beam Module

All beam properties are defined in this file. This includes:

• PBEAM

• PBEAML

• PBCOMP

• PBRSECT

All beams are LineProperty objects. Multi-segment beams are IntegratedLineProperty objects.

class pyNastran.bdf.cards.properties.beam.PBCOMP(pid, mid, y, z, c, mids, area=0.0, i1=0.0, i2=0.0, i12=0.0, j=0.0, nsm=0.0, k1=1.0, k2=1.0, m1=0.0, m2=0.0, n1=0.0, n2=0.0, symopt=0, comment='')

Bases: pyNastran.bdf.cards.properties.bars.LineProperty

1	2	3	4	5	6	7	8	9
PBCOMP	PID	MID	A	I1	I2	I12	J	NSM
	K1	K2	M1	M2	N1	N2	SYMOPT
	Y1	Z1	C1	MID1
	Y2	Z2	C2	MID2
	…	…	…

Creates a PBCOMP card

Parameters

pidint

Property ID

midint

Material ID

midsList[int]

Material ID for the i-th integration point

y / zList[float]

The (y,z) coordinates of the lumped areas in the element coordinate system

cList[float]; default=0.0

Fraction of the total area for the i-th lumped area default not supported…

areafloat

Area of beam cross section

i1 / i2float; default=0.0

Area moment of inertia about plane 1/2 about the neutral axis

i12float; default=0.0

area product of inertia

jfloat; default=0.0

Torsional moment of interia

nsmfloat; default=0.0

Nonstructural mass per unit length

k1 / k2float; default=1.0

Shear stiffness factor K in K*A*G for plane 1/2

m1 / m2float; default=0.0

The (y,z) coordinates of center of gravity of nonstructural mass

n1 / n2float; default=0.0

The (y,z) coordinates of neutral axis

symoptint; default=0

Symmetry option to input lumped areas for the beam cross section 0 < Integer < 5

commentstr; default=’’

a comment for the card

MassPerLength()

Mids()

classmethod _init_from_empty()

classmethod add_card(card, comment='')

Adds a PBCOMP card from BDF.add_card(...)

Parameters

cardBDFCard()

a BDFCard object

commentstr; default=’’

a comment for the card

cross_reference(model: BDF) → None

Cross links the card so referenced cards can be extracted directly

Parameters

modelBDF()

the BDF object

j = None

Polar Moment of Inertia \(J\)

mid = None

Material ID

nsm = None

Non-structural mass per unit length \(\frac{m}{L}\)

pid = None

Property ID

raw_fields()

repr_fields()

Gets the fields in their simplified form

Returns

fieldsList[varies]

the fields that define the card

type = 'PBCOMP'

uncross_reference() → None

Removes cross-reference links

validate()

card checking method that should be overwritten

write_card(size: int = 8, is_double: bool = False) → str

Writes the card with the specified width and precision

Parameters

sizeint (default=8)

size of the field; {8, 16}

is_doublebool (default=False)

is this card double precision

Returns

msgstr

the string representation of the card

class pyNastran.bdf.cards.properties.beam.PBEAM(pid, mid, xxb, so, area, i1, i2, i12, j, nsm=None, c1=None, c2=None, d1=None, d2=None, e1=None, e2=None, f1=None, f2=None, k1=1.0, k2=1.0, s1=0.0, s2=0.0, nsia=0.0, nsib=None, cwa=0.0, cwb=None, m1a=0.0, m2a=0.0, m1b=None, m2b=None, n1a=0.0, n2a=0.0, n1b=None, n2b=None, comment='')

Bases: pyNastran.bdf.cards.properties.bars.IntegratedLineProperty

Defines the properties of a beam element (CBEAM entry). This element may be used to model tapered beams.

PBEAM	PID	MID	A(A)	I1(A)	I2(A)	I12(A)	J(A)	NSM(A)
	C1(A)	C2(A)	D1(A)	D2(A)	E1(A)	E2(A)	F1(A)	F2(A)

The next two continuations are repeated for each intermediate station as described in Remark 5. and SO and X/XB must be specified.

SO	X/XB	A	I1	I2	I12	J	NSM
C1	C2	D1	D2	E1	E2	F1	F2

The last two continuations are: +——-+——-+——-+——-+——–+——–+——-+——-+ | K1 | K2 | S1 | S2 | NSI(A) | NSI(B) | CW(A) | CW(B) | +——-+——-+——-+——-+——–+——–+——-+——-+ | M1(A) | M2(A) | M1(B) | M2(B) | N1(A) | N2(A) | N1(B) | N2(B) | +——-+——-+——-+——-+——–+——–+——-+——-+

Todo

fix 0th entry of self.so, self.xxb

Creates a PBEAM card

Parameters

pidint

property id

midint

material id

xxbList[float]

The percentage locations along the beam [0., …, 1.]

soList[str]

YES, YESA, NO

areaList[float]

area

i1, i2, i12, jList[float]

moments of inertia

nsmList[float]

nonstructural mass per unit length

c1/c2, d1/d2, e1/e2, f1/f2List[float]; default=None -> [0.]*nxxb

the y/z locations of the stress recovery points c1 - point C.y c2 - point C.z

k1 / k2float; default=1.

