def _run_mass_properties(model2, nnodes, nelements, run_mass_properties=True):
"""helper method"""
if not (run_mass_properties and nelements):
return
if nelements > 1 and nnodes == 0: # pragma: no cover
raise RuntimeError('no nodes exist')
mass1, cg1, inertia1 = mass_properties(model2,
reference_point=None,
sym_axis=None)
mass2, cg2, inertia2 = mass_properties_nsm(model2,
reference_point=None,
sym_axis=None)
#if not quiet:
#if model2.wtmass != 1.0:
#print('weight = %s' % (mass1 / model2.wtmass))
#print('mass = %s' % mass1)
#print('cg = %s' % cg1)
#print('Ixx=%s, Iyy=%s, Izz=%s \nIxy=%s, Ixz=%s, Iyz=%s' % tuple(inertia1))
assert np.allclose(mass1, mass2), 'mass1=%s mass2=%s' % (mass1, mass2)
assert np.allclose(cg1, cg2), 'mass=%s\ncg1=%s cg2=%s' % (mass1, cg1, cg2)
if not np.allclose(inertia1, inertia2, atol=1e-5): # pragma: no cover
raise ValueError(
'mass=%s cg=%s\ninertia1=%s\ninertia2=%s\ndinertia=%s' %
(mass1, cg1, inertia1, inertia2, inertia1 - inertia2))
unused_mass3, unused_cg3, unused_inertia3 = mass_properties_breakdown(
model2)[:3]
def test_nsmadd(self):
"""tests the NSMADD and all NSM cards"""
eid_quad = 1
unused_eid_tri = 2
unused_eid_conrod = 3
unused_eid_crod = 4
unused_eid_pbeaml = 5
unused_eid_pbarl = 6
unused_pid_pbeaml = 40
pid_pshell = 10
unused_pid_pbeaml = 21
unused_pid_pbarl = 31
unused_pid_prod = 41
mid = 100
E = 3.0e7
G = None
nu = 0.3
nids = [1, 2, 3, 4]
model = BDF(debug=False)
model.add_grid(1, [0., 0., 0.])
model.add_grid(2, [1., 0., 0.])
model.add_grid(3, [1., 1., 0.])
model.add_grid(4, [0., 1., 0.])
model.add_cquad4(eid_quad, pid_pshell, nids) # area=1.0
model.add_mat1(mid, E, G, nu, rho=0.0)
model.add_pshell(pid_pshell, mid1=mid, t=0.1) #, nsm=None)
model.add_nsm1(1000, 'PSHELL', 1.0, pid_pshell,
comment='nsm1') # correct; 1.0
model.add_nsml1(2000, 'PSHELL', 1.0, pid_pshell,
comment='nsml1') # correct; 1.0
model.add_nsml(3000, 'PSHELL', pid_pshell, 1.0,
comment='nsml') # correct; 1.0
model.add_nsml(4000, 'PSHELL', pid_pshell, 1.0,
comment='nsml') # correct; 1.0
model.add_nsmadd(5000, [1000, 2000, 3000, 4000], comment='nsmadd')
model.add_nsmadd(5000, [1000, 2000, 3000, 4000], comment='nsmadd')
model.cross_reference()
model.pop_xref_errors()
mass, unused_cg, unused_I = mass_properties_nsm(model, nsm_id=5000)
self.assertAlmostEqual(mass, 8.0)
model2 = save_load_deck(model)
mass, unused_cg, unused_I = mass_properties_nsm(model2, nsm_id=5000)
def check_solid(self, model, eid, etype, pid, ptype, mid, mtype, nsm, rho,
V):
"""checks that various solid methods work"""
mass = rho * V
element = model.elements[eid]
assert max(element.node_ids) > 0
assert pid in model.properties, 'pid is missing for\n%s' % str(element)
self.assertEqual(element.type, etype)
self.assertEqual(element.eid, eid)
self.assertEqual(element.pid_ref.type, ptype)
self.assertEqual(element.Pid(), pid)
self.assertEqual(element.pid_ref.mid_ref.type, mtype)
self.assertEqual(element.Mid(), mid)
self.assertEqual(element.Volume(), V)
self.assertEqual(element.Mass(), mass)
mass_mp = mass_properties(model, element_ids=eid)[0]
mass_mp_nsm = mass_properties_nsm(model, element_ids=eid)[0]
assert np.allclose(mass, mass_mp)
assert np.allclose(mass, mass_mp_nsm)
def check_solid(self, model, eid, etype, pid, ptype, mid, mtype, nsm, rho,
