Clamped Neo-Hookean Material

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Constitutive Law

This MPM Material is an isotropic, elastic-plastic material in large strains using a hyperelastic formulation. The elastic part is a neo-Hookean material. Plasticity occurs when the elongation in either tensile of compressive elongation reaches a critical value. This material is based on similar material using in a paper to animate snow mechanics[1]. Although the model was based on engineering analysis of snow, it was simplified for efficiency in animation and for ease it creating a variety of responses.

The elastic regime of the material using a neo-Hookean material:       [math]\displaystyle{ W = \Phi\bigl(F,G(J_P),\lambda(J_P)\bigr) }[/math]

Material Properties

The material properties are given in the following table.

Property Description Units Default
CritComp Critical compression extension none 0.025
CritComp Critical tensile extension none 0.0075
xihard Hardening coefficient none 10
Elastic Enter 0 to basic elastic stresses on the model in Ref. [1]. Enter 1 to base elastic stresses on the neo-Hookean material. none 0
(other) Properties to define underlying neo-Hookean material (note that UJOption is always 1 when Elastic is 0, but can be any option when Elastic is 1) varies varies

Examples

These commands model snow:


References

  1. 1.0 1.1 A. Stomakhin, C. Schroeder, L. Chai, J. Teran, and A. Selle, "A material point method for snow simulation," ACM Trans. Graph., Vol. 32, No. 4, Article 102, July 2013.