Computer aided material selection for circular tubes designed to resist axial crushing

Abstract

We consider optimal design of cylindrical shells under axial compression. The main motivation is the comprehensive study of Weaver and Ashby [Material limits for shape efficiency. Progress in Materials Science 1997;41:61–128] concerning tubes designed to resist local buckling, global buckling and yield. In this paper we add another mode to this set of possible failure mechanisms, namely axial crushing. This failure-mode turns out to be dominate for many materials in several relevant load-cases. In many cases, taking this mode into account changes the optimal design substantially. By analyzing the formulae for the failure-modes we obtain piecewise defined functions describing the optimal cross-section and the minimum mass of the tube. Combined with advanced computer aided material selection tools like the Cambridge Engineering Selector (CES), these functions enable us to identify the best possible materials which give the lightest possible tubes.