__author__ = ['Tomas Mendez Echenagucia <*****@*****.**>']
__copyright__ = 'Copyright 2017, BLOCK Research Group - ETH Zurich'
__license__ = 'MIT License'
__email__ = '*****@*****.**'
# Structure
mdl = Structure(name='shell_bench', path=compas_fea.TEMP)
# Nodes and Elements
xyz = [[0, 0, 0], [1, 0, 0], [2, 0, 0], [0, 1, 0], [1, 1, 0], [2, 1, 0],
[0, 2, 0], [1, 2, 0], [2, 2, 0]]
nodes = mdl.add_nodes(xyz)
shells = [[0, 1, 4, 3], [1, 2, 5, 4], [3, 4, 7, 6], [4, 5, 8, 7]]
shells = [mdl.add_element(shell, 'ShellElement') for shell in shells]
# Sets
elset_shells = mdl.add_set('elset_shells', 'element', shells)
# Materials
mdl.add(Steel(name='mat_steel'))
# Sections
mdl.add(ShellSection(name='sec_shell', t=0.01))
from compas_fea.structure import GravityLoad
from compas_fea.structure import PinnedDisplacement
from compas_fea.structure import PointLoad
from compas_fea.structure import ShellSection
from compas_fea.structure import Structure
# Author(s): Andrew Liew (github.com/andrewliew)
# Create empty Structure object
mdl = Structure(name='introduction', path='C:/temp/')
# Add nodes
mdl.add_node(xyz=[-5., -5., 0.])
mdl.add_nodes(nodes=[[5., -5., 0.], [5., 5., 0.], [-5., 5., 0.], [0., 0., 5.]])
# print('Node number 3:', mdl.nodes[3])
# print('Node number 3 xyz:', mdl.node_xyz(3))
# print('Node count: ', mdl.node_count())
# print('Node index: ', mdl.node_index)
# print('Check node at [0, 0, 0]: ', mdl.check_node_exists([0, 0, 0]))
# print('Check node at [5, 5, 0]: ', mdl.check_node_exists([5, 5, 0]))
# print('Node bounds: ', mdl.node_bounds())
# Add elements
mdl.add_elements(elements=[[0, 4], [1, 4], [2, 4], [3, 4]],
type='BeamElement',
axes={'ex': [1, 0, 0]})
mdl.add_element(nodes=[0, 1, 4], type='ShellElement')
def compute_compas_fea(file_path, load_path, fea_engine='abaqus', recompute=True):
""" Use abaqus (via compas_fea) to perform elastic FEA on the given frame
under a given load case. If no load path is specified, elemental gravity
will be assumbed to be applied.
Parameters
----------
file_path : string
full path to the frame shape's json file.
load_path : type
full path to the load case's json file.
Returns
-------
nD: dict
Reactional nodal displacement
key is the node id.
value is
(nodal_id, dx, dy, dz, theta_x, theta_y, theta_z).
fR: dict
Fixities reaction force, moment.
key is the nodal id.
value is [Fxyz, Mxyz] in the global axes.
eR: dict
Element-wise reaction force, moment (two ends).
key is the element id.
(Fxyz_1, Mxyz_1, Fxyz_2, Mxyz_2)
"""
root_dir = os.path.dirname(os.path.abspath(__file__))
temp_dir = os.path.join(root_dir, 'compas_fea-temp')
if not os.path.exists(temp_dir):
os.makedirs(temp_dir)
file_json_name = file_path.split(os.sep)[-1]
file_name = file_json_name.split('.')[0]
print('compas_fea initing: file name {}'.format(file_name))
if not recompute:
nD, fR, eR = parse_abaqus_result_json(file_name, temp_dir)
return nD, fR, eR
with open(file_path, 'r') as f:
json_data = json.loads(f.read())
load_json_data = {}
if load_path:
with open(load_path, 'r') as f:
load_json_data = json.loads(f.read())
# init an empty structure
mdl = Structure(name=file_name, path=os.path.join(temp_dir, ''))
# nodes
mdl.add_nodes(nodes=parse_frame_nodes(json_data))
# elements
elements = parse_elements(json_data)
# align local axes with conmech
sc = stiffness_checker(json_file_path=file_path, verbose=False)
e_rot_mats = sc.get_element_local2global_rot_matrices()
assert len(e_rot_mats) == len(elements)
for e, mat in zip(elements, e_rot_mats):
