def harmonic(geom_file, freq_range, freq_steps, damping):
# add shell elements from mesh ---------------------------------------------
with open(geom_file, 'rb') as fh:
geom_data = json.load(fh)
mesh = Mesh.from_data(geom_data['mesh'])
s = structure.Structure()
s.add_nodes_elements_from_mesh(mesh, element_type='ShellElement')
# add displacements --------------------------------------------------------
pts = geom_data['pts']
nkeys = []
for pt in pts:
nkeys.append(s.check_node_exists(pt))
s.add_set(name='support_nodes', type='NODE', selection=nkeys)
supppots = FixedDisplacement(name='supports', nodes='support_nodes')
s.add_displacement(supppots)
# add materials and sections -----------------------------------------------
E35 = 35 * 10**9
concrete = ElasticIsotropic(name='MAT_CONCRETE', E=E35, v=0.2, p=2400)
s.add_material(concrete)
section = ShellSection(name='SEC_CONCRETE', t=0.020)
s.add_section(section)
prop = ElementProperties(type='SHELL',
material='MAT_CONCRETE',
section='SEC_CONCRETE',
elsets=['ELSET_ALL'])
s.add_element_properties(prop)
# add loads ----------------------------------------------------------------
f_pts = geom_data['f_pts']
nodes = [s.check_node_exists(pt) for pt in f_pts]
s.add_set(name='load_nodes', type='NODE', selection=nodes)
load = PointLoad(name='hload',
nodes='load_nodes',
x=0,
y=0,
z=1,
xx=0,
yy=0,
zz=0)
s.add_load(load)
# add modal step -----------------------------------------------------------
step = HarmonicStep(name='harmonic_analysis',
displacements=['supports'],
loads=['hload'],
freq_range=freq_range,
freq_steps=freq_steps,
damping=damping)
s.add_step(step)
fnm = path + 'harmonic.inp'
ansys.inp_generate(s, filename=fnm)
# temp = path+'_Temp/'
s.analyse(path=path, name='harmonic.inp', temp=None, software='ansys')
return s
# Properties
ep = Properties(name='ep', material='mat_steel', section='sec_pipe', elsets='elset_lines')
mdl.add_element_properties(ep)
# Displacements
mdl.add_displacements([
PinnedDisplacement(name='disp_pins', nodes='nset_pins'),
RollerDisplacementXZ(name='disp_rollers', nodes='nset_rollers')])
# Loads
mdl.add_loads([
PointLoad(name='load_h', nodes='nset_load_h', x=4000),
PointLoad(name='load_v', nodes='nset_load_v', z=-6000),
])
# Steps
mdl.add_steps([
GeneralStep(name='step_bc', displacements=['disp_pins', 'disp_rollers']),
GeneralStep(name='step_loads', loads=['load_h', 'load_v'], iterations=50)])
mdl.steps_order = ['step_bc', 'step_loads']
# Summary
mdl.summary()
# Run (Sofistik)
# Sections
mdl.add_section(RectangularSection(name='sec_rect', b=1, h=1))
# Properties
ep = Properties(name='ep', material='mat_elastic', section='sec_rect', elsets='elset_lines')
mdl.add_element_properties(ep)
# Displacements
mdl.add_displacement(FixedDisplacement(name='disp_fixed', nodes='nset_support'))
# Loads
mdl.add_load(PointLoad(name='load_point', nodes='nset_load', z=600))
# Steps
mdl.add_steps([
GeneralStep(name='step_bc', displacements=['disp_fixed']),
GeneralStep(name='step_load', loads=['load_point'])])
mdl.steps_order = ['step_bc', 'step_load']
# Summary
mdl.summary()
