• Structural Engineering and Mechanics
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• 제81권1호
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• pp.39-50
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• 2022

Layer separation (delamination) is an essential threat to fiber-reinforced polymer (FRP) plates under dynamic, static, and fatigue loads. Under compressive load, the growth of delamination will lead to structural instability. The aim of this paper is to present a method using shape memory alloy (SMA) stitches to suppress the delamination growth in a FRP plate and to improve the buckling behavior of the plate with a rectangular hole. The present paper is divided into two parts. Firstly, a closed-form (CF) formulation for evaluating the buckling load of the FRP plate is presented. Secondly, the finite element method (FEM) will be employed to calculate the buckling loads of the plates which serves to validate the results obtained from the closed-form method. The novelty of this work is the development of the closed-form solution using the p-Ritz energy approach regarding the stress-dependent phase transformation of SMA to trace the equilibrium path. For the FEM, the Lagoudas constitutive model of the SMA material is implemented in FORTRAN programming language using a user material subroutines (VUMAT). The model is simulated in ABAQUS/Explicit solver due to the nature of the loading type. The cohesive zone model (CZM) is applied to simulate the delamination growth.

• 대한조선학회논문집
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• 제32권1호
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• pp.132-140
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• 1995

선체의 중량을 감소시키기 위한 구조적인 형식중의 하나가 샌드위치 type이고 고속선의 면재는 F.R.P.와 Kevlar/Epoxy를, 심재로는 P.V.C.foam을 많이 사용한다. 본 연구에서는 면재의 두께가 두껍고 윗면재와 아랫면재의 두께가 다른 비대칭인 경우에 대하여 Rayleigh-Ritz의 에너지방법으로 해석하였다. 그리고 얇은 면재와의 비교를 위하여 등방성이고 중립축에 대칭인 평판을 기준하여 굽힘응력, 전단응력, 국부적인 굽힘응력, 막응력효과를 고려한 응력들을 면재2종류와 심재3종류에 대해서 비교하고 해석하였다.