This set of verification problems is primarily intended to test the variables that are passed into UANISOHYPER_INV in Abaqus/Standard or VUANISOHYPER_INV in Abaqus/Explicit. These tests also verify that the derivatives of the strain energy function defined by the user are transferred properly to the solution process. In each test the material properties are specified using the user strain energy potential for the testing elements, for which the strain energy function and the associated derivatives are defined in user subroutines UANISOHYPER_INV and VUANISOHYPER_INV. Each test contains one reference element with material properties specified with anisotropic hyperelasticity, which provides the reference solution. Three different sets of material data are used, as described below.

Material 1:

Holzapfel-Gasser-Ogden material with two families of fibers:

Holzapfel-Gasser-Ogden coefficients:
= 7.64., = 996.6, = 524.6, = 0.226.
Fiber directions (N=2):
with
Compressible case:

Material 2:

Polynomial (N=2) isotropic hyperelastic behavior

Polynomial coefficients (N=2):
	= 100.0
	= 50.0
	= 10.0
	= 20.0
	= 30.0
Compressible case: = 0.01, =0.0

Material 3:

Generalized Fung energy function implemented in terms of pseudo invariants. Two implementations are considered: one with the components of the modified Green strain expressed in terms of type invariants, and the other in terms of and type invariants.

Fung coefficients:
	= 0.9925
	= 0.0749
	= 0.4180
	= 0.0295
	= 0.0193
	= 0.0089
	= 5.0
	= 5.0
	= 5.0
Compressible case: = 0.1