# Run (Sofistik)
# Note: Sofistik depends on input with correct SI units, model and data must be
# converted from lbs and inches.
mdl.add(
Properties(name='ep_plate',
material='mat_elastic',
section='sec_plate',
elset='elset_mesh'))
# Displacements
mdl.add([
PinnedDisplacement(name='disp_left', nodes='nset_left'),
RollerDisplacementX(name='disp_right', nodes='nset_right'),
])
# Loads
mdl.add(PointLoad(name='load_point', nodes='nset_load', y=100, z=-300))
# Steps
mdl.add([
GeneralStep(name='step_bc', displacements=['disp_left', 'disp_right']),
GeneralStep(name='step_load',
loads=['load_point'],
tolerance=1,
iterations=500),
])
mdl.steps_order = ['step_bc', 'step_load']
# Summary
mdl.summary()
mdl.add([
Properties(name='ep_circ',
material='mat_elastic',
section='sec_circ',
elset='elset_beams'),
Properties(name='ep_shell',
material='mat_elastic',
section='sec_shell',
elset='elset_shell'),
])
# Add loads
mdl.add([
PointLoad(name='load_point', nodes='nset_top', x=10000, z=-10000),
GravityLoad(name='load_gravity', elements='elset_beams'),
])
# print('load_point components: ', mdl.loads['load_point'].components)
# Add displacements
mdl.add(PinnedDisplacement(name='disp_pinned', nodes='nset_base'))
# print('disp_pinned components: ', mdl.displacements['disp_pinned'].components)
# Add steps
mdl.add([
GeneralStep(name='step_bc', displacements=['disp_pinned']),
# Properties
mdl.add(
Properties(name='ep_tets',
material='mat_elastic',
section='sec_solid',
elset='elset_tets'))
# Displacementss
mdl.add(PinnedDisplacement(name='disp_pinned', nodes='nset_base'))
# Loads
mdl.add(PointLoad(name='load_top', nodes='nset_top', y=100, z=100))
# Steps
mdl.add([
GeneralStep(name='step_bc', displacements=['disp_pinned']),
GeneralStep(name='step_load', loads=['load_top']),
])
mdl.steps_order = ['step_bc', 'step_load']
# Summary
mdl.summary()
# Run
# Section
mdl.add(CircularSection(name='cirsec', r=.05))
mdl.add(
Properties(name='ep',
material='mat_elastic',
section='cirsec',
elset='elset_lines'))
# Displacements
boundary = network.leaves()
mdl.add(PinnedDisplacement(name='disp', nodes=boundary))
# Loads
mdl.add(PointLoad(name='load_weights', nodes='load_pts', z=-100))
# Steps
mdl.add([
GeneralStep(name='step_bc', displacements=['disp']),
GeneralStep(name='step_load', loads='load_weights'),
])
mdl.steps_order = ['step_bc', 'step_load']
# Summary
# mdl.summary()
# Run
exe = '/Applications/OpenSees3.2.1/OpenSees'
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
# Properties
mdl.add(
Properties(name='ep_shell',
material='mat_elastic',
section='sec_shell',
elset='mesh'))
# Displacements
mdl.add(PinnedDisplacement(name='disp_pin', nodes='supports'))
# Loads
mdl.add(GravityLoad(name='gravity', elements='all'))
mdl.add(PointLoad(name='load_points', nodes='lpts1', x=0, y=0, z=-1000))
# Steps
mdl.add([
GeneralStep(name='step_bc', displacements=['disp_pin']),
GeneralStep(name='step_load', loads=['gravity', 'load_points']),
])
mdl.steps_order = ['step_bc', 'step_load']
# Summary
mdl.summary()
# Run
elsets='spring_top_left'),
Properties(name='ep_tr',
section='spring_elastic',
elsets='spring_top_right')
])
# Displacements
mdl.add_displacements([
PinnedDisplacement(name='disp_pins', nodes='pins'),
RollerDisplacementXZ(name='disp_roller', nodes='middle')
])
# Loads
mdl.add_load(PointLoad(name='load_middle', nodes='middle', z=-500))
# Steps
mdl.add_steps([
GeneralStep(name='step_bc', displacements=['disp_pins', 'disp_roller']),
GeneralStep(name='step_load', loads=['load_middle'])
])
mdl.steps_order = ['step_bc', 'step_load']
# Summary`
mdl.summary()
# Run (Sofistik)
# Properties
ep = Properties(name='ep_strut',
material='mat_elastic',
section='sec_truss',
elsets='elset_struts')
mdl.add_element_properties(ep)
# Displacements
mdl.add_displacement(PinnedDisplacement(name='disp_pinned', nodes='nset_pins'))
