Mechanical APDL Structural Analysis Guide

TBDATA,2,2 !Define α 1

TBDATA,3,-0.250152 !Define μ 2

TBDATA,4,-2 !Define α 2

TBDATA,5,6.93063E-5 !Define incompressibility parameter

!(as 2/K, K is the bulk modulus)

!(Second incompressibility parameter d 2 is zero)

Refer to Ogden Hyperelastic Material Constants for a description of the material constants required for
this option.

8.4.1.2.3. Neo-Hookean Hyperelastic Option (TB,HYPER,,,,NEO)

The Neo-Hookean option (TB,HYPER,,,,NEO) represents the simplest form of strain energy potential, and
has an applicable strain range of 20-30%.

An example input listing showing a typical use of the Neo-Hookean option is presented below.

TB,HYPER,1,,,NEO !Activate Neo-Hookean data table

TBDATA,1,0.577148 !Define mu shear modulus

TBDATA,2,7.0e-5 !Define incompressibility parameter

!(as 2/K, K is the bulk modulus)

Refer to Neo-Hookean Hyperelastic Material for a description of the material constants required for this
option.

8.4.1.2.4. Polynomial Form Hyperelastic Option (TB,HYPER,,,,POLY )

The polynomial form option (TB,HYPER,,,,POLY) allows you to define an unlimited number of parameters
through the NPTS argument of the TB command. For example, to define a 3 parameter model you
would issue TB,HYPER,1,,3,POLY.

Similar to the higher order Mooney-Rivlin options, the polynomial form option may provide a better
approximation to a solution at higher strain.

For NPTS = 1 and constant c 01 = 0, the polynomial form option is equivalent to the Neo-Hookean option

(see Neo-Hookean Hyperelastic Option (TB,HYPER,,,,NEO) (p. 204) for an example input listing). Also, for
NPTS = 1, it is equivalent to the 2 parameter Mooney-Rivlin option. For NPTS = 2, it is equivalent to
the 5 parameter Mooney-Rivlin option, and for NPTS = 3, it is equivalent to the 9 parameter Mooney-
Rivlin option (see Mooney-Rivlin Hyperelastic Option (TB,HYPER,,,,MOONEY ) (p. 203) for an example input
listing).

Refer to Polynomial Form Hyperelastic Material Constants for a description of the material constants
required for this option.

8.4.1.2.5. Arruda-Boyce Hyperelastic Option (TB,HYPER,,,,BOYCE)

The Arruda-Boyce option (TB,HYPER,,,,BOYCE) has an applicable strain level of up to 300%.

An example input listing showing a typical use of the Arruda-Boyce option is presented below.

TB,HYPER,1,,,BOYCE !Activate Arruda-Boyce data table

TBDATA,1,200.0 !Define initial shear modulus

TBDATA,2,5.0 !Define limiting network stretch

TBDATA,3,0.001 !Define incompressibility parameter

!(as 2/K, K is the bulk modulus)

Refer to Arruda-Boyce Hyperelastic Material Constants for a description of the material constants required
for this option.

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Nonlinear Structural Analysis