diff --git a/MaterialLib/SolidModels/MFront/Lubby2.mfront b/MaterialLib/SolidModels/MFront/Lubby2.mfront
index 6544e0a2ed9b37f94feda5bdccbbcf91533f66e5..e3f7a5d1e74d1fcb22787aeb0467f09c912ec190 100644
--- a/MaterialLib/SolidModels/MFront/Lubby2.mfront
+++ b/MaterialLib/SolidModels/MFront/Lubby2.mfront
@@ -18,7 +18,6 @@ rheological model
@Parameter local_zero_tolerance = 1.e-14;
@ModellingHypotheses{".+"};
-@RequireStiffnessTensor<UnAltered>;
// Intercept of yield function
@MaterialProperty real GK0;
@@ -40,14 +39,21 @@ epsK.setEntryName("KelvinStrain");
@StateVariable Stensor epsM;
epsM.setEntryName("MaxwellStrain");
+//! Second Lamé coefficient
+@LocalVariable stress mu;
+
+@InitLocalVariables
+{
+ mu = computeMu(young, nu);
+}
+
@Integrator
{
// Implicit system
constexpr auto id4 = Stensor4::Id();
constexpr auto Pdev = Stensor4::K();
- const auto sigma_eff =
- std::max(sigmaeq(sig), local_zero_tolerance * D(0, 0));
+ const auto sigma_eff = std::max(sigmaeq(sig), local_zero_tolerance * mu);
const auto s = deviator(sig);
const auto k = deviator(epsK + depsK);
@@ -66,8 +72,11 @@ epsM.setEntryName("MaxwellStrain");
// calculate Maxwell strain residual
fepsM = depsM - dt / (2.0 * etaM) * s;
+ // Pdev * D
+ const auto Pdev_D = 2 * mu * Pdev;
+
// Jacobian
- const auto dsigma_eff_ddeel = 3. / (2. * sigma_eff) * s | (Pdev * D);
+ const auto dsigma_eff_ddeel = 3. / (2. * sigma_eff) * s | (Pdev_D);
const auto detaK_ddeel = etaK * mvK * dsigma_eff_ddeel;
const auto detaM_ddeel = etaM * mvM * dsigma_eff_ddeel;
const auto dGK_ddeel = GK * mK * dsigma_eff_ddeel;
@@ -77,12 +86,12 @@ epsM.setEntryName("MaxwellStrain");
dfeel_ddepsM = id4;
dfepsK_ddeel = (dt / (2.0 * etaK * etaK) * s_m_2G_eK ^ detaK_ddeel) -
- (dt / (2.0 * etaK) * Pdev * D) + (dt / etaK * k ^ dGK_ddeel);
+ (dt / (2.0 * etaK) * Pdev_D) + (dt / etaK * k ^ dGK_ddeel);
dfepsK_ddepsK = (1. + dt * GK / etaK) * id4;
// dfepsK_ddepsM is all zero --> nothing to do
dfepsM_ddeel = (dt / (2.0 * etaM * etaM) * s ^ detaM_ddeel) -
- (dt / (2.0 * etaM) * Pdev * D);
+ (dt / (2.0 * etaM) * Pdev_D);
// dfepsM_ddepsK is all zero --> nothing to do
dfepsM_ddepsM = id4;
}
diff --git a/MaterialLib/SolidModels/MFront/Lubby2mod.mfront b/MaterialLib/SolidModels/MFront/Lubby2mod.mfront
index 7e14479a0b3e435c33123bd3cd90a60f5394cd04..6a89e44f30e5947e9989f5c0b7d4d6dbbac239ce 100644
--- a/MaterialLib/SolidModels/MFront/Lubby2mod.mfront
+++ b/MaterialLib/SolidModels/MFront/Lubby2mod.mfront
@@ -2,7 +2,8 @@
@DSL Implicit;
@Behaviour Lubby2mod;
@Author Thomas Nagel, Thomas Helfer;
-@Description {Lubby2 model for stationary
+@Description
+{Lubby2 model for stationary
and transient creep based on Burgers
rheological model.
Reduced implementation.
@@ -16,7 +17,6 @@ Reduced implementation.
