and coded in Matlab. The transient analysis of delaminated composite plate with integrated Active Fiber Composite (AFC) was investigated in the present article. The formulation of the governing equation was based on the minimum total potential energy approach. The Newmark time integration technique was employed to solve the differential equations. A parametric study on the effects of boundary conditions and AFC patch location, in presence of delamination on the laminated plate were studied.

• Structural Engineering and Mechanics
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• 제72권6호
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• pp.763-774
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• 2019

The main aim of this paper is enhancing design of traditional laminated composite plates subjected to static loads. In this regard, this paper suggests embedding a lightweight porous layer in the middle of laminated composite as the core layer of the resulted sandwich plate. The static responses of the suggested structures with uniform, symmetric and non-symmetric porosity distributions are compared to optimize their design. Using the first order shear deformation theories, the static governing equations of the suggested laminated composite plates with a porous layer (LCPPL) rested on two-parameter foundation are obtained. A finite element method is also utilized to solve the governing equations of LCPPLs. Effects of laminated composite and porosity characteristics as well as geometry dimension, edges' boundary conditions and foundation coefficients on the static deflection and stress distribution of the suggested composite plates have been investigated. The results reveal that the use of core between the layers of laminated composites leads to a sharp reduction in the static deflections of LCPPLs. Furthermore, in compare with perfect cores, the use of porous core between the layers of laminated composite plates can offer a considerable reduction in structural weight without a significant difference in their static responses.

• Steel and Composite Structures
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• 제22권6호
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• pp.1261-1280
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• 2016

We study chaotic motion in a nonlinear laminated composite plate under subsonic fluid flow and a simultaneous external load in this paper. We derive equations of motion of the plate using the von-$K{\acute{a}}rm{\acute{a}}n^{\prime}s$ hypothesis and the Hamilton's principle. Galerkin's approach is adopted as the solution method. We then conduct a divergence analysis to obtain critical velocities of the transient flow. Melnikov's integral approach is used to find the critical parameters in which chaos takes place. Effects of different parameters including the aspect ratio, plate material and the ply angle in laminates on the critical flow speed are investigated. In a parametric study, we show that how the linear and nonlinear stiffness of the plate and the load frequency and amplitude would influence the chaotic behavior of the plate.

• Advances in Computational Design
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• 제3권2호
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• pp.113-132
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• 2018

This paper presents the vibration and harmonic analysis of orthotropic laminated composite plate. The response of plate is determined using Finite Element Method. The eight noded shell 281 elements are used to analyze the orthotropic plates and results are obtained so that the right choice can be made in applications such as aircrafts, rockets, missiles, etc. to reduce the vibration amplitudes. Initially the model response for orthotropic plate and harmonic response for isotropic plate is verified with the available literature. The results are in good agreement with the available literature. Numerical results for the natural frequency and harmonic response amplitude are presented. Effects of boundary conditions, thickness to width ratio and number of layers on natural frequency and harmonic response of the orthographic plates are also investigated. The natural frequency, mode shape and harmonic analysis of laminated composite plate has been determined using finite element package ANSYS.