Shear stiffness factor K in K*A*G for plane 1/2.

s1 / s2float; default=0.

Shear relief coefficient due to taper for plane 1/2.

nsia / nsiafloat; default=0. / nsia

non structural mass moment of inertia per unit length about nsm center of gravity at Point A/B.

cwa / cwbfloat; default=0. / cwa

warping coefficient for end A/B.

m1a / m2afloat; default=0. / 0.

y/z coordinate of center of gravity of nonstructural mass for end A.

m1b / m2bfloat; default=m1a / m2a

y/z coordinate of center of gravity of nonstructural mass for end B.

n1a / n2afloat; default=0. / 0.

y/z coordinate of neutral axis for end A.

n1b / n2bfloat; default=n1a / n2a

y/z coordinate of neutral axis for end B.

commentstr; default=’’

a comment for the card

I1_I2_I12() → Tuple[float, float, float]

MassPerLength() → float

mass = L*(Area*rho+nsm) mass/L = Area*rho+nsm

classmethod _init_from_empty()

_interpolate_sections()

now we interpolate to fix up missing data from arrays that were potentially out of order (they’re sorted now)

we’ve also already checked xxb=0.0 and xxb=1.0 for I1, I2, I12, J

classmethod add_card(card, comment='')

Adds a PBEAM card from BDF.add_card(...)

Parameters

cardBDFCard()

a BDFCard object

commentstr; default=’’

a comment for the card

cross_reference(model: BDF) → None

Cross links the card so referenced cards can be extracted directly

Parameters

modelBDF()

the BDF object

cwa = None

warping coefficient for end A.

cwb = None

warping coefficient for end B.

get_optimization_value(name_str: str) → float

k1 = None

Shear stiffness factor K in K*A*G for plane 1.

k2 = None

Shear stiffness factor K in K*A*G for plane 2.

m1a = None

y coordinate of center of gravity of nonstructural mass for end A.

m1b = None

y coordinate of center of gravity of nonstructural mass for end B.

m2a = None

z coordinate of center of gravity of nonstructural mass for end A.

m2b = None

z coordinate of center of gravity of nonstructural mass for end B.

mid = None

Material ID

n1a = None

y coordinate of neutral axis for end A.

n1b = None

y coordinate of neutral axis for end B.

n2a = None

z coordinate of neutral axis for end A.

n2b = None

z coordinate of neutral axis for end B.

nsia = None

non structural mass moment of inertia per unit length about nsm center of gravity at Point A.

nsib = None

non structural mass moment of inertia per unit length about nsm center of gravity at Point B.

pid = None

Property ID

raw_fields()

repr_fields()

Gets the fields in their simplified form

Returns

fieldsList[varies]

the fields that define the card

s1 = None

Shear relief coefficient due to taper for plane 1.

s2 = None

Shear relief coefficient due to taper for plane 2.

set_optimization_value(name_str: str, value: float) → None

type = 'PBEAM'

uncross_reference() → None

Removes cross-reference links

update_by_pname_fid(pname_fid, value)

validate()

card checking method that should be overwritten

write_card(size: int = 8, is_double: bool = False) → str

Writes the card with the specified width and precision

Parameters

sizeint (default=8)

size of the field; {8, 16}

is_doublebool (default=False)

is this card double precision

Returns

msgstr

the string representation of the card

write_card_16(is_double=False)

class pyNastran.bdf.cards.properties.beam.PBEAML(pid: int, mid: int, beam_type: str, xxb, dims, so=None, nsm=None, group: str = 'MSCBML0', comment: str = '')

Bases: pyNastran.bdf.cards.properties.bars.IntegratedLineProperty

1	2	3	4	5	6	7	8	9
PBEAML	PID	MID	GROUP	TYPE
	DIM1(A)	DIM2(A)	etc.	DIMn(A)	NSM(A)	SO(1)	X(1)/XB	DIM1(1)
	DIM2(1)	etc.	DIMn(1)	NSM(1)	SO(2)	X(2)/XB	DIM1(2)	DIM2(2)
	etc.	DIMn(2)	NSM(m)	etc.	SO(m)	X(m)/XB	DIM1(m)	etc.
	DIMn(m)	NSM(m)	SO(B)	1.0	DIM1(B)	DIM2(B)	etc.	DIMn(B)
	NSM(B)

Creates a PBEAML card

Parameters

pidint

property id

midint

material id

beam_typestr

the section profile

xxbList[float]

The percentage locations along the beam [0., …, 1.]

dimsList[dim]

dimList[float]

The dimensions for each section

soList[str]; default=None

YES, YESA, NO None : [0.] * len(xxb)

nsmList[float]; default=None

nonstructural mass per unit length None : [0.] * len(xxb)

groupstr; default=’MSCBML0’

this parameter can lead to a very broken deck with a very bad error message; don’t touch it!

commentstr; default=’’

a comment for the card

Area()

Gets the Area \(A\) of the PBEAML.

\[A = \int \, A(x) dx\]

Notes

a spline is fit to \(A(x)\) and then integrated.

