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rAKA/examples/python/phase_field_model/phasefield-static.py
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phasefield-static.py
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#!/usr/bin/env python
# coding: utf-8
__copyright__ = (
"Copyright (©) 2021-2023 EPFL (Ecole Polytechnique Fédérale de Lausanne)"
"Laboratory (LSMS - Laboratoire de Simulation en Mécanique des Solides)"
)
__license__ = "LGPLv3"
import numpy as np
import akantu as aka
aka.parseInput("material_static.dat")
dim = 2
mesh = aka.Mesh(dim)
mesh.read("plate_static.msh")
# Creation of the model coupler
model = aka.CouplerSolidPhaseField(mesh)
# The model coupler contains the solid mechanics model and the phasefield model
solid = model.getSolidMechanicsModel()
phase = model.getPhaseFieldModel()
# Each model can be initialized with the desired method
solid.initFull(_analysis_method=aka._static)
solver = solid.getNonLinearSolver("static")
solver.set("max_iterations", 100)
solver.set("threshold", 1e-8)
solver.set("convergence_type", aka.SolveConvergenceCriteria.solution)
solid.getNewSolver("linear_static", aka.TimeStepSolverType.static,
aka.NonLinearSolverType.linear)
solid.setIntegrationScheme("linear_static", "displacement",
aka.IntegrationSchemeType.pseudo_time)
phase.initFull(_analysis_method=aka._static)
phase.getNewSolver(
"nonlinear_static",
aka.TimeStepSolverType.static,
aka.NonLinearSolverType.newton_raphson,
)
phase.setIntegrationScheme(
"nonlinear_static", "damage", aka.IntegrationSchemeType.pseudo_time
)
solver = phase.getNonLinearSolver("nonlinear_static")
solver.set("max_iterations", 100)
solver.set("threshold", 1e-4)
solver.set("convergence_type", aka.SolveConvergenceCriteria.solution)
# Setting the boundary conditions
solid.applyBC(aka.FixedValue(0, aka._y), "bottom")
solid.applyBC(aka.FixedValue(0, aka._x), "left")
# Initialization for bulk vizualisation
solid.setBaseName("phasefield-static")
solid.addDumpFieldVector("displacement")
solid.addDumpFieldVector("external_force")
solid.addDumpField("strain")
solid.addDumpField("stress")
solid.addDumpField("damage")
solid.addDumpField("blocked_dofs")
nb_dofs = solid.getMesh().getNbNodes() * dim
displacement = solid.getDisplacement()
displacement = displacement.reshape(nb_dofs)
blocked_dofs = solid.getBlockedDOFs()
blocked_dofs = blocked_dofs.reshape(nb_dofs)
damage = phase.getDamage()
# Solving the problem using a staggered approach
# The damage and displacement problems are solved until convergence for each
# loading step
tolerance = 1e-5
steps = 1000
increment = 5e-6
for n in range(steps):
print("Computing iteration " + str(n + 1) + "/" + str(steps))
# Increment top displacement for mode I fracture
solid.applyBC(aka.IncrementValue(increment, aka._y), "top")
mask = blocked_dofs == False # NOQA: E712
iiter = 0
error_disp = 1
error_dam = 1
displacement_prev = displacement[mask].copy()
damage_prev = damage.copy()
damage_prev = damage_prev
# solve using staggered scheme
while error_disp > tolerance or error_dam > tolerance:
model.solve("linear_static", "")
displacement_new = displacement[mask]
damage_new = damage
delta_disp = displacement_new - displacement_prev
delta_dam = damage_new - damage_prev
error_disp = np.linalg.norm(delta_disp)
error_dam = np.linalg.norm(delta_dam)
iiter += 1
displacement_prev = displacement_new.copy()
damage_prev = damage_new.copy()
print(error_dam, error_disp)
if iiter > 500:
raise Exception("Convergence not reached")
if n % 50 == 0:
solid.dump()
solid.dump()
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