volume):
"""checks that various solid methods work"""
mass = rho * volume
element = model.elements[eid]
assert max(element.node_ids) > 0
assert pid in model.properties, 'pid is missing for\n%s' % str(element)
self.assertEqual(element.type, etype)
self.assertEqual(element.eid, eid)
self.assertEqual(element.pid_ref.type, ptype)
self.assertEqual(element.Pid(), pid)
self.assertEqual(element.pid_ref.mid_ref.type, mtype)
self.assertEqual(element.Mid(), mid)
self.assertEqual(element.Volume(), volume)
self.assertEqual(element.Mass(), mass)
mass_mp = mass_properties(model, element_ids=eid)[0]
mass_mp_nsm = mass_properties_nsm(model, element_ids=eid)[0]
unused_centroid, unused_xe, unused_ye, unused_ze = element.material_coordinate_system(
)
assert np.allclose(mass, mass_mp)
assert np.allclose(mass, mass_mp_nsm)
def mass_properties_nsm(self,
element_ids=None,
mass_ids=None,
nsm_id=None,
reference_point=None,
sym_axis=None,
scale=None,
inertia_reference='cg',
xyz_cid0_dict=None,
debug=False):
"""
Calculates mass properties in the global system about the
reference point. Considers NSM, NSM1, NSML, NSML1.
Parameters
----------
model : BDF()
a BDF object
element_ids : list[int]; (n, ) ndarray, optional
An array of element ids.
mass_ids : list[int]; (n, ) ndarray, optional
An array of mass ids.
nsm_id : int
the NSM id to consider
reference_point : ndarray/int, optional
type : ndarray
An array that defines the origin of the frame.
default = <0,0,0>.
type : int
the node id
sym_axis : str, optional
The axis to which the model is symmetric.
If AERO cards are used, this can be left blank.
allowed_values = 'no', x', 'y', 'z', 'xy', 'yz', 'xz', 'xyz'
scale : float, optional
The WTMASS scaling value.
default=None -> PARAM, WTMASS is used
float > 0.0
inertia_reference : str; default='cg'
'cg' : inertia is taken about the cg
'ref' : inertia is about the reference point
xyz_cid0_dict : dict[nid] : xyz; default=None -> auto-calculate
mapping of the node id to the global position
debug : bool; default=False
developer debug; may be removed in the future
Returns
-------
mass : float
The mass of the model.
cg : ndarray
The cg of the model as an array.
inertia : ndarray
Moment of inertia array([Ixx, Iyy, Izz, Ixy, Ixz, Iyz]).
I = mass * centroid * centroid
.. math:: I_{xx} = m (dy^2 + dz^2)
.. math:: I_{yz} = -m * dy * dz
where:
.. math:: dx = x_{element} - x_{ref}
.. seealso:: http://en.wikipedia.org/wiki/Moment_of_inertia#Moment_of_inertia_tensor
.. note::
This doesn't use the mass matrix formulation like Nastran.
It assumes m*r^2 is the dominant term.
If you're trying to get the mass of a single element, it
will be wrong, but for real models will be correct.
Examples
--------
**mass properties of entire structure**
>>> mass, cg, inertia = model.mass_properties()
>>> Ixx, Iyy, Izz, Ixy, Ixz, Iyz = inertia
**mass properties of model based on Property ID**
>>> pids = list(model.pids.keys())
>>> pid_eids = model.get_element_ids_dict_with_pids(pids)
>>> for pid, eids in sorted(pid_eids.items()):
>>> mass, cg, inertia = mass_properties(model, element_ids=eids)
Warnings
--------
- If eids are requested, but don't exist, no warning is thrown.
Decide if this is the desired behavior.
