shell Module

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

• PCOMP

• PCOMPG

• PLPLANE

• PSHEAR

• PSHELL

• PPLANE

All shell properties are Property objects.

class pyNastran.bdf.cards.properties.shell.CompositeShellProperty

Bases: pyNastran.bdf.cards.base_card.Property

Common class for:

• PCOMP

• PCOMPG

dummy init

MassPerArea(iply='all', method='nplies', tflag: int = 1, tscales=None)

MassPerArea_structure() → float

Material(iply: int) → Union[MAT1, MAT8, MAT9]

Gets the material of the \(i^{th}\) ply (not the ID unless it is not cross-referenced).

Parameters

iplyint

the ply ID (starts from 0)

Mid(iply: int) → int

Gets the Material ID of the \(i^{th}\) ply.

Parameters

iplyint/str; default=’all’

the string ‘all’ (default) or the mass per area of the \(i^{th}\) ply

Returns

material_idint

the material id of the ith ply

Mids() → List[int]

Nsm() → float

Rho(iply: int) → float

property TRef

Theta(iply: int) → float

Thickness(iply: Union[int, str] = 'all', tflag: int = 1, tscales=None)

_adjust_ply_id(iply: int) → int

Gets the ply ID that’s stored in self.plies.

When a ply is not symmetric, this function returns the input iply. When a ply is symmetrical and the iply value is greater than the number of plies, we return the mirrored ply. For the case of a symmetrical ply, the element will always have an even number of layers.

Parameters

iplyint

the ply ID (0-based)

Raises

• IndexError if iply is invalid

::

Case 1 (nplies=6, len(plies)=3, lam=’SYM’):

ply 2 ply 1 ply 0 ——- sym ply 0 / 3 ply 1 / 4 ply 2 / 5

Ask for ply 3, return ply 0 Ask for ply 4, return ply 1 Ask for ply 5, return ply 2

Case 2 (nplies=5, len(plies)=5, lam=’NO’):

ply 5 ply 4 ply 3 ply 1 ply 0

Ask for ply 3, return ply 1 Ask for ply 4, return ply 2

cross_reference(model: BDF) → None

Cross links the card so referenced cards can be extracted directly

Parameters

modelBDF()

the BDF object

get_density(iply: int) → float

Gets the density of the \(i^{th}\) ply

Parameters

iplyint

the ply ID (starts from 0)

get_mass_per_area(iply='all', method: str = 'nplies') → float

Gets the Mass/Area for the property.

\[\frac{m}{A} = \sum(\rho t) + nsm\]

or

\[\frac{m}{A} - nsm = \sum(\rho t)\]

and

\[\frac{m_i}{A} = rho_i t_i + nsm_i\]

where \(nsm_i\) is the non-structural mass of the \(i^{th}\) ply

Parameters

iplystr/int; default=’all’

str : the string ‘all’ (default) or the mass per area of the \(i^{th}\) ply

methodstr

the method to compute MassPerArea {nplies, rho*t, t}

• Case 1 (iply = all)

  method has no effect because the total nsm is defined

• Case 2 (iply != all)

  method ‘nplies’ smear the nsm based on \(n_{plies}\) (default)

  \(nsm_i = nsm / n_{plies}\) # smear based on nplies

• Case 3 (iply != all)

  method ‘rho*t’ smear the nsm based on the mass distribution

  \[nsm_i = \rho_i t_i \frac{nsm}{\sum(\rho_i t_i)}\]
  \[nsm_i = \rho_i t_i \frac{nsm}{\frac{m}{A} - nsm}\]

• Case 4 (iply != all)

  method ‘t’ smear the nsm based on the thickness distribution

  \[nsm_i = t_i \frac{nsm}{\sum(t_i)}\]

.. note:: final mass calculation will be done later

get_mass_per_area_rho(rhos: List[float], iply='all', method: str = 'nplies') → float

Gets the Mass/Area for the property.

\[\frac{m}{A} = \sum(\rho t) + nsm\]

or

\[\frac{m}{A} - nsm = \sum(\rho t)\]

and

\[\frac{m_i}{A} = rho_i t_i + nsm_i\]

where \(nsm_i\) is the non-structural mass of the \(i^{th}\) ply

Parameters

rhosList[float]

the densities of each ply

iplystr/int; default=’all’

the mass per area of the \(i^{th}\) ply

methodstr

the method to compute MassPerArea {nplies, rho*t, t}

• Case 1 (iply = all)

  method has no effect because the total nsm is defined

• Case 2 (iply != all)

  method ‘nplies’ smear the nsm based on \(n_{plies}\) (default)