I11()

gets I11

I12()

I22()

gets I22

J()

gets J

MassPerLength()

Gets the mass per length \(\frac{m}{L}\) of the PBEAML.

\[\frac{m}{L} = A(x) \rho + nsm\]

\[\frac{m}{L} = nsm L + \rho \int \, A(x) dx\]

property Type

gets Type

_finalize_hdf5(encoding)

hdf5 helper function

classmethod _init_from_empty()

_properties = ['valid_types', 'Type']

classmethod add_card(card, comment='')

Adds a PBEAML card from BDF.add_card(...)

Parameters

cardBDFCard()

a BDFCard object

commentstr; default=’’

a comment for the card

beam_type = None

Section Type (e.g. ‘ROD’, ‘TUBE’, ‘I’, ‘H’)

cross_reference(model: BDF) → None

Cross links the card so referenced cards can be extracted directly

Parameters

modelBDF()

the BDF object

.. warning:: For structural problems, PBEAML entries must

reference a MAT1 material entry

.. warning:: For heat-transfer problems, the MID must

reference a MAT4 or MAT5 material entry.

.. todo:: What happens when there are 2 subcases?

get_mass_per_lengths()

helper method for MassPerLength a*rho + nsm

mid = None

Material ID

pid = None

Property ID

raw_fields()

repr_fields()

Gets the fields in their simplified form

Returns

fieldsList[varies]

the fields that define the card

type = 'PBEAML'

uncross_reference() → None

Removes cross-reference links

update_by_pname_fid(pname_fid: str, value: float)

valid_types = {'BAR': 2, 'BOX': 4, 'BOX1': 6, 'CHAN': 4, 'CHAN1': 4, 'CHAN2': 4, 'CROSS': 4, 'DBOX': 10, 'H': 4, 'HAT': 4, 'HAT1': 5, 'HEXA': 3, 'I': 6, 'I1': 4, 'L': 4, 'ROD': 1, 'T': 4, 'T1': 4, 'T2': 4, 'TUBE': 2, 'TUBE2': 2, 'Z': 4}

validate()

card checking method that should be overwritten

verify(model, isubcase)

write_card(size: int = 8, is_double: bool = False) → str

Todo

having bug with PBEAML

class pyNastran.bdf.cards.properties.beam.PBMSECT(pid, mid, form, options, comment='')

Bases: pyNastran.bdf.cards.properties.bars.LineProperty

not done

dummy init

Area()

Gets the area \(A\) of the CBEAM.

I11()

gets I11

I22()

gets I22

J()

gets J

MassPerLength()

Gets the mass per length \(\frac{m}{L}\) of the CBEAM.

\[\frac{m}{L} = A \rho + nsm\]

Nsm()

Gets the non-structural mass \(nsm\) of the CBEAM.

_finalize_hdf5(encoding)

classmethod _init_from_empty()

_properties = ['outp_id']

classmethod add_card(card, comment='')

Adds a PBMSECT card from BDF.add_card(...)

Parameters

cardList[str]

this card is special and is not a BDFCard like other cards

commentstr; default=’’

a comment for the card

cross_reference(model: BDF) → None

Cross links the card so referenced cards can be extracted directly

Parameters

modelBDF()

the BDF object

mid = None

Material ID

property outp_id

pid = None

Property ID

plot(model, figure_id=1, show=False)

Plots the beam section

Parameters

modelBDF()

the BDF object

figure_idint; default=1

the figure id

showbool; default=False

show the figure when done

raw_fields()

not done…

repr_fields()

not done…

type = 'PBMSECT'

uncross_reference() → None

Removes cross-reference links

validate()

card checking method that should be overwritten

write_card(size: int = 8, is_double: bool = False) → str

Writes the card with the specified width and precision

Parameters

sizeint (default=8)

size of the field; {8, 16}

is_doublebool (default=False)

is this card double precision

Returns

msgstr

the string representation of the card

pyNastran.bdf.cards.properties.beam.update_pbeam_negative_integer(pname_fid)

Converts the negative PBEAM value to a positive one

Parameters

pname_fidint

for a PBEAM this should be between [-5, -167] the negative values correspond to the numbers in the MPT OP2 table

Returns

pname_fidstr

a pname is of ‘J(3)’ is far more clear than -37

TODO: only handles istation=0 for now (e.g., ‘J(1)’)