def _apply_material_properties(self,mp,dim):
#define properties
mp.GetProperties()[1].SetValue(KratosMultiphysics.YOUNG_MODULUS, 21000)
mp.GetProperties()[1].SetValue(KratosMultiphysics.POISSON_RATIO, 0.3)
mp.GetProperties()[1].SetValue(KratosMultiphysics.YIELD_STRESS, 5.5)
mp.GetProperties()[1].SetValue(KratosMultiphysics.REFERENCE_HARDENING_MODULUS, 1.0)
mp.GetProperties()[1].SetValue(KratosMultiphysics.ISOTROPIC_HARDENING_MODULUS, 0.12924)
mp.GetProperties()[1].SetValue(KratosMultiphysics.INFINITY_HARDENING_MODULUS, 0.0)
mp.GetProperties()[1].SetValue(KratosMultiphysics.HARDENING_EXPONENT, 1.0)
g = [0,0,0]
mp.GetProperties()[1].SetValue(KratosMultiphysics.VOLUME_ACCELERATION,g)
if(dim == 2):
cl = StructuralMechanicsApplication.LinearJ2PlasticityPlaneStrain2DLaw()
else:
cl = StructuralMechanicsApplication.LinearJ2Plasticity3DLaw()
mp.GetProperties()[1].SetValue(KratosMultiphysics.CONSTITUTIVE_LAW,cl)
def create_constitutive_Law():
return StructuralMechanicsApplication.LinearJ2Plasticity3DLaw()
def test_J2_Plasticity_3D(self):
nnodes = 8
dim = 3
# Define a model and geometry
model_part = KratosMultiphysics.ModelPart("test")
geom = self._create_geometry(model_part, dim, nnodes)
# Material properties
prop_id = 0
properties = model_part.Properties[prop_id]
properties.SetValue(KratosMultiphysics.YOUNG_MODULUS, 21000)
properties.SetValue(KratosMultiphysics.POISSON_RATIO, 0.3)
properties.SetValue(KratosMultiphysics.YIELD_STRESS, 5.5)
properties.SetValue(KratosMultiphysics.REFERENCE_HARDENING_MODULUS,
1.0)
properties.SetValue(KratosMultiphysics.ISOTROPIC_HARDENING_MODULUS,
0.12924)
properties.SetValue(KratosMultiphysics.INFINITY_HARDENING_MODULUS, 0.0)
properties.SetValue(KratosMultiphysics.HARDENING_EXPONENT, 1.0)
N = KratosMultiphysics.Vector(nnodes)
DN_DX = KratosMultiphysics.Matrix(nnodes, dim)
# Construct a constitutive law
cl = StructuralMechanicsApplication.LinearJ2Plasticity3DLaw()
self._cl_check(cl, properties, geom, model_part, dim)
# Set the parameters to be employed
dict_options = {
'USE_ELEMENT_PROVIDED_STRAIN': False,
'COMPUTE_STRESS': True,
'COMPUTE_CONSTITUTIVE_TENSOR': True,
}
cl_options = self._set_cl_options(dict_options)
stress_vector = KratosMultiphysics.Vector(cl.GetStrainSize())
strain_vector = KratosMultiphysics.Vector(cl.GetStrainSize())
constitutive_matrix = KratosMultiphysics.Matrix(
cl.GetStrainSize(), cl.GetStrainSize())
# Setting the parameters - note that a constitutive law may not need them all!
F = self._create_F()
detF = 1.0
cl_params = self._set_cl_parameters(cl_options, F, detF, strain_vector,
stress_vector, constitutive_matrix,
N, DN_DX, model_part, properties,
geom)
cl.InitializeMaterial(properties, geom, N)
# Check the results
nr_timesteps = 10
rstress = []
for i in range(nr_timesteps):
rstress.append(KratosMultiphysics.Vector(cl.GetStrainSize()))
rstress[0][0] = 4.03846
rstress[0][1] = 4.03846
rstress[0][2] = 2.42308
rstress[0][3] = 0.80769
rstress[0][4] = 0.0
rstress[0][5] = 0.80769
rstress[1][0] = 8.07692
rstress[1][1] = 8.07692
rstress[1][2] = 4.84615
rstress[1][3] = 1.61538
rstress[1][4] = 0.0
rstress[1][5] = 1.61538
rstress[2][0] = 11.6595
rstress[2][1] = 11.6595
rstress[2][2] = 8.18099
rstress[2][3] = 1.73926
rstress[2][4] = 0.0
rstress[2][5] = 1.73926
rstress[3][0] = 15.1595
rstress[3][1] = 15.1595
rstress[3][2] = 11.681
rstress[3][3] = 1.73926
rstress[3][4] = 0.0
rstress[3][5] = 1.73926
rstress[4][0] = 18.6595
rstress[4][1] = 18.6595
rstress[4][2] = 15.181
rstress[4][3] = 1.73926
rstress[4][4] = 0.0
rstress[4][5] = 1.73926
rstress[5][0] = 22.1595
rstress[5][1] = 22.1595
rstress[5][2] = 18.681
rstress[5][3] = 1.73927
rstress[5][4] = 0.0
rstress[5][5] = 1.73927
rstress[6][0] = 25.6595
rstress[6][1] = 25.6595
rstress[6][2] = 22.181
rstress[6][3] = 1.73927
rstress[6][4] = 0.0
rstress[6][5] = 1.73927
rstress[7][0] = 29.1595
rstress[7][1] = 29.1595
rstress[7][2] = 25.681
rstress[7][3] = 1.73928
rstress[7][4] = 0.0
rstress[7][5] = 1.73928
rstress[8][0] = 32.6595
rstress[8][1] = 32.6595
rstress[8][2] = 29.181
rstress[8][3] = 1.73928
rstress[8][4] = 0.0
rstress[8][5] = 1.73928
rstress[9][0] = 36.1595
rstress[9][1] = 36.1595
rstress[9][2] = 32.681
rstress[9][3] = 1.73929
rstress[9][4] = 0.0
rstress[9][5] = 1.73929
initial_strain = KratosMultiphysics.Vector(cl.GetStrainSize())
initial_strain[0] = 0.001
initial_strain[1] = 0.001
initial_strain[2] = 0.0
initial_strain[3] = 0.001
initial_strain[4] = 0.0
initial_strain[5] = 0.001
t = dt = 1. / nr_timesteps
c = 0
while (t <= 1. + dt / 10.):
strain = t * initial_strain
cl_params.SetStrainVector(strain)
# Chauchy
cl.CalculateMaterialResponseCauchy(cl_params)
cl.FinalizeMaterialResponseCauchy(cl_params)
cl.FinalizeSolutionStep(properties, geom, N,
model_part.ProcessInfo)
stress = cl_params.GetStressVector()
for j in range(cl.GetStrainSize()):
self.assertAlmostEqual(rstress[c][j], stress[j], 4)
t += dt
c += 1
