Optimized thick-wall cylinders by virtue of Poissonʹs ratio selection: Part 1: Isochoric pressure application

The principal stress distributions in thick-wall cylinders due to variation in the Poissonʹs ratio are predicted using analytical and finite element methods. Analyses of appropriate brittle and ductile failure criteria show that under the isochoric pressure conditions investigated that auextic (i.e. those possessing a negative Poissonʹs ratio) materials act as stress concentrators; hence they are predicted to fail before their conventional (i.e. possessing a positive Poissonʹs ratio) material counterparts. The key finding of the work presented shows that for constrained thick-wall cylinders the maximum tensile principal stress can vanish at a particular Poissonʹs ratio and aspect ratio. This phenomenon is exploited in order to present an optimized design criterion for thick-wall cylinders. Moreover, via the use of a cogent finite element model, this criterion is also shown to be applicable for the design of micro-porous materials.