Buckling and Post-buckling Analysis of a Sandwich Panel with Flexible Core Reinforced with Memory Alloy Wires (SMA)

Shape Memory Alloys (SMAs) are a group of intelligent materials which have distinct and superior properties compared to other alloys. The stress-strain behavior of these materials involves two specific nonlinear phenomena, namely the Shape Memory effect and the quasi-elastic effect. The behavior of the alloy whilst subject to these two phenomena is such that after it enters the plastic state, the material will regain its original form. The research is based on the modeling of these two behaviors of memory alloys in the ABAQUS software using UMAT code. In this study, the simulation of buckling and post-buckling of sandwich panels have been investigated. Preparing a UMAT memory alloy properties code, enables the designer to use any ABAQUS features to analyze the behavior of smart structures made with the shape memory alloy. Also, in this research, the first buckling critical force of the first five modes for different percentages of the alloy in the shell and core have been studied, and then the effects of volumetric percentage change of alloys, distance from neutral axis, fiber angle variations, and finally stability and post-buckling behavior of the memory alloy as the result of initial strain have been investigated. The investigations have shown large changes in the shape memory alloy due to the great recovery stress during the phase shift.