Ogden's model of a compressible hyperelastic material is described by the strain energy function $$\psi=\psi_v+\psi_d,\quad \psi_v=\frac{1}{2}\kappa(J-1)^2,\quad \psi_d=\sum^\infty_{r=1}\frac{\mu_r}{\alpha_r}\left(\bar\lambda_1^{\alpha_r}+\bar\lambda_2^{\alpha_r}+\bar\lambda_3^{\alpha_r}-3\right),$$ where $\alpha_r,$ $\mu_r$ are couples of material model parameters, $\kappa$ is the bulk modulus, $J=\det\mathbf{F}$ is the determinant of the deformation gradient $\mathbf{F},$ and $\bar\lambda_A=J^{-2/3}\lambda_A$ are the modified principal stretches.

PMD does not support calculations with a zero elastic modulus $E,$ therefore, it is necessary to transform the material parameters first. Given the shear modulus as $2\mu=\sum^\infty_{r=1}\mu_r\alpha_r,$ we can determine the tangential elastic modulus in the non-deformed state and the Poisson ratio using formulas $$E=\frac{9\kappa\mu}{3\kappa+\mu},\quad \nu=\frac{3\kappa-2\mu}{2(3\kappa+\mu)}.$$

Material quantites are defined in the file name.i2, where the parameters $\alpha_1,\alpha_2,\alpha_3,\mu_2,\mu_3$ are entered on the 11th–15th position of the MP batch:

The model is activated by the key $\mathtt{KLARG}=6$ in the file name.iP.