Analysis and design of sandwich plates with inserts—a high-order sandwich plate theory approach

Abstract

Sandwich structures are very susceptible to failure due to local stress concentrations induced in areas of load introduction, supports, geometrical and material discontinuities. These local stress concentrations are caused by localised bending effects, where the individual face sheets tend to bend about their own middle surface rather than about the middle surface of the sandwich. This paper deals with such local effects seen around inserts in structural sandwich plates. A high-order theory for bending of sandwich plates, developed and adapted especially for the purpose of studying sandwich plates with inserts and other “hard points”, is introduced. The theory, which accounts for the transverse flexibility of the core material, includes separate descriptions of the face sheets and the core materials as well as general specification of loads and boundary conditions. The theory is formulated in terms of first-order partial differential equations , which are solved numerically using the “multi-segment method of integration”. Examples involving sandwich plates with “through-the-thickness” inserts subjected to axisymmetric and non-axisymmetric external loading are presented. The paper is concluded by a discussion of design aspects.