def _create_solution_scheme(self):
scheme_type = self.settings["scheme_type"].GetString()
# Setting the Rayleigh damping parameters
process_info = self.main_model_part.ProcessInfo
process_info[
StructuralMechanicsApplication.
RAYLEIGH_ALPHA] = self.settings["rayleigh_alpha"].GetDouble()
process_info[
StructuralMechanicsApplication.
RAYLEIGH_BETA] = self.settings["rayleigh_beta"].GetDouble()
# Setting the time integration schemes
if (scheme_type == "central_differences"):
mechanical_scheme = StructuralMechanicsApplication.ExplicitCentralDifferencesScheme(
self.settings["max_delta_time"].GetDouble(),
self.settings["fraction_delta_time"].GetDouble(),
self.settings["time_step_prediction_level"].GetDouble())
elif (scheme_type == "multi_stage"):
mechanical_scheme = StructuralMechanicsApplication.ExplicitMultiStageKimScheme(
self.settings["fraction_delta_time"].GetDouble())
else:
err_msg = "The requested scheme type \"" + scheme_type + "\" is not available!\n"
err_msg += "Available options are: \"central_differences\", \"multi_stage\""
raise Exception(err_msg)
return mechanical_scheme
def create_solver(mp, scheme_name):
# Define a minimal newton raphson dynamic solver
linear_solver = KratosMultiphysics.SkylineLUFactorizationSolver()
builder_and_solver = KratosMultiphysics.ResidualBasedBlockBuilderAndSolver(
linear_solver)
if scheme_name == "newmark":
scheme = KratosMultiphysics.ResidualBasedNewmarkDisplacementScheme()
elif scheme_name == "pseudo_static":
scheme = KratosMultiphysics.ResidualBasedPseudoStaticDisplacementScheme(
StructuralMechanicsApplication.RAYLEIGH_BETA)
elif scheme_name == "backward_euler":
scheme = KratosMultiphysics.ResidualBasedBDFDisplacementScheme(1)
elif scheme_name == "bdf2":
scheme = KratosMultiphysics.ResidualBasedBDFDisplacementScheme(2)
elif scheme_name == "explicit":
dynamic_settings = KratosMultiphysics.Parameters("""
{
"time_step_prediction_level" : 0,
"max_delta_time" : 1.0e-5,
"fraction_delta_time" : 0.9
}
""")
scheme = StructuralMechanicsApplication.ExplicitCentralDifferencesScheme(
dynamic_settings)
elif scheme_name == "explicit_multi_stage":
dynamic_settings = KratosMultiphysics.Parameters("""
{
"fraction_delta_time" : 0.333333333333333333333333333333333333
}
""")
scheme = StructuralMechanicsApplication.ExplicitMultiStageKimScheme(
dynamic_settings)
else:
damp_factor_m = 0.0
scheme = KratosMultiphysics.ResidualBasedBossakDisplacementScheme(
damp_factor_m)
# Creating solver
compute_reactions = False
reform_step_dofs = True
move_mesh_flag = True
# Explicit solver
if "explicit" in scheme_name:
strategy = StructuralMechanicsApplication.MechanicalExplicitStrategy(
mp, scheme, compute_reactions, reform_step_dofs, move_mesh_flag)
else: # Implicit solver otherwise
max_iters = 10
# Convergence_criterion = KratosMultiphysics.ResidualCriteria(1e-14,1e-20)
convergence_criterion = KratosMultiphysics.ResidualCriteria(1e-4, 1e-9)
convergence_criterion.SetEchoLevel(0)
strategy = KratosMultiphysics.ResidualBasedNewtonRaphsonStrategy(
mp, scheme, linear_solver, convergence_criterion,
builder_and_solver, max_iters, compute_reactions, reform_step_dofs,
move_mesh_flag)
strategy.SetEchoLevel(0)
strategy.Check()
return strategy
def _create_dynamic_explicit_strategy(mp,scheme_name):
if (scheme_name=='central_differences'):
scheme = StructuralMechanicsApplication.ExplicitCentralDifferencesScheme(0.00,0.00,0.00)
elif scheme_name=='multi_stage':
scheme = StructuralMechanicsApplication.ExplicitMultiStageKimScheme(0.33333333333333333)
strategy = StructuralMechanicsApplication.MechanicalExplicitStrategy(mp,scheme,0,0,1)
strategy.SetEchoLevel(0)
return strategy
