CREASING SINGULARITIES IN COMPRESSIBLE ELASTIC-MATERIALS

The deformation and stress fields near a crease in the surface of an isotropic, compressible elastic body in equilibrium are in general singular. The order of the singularity depends on the constitutive behavior in the limit of zero volume. In this paper the problem of the creasing of a semicircular cylinder folded about its axis is solved exactly for a family of materials that includes the Blatz-Ko material (a foam rubber). Conditions under which strong ellipticity is lost are derived.