- If the NSMx ALL option is used, the mass from all elements
will be considered, even if not included in the element set
"""
self.deprecated(
'mass, cg, inertia = model.mass_properties_nsm(...)',
'from pyNastran.bdf.mesh_utils.mass_properties import mass_properties_nsm\n'
'mass, cg, inertia = mass_properties_nsm(model, ...)', '1.3')
mass, cg, inertia = mass_properties_nsm(
self,
element_ids=element_ids,
mass_ids=mass_ids,
nsm_id=nsm_id,
reference_point=reference_point,
sym_axis=sym_axis,
scale=scale,
inertia_reference=inertia_reference,
xyz_cid0_dict=xyz_cid0_dict,
debug=debug)
return (mass, cg, inertia)
def test_nsm_cquad4(self):
eid_quad = 1
eid_tri = 2
eid_conrod = 3
eid_crod = 4
eid_pbeaml = 5
eid_pbarl = 6
pid_pbeaml = 40
pid_pshell = 10
pid_pbeaml = 21
pid_pbarl = 31
pid_prod = 41
mid = 100
E = 3.0e7
G = None
nu = 0.3
nids = [1, 2, 3, 4]
model = BDF(debug=False)
model.add_grid(1, [0., 0., 0.])
model.add_grid(2, [1., 0., 0.])
model.add_grid(3, [1., 1., 0.])
model.add_grid(4, [0., 1., 0.])
model.add_cquad4(eid_quad, pid_pshell, nids) # area=1.0
model.add_ctria3(eid_tri, pid_pshell, nids[:-1]) # area=0.5
model.add_conrod(eid_conrod,
mid, [1, 2],
A=1.0,
j=0.0,
c=0.0,
nsm=0.0,
comment='')
x = [0., 0., 1.]
g0 = None
model.add_cbar(eid_pbarl,
pid_pbarl, [1, 2],
x,
g0,
offt='GGG',
pa=0,
pb=0,
wa=None,
wb=None,
comment='')
model.add_cbeam(eid_pbeaml,
pid_pbeaml,
nids,
x,
g0,
offt='GGG',
bit=None,
pa=0,
pb=0,
wa=None,
wb=None,
sa=0,
sb=0,
comment='')
model.add_crod(eid_crod, pid_prod, [1, 2])
model.add_prod(pid_prod, mid, A=0.1)
model.add_pshell(pid_pshell, mid1=mid, t=0.1) #, nsm=None)
bar_type = 'BAR'
dims = [1., 2.]
xxb = [0.]
model.add_pbarl(pid_pbarl,
mid,
bar_type,
dims,
group='MSCBML0',
nsm=0.,
comment='')
beam_type = 'BAR'
dims = [[1., 2.]]
nsm = [0.0]
model.add_pbeaml(pid_pbeaml,
mid,
beam_type,
xxb,
dims,
so=None,
nsm=nsm,
group='MSCBML0',
comment='')
model.add_mat1(mid, E, G, nu, rho=0.0)
# TODO: these are correct barring incorrect formulas
model.add_nsm1(1000, 'PSHELL', 1.0, pid_pshell,
comment='nsm1') # correct; 1.5
model.add_nsm1(1001, 'ELEMENT', 1.0, eid_quad) # correct; 1.0
model.add_nsm1(1002, 'ELEMENT', 1.0,
[eid_quad, eid_tri]) # correct; 1.5
model.add_nsm1(1003, 'ELEMENT', 1.0, [eid_pbeaml]) # correct; 1.0
model.add_nsm1(1004, 'ELEMENT', 1.0, eid_pbarl) # correct; 1.0
model.add_nsm1(1005, 'ELEMENT', 1.0,
'ALL') # crash according to QRG b/c mixed type; 2.5
model.add_nsm1(1006, 'PSHELL', 1.0, 'ALL') # correct; 1.5
model.add_nsm1(1007, 'PSHELL', 1.0, [10, 'THRU', 12]) # correct; 1.5
model.add_nsm1(1008, 'PSHELL', 1.0,
[10, 'THRU', 12, 'BY', 2]) # correct; 1.5
model.add_nsm1(1009, 'PBARL', 1.0, pid_pbarl) # correct; 1.0
model.add_nsm1(1010, 'PBEAML', 1.0, pid_pbeaml) # correct; 1.0
model.add_nsm1(1011, 'PROD', 1.0, pid_prod) # correct; 1.0
model.add_nsm1(1012, 'CONROD', 1.0, eid_conrod) # correct; 1.0
#model.add_nsml1(sid, nsm_type, value, ids)
model.add_nsml1(2000, 'PSHELL', 1.0, pid_pshell,
comment='nsml1') # correct; 1.0
model.add_nsml1(2001, 'ELEMENT', 1.0, eid_quad) # correct; 1.0
