def fit_yield_function(yield_function_name, yield_point_criteria, uniaxial_response,
multiaxial_responses):
# Generate LoadResponse objects:
uni_resp = LoadResponse(
true_stress=uniaxial_response['vol_avg_stress'],
equivalent_plastic_strain=uniaxial_response['vol_avg_equivalent_plastic_strain'],
)
multi_resp = []
for resp_dat in multiaxial_responses:
multi_resp.append(
LoadResponse(
true_stress=resp_dat['vol_avg_stress'],
equivalent_plastic_strain=resp_dat['vol_avg_equivalent_plastic_strain'],
)
)
response_set = LoadResponseSet(multi_resp)
response_set.calculate_yield_stresses(yield_point_criteria)
response_set.fit_yield_function(yield_function_name, uniaxial_response=uni_resp)
out = {
'fitted_yield_functions': [
{
'name': yield_function_name,
**i['yield_function'].get_parameters()
}
for i in response_set.yield_functions
]
}
return out
def test_get_yield_stress_value_idx(self):
"""Check specifying `value_idx` in `LoadResponse.get_yield_stress` works as
expected."""
num_increments = 11
equiv_strain = np.linspace(0, 1e-3, num=num_increments)
stress = np.random.random((num_increments, 3, 3))
resp = LoadResponse(true_stress=stress, equivalent_strain=equiv_strain)
vals = [0.00035, 0.00045]
yield_point_criteria = YieldPointCriteria('equivalent_strain', vals)
yield_stress_all_vals = resp.get_yield_stress(yield_point_criteria)
yield_stress_by_vals = [
resp.get_yield_stress(yield_point_criteria, value_idx=i)
for i in range(2)
]
# Combine into dicts to compare (keyed by YPC value index):
all_vals_dict = {
ypc_val_idx: stress
for stress, ypc_val_idx in zip(*yield_stress_all_vals)
}
by_vals_dict = {
ypc_val_idx[0]: stress
for stress, ypc_val_idx in yield_stress_by_vals
}
for ypc_val_idx, stress in all_vals_dict.items():
self.assertTrue(np.allclose(stress, by_vals_dict[ypc_val_idx]))
def test_raise_on_distinct_incremental_data(self):
'Check LoadResponseSet raises when passed response objects with distinct data.'
num_increments = 11
equiv_strain = np.linspace(0, 1e-3, num=num_increments)
stress = np.random.random((num_increments, 3, 3))
response_1 = LoadResponse(true_stress=stress)
response_2 = LoadResponse(equivalent_strain=equiv_strain)
with self.assertRaises(InhomogeneousDataError):
LoadResponseSet([response_1, response_2])
def test_is_uniaxial(self):
'Test a known uniaxial load response reports as such.'
num_increments = 10
# Not a good proxy for realistic series of increasing stress states, but OK here:
stress = np.random.random((num_increments, 3, 3))
stress *= 1e4
stress[:, 1, 1] *= 1e5 # The "uniaxial" component
resp = LoadResponse(true_stress=stress)
self.assertTrue(resp.is_uniaxial())
def test_varying_response_length_OK(self):
'Check LoadResponseSet can be initialised with response objects of varying length.'
num_increments_1 = 11
equiv_strain_1 = np.linspace(0, 1e-3, num=num_increments_1)
stress_1 = np.random.random((num_increments_1, 3, 3))
num_increments_2 = 5
equiv_strain_2 = np.linspace(0, 1e-3, num=num_increments_2)
stress_2 = np.random.random((num_increments_2, 3, 3))
response_1 = LoadResponse(true_stress=stress_1,
equivalent_strain=equiv_strain_1)
response_2 = LoadResponse(true_stress=stress_2,
equivalent_strain=equiv_strain_2)
LoadResponseSet([response_1, response_2])
def test_set_single_yield_stress_consistent_insufficient_yield(self):
"""Check yield stresses of set are consistent with those from individual
responses, including responses with unachieved yield points."""
num_increments = 11
num_responses = 5
equiv_strain = np.tile(np.linspace(0, 1e-3, num=num_increments),
(num_responses, 1))
# Set the equivalent strain of one response to not meet the yield point:
equiv_strain[1] /= 10
stress = np.random.random((num_responses, num_increments, 3, 3))
responses = [
LoadResponse(true_stress=stress[idx],
equivalent_strain=equiv_strain[idx])
for idx in range(num_responses)
]
load_set = LoadResponseSet(responses)
yield_point_criteria = YieldPointCriteria('equivalent_strain', 2e-4)
load_set.calculate_yield_stresses(yield_point_criteria)
ypc_idx = 0
ypc_val_idx = 0
resp_idx = 3
for i in load_set.yield_stresses:
if i['YPC_idx'] == ypc_idx and i['YPC_value_idx'] == ypc_val_idx:
all_resp_idx = np.array(
load_set.yield_stresses[ypc_idx]['response_idx'])
value_idx = np.where(all_resp_idx == resp_idx)[0][0]
yld_stress_all = load_set.yield_stresses[ypc_idx]['values'][
value_idx]
break
yld_stress_resp = responses[resp_idx].get_yield_stress(
yield_point_criteria,
value_idx=ypc_val_idx,
)[0]
self.assertTrue(np.allclose(yld_stress_all, yld_stress_resp))