Model and animation by Sheldon Imaoka. [ANSYS 6.1]
Zipped AVI animation of equivalent stresses in a rigid-deformable contact model. A criterion is used to deactivate an element once its maximum strain exceeds a certain value. As a rigid sphere is pushed against shell elements (these shell elements are visualized with their thicknesses in 3D), the thinner shells fail first, thus 'breaking open' the seal.