To define the material properties for non-linear hyper-elastic (Elastomeric) materials
An elastomer is a polymer which shows non-linear elastic stress-strain behaviour. The term elastomer is often used to refer to materials which show a rubber-like behaviour. Elastomeric materials are elastic in the classical sense. Upon unloading, the stress-strain curve is retraced and there is no permanent deformation. Elastomeric materials are initially isotropic. Figure below shows a typical stress-strain curve for an elastomeric material.