The meaning of specific internal energy and dissipated inelastic specific energy in VUMAT

Updating Internal and Dissipated Inelastic Energies in VUMAT

When writing a VUMAT, the following quantities must be defined:

» Stress at the end of an increment

» SDVs (if there is any) at the end of an increment

But internal and dissipated energies at the end of the increment may be defined.

If you have any problem with the VUMAT results (stresses, strains, etc.) it can not be due to updating energies. You should investigate stress updating terms.

Specific Internal Energy and Dissipated Inelastic Specific Energy

The internal energy (IE) is the sum of the recoverable elastic strain energy, EE; the dissipated inelastic energy (dissipated through inelastic processes such as plasticity), PE; the energy dissipated through viscoelasticity or creep, CDE; and the artificial strain energy (includes energy stored in hourglass resistances and transverse shear in shell and beam elements), AE:

IE = EE + PE + CDE + AE

Specific here means per unit of mass.

See Also:

Training Package: Introduction to UMAT and VUMAT Subroutines

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