# compas_fea local axis convention is differrent to the one used in conmech:
# in compas_fea
# 'ex' axis represents the cross-section’s major axis
# 'ey' is the cross-section’s minor axis
# 'ez' is the axis along the element
# TODO: this numpy array to list conversion
# is essential to make compas_fea work...
ez = list(mat[0][0:3]) # conmech longitude axis
ex = list(mat[1][0:3]) # conmech cross sec major axis
ey = list(mat[2][0:3]) # conmech cross sec minor axis
mdl.add_element(nodes=e,
type='BeamElement',
axes={'ex': ex, 'ey': ey, 'ez': ez})
# print(mdl.elements[mdl.check_element_exists(nodes=e)])
assert_equal(mdl.element_count(), len(elements))
# Sets
# just convenient aliases for referring to a group of elements
mdl.add_set(name='elset_all', type='element', selection=list(range(mdl.element_count())))
mdl.add_set(name='nset_all', type='node', selection=list(range(mdl.node_count())))
fixities = parse_fixties(json_data)
mdl.add_set(name='nset_fix', type='node', selection=[f[0] for f in fixities])
if load_json_data:
pt_loads, include_sw = parse_load_case(load_json_data)
# mdl.add_set(name='nset_pt_load', type='node', selection=[l[0] for l in pt_loads])
else:
pt_loads = []
include_sw = True
if pt_loads:
mdl.add_set(name='nset_v_load_all', type='node', selection=[pl[0] for pl in pt_loads])
# Materials
# Young’s modulus E [in units of Pa]
# Poisson’s ratio v and density p [kg per cubic metre].
mat_json = json_data['material_properties']
mat_name = 'mat_' + mat_json['material_name']
E_scale = parse_pressure_scale_conversion(mat_json['youngs_modulus_unit'])
p_scale = parse_density_scale_conversion(mat_json['density_unit'])
mdl.add(ElasticIsotropic(name=mat_name,
E=E_scale * mat_json['youngs_modulus'],
v=mat_json['poisson_ratio'],
p=p_scale * mat_json['density']))
# G_scale = parse_pressure_scale_conversion(mat_json['shear_modulus_unit'])
# print('{}, {}'.format(mdl.materials['mat_' + mat_json['material_name']].G, G_scale * mat_json['shear_modulus']))
# assert_almost_equal(mdl.materials['mat_' + mat_json['material_name']].G['G'], G_scale * mat_json['shear_modulus'])
# print('-----------material')
# print(mdl.materials[mat_name])
# Sections
# SI units should be used, this includes the use of metres m for cross-section dimensions, not millimetres mm.
sec_name = 'sec_circ'
mdl.add(CircularSection(name=sec_name, r=parse_circular_cross_sec_radius(json_data)))
# print('-----------cross section')
# print(mdl.sections[sec_name])
# Properties, associate material & cross sec w/ element sets
mdl.add(Properties(name='ep_all', material=mat_name, section=sec_name, elset='elset_all'))
# Displacements
# pin supports
for i, fix in enumerate(fixities):
f_dof = []
for j in range(6):
if fix[j+1] == 1:
f_dof.append(0)
else:
f_dof.append(None)
mdl.add(GeneralDisplacement(name='disp_fix_'+str(i), nodes=[fix[0]], x=f_dof[0], y=f_dof[1], z=f_dof[2], xx=f_dof[3], yy=f_dof[4], zz=f_dof[5]))
# print('-----------fixities')
# for i in range(len(fixities)):
# print(mdl.displacements['disp_fix_'+str(i)])
# Loads
if pt_loads:
mdl.add([PointLoad(name='load_v_'+str(i), nodes=[pl[0]],
x=pl[1], y=pl[2], z=pl[3],
xx=pl[4], yy=pl[5], zz=pl[6])
for i, pl in enumerate(pt_loads)])
if include_sw:
mdl.add(GravityLoad(name='load_gravity', elements='elset_all'))
else:
mdl.add(GravityLoad(name='load_gravity', elements='elset_all'))
# print('-----------loads')
# print(mdl.loads['load_gravity'])
# for i in range(len(pt_loads)):
# print(mdl.loads['load_v_'+str(i)])
# Steps
loads_names = []
if pt_loads:
loads_names.extend(['load_v_'+str(i) for i in range(len(pt_loads))])
if include_sw:
loads_names.append('load_gravity')
mdl.add([
GeneralStep(name='step_bc', displacements=['disp_fix_'+str(i) for i in range(len(fixities))]),
GeneralStep(name='step_loads', loads=loads_names)
])
# a boundary condition step such as 'step_bc' above, should always be applied as the first step to prevent rigid body motion
mdl.steps_order = ['step_bc', 'step_loads']
# Summary
mdl.summary()
# Run
# node
# 'u': nodal displacement: ux, uy, uz, um (magnitude)
# 'ur': nodal rotation
# 'rf': reaction force
# 'cf': concentrated force (external load)
# 'cm': concentrated moment (external load)
# element
# 's': beam stress (conmech cannot compute this at
# version 0.1.1)
# For beam, the following values are evaluated
# at the "integration point" 'ip1' (middle point)
# and pts along the axis: 'sp3, sp7, sp11, sp15'
# sxx: axial
# syy: hoop
# sxy: torsion
# smises: Von Mises
# smaxp: max principal
# sminp: min principal
# 'sf': beam section force
# sf1: axial
# sf2: shear x
# sf3: shear y
if fea_engine == 'abaqus':
mdl.analyse_and_extract(software='abaqus', fields=['u', 'ur', 'rf', 'rm', 'sf'], ndof=6, output=True)
nD, fR, eR = parse_abaqus_result_json(file_name, temp_dir)
elif fea_engine == 'opensees':
mdl.analyse_and_extract(software='opensees', fields=['u'], exe=OPENSEES_PATH, ndof=6, output=True, save=True)
raise NotImplementedError('opensees from compas_fea is not fully supported at this moment...')
nD = {}
fR = {}
eR = {}
# nD = mdl.get_nodal_results(step='step_load', field='ux', nodes='nset_all')
print(mdl.results)
else:
raise NotImplementedError('FEA engine not supported!')
return nD, fR, eR