@ModellingHypotheses{".+"};
@Brick StandardElasticity;
-@RequireStiffnessTensor<UnAltered>;
// Intercept of yield function
@MaterialProperty real GK0;
@@ -40,41 +40,53 @@ epsK.setEntryName("KelvinStrain");
//! increment of the Maxwell strain
@LocalVariable Stensor depsM;
-@Integrator {
-
- const auto seq = sigmaeq(sig);
- const auto iseq = 1. / std::max(seq, 1.e-14 * D(0, 0));
- const auto s = deviator(sig);
- constexpr auto Pdev = Stensor4::K();
-
- const auto etaK = etaK0 * std::exp(mvK * seq);
- const auto etaM = etaM0 * std::exp(mvM * seq);
- const auto GK = GK0 * std::exp(mK * seq);
-
- // calculate Kelvin strain residual
- const auto etaK_impl = etaK + dt * GK * theta;
- depsK = dt / (2. * etaK_impl) * (s - 2 * GK * epsK);
-
- // calculate Maxwell strain residual
- depsM = dt / (2 * etaM) * s;
-
- // residuals
- feel += depsM + depsK;
-
- // Jacobian
- const auto dseq_ddeel = 3. * iseq / 2. * s | (Pdev * D);
- const auto detaK_ddeel = etaK * mvK * dseq_ddeel;
- const auto detaM_ddeel = etaM * mvM * dseq_ddeel;
- const auto dGK_ddeel = GK * mK * dseq_ddeel;
- //
- dfeel_ddeel +=
- -(dt / (2 * etaK_impl * etaK_impl) * (s - 2 * GK * epsK) ^ detaK_ddeel) +
- (dt / (2 * etaK_impl) * Pdev * D) - dt / etaK_impl * (epsK ^ dGK_ddeel) -
- dt / (2 * etaK_impl * etaK_impl) * dt * theta *
- ((s - 2 * GK * epsK) ^ dGK_ddeel) -
- (dt / (2 * etaM * etaM) * s ^ detaM_ddeel) + (dt / (2 * etaM) * Pdev * D);
+//! Second Lamé coefficient
+@LocalVariable stress mu;
+
+@InitLocalVariables
+{
+ mu = computeMu(young, nu);
+}
+
+@Integrator
+{
+ const auto seq = sigmaeq(sig);
+ const auto iseq = 1. / std::max(seq, 1.e-14 * mu);
+ const auto s = deviator(sig);
+ constexpr auto Pdev = Stensor4::K();
+
+ const auto etaK = etaK0 * std::exp(mvK * seq);
+ const auto etaM = etaM0 * std::exp(mvM * seq);
+ const auto GK = GK0 * std::exp(mK * seq);
+
+ // calculate Kelvin strain residual
+ const auto etaK_impl = etaK + dt * GK * theta;
+ depsK = dt / (2. * etaK_impl) * (s - 2 * GK * epsK);
+
+ // calculate Maxwell strain residual
+ depsM = dt / (2 * etaM) * s;
+
+ // residuals
+ feel += depsM + depsK;
+
+ // Jacobian
+ // Pdev_D
+ const auto Pdev_D = 2 * mu * Pdev;
+ const auto dseq_ddeel = 3. * iseq / 2. * s | (Pdev_D);
+ const auto detaK_ddeel = etaK * mvK * dseq_ddeel;
+ const auto detaM_ddeel = etaM * mvM * dseq_ddeel;
+ const auto dGK_ddeel = GK * mK * dseq_ddeel;
+ //
+ dfeel_ddeel +=
+ -(dt / (2 * etaK_impl * etaK_impl) * (s - 2 * GK * epsK) ^
+ detaK_ddeel) +
+ (dt / (2 * etaK_impl) * Pdev_D) - dt / etaK_impl * (epsK ^ dGK_ddeel) -
+ dt / (2 * etaK_impl * etaK_impl) * dt * theta *
+ ((s - 2 * GK * epsK) ^ dGK_ddeel) -
+ (dt / (2 * etaM * etaM) * s ^ detaM_ddeel) + (dt / (2 * etaM) * Pdev_D);
}
-@UpdateAuxiliaryStateVariables {
