Experimental models

The exported models are listed on the Material models page. Provenance and permissions for these variants follow the corresponding stable model pages: VEPD Detrez 2010, VEVP Zhao 2021, and VEVP MOAMMM.

Importing variants

The variants live in a separate submodule. To use one, import the symbol explicitly:

using FerriteSolidMechanics
using FerriteSolidMechanics.Experimental: VEPD_Detrez2010_Optimized, VEPD_Detrez2010_Implicit, VEPD_Detrez2010_ExactVisco, VEPD_Detrez2010_ClosedCVEndStep, VEVP_Zhao2021_AD_Simplified, VEVP_Zhao2021_AT_Matlab, VEVP_MOAMMM_VarsN

VEVP_MOAMMM_VarsN

src/models/experimental/VEVP_MOAMMM_VarsN.jl. Archived previous implementation of VEVP_MOAMMM with a flat Vector{Float64} state buffer (vars/vars_n) rather than the named typed fields of the exported version. It follows the same constitutive equations and Drucker–Prager/Perzyna local solver, stores history in the original Fortran STATEV-style layout, and uses the same Tensors.gradient AD tangent.

VEVP_Zhao2021_AD_Simplified

src/models/experimental/VEVP_Zhao2021_AD_Simplified.jl. Comparison variant of VEVP_Zhao2021_AD with the same history fields (Cik, muVk, strain_maxk). It uses a simpler stress path: the stress returned from the local solve is assembled from trial/previous-state branch stresses, while the updated history fields are still stored for the next step. It supports the same optional dt_scale keyword as VEVP_Zhao2021_AD and applies it to dt inside the constitutive update.

VEVP_Zhao2021_AT_Matlab

src/models/experimental/VEVP_Zhao2021_AT_Matlab.jl. Archived previous AT implementation with Matrix{Float64} storage, following the CAPRICCIO/Zhao Matlab routines more directly than the exported VEVP_Zhao2021_AT. It is kept so the translation is not lost; use VEVP_Zhao2021_AT for new work. It supports the same optional dt_scale keyword as VEVP_Zhao2021_AT.

VEPD_Detrez2010_Optimized

src/models/experimental/VEPD_Detrez2010_Optimized.jl. Experimental variant that closely follows VEPD_Detrez2010 under separate type and state names. It uses the same state quantities (Fp, p, Cv) and the same broad update structure: plastic return loop, linear (1 + Delta p*N) plastic map, exponential Maxwell-branch update, damage scaling, and AD tangent assembly.

This variant is not a full drop-in replacement for VEPD_Detrez2010: it lacks the positional constructor and a model-specific revert_state! method.

VEPD_Detrez2010_Implicit

src/models/experimental/VEPD_Detrez2010_Implicit.jl. Variant of VEPD_Detrez2010 that keeps the same plastic-return structure and linear (1 + Delta p*N) plastic flow map, but uses an implicit/rational Maxwell-branch update: Cv_next = (Cv_n + (2dt/tau) C) / (1 + 2dt/tau). It also omits the damage cap used by VEPD_Detrez2010 and does not define a model-specific revert_state!.

VEPD_Detrez2010_ExactVisco

src/models/experimental/VEPD_Detrez2010_ExactVisco.jl. Comparison variant of VEPD_Detrez2010 around the Maxwell-branch evolution. Both this variant and VEPD_Detrez2010 use an exponential Maxwell update, so this is not a higher-accuracy viscoelastic option. It also differs mechanically from VEPD_Detrez2010: the Arruda–Boyce network stress is omitted, the network parameters n_ab and mu_ab are stored but unused, and damage is not clamped to 1.0. This variant also does not implement a model-specific revert_state!.

VEPD_Detrez2010_ClosedCVEndStep

src/models/experimental/VEPD_Detrez2010_ClosedCVEndStep.jl. Archived copy of the former VEPD_Detrez2010 default implementation: end-step plastic return mapping with closed-form $\boldsymbol{C}^{\mathrm{v}}$ Maxwell updates. It is available as FerriteSolidMechanics.Experimental.VEPD_Detrez2010_ClosedCVEndStep.

This variant is kept as a performance/reference baseline for the current VEPD_Detrez2010 default settings plastic_update=:end_step, maxwell_update=:closed_form_cv. In the local scratch benchmark it was about 2–4% faster than the current default implementation, with zero differences in the compared final $\sigma_{11}$, accumulated plastic strain, and $\boldsymbol{C}^{\mathrm{v}}$ branch states.