Axisymmetric stress propagation in a sandwich medium

Abstract

The Saint Venant's principle is accepted to be valid in most of the problems in structural mechanics. However, there are exceptions to this principle. The limitations of Saint Venant's principle as applied to sandwich type structures have been indicated by earlier researchers. The authors have already reported results of detailed numerical experiments on long rectangular strips. The aim of the investigation reported herein is to study the propagation of stress disturbance in the case of a sandwich medium subjected to an axisymmetric system of self-equilibrating loads, using a theory of elasticity approach. An infinite three-layer sandwich plate, subjected to two equal and opposite central concentrated loads, is considered. Three face-to-core modulus ratios are considered and representative numerical results are presented. In all cases it is observed that significant stresses do exist in the core at relatively large distances from the load point, compared to the homogeneous type of construction. The stress becomes negligible only at a distance of about four times the thickness of the plate from the load point in the case of very soft cores, the distance being less for more rigid cores.