- epsK += depsK;
-} // end of @UpdateAuxiliaryStateVariables
+@UpdateAuxiliaryStateVariables
+{
+ epsK += depsK;
+} // end of @UpdateAuxiliaryStateVariables
diff --git a/Tests/Data/Mechanics/Burgers/cube_1e0_mfront_mod_pcs_0_ts_101_t_1.000000.vtu b/Tests/Data/Mechanics/Burgers/cube_1e0_mfront_mod_pcs_0_ts_101_t_1.000000.vtu
index e996fa3b05134d9e23ef97943799fc916e2e2be6..5d9a6c71b23f8a20bbec2a7e9fa3d5d6a653531a 100644
--- a/Tests/Data/Mechanics/Burgers/cube_1e0_mfront_mod_pcs_0_ts_101_t_1.000000.vtu
+++ b/Tests/Data/Mechanics/Burgers/cube_1e0_mfront_mod_pcs_0_ts_101_t_1.000000.vtu
@@ -1,3 +1,3 @@
version https://git-lfs.github.com/spec/v1
-oid sha256:9dad753d851bbe651cd165f809eb49627553be68e13e5926e2ca012aadadabd3
-size 4958
+oid sha256:16419e1d28c6c77c05ddb57aabdd588d0d044464646cd3a5bededc32704e6d6b
+size 4926
diff --git a/Tests/Data/Mechanics/Burgers/cube_1e0_mfront_mod_pcs_0_ts_1_t_0.000100.vtu b/Tests/Data/Mechanics/Burgers/cube_1e0_mfront_mod_pcs_0_ts_1_t_0.000100.vtu
index aa613d73b422e28e1b7653fe474e4584820f5e62..4b84bc1e60866aeead1ab1d8831f17fd47e55fc0 100644
--- a/Tests/Data/Mechanics/Burgers/cube_1e0_mfront_mod_pcs_0_ts_1_t_0.000100.vtu
+++ b/Tests/Data/Mechanics/Burgers/cube_1e0_mfront_mod_pcs_0_ts_1_t_0.000100.vtu
@@ -1,3 +1,3 @@
version https://git-lfs.github.com/spec/v1
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-size 4954
+oid sha256:fedb53fe407a034738a2dd0551cc7a09b04a30466b1923d22630bc25f538017c
+size 4922
diff --git a/Tests/Data/Mechanics/Burgers/cube_1e0_mfront_pcs_0_ts_101_t_1.000000.vtu b/Tests/Data/Mechanics/Burgers/cube_1e0_mfront_pcs_0_ts_101_t_1.000000.vtu
index bd2a2c62cd70fa22acaeccdf6e8faa0fe7058eee..afbf9005aa5db7d8e137918802fcbdc77ba08103 100644
--- a/Tests/Data/Mechanics/Burgers/cube_1e0_mfront_pcs_0_ts_101_t_1.000000.vtu
+++ b/Tests/Data/Mechanics/Burgers/cube_1e0_mfront_pcs_0_ts_101_t_1.000000.vtu
@@ -1,3 +1,3 @@
version https://git-lfs.github.com/spec/v1
-oid sha256:a0b94bfc571ee4a6a4eb8c2f311d4869523cf0216ba680466b6ffca899eb9f32
-size 4024
+oid sha256:5e866258789aa2f922b2e664bad826d050ed3208c730089ecc5284b708ae220c
+size 5054
diff --git a/Tests/Data/Mechanics/Burgers/cube_1e0_mfront_pcs_0_ts_1_t_0.000100.vtu b/Tests/Data/Mechanics/Burgers/cube_1e0_mfront_pcs_0_ts_1_t_0.000100.vtu
index b05609454ae6d6020c0d54be7ccd114dcc00bbc9..4b84bc1e60866aeead1ab1d8831f17fd47e55fc0 100644
--- a/Tests/Data/Mechanics/Burgers/cube_1e0_mfront_pcs_0_ts_1_t_0.000100.vtu
+++ b/Tests/Data/Mechanics/Burgers/cube_1e0_mfront_pcs_0_ts_1_t_0.000100.vtu
@@ -1,3 +1,3 @@
version https://git-lfs.github.com/spec/v1
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-size 3896
+oid sha256:fedb53fe407a034738a2dd0551cc7a09b04a30466b1923d22630bc25f538017c
+size 4922