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Ogden

Module: solid

Category: material

Type string: "Ogden"

Parameters

Name Description Default Range Units
density density 1 \(\ge 0\) M/L^3
k bulk modulus 0 \(\ge 0\) P
pressure_model pressure_model 0 \([0, 3]\)
c1 c1 0 \(\in \mathbb{R}\) P
c2 c2 0 \(\in \mathbb{R}\) P
c3 c3 0 \(\in \mathbb{R}\) P
c4 c4 0 \(\in \mathbb{R}\) P
c5 c5 0 \(\in \mathbb{R}\) P
c6 c6 0 \(\in \mathbb{R}\) P
m1 m1 1 \(\neq 0\)
m2 m2 1 \(\neq 0\)
m3 m3 1 \(\neq 0\)
m4 m4 1 \(\neq 0\)
m5 m5 1 \(\neq 0\)
m6 m6 1 \(\neq 0\)

Description

This material describes an incompressible hyperelastic Ogden material 1.

The uncoupled hyperelastic strain energy function for this material is given in terms of the eigenvalues of the deformation tensor:

\[ \Psi=\sum\limits_{i=1}^{N}\frac{c_{i}}{m_{i}^{2}}\left(\tilde{\lambda}_{1}^{m_{i}}+\tilde{\lambda}_{2}^{m_{i}}+\tilde{\lambda}_{3}^{m_{i}}-3\right)+U\left(J\right). \]

Here, \(\tilde{\lambda}_{i}^{2}\) are the eigenvalues of \(\mathbf{\tilde{C}}\), \(c_{i}\) and \(m_{i}\) are material coefficients and \(N\) ranges from 1 to 6. Note that you only have to include the material parameters for the terms you intend to use.

Example:

<material id="1" type="Ogden">
  <m1>2.4</m1>
  <c1>1</c1>
  <k>100</k>
</material>


  1. Simo, J.C. and Taylor, R.L., "Quasi-incompressible finite elasticity in principal stretches: Continuum basis and numerical algorithms", Computer Methods in Applied Mechanics and Engineering 85 (1991), pp. 273-310.