Skip to content

Creep and inelasticity

Time-dependent and path-dependent materials require more than a rate formula. AgentFEM treats committed/trial state, consistent linearization, cutback, rollback, restart, output, and benchmark evidence as part of the material's global finite-element contract.

Current boundary

  • 3D global power-law creep with regional materials, backward Euler, shared quadrature state, analytical tangent, physical-time cutback, creep fields, dissipation, and portable full-Step restart;
  • MPI-safe regional quadrature updates and rank-count-portable J2/creep full-Step archives; J2 distributed global Newton has public thick-cylinder structural evidence, while native axisymmetric creep now reproduces NAFEMS R0027 Test 7. An independent distributed creep component benchmark remains distinct from the existing MPI regional patch and restart tests;
  • scalar, finite-element or accepted-history temperature input consumed at creep integration points by the normalized Arrhenius rate, shared E(T)/nu(T)/alpha(T), thermal strain and consistent tangent;
  • natural-load work, prescribed-motion work, elastic energy, creep dissipation, internal energy and mechanical residual histories;
  • Kachanov–Rabotnov, Sinh, and related relations at explicitly marked material-point/evaluation maturity unless a global consumer is present;
  • modified-theta projection as a curve-assessment tool;
  • source-identified creep time fractions and explicit creep--fatigue interaction diagrams as an engineering postprocessor; declared dwell intervals may be extracted from named stress and temperature histories;
  • small-strain J2 plasticity through a stateful global route, including an experimental multi-backstress Chaboche combined-hardening material using the same Step, quadrature transaction, output and restart lifecycle.

The maturity label is part of the interface: the presence of a formula does not silently imply a validated global analysis procedure.

For cyclic plasticity, constitutive.chaboche(...) accepts one or more (C_i, gamma_i) pairs plus optional exponential isotropic saturation. It publishes S, PE, PEEQ, total backstress ALPHA, and MISES. Its local consistency, reversal response, global cycle and restart are automated; a structure-level stabilized-hysteresis comparison and complete recovery- dissipation energy closure remain promotion gates.

Go deeper