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This option is used to define a hyperfoam material. There is one optional parameters, N. N determines the order of the strain energy potential. Default is N=1. All constants may be temperature dependent.
The hyperfoam strain energy potential takes the form
| ![$\displaystyle U=\sum_{i=1}^{N} \frac{2 \mu_i}{\alpha_i^2} \left[ \lambda_1^{\al...
...ha_i}+\lambda_3^{\alpha_i}-3+\frac{1}{\beta_i}(J^{-\alpha_i \beta_i}-1) \right]$](img1577.png) | (413) | 
 ,
,  and
 and  are the principal
stretches. The parameters
 are the principal
stretches. The parameters  are related to the Poisson coefficients
 are related to the Poisson coefficients
 by:
 by:
|  | (414) | 
and
|  | (415) | 
First line:
Following line for N=1:
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Following line for N=2:
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Following lines, in a pair, for N=3: First line of pair:
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Example: *HYPERFOAM,N=2 0.164861,8.88413,2.302e-5,-4.81798,0.,0.
defines a hyperfoam material with two terms in the series.
Example files: beamhf.
 
 
 
 
 
 
