Using Damage Initiation Laws

Some materials, such as softening materials, need the use damage initiation laws. This section briefly lists the properties. Damage initiation law properties are assigned within a material definition that uses the law:

Material (matid),(name),(type)
         ⋮
     Initiation (Law_Name or number)
     (Law properties)
         ⋮
Done

where the Initiation command selects the law (using the law name or number from the table below). The law selection is followed by commands to set any properties specific to that law.

The following list has the available damage initiation laws. Click any one to see the law and the properties needed for that law.

  1. IsoFailure - Failure based on normal and shear stress in isotropic material based on principal stress calculations<>/li>
  2. TIFailure - for failure of transeversly isotropic materials.
  3. OrthoFailure - Damage initiates when axial stress or shear stress in each of three material symmetry planes exceed the material strength in that direction.

More documentation on these hardening laws is available on the OSUPDocs Wiki.

Isotropic Failure by Principle Stress (number=1)

The damage initiates when either the maximum principle stress exceeds the tensile strength or the maximum shear stress exceeds the shear strength. This law couples failure when needed and allows pressure dependent shear strength. For more details see the OSUPDocs Wiki. The input properties are:

Transversely Isotropic Failure Initiation (number=2)

The damage initiates when axial stress exceeds axial tensile strength, axial shear stress exceeds axial shear strength, principle stress in the transverse plane exceeds transverse shear strength, or maximum shear stress in transverse plane exceeds the shear strength.

All strength values default to a large number, which means failure will not occur in that mode.

Orthotropic Failure Initiation (number=3)

This law is currently in development. See the OSUPdocs Wiki for details and all its properties.

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