#123 using sqrt(potential) as overstress

pou036 · Jun 20, 2018 · 9cac796 · 9cac796
1 parent 73423ed
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Showing 4 changed files with 11 additions and 43 deletions.
diff --git a/include/materials/RedbackMechMaterialLne.h b/include/materials/RedbackMechMaterialLne.h
@@ -38,7 +38,6 @@ class RedbackMechMaterialLne : public RedbackMechMaterial
   virtual Real getFlowIncrement(Real, Real, Real, Real, Real, Real) override;
   virtual void get_py_qy(Real, Real, Real &, Real &, Real, bool &, Real &) override;
   virtual void form_damage_kernels(Real) override;
-  void getDerivativeFlowIncrement(Real &, Real &, const RankTwoTensor &, Real, Real, Real, Real, Real, Real);
 };
 
 #endif // REDBACKMECHMATERIALLNE_H
diff --git a/src/materials/RedbackMechMaterialLne.C b/src/materials/RedbackMechMaterialLne.C
@@ -87,33 +87,6 @@ RedbackMechMaterialLne::getFlowIncrement(
   return _ref_pe_rate * _dt * std::pow(s / sigma_0, _exponent) * _exponential;
 }
 
-void
-RedbackMechMaterialLne::getDerivativeFlowIncrement(Real & dfi_dp,
-                                                  Real & dfi_dq,
-                                                  const RankTwoTensor & /*sig*/,
-                                                  Real p,
-                                                  Real q,
-                                                  Real pc,
-                                                  Real /*q_yield_stress*/,
-                                                  Real /*p_yield_stress*/,
-                                                  Real s)
-{
-  Real sigma_0 = std::fabs(pc - _p_t);
-
-  // Compute numerically derivatives of s with respect to p and q
-  Real p_y2, q_y2, s2, ds_dp, ds_dq;
-  bool is_plastic;
-  Real delta_p = sigma_0 / 1000.; // TODO: this value influences the convergence and should be dynamic!
-  Real delta_q = _M * delta_p;
-  get_py_qy(p + delta_p, q, p_y2, q_y2, -pc, is_plastic, s2);
-  ds_dp = (s2 - s) / delta_p;
-  get_py_qy(p, q + delta_q, p_y2, q_y2, -pc, is_plastic, s2);
-  ds_dq = (s2 - s) / delta_q;
-  Real tmp = _ref_pe_rate * _dt * _exponent * _exponential * std::pow(s / sigma_0, _exponent - 1) / sigma_0;
-  dfi_dp = tmp * ds_dp;
-  dfi_dq = tmp * ds_dq;
-}
-
 void
 RedbackMechMaterialLne::getJac(const RankTwoTensor & sig,
                               const RankFourTensor & E_ijkl,
@@ -170,8 +143,8 @@ RedbackMechMaterialLne::getJac(const RankTwoTensor & sig,
   dfi_ds = _exponent * _ref_pe_rate * _dt * std::pow(s / sigma_0, _exponent-1) * _exponential / sigma_0;
 
   // derivatives of flow increment with respect to p and q
-  dfi_dp = dfi_ds * std::pow(_M_f, 2) * h * X;
-  dfi_dseqv = dfi_ds * 2 * sig_eqv;
+  dfi_dp = dfi_ds * std::pow(_M_f, 2) * h * X / (2 * s);
+  dfi_dseqv = dfi_ds * sig_eqv / s;
 
   f1 = (Y - 1.0) / norm;
   f2 = 3.0 / norm;
@@ -210,7 +183,7 @@ RedbackMechMaterialLne::get_py_qy(
   is_plastic = (potential > 0);
 
   // use potential for overstress
-  s = potential;
+  s = std::sqrt(potential);
   // yield point actually irrelevant!
   p_y = 1e99;
   q_y = 1e99;

diff --git a/tests/benchmark_3_M/bench_Lne.i b/tests/benchmark_3_M/bench_Lne.i
@@ -168,12 +168,10 @@
   [eqv_plastic_strain_rate]
     order = CONSTANT
     family = MONOMIAL
-    block = '0'
   []
   [Mod_Gruntfest_number]
     order = CONSTANT
     family = MONOMIAL
-    block = '0 1'
   []
   [plastic_volumetric_strain]
     order = CONSTANT
@@ -186,12 +184,10 @@
   [mean_stress]
     order = CONSTANT
     family = MONOMIAL
-    block = '0'
   []
   [returnmap_iter]
     order = CONSTANT
     family = MONOMIAL
-    block = '0'
   []
   [total_porosity]
     order = FIRST
@@ -347,6 +343,8 @@
 
 [Executioner]
   # Preconditioned JFNK (default)
+  # petsc_options_iname = '-pc_type -pc_hypre_type -snes_linesearch_type -ksp_gmres_restart'
+  # petsc_options_value = 'hypre boomeramg cp 201'
   type = Transient
   start_time = 0.0
   end_time = 0.006
@@ -355,8 +353,6 @@
   l_max_its = 200
   nl_max_its = 10
   solve_type = PJFNK
-  petsc_options_iname = '-pc_type -pc_hypre_type -snes_linesearch_type -ksp_gmres_restart'
-  petsc_options_value = 'hypre boomeramg cp 201'
   nl_abs_tol = 1e-10 # 1e-10 to begin with
   reset_dt = true
   line_search = basic

diff --git a/tests/benchmark_3_M/gold/bench_Lne_out.csv b/tests/benchmark_3_M/gold/bench_Lne_out.csv
@@ -1,8 +1,8 @@
 time,eqv_plastic_strain_rate,max_returnmap_iter,mean_stress,mises_strain,mises_stress,plastic_volumetric_strain
 0,0,0,0,0,0,0
-0.001,0.028629157619691,2.5,-0.17859948910417,0.00036787944117144,0.29523979785722,1.066672981115e-05
-0.002,0.14098963167227,3,-0.3177205300469,0.00036787944117144,0.49861752840918,2.880731325028e-05
-0.003,0.24400603493792,3.5,-0.41195422416808,0.00036787944117144,0.61857382307785,4.1005067198006e-05
-0.004,0.31331794045741,3.75,-0.47193413993035,0.00036787944117144,0.68483781911848,4.5426973735366e-05
-0.005,0.35477076606155,4,-0.50927459792852,0.00036787944117144,0.7206264329876,4.3683013138673e-05
-0.006,0.37845375746288,4,-0.53249926173661,0.00036787944117144,0.73991765623407,3.7688623828489e-05
+0.001,0.1060669294748,2.5,-0.16636574288352,0.00036787944117144,0.24834042897467,5.2047918852415e-05
+0.002,0.23342559641361,3.5,-0.27597618620864,0.00036787944117144,0.3947073074006,9.8638195525807e-05
+0.003,0.31112780429574,3,-0.34664254198654,0.00036787944117144,0.47897361151358,0.00013383323291223
+0.004,0.35617031097491,3,-0.39179972075719,0.00036787944117144,0.52848398798822,0.00015959310420521
+0.005,0.38295074230399,3,-0.420618561244,0.00036787944117144,0.55799406288187,0.00017881427145916
+0.006,0.39909656653373,3,-0.43904406162704,0.00036787944117144,0.57579312558425,0.00019369939288095