# Loads
mdl.add_load(PointLoad(name='load_top', nodes='nset_top', z=-100000))
# Steps
mdl.add_steps([
GeneralStep(name='step_bc', displacements='disp_pinned'),
GeneralStep(name='step_load', loads='load_top', nlmat=False)
])
mdl.steps_order = ['step_bc', 'step_load']
# Summary
mdl.summary()
# Run (Abaqus)
# Displacements
deg = pi / 180
mdl.add_displacements([
PinnedDisplacement(name='disp_bc_left', nodes='nset_left'),
GeneralDisplacement(name='disp_bc_right',
nodes='nset_right',
y=0,
z=0,
xx=0),
GeneralDisplacement(name='disp_left', nodes='nset_left', yy=30 * deg),
])
# Loads
mdl.add_load(PointLoad(name='load_weights', nodes='nset_weights', z=-200.0))
# Steps
mdl.add_steps([
GeneralStep(name='step_bc',
displacements=['disp_bc_left', 'disp_bc_right']),
GeneralStep(name='step_load',
loads=['load_weights'],
displacements=['disp_left'])
])
mdl.steps_order = ['step_bc', 'step_load']
# Summary
mdl.summary()
elsets='elset_diag'),
Properties(name='ep_stays',
material='mat_steel',
section='sec_stays',
elsets='elset_stays')
])
# Displacements
mdl.add_displacement(PinnedDisplacement(name='disp_pinned', nodes='nset_pins'))
# Loads
# Note: GravityLoad doesnt activate for OpenSees
mdl.add_loads([
PointLoad(name='load_pl_v', nodes='nset_load_v', z=-15500),
PointLoad(name='load_pl_h', nodes='nset_load_h', x=5000),
GravityLoad(name='load_gravity', elements=['elset_diag', 'elset_main'])
])
# Steps
mdl.add_steps([
GeneralStep(name='step_bc', displacements=['disp_pinned']),
GeneralStep(name='step_loads',
loads=['load_pl_v', 'load_pl_h', 'load_gravity'],
factor=1.5,
increments=200)
])
mdl.steps_order = ['step_bc', 'step_loads']
# print(mdl.sections['section'])
mdl.add(
ElementProperties(name='property',
material='steel',
section='section',
elset='trusses'))
# print(mdl.element_properties['property'])
mdl.add(PinnedDisplacement(name='pinned', nodes='supports'))
# print(mdl.displacements['pinned'])
mdl.add([
PointLoad(name='pointloads', nodes='loads', y=-50000),
GravityLoad(name='gravity', elements='trusses', z=0, y=1),
])
# print(mdl.loads['pointloads'])
# print(mdl.loads['gravity'])
mdl.add([
GeneralStep(name='bc', displacements='pinned'),
GeneralStep(name='loads', loads=['pointloads', 'gravity'], factor=1.5),
])
mdl.steps_order = ['bc', 'loads']
# print(mdl.steps['bc'])
# print(mdl.steps['loads'])
elset='elset_ties'),
Properties(name='ep_concrete',
material='mat_concrete',
section='sec_solid',
elset='elset_tets'),
])
# Displacements
mdl.add(RollerDisplacementY(name='disp_rollers', nodes='nset_supports'))
# Loads
mdl.add([
GravityLoad(name='load_gravity', elements='elset_tets'),
PointLoad(name='load_point', nodes='nset_load', z=-5),
])
# Steps
mdl.add([
GeneralStep(name='step_bc', displacements=['disp_rollers']),
GeneralStep(name='step_loads',
loads=['load_gravity', 'load_point'],
factor=1.35),
])
mdl.steps_order = ['step_bc', 'step_loads']
# Summary
mdl.summary()
# Properties
mdl.add(
Properties(name='ep_shell',
material='mat_steel',
section='sec_shell',
elset='elset_shells'))
# Displacements
mdl.add(FixedDisplacement(name='disp_pins', nodes=[0, 2, 8, 6]))
# Loads
mdl.add(PointLoad(name='load_v', nodes=[4], z=-1000))
# Steps
mdl.add(
GeneralStep(name='step_bc_loads',
displacements=['disp_pins'],
loads=['load_v'],
nlgeom=False))
mdl.steps_order = ['step_bc_loads']
# Summary
# mdl.summary()
# Run (Abaqus)
mdl.add_set(name='nset_top', type='node', selection=nodes_top)
mdl.add_set(name='nset_bot', type='node', selection=nodes_bot)
#print(mdl.sets['nset_top'])
#print(mdl.sets['nset_bot'])
mdl.add([
ElasticIsotropic(name='mat_elastic', E=50 * 10**9, v=0.3, p=1),
SolidSection(name='sec_solid'),
ElementProperties(name='ep_tets',
material='mat_elastic',
section='sec_solid',
elset='mesh_tets'),
PinnedDisplacement(name='disp_pinned', nodes='nset_bot'),
PointLoad(name='load_top', nodes='nset_top', y=20000, z=10000),
