New method for predicting the wrinkling stress in sandwich panels

Abstract

It is necessary to accurately and efficiently calculate the wrinkling stresses of sandwich panels under in-plane compression. However, the simple equations used in engineering may obtain inaccurate results, whereas finite element methods with higher accuracy may be computationally expensive. This study proposes a new method for solving the wrinkling problem of sandwich panels using structural optimization theory at a low computational cost. A sandwich panel was divided into several virtual plies, which were assigned design variables to describe the vertical displacement during wrinkling. The wrinkling stress was obtained by minimizing the admissible in-plane compressive stress. The method was verified using finite element and experimental methods, as good agreement was found. The differences were less than 5% and 20% with the finite element and experimental results, respectively. Moreover, this method can easily compute the wrinkling stress of sandwich panels with functionally graded material cores with a little increase in computational cost. This method allows engineers to compute the wrinkling stress effectively and efficiently without the need for complex numerical models.