model.add_nsml1(2002, 'ELEMENT', 1.0,
[eid_quad, eid_tri]) # correct; 1.0
model.add_nsml1(2003, 'ELEMENT', 1.0, [eid_pbeaml]) # correct; 1.0
model.add_nsml1(2004, 'ELEMENT', 1.0, eid_pbarl) # correct; 1.0
model.add_nsml1(2005, 'ELEMENT', 1.0,
'ALL') # crash according to QRG b/c mixed type; 1.0
model.add_nsml1(2006, 'PSHELL', 1.0, 'ALL') # correct; 1.0
model.add_nsml1(2007, 'PSHELL', 1.0, [10, 'THRU', 12]) # correct; 1.0
model.add_nsml1(2008, 'PSHELL', 1.0,
[10, 'THRU', 12, 'BY', 2]) # correct; 1.0
model.add_nsml1(2009, 'PBARL', 1.0, pid_pbarl) # correct; 1.0
model.add_nsml1(2010, 'PBEAML', 1.0, pid_pbeaml) # correct; 1.0
model.add_nsml1(2011, 'PROD', 1.0, pid_prod) # correct; 1.0
model.add_nsml1(2012, 'CONROD', 1.0, eid_conrod) # correct; 1.0
#model.add_nsml1(2011, 'PSHELL', 1.0, ['1240', 'THRU', '1250', None, None, # correct; 0.0
#'2567', 'THRU', '2575',
#'35689', 'THRU', '35700', None, None,
#'76', 'THRU', '85',])
#print(model.nsms[2011])
model.add_nsm(3000, 'PSHELL', pid_pshell, 1.0,
comment='nsm') # correct; 1.5
model.add_nsm(3001, 'ELEMENT', eid_quad, 1.0) # correct; 1.0
model.add_nsm(3003, 'ELEMENT', [eid_pbeaml], 1.0) # correct; 1.0
model.add_nsm(3004, 'ELEMENT', eid_pbarl, 1.0) # correct; 1.0
model.add_nsm(3009, 'PBARL', pid_pbarl, 1.0) # correct; 1.0
model.add_nsm(3010, 'PBEAML', pid_pbeaml, 1.0) # correct; 1.0
model.add_nsm(3011, 'PROD', pid_prod, 1.0) # correct; 1.0
model.add_nsm(3012, 'CONROD', eid_conrod, 1.0) # correct; 1.0
model.add_nsml(4000, 'PSHELL', pid_pshell, 1.0,
comment='nsml') # correct; 1.0
model.add_nsml(4001, 'ELEMENT', eid_quad, 1.0) # correct; 1.0
model.add_nsml(4003, 'ELEMENT', [eid_pbeaml], 1.0) # correct; 1.0
model.add_nsml(4004, 'ELEMENT', eid_pbarl, 1.0) # correct; 1.0
model.add_nsml(4009, 'PBARL', pid_pbarl, 1.0) # correct; 1.0
model.add_nsml(4010, 'PBEAML', pid_pbeaml, 1.0) # correct; 1.0
model.add_nsml(4011, 'PROD', pid_prod, 1.0) # correct; 1.0
model.add_nsml(4012, 'CONROD', eid_conrod, 1.0) # correct; 1.0
model.pop_parse_errors()
model.cross_reference()
model.pop_xref_errors()
expected_dict = {
# NSM1
1000: 1.5,
1001: 1.0,
1002: 1.5,
1003: 1.0,
1004: 1.0,
1005: -1.0, # crash
1006: 1.5,
1007: 1.5,
1008: 1.5,
1009: 1.0,
1010: 1.0,
1011: 1.0,
1012: 1.0,
#model.add_nsml1(sid, nsm_type, value, ids)
# NSML1
2000: 1.0,
2001: 1.0,
2002: 1.0,
2003: 1.0,
2004: 1.0,
2005: -1.0, # crash
2006: 1.0,
2007: 1.0,
2008: 1.0,
2009: 1.0,
2010: 1.0,
2011: 1.0,
2012: 1.0,
# NSM
3000: 1.5,
3001: 1.0,
3003: 1.0,
3004: 1.0,
3009: 1.0,
3010: 1.0,
3011: 1.0,
3012: 1.0,
# NSM1
4000: 1.0,
4001: 1.0,
4003: 1.0,
4004: 1.0,
4009: 1.0,
4010: 1.0,
4011: 1.0,
4012: 1.0,
}
for nsm_id in sorted(model.nsms):
mass1_expected = expected_dict[nsm_id]
if mass1_expected == -1.0:
with self.assertRaises(RuntimeError):
mass1, unused_cg, unused_I = mass_properties_nsm(
model, nsm_id=nsm_id, debug=False)
else:
mass1, unused_cg, unused_I = mass_properties_nsm(model,
nsm_id=nsm_id,
debug=False)
if mass1 != mass1_expected:
unused_mass2 = mass_properties_nsm(model,
nsm_id=nsm_id,
debug=True)[0]