  \(nsm_i = nsm / n_{plies}\) # smear based on nplies

• Case 3 (iply != all)

  method ‘rho*t’ smear the nsm based on the mass distribution

  \[nsm_i = \rho_i t_i \frac{nsm}{\sum(\rho_i t_i)}\]
  \[nsm_i = \rho_i t_i \frac{nsm}{\frac{m}{A} - nsm}\]

• Case 4 (iply != all)

  method ‘t’ smear the nsm based on the thickness distribution

  \[nsm_i = t_i \frac{nsm}{\sum(t_i)}\]

.. note:: final mass calculation will be done later

get_mass_per_area_structure(rhos: List[float]) → float

Gets the Mass/Area for the property structure only (doesn’t consider nsm).

\[\frac{m}{A} = \sum(\rho t)\]

Parameters

rhosList[float]

the densities of each ply

get_material_id(iply: int) → int

iply - 0 based

get_material_ids(include_symmetry: bool = True)

get_nonstructural_mass() → float

Gets the non-structural mass \(i^{th}\) ply

get_sout(iply: int) → str

Gets the the flag identifying stress/strain outpur of the \(i^{th}\) ply (not the ID). default=’NO’.

Parameters

iplyint

the ply ID (starts from 0)

get_souts(include_symmetry: bool = True) → numpy.ndarray

get_theta(iply: int) → float

Gets the ply angle of the \(i^{th}\) ply (not the ID)

Parameters

iplyint

the ply ID (starts from 0)

get_thetas(include_symmetry: bool = True) → numpy.ndarray

get_thickness(iply: Union[int, str] = 'all') → float

Gets the thickness of the \(i^{th}\) ply.

Parameters

iplyint/str; default=’all’

the string ‘all’ (default) or the mass per area of the \(i^{th}\) ply

Returns

thicknessfloat

the thickness of the ply or plies

get_thicknesses(include_symmetry: bool = True) → numpy.ndarray

get_z_locations() → numpy.ndarray

Gets the z locations for the various plies.

Parameters

iplyint

the ply ID (starts from 0)

Assume there are 2 plies, each of 1.0 thick, starting frommath:z=0.

>>> pcomp.get_z_locations()

[0., 1., 2.]

property is_symmetrical

Is the laminate symmetrical?

Returns

is_symmetricalbool

is the SYM flag active?

property material_ids

Gets the material IDs of all the plies

Returns

midsMATx

the material IDs

property nplies

Gets the number of plies including the core.

if Lam=SYM:
  returns nplies * 2   (even)
else:
  returns nplies

sout(iply: int) → str

uncross_reference() → None

Removes cross-reference links

class pyNastran.bdf.cards.properties.shell.PCOMP(pid: int, mids: List[int], thicknesses: List[float], thetas: Optional[List[float]] = None, souts: Optional[List[str]] = None, nsm: float = 0.0, sb: float = 0.0, ft: Optional[str] = None, tref: float = 0.0, ge: float = 0.0, lam: Optional[str] = None, z0: Optional[float] = None, comment: str = '')

Bases: pyNastran.bdf.cards.properties.shell.CompositeShellProperty

1	2	3	4	5	6	7	8	9
PCOMP	PID	Z0	NSM	SB	FT	TREF	GE	LAM
	MID1	T1	THETA1	SOUT1	MID2	T2	THETA2	SOUT2
	MID3	T3	THETA3	SOUT3	etc.

PCOMP	701512	0.0+0	1.549-2			0.0+0	0.0+0	SYM
	300704	3.7-2	0.0+0	YES	300704	3.7-2		YES
	300704	3.7-2	-45.	YES	300704	3.7-2		YES
	300705	.5	0.0+0	YES

Creates a PCOMP card

pidint

property id

midsList[int, …, int]

material ids for each ply

thicknessesList[float, …, float]

thicknesses for each ply

thetasList[float, …, float]; default=None

ply angle None : [0.] * nplies

soutsList[str, …, str]; default=None

should the stress? be printed; {YES, NO} None : [NO] * nplies

nsmfloat; default=0.

nonstructural mass per unit area

sbfloat; default=0.

Allowable shear stress of the bonding material. Used by the failure theory

ftstr; default=None

failure theory; {HILL, HOFF, TSAI, STRN, None}

treffloat; default=0.

reference temperature

gefloat; default=0.

structural damping

lamstr; default=None

symmetric flag; {SYM, MEM, BEND, SMEAR, SMCORE, None} None : not symmmetric

z0float; default=None

Distance from the reference plane to the bottom surface None : -1/2 * total_thickness

commentstr; default=’’

a comment for the card

classmethod _init_from_empty()

_properties = ['_field_map', 'plies', 'nplies', 'material_ids']

classmethod add_card(card: BDFCard, comment='')

