On the development of volumetric strain energy functions

To describe elastic material behavior the starting point is the isochoric-v olumetric decoupling of the strain energy function. The volumetric part is the central subject of this contribution. First, some volumetric functions given in the literature are discussed with respect to physical conditions, then three new volumetric functions are developed which fulfill all imposed conditions. One proposed function which contains two material parameters i n addition to the compressibility parameter is treated in detail. Some para meter fits are carried out on the basis of well-known volumetric strain ene rgy functions and experimental data. A generalization of the proposed funct ion permits an unlimited number of additional material parameters. Dedicate d to Professor Franz Ziegler on the occasion of his 60th birthday.