raise RuntimeError('nsm_id=%s mass != %s; mass1=%s' %
(nsm_id, mass1_expected, mass1))
#print('mass[%s] = %s' % (nsm_id, mass))
#print('----------------------------------------------')
model2 = save_load_deck(model, run_test_bdf=False)
model2.reset_rslot_map()
#print(model2._type_to_slot_map)
model2.elements = {}
type_to_id_map = {}
for card_type, ids in model2._type_to_id_map.items():
if card_type in [
'CQUAD4', 'CTRIA3', 'CBEAM', 'CONROD', 'CBAR', 'CROD'
]:
pass
elif card_type in [
'NSM', 'NSM1', 'NSML', 'NSML1', 'MAT1', 'PBARL', 'PBEAM',
'PSHELL', 'PCOMP', 'PROD', 'PBEAML', 'GRID'
]:
type_to_id_map[card_type] = ids
else:
raise NotImplementedError(str((card_type, ids)))
model2._type_to_id_map = type_to_id_map
model2.log = SimpleLogger(level='error')
# don't crash on the null case
for nsm_id in sorted(model2.nsms):
mass, unused_cg, unused_I = mass_properties_nsm(model2,
nsm_id=nsm_id,
debug=False)
self.assertEqual(mass, 0.0)
def test_shear(self):
"""tests a CSHEAR, PSHEAR"""
pid = 10
pid_pshell = 11
mid = 100
log = get_logger(level='warning')
model = BDF(log=log)
model.add_grid(1, [0., 0., 0.])
model.add_grid(2, [1., 0., 0.])
model.add_grid(3, [1., 1., 0.])
model.add_grid(4, [0., 1., 0.])
nsm = 10.0
t = 1.0
rho = 1.0
cshear = model.add_cshear(10, pid, [1, 2, 3, 4],
comment='cshear')
cquad4 = model.add_cquad4(14, pid_pshell, [1, 2, 3, 4],
comment='cquad4')
model.add_pshear(pid, mid, t=t,
nsm=nsm, f1=0., f2=0., comment='pshear')
model.add_pshell(pid_pshell, mid1=mid, t=t, mid2=None, twelveIt3=1.0,
mid3=None, tst=0.833333,
nsm=nsm, z1=None, z2=None,
mid4=None, comment='')
E = 3.0e7
G = None
nu = 0.3
model.add_mat1(mid, E, G, nu, rho=rho)
model.validate()
model.cross_reference()
model.pop_xref_errors()
area = 1.0
mass_expected = area * (rho * t + nsm)
mass = model.mass_properties()[0]
assert np.allclose(mass, mass_expected*2), 'mass_properties all: mass=%s mass_expected=%s' % (mass, mass_expected*2)
mass = model.mass_properties(element_ids=10)[0]
assert np.allclose(mass, mass_expected), 'mass_properties reduced: mass=%s mass_expected=%s' % (mass, mass_expected)
mass = mass_properties_nsm(model)[0]
assert np.allclose(mass, mass_expected*2), 'mass_properties_nsm all: mass=%s mass_expected=%s' % (mass, mass_expected*2)
mass = mass_properties_nsm(model, element_ids=10)[0]
assert np.allclose(mass, mass_expected), 'mass_properties_nsm reduced: mass=%s mass_expected=%s' % (mass, mass_expected)
bdf_file = StringIO()
model.write_bdf(bdf_file)
model.uncross_reference()
model.cross_reference()
model.pop_xref_errors()
model.get_area_breakdown(property_ids=None, stop_if_no_area=True)
model.get_mass_breakdown(property_ids=None, stop_if_no_mass=True, detailed=False)
model.get_mass_breakdown(property_ids=None, stop_if_no_mass=True, detailed=True)
model.get_volume_breakdown(property_ids=None, stop_if_no_volume=True)
assert np.allclose(cshear.Mass(), mass_expected), cshear.Mass()
model.uncross_reference()
model.safe_cross_reference()
model.uncross_reference()
#bdf_file = model.write_bdf(bdf_file)
save_load_deck(model)