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

Parameters

cardBDFCard()

a BDFCard object

commentstr; default=’’

a comment for the card

ft = None

Failure Theory [‘HILL’, ‘HOFF’, ‘TSAI’, ‘STRN’, None]

get_ABD_matrices(theta_offset: float = 0.0) → numpy.ndarray

Gets the ABD matrix

Parameters

theta_offsetfloat

rotates the ABD matrix; measured in degrees

get_Qbar_matrix(mid_ref: Union[MAT1, MAT8], theta: float) → np.ndarray

theta must be in radians

get_Sbar_matrix(mid_ref, theta: float) → numpy.ndarray

theta must be in radians

get_individual_ABD_matrices(theta_offset: float = 0.0) → Tuple[numpy.ndarray, numpy.ndarray, numpy.ndarray]

Gets the ABD matrix

Parameters

theta_offsetfloat

rotates the ABD matrix; measured in degrees

get_z0_z1_zmean()

is_balanced_symmetric(debug=True)

assumes materials with different mids are unique

lam = None

symmetric flag - default = No Symmetry (=None)

nsm = None

Non-Structural Mass per unit Area

pid = None

Property ID

property plies

raw_fields()

repr_fields()

Gets the fields in their simplified form

Returns

fieldsList[varies]

the fields that define the card

tref = None

Reference Temperature (default=0.0)

type = 'PCOMP'

update_by_pname_fid(pname_fid: Union[str, int], value: Union[int, float, str]) → None

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.shell.PCOMPG(pid: int, global_ply_ids: List[int], mids: List[int], thicknesses: List[float], thetas: Optional[List[float]] = None, souts: Optional[List[str]] = None, nsm: float = 0.0, sb: float = 0.0, ft: Optional[str] = None, tref: float = 0.0, ge: float = 0.0, lam: Optional[str] = None, z0: Optional[float] = None, comment: str = '')

Bases: pyNastran.bdf.cards.properties.shell.CompositeShellProperty

1	2	3	4	5	6	7	8	9
PCOMPG	PID	Z0	NSM	SB	FT	TREF	GE	LAM
	GPLYID1	MID1	T1	THETA1	SOUT1
	GPLYID2	MID2	T2	THETA2	SOUT2

Creates a PCOMPG card

Parameters

pidint

property id

global_ply_idsList[int]

the ply id

midsList[int, …, int]

material ids for each ply

thicknessesList[float, …, float]

thicknesses for each ply

thetasList[float, …, float]; default=None

ply angle None : [0.] * nplies

soutsList[str, …, str]; default=None

should the stress? be printed; {YES, NO} None : [NO] * nplies

nsmfloat; default=0.

nonstructural mass per unit area

sbfloat; default=0.

Allowable shear stress of the bonding material. Used by the failure theory

ftstr; default=None

failure theory; {HILL, HOFF, TSAI, STRN, None}

treffloat; default=0.

reference temperature

gefloat; default=0.

structural damping

lamstr; default=None

symmetric flag; {SYM, MEM, BEND, SMEAR, SMCORE, None} None : not symmmetric

z0float; default=None

Distance from the reference plane to the bottom surface None : -1/2 * total_thickness

commentstr; default=’’

a comment for the card

GlobalPlyID(iply: int) → int

returns the global ply id for the specified layer

classmethod _init_from_empty()

_properties = ['_field_map', 'plies', 'nplies', 'material_ids']

classmethod add_card(card: BDFCard, comment: str = '')

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

Parameters

cardBDFCard()

a BDFCard object

commentstr; default=’’

a comment for the card

ft = None

Failure Theory

[‘HILL’, ‘HOFF’, ‘TSAI’, ‘STRN’, None]

get_global_ply_ids(include_symmetry: bool = True) → numpy.ndarray

lam = None

symmetric flag - default = No Symmetry (NO)

nsm = None

Non-Structural Mass per unit Area

pid = None

Property ID

property plies

pname_fid_map = {}

raw_fields()

repr_fields()

Gets the fields in their simplified form

Returns

fieldsList[varies]

the fields that define the card

tref = None

Reference Temperature (default=0.0)

type = 'PCOMPG'

update_by_pname_fid(pname_fid: Union[str, int], value) → None

validate() → None

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.shell.PLPLANE(pid, mid, cid=0, stress_strain_output_location='GRID', comment='')

Bases: pyNastran.bdf.cards.base_card.Property

Fully Nonlinear Plane Element Properties (SOL 601) Defines the properties of a fully nonlinear (i.e., large strain and large rotation) hyperelastic plane strain or axisymmetric element.

1	2	3	4	5
PLPLANE	PID	MID	CID	STR

MSC

1	2	3	4	5	6
PLPLANE	PID	MID	CID	STR	T

NX

Referenced by:

#- CQUAD, CQUAD4, CQUAD8, CQUADX, CTRIA3, CTRIA6, CTRIAX (MSC) #- CPLSTS3, CPLSTS4, CPLSTS6, CPLSTS8 entries (NX 10)

Creates a PLPLANE card, which defines the properties of a fully nonlinear (i.e., large strain and large rotation) hyperelastic plane strain or axisymmetric element.

