QUASI-STATIC FINITE ELEMENT ANALYSIS OF CELLULAR STRUCTURES CONSIDERING GEOMETRIC IMPERFECTIONS

Abstract

Many types of cellular structures have been proposed to be used as cores in sandwich panels. A validated FE model is often used for analyzing the mechanical properties of such structures. In the case of novel architectures, when an automated manufacturing process has not been fully developed yet, the physical structure is expensive and time consuming to be obtained in a large number of samples necessary for different experimental tests. Instead, few experimental tests are used to validate the FE model of the cellular structure, allowing further on the performance of other FE analyses. Within the correlation process, considering the stiffness response, the theoretical results overestimate the experimental ones, the FE model being difficult to validate. One reason for this is the geometry of the structure which is considered to be ideal in the FE model while in reality it is not. In this paper, geometrical imperfections are considered for developing the FE model of a particular cellular structure, developed at Transilvania University of Braşov. The implementation steps for the geometric imperfections are presented and described. It is studied the influence of the geometric imperfections caused by the manufacturing process, on the out-of-plane stiffness response of the structure. It is proved that more accurate stiffness prediction can be obtained within FE analyses by implementing geometric imperfections.