Edge effects in elastic bulging

Elastic bulging occurs when an elastic material deforms through a small opening in a rigid boundary. This problem is complementary to the indentation problem where displacement is applied to a small part of an elastic material. Understanding bulging is crucial in a number of applications related to swelling such as the deformation of the brain following a decompressive craniectomy. In particular, it is known that large stresses develop close to the opening leading to potential material damage. To alleviate this problem, it is conceivable to modify the shape of the edge to reduce stress increases. Here, we study edge effects during planar bulging and show how an opening should be shaped to remove stress singularities.