In this thesis, we work in the setting of nonlinear compressible and incompressible hyperelasticity. We focus on surface instabilities, in particular sulcus (crease) formation and surface wrinkling at the free boundary of a deformed elastic body. We associate the occurrence of these phenomena with the concepts of strong and weak local minimisers in the calculus of variations.We study conditions under which crease formation is energetically favourable, and give new algebraic criteria for the initiation of surface wrinkling by studying solutions of the underlying linearised equilibrium equations.This study was originally initiated in order to understand the failure (via creasing)of a rubber component used in oil exploration equipment.
|Date of Award||22 Jul 2020|
|Supervisor||Chris Bowen (Supervisor), Jeyabal Sivaloganathan (Supervisor) & Vincent Coveney (Supervisor)|