Materials and Properties

Within this section, supported materials are discussed.

This page discusses:

Materials Allowed in Topology Optimizations

All linear, some nonlinear, constitutive, and anisotropic material laws for Abaqus are supported as design elements:

  • Linear-elastic, isotropic material 
    
*ELASTIC, TYPE=ISOTROPIC
  • Linear-elastic, anisotropic material 
    
*ELASTIC, TYPE=ENGINEERING CONSTANTS
*ELASTIC, TYPE=LAMINA
*ELASTIC, TYPE=ORTHOTROPIC
*ELASTIC, TYPE=ANISOTROPIC
    not supported as design elements: 
    
*ELASTIC, TYPE=TRACTION
*ELASTIC, TYPE=COUPLED TRACTION
  • Hyperelastic:

    Some material cards of *HYPERELASTIC are supported as design elements, see also the figure below. 

    
 ARRUDA-BOYCE
 MOONEY-RIVLIN
 NEO HOOKE
 OGDEN
 POLYNOMIAL
 REDUCED POLYNOMIAL
 VAN DER WAALS
 YEOH
    Not supported as design elements: 
    
MARLOW
USER
    Using the TEST DATA INPUT parameter in *HYPERELASTIC (that is usually followed by *UNIAXIAL TEST DATA or other test data) is not allowed.

  • The material card *PLASTIC is supported as design element, see also the figure below. Supported for the type HARDENING=ISOTROPIC (default). A main limitation is that each material point (gauss point) is only allowed to be unloaded once and it should not be elastic-plastic again. Meaning that cyclic loading is not supported.
  • *CONCRETE is supported for design elements
  • The material card *HYPOELASTIC is support as design element, see also figure the following figure.
Some of the *PLASTIC (a), *HYPOELASTIC (b) and *HYPERELASTIC (c) cards in Abaqus are supported for design elements.

  • Dependency of temperature or other field variables (Parameter DEPENDENCIES).

Materials Allowed in Shape Optimization

  • All linear and nonlinear elastic materials:
  • 
*ELASTIC
*HYPERELASTIC
*HYPERFOAM
*HYPOELASTIC
*POROUS ELASTIC
  • Plasticity
  • Dependency of temperature or other field variables (Parameter DEPENDENCIES).

Shell Property Definition Limitation

Topology & Sizing Optimization

The following section assignment for a design domain element(s) in topology or sizing optimization will cause an abort


*SHELL SECTION, NODAL THICKNESS = ...
*SHELL SECTION, SHELL THICKNESS = ...

For topology and sizing optimization, only uniform shell thickness is allowed for the design domain elements. Composite shell sections with a single ply are also allowed.

Shape Optimization

For shape optimization, composite shell sections with multiple plies are supported.

Bead Optimization

For shape optimization, composite shell sections with multiple plies are supported.

Also supported are single value thickness and offset definitions per *SHELL SECTION,no distribution definitions.

Example of supported offset definition:

*SHELL SECTION, ..., OFFSET = <numeric> | SPOS | SNEG

Beam Property Definition Limitation

For topology and sizing optimization, elements with *BEAM GENERAL SECTION property are not allowed in the design domain. A work-around is to define an equivalent *BEAM SECTION property for these elements or to remove them from the optimization domain.

Remark

The use of nonlinear materials in an optimization is only permitted for users of the Tosca Structure.nonlinear. license. This applies for the commands and parameters below:


*CONCRETE
*HYPERELASTIC
*HYPERFOAM
*HYPOELASTIC
*PLASTIC
*POROUSELASTIC
*VISCOELASTIC

If no license is held for this mode, the optimization stops once the parameters or commands listed above are used. This does not apply if a linear perturbation step is used.