GeneralStep(name='step_bc', displacements='disp_pinned'),
GeneralStep(name='step_load', loads='load_top'),
])
mdl.steps_order = ['step_bc', 'step_load']
mdl.summary()
mdl.analyse_and_extract(software='abaqus', fields=['u', 's'])
rhino.plot_data(mdl, step='step_load', field='um')
rhino.plot_data(mdl, step='step_load', field='smises')
#rhino.plot_voxels(mdl, step='step_load', field='um', vdx=0.100)
# make an extract faces slice
# show in App
Properties(name='ep_wall',
material='mat_concrete',
section='sec_wall',
elset='elset_wall',
rebar=reb_wall),
])
# Displacements
mdl.add(FixedDisplacement(name='disp_fixed', nodes='nset_fixed'))
# Loads
mdl.add([
GravityLoad(name='load_gravity', elements=['elset_wall', 'elset_plinth']),
PointLoad(name='load_points', nodes='nset_loads', z=-20 * 10**3),
])
# Steps
mdl.add([
GeneralStep(name='step_bc', displacements=['disp_fixed']),
GeneralStep(name='step_loads', loads=['load_gravity', 'load_points']),
])
mdl.steps_order = ['step_bc', 'step_loads']
# Summary
mdl.summary()
# Run
#-------------------------------------------------------------------------------
# Properties
mdl.add(
Properties(name='ep_beam',
material='mat_elastic',
section='sec_beam',
elset='elset_beams'))
#-------------------------------------------------------------------------------
# Displacements
mdl.add(FixedDisplacement(name='disp_fixed', nodes='nset_support'))
#-------------------------------------------------------------------------------
# Loads
mdl.add(PointLoad(name='load_point', nodes='nset_load', z=-1100.99))
#-------------------------------------------------------------------------------
# Steps
mdl.add([
GeneralStep(name='step_bc', displacements=['disp_fixed']),
GeneralStep(name='step_load', loads=['load_point']),
])
mdl.steps_order = ['step_bc', 'step_load']
#-------------------------------------------------------------------------------
# Summary
mdl.summary()
#-------------------------------------------------------------------------------
# Run
# Properties
mdl.add_element_properties(
Properties(name='ep_tets',
material='mat_elastic',
section='sec_solid',
elsets='elset_tets'))
# Displacementss
mdl.add_displacement(PinnedDisplacement(name='disp_pinned', nodes='base'))
# Loads
mdl.add_load(PointLoad(name='load_top', nodes='top', y=1000, z=1000))
# Steps
mdl.add_steps([
GeneralStep(name='step_bc', displacements=['disp_pinned']),
GeneralStep(name='step_load', loads=['load_top'])
])
mdl.steps_order = ['step_bc', 'step_load']
# Summary
mdl.summary()
# Run (Abaqus)
mdl.add(
ElementProperties(name='ep',
material='concrete',
section='shell',
elset='mesh'))
#print(mdl.element_properties['ep'])
mdl.add(PinnedDisplacement(name='pinned', nodes='supports'))
#print(mdl.displacements['pinned'])
mdl.add([
GravityLoad(name='gravity', elements='mesh'),
PointLoad(name='loads', nodes='loads', z=-1000),
AreaLoad(name='pressure', elements='area', z=7000),
])
#print(mdl.loads['loads'])
#print(mdl.loads['gravity'])
#print(mdl.loads['pressure'])
mdl.add([
GeneralStep(name='bc', displacements='pinned'),
GeneralStep(name='loads',
loads=['gravity', 'loads', 'pressure'],
factor=1.5),
BucklingStep(name='buckling',
modes=3,
loads=['gravity', 'loads', 'pressure'],
Properties(name='ep_beam',
material='mat_elastic',
section='sec_circular',
elset='elset_beam'))
# Displacements
mdl.add([
PinnedDisplacement(name='disp_left', nodes='nset_left'),
GeneralDisplacement(name='disp_right', nodes='nset_right', y=0, z=0, xx=0),
GeneralDisplacement(name='disp_move', nodes='nset_right', yy=30 * deg),
])
# Loads
mdl.add(PointLoad(name='load_weights', nodes='nset_weights', z=-1))
# Steps
mdl.add([
GeneralStep(name='step_bc', displacements=['disp_left', 'disp_right']),
GeneralStep(name='step_load',
loads=['load_weights'],
displacements=['disp_move']),
])
mdl.steps_order = ['step_bc', 'step_load']
# Summary
mdl.summary()