On Constitutive Equations For Elastomers And Elastomeric Foams

William W. Feng John O. Hallquist Livermore Software Technology Corporation The Hill-Ogden elastic constitutive equation for incompressible and compressible rubber-like materials is presented. The derivation and computer programs to determine the material constants for these equations from uniaxial and biaxial tests are included. These constitutive equations and the computer programs for determining the material constants have been implemented into LS-DYNA. A few examples are shown. Some special cases are given to demonstrate the versatility of these constitutive equations. The Mooney-Rivlin constitutive equation is a special case. The Feng-Christensen viscoelastic foam model in one-dimensional compression, developed in 1986, can be written in a mathematical form and implemented in finite element codes.