Stress propagation in sandwich strips

Abstract

The St. Venant's principle is generally accepted to be valid in most of the problems in structural mechanics. Earlier researchers have drawn attention to the fact that routine application of this principle in the analysis of sandwich type structures is not justified in general. In an earlier paper, the authors have reported results of detailed numerical experiments on sandwich strips, using a finite element model. The aim of the investigation reported herein is to study the applicability of St. Venant's principle to the problem of a sandwich strip quantitatively, using a theory of elasticity solution with a stress function approach. Infinitely long three-layered sandwich strip, subjected to two equal and opposite line loadings, is considered. Three face-to-core modulus ratios are considered and representative numerical results are presented. In all cases it is observed that significant edge disturbances do exist at relatively large distances from the load point, compared to homogeneous type of construction.The edge disturbance becomes negligible only at a distance of about ‘5h’ the load point in the case of very soft cores, the distance being less for more rigid cores.