Parameters

pidint

property id

midint

material id; MATHP / MATHE

cidint; default=0

???

stress_strain_output_locationstr; default=’GRID’

???

commentstr; default=’’

a comment for the card

Cid()

Mid()

returns the material id

classmethod _init_from_empty()

classmethod add_card(card, comment='')

Adds a PLPLANE 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

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 = 'PLPLANE'

uncross_reference() → None

Removes cross-reference links

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.shell.PPLANE(pid, mid, t=0.0, nsm=0.0, formulation_option=0, comment='')

Bases: pyNastran.bdf.cards.base_card.Property

NX specific card

MassPerArea(tflag=1, tscales=None)

Calculates mass per area.

\[\]

rac{m}{A} = nsm + ho t

Mid()

returns the material id

Thickness()

returns the thickness of the element

classmethod _init_from_empty()

classmethod add_card(card, comment='')

Adds a PPLANE 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

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 = 'PPLANE'

uncross_reference() → None

Removes cross-reference links

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.shell.PSHEAR(pid: int, mid: int, t: float, nsm: float = 0.0, f1: float = 0.0, f2: float = 0.0, comment: str = '')

Bases: pyNastran.bdf.cards.base_card.Property

Defines the properties of a shear panel (CSHEAR entry).

1	2	3	4	5	6	7
PSHEAR	PID	MID	T	NSM	F1	F2

Creates a PSHEAR card

Parameters

pidint

property id

midint

material id

tfloat

shear panel thickness

nsmfloat; default=0.

nonstructural mass per unit length

f1float; default=0.0

Effectiveness factor for extensional stiffness along edges 1-2 and 3-4

f2float; default=0.0

Effectiveness factor for extensional stiffness along edges 2-3 and 1-4

commentstr; default=’’

a comment for the card

MassPerArea(tflag=1, tscales=None)

Calculates mass per area.

\[\]

rac{m}{A} = nsm + ho t

Mid()

returns the material id

Rho()

returns the material density

Thickness()

returns the thickness of the element

classmethod _init_from_empty()

classmethod add_card(card, comment='')

Adds a PSHEAR 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

mid = None

Material ID

pid = None

Property ID

pname_fid_map = {4: 't', 'T': 't'}

raw_fields()

type = 'PSHEAR'

uncross_reference() → None

Removes cross-reference links

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.shell.PSHELL(pid: int, mid1: Optional[int] = None, t: Optional[float] = None, mid2: Optional[int] = None, twelveIt3: float = 1.0, mid3: Optional[int] = None, tst: float = 0.833333, nsm: float = 0.0, z1: Optional[float] = None, z2: Optional[float] = None, mid4: Optional[int] = None, comment: str = '')

Bases: pyNastran.bdf.cards.base_card.Property

1	2	3	4	5	6	7	8	9
PSHELL	PID	MID1	T	MID2	12I/T**3	MID3	TS/T	NSM
	Z1	Z2	MID4
PSHELL	41111	1	1.0000	1		1		0.02081

Creates a PSHELL card

Parameters

pidint

property id

mid1int; default=None

defines membrane material defines element density (unless blank)

mid2int; default=None

defines bending material defines element density if mid1=None

mid3int; default=None

defines transverse shear material (only defined if mid2 > 0)

mid4int; default=None

defines membrane-bending coupling material (only defined if mid1 > 0 and mid2 > 0; can’t be mid1/mid2)

twelveIt3float; default=1.0

Bending moment of inertia ratio, 12I/T^3. Ratio of the actual bending moment inertia of the shell, I, to the bending moment of inertia of a homogeneous shell, T^3/12. The default value is for a homogeneous shell.

nsmfloat; default=0.0

non-structural mass per unit area

z1 / z2float; default=None

fiber distance location 1/2 for stress/strain calculations z1 default : -t/2 if thickness is defined z2 default : t/2 if thickness is defined

commentstr; default=’’

a comment for the card

MassPerArea(tflag=1, tscales=None)

Calculates mass per area.

\[\]

rac{m}{A} = nsm + ho t

MassPerArea_no_xref(model, tflag=1, tscales=None)

Calculates mass per area.

\[\]

rac{m}{A} = nsm + ho t

MassPerArea_structure()

Calculates mass per area without considering non-structural mass.

\[\]

rac{m}{A} = nsm + ho t

Mid() → Optional[int]

returns the material id used for mass

Mid1() → Optional[int]

returns the extension material id

Mid2() → Optional[int]

returns the bending material id

Mid3() → Optional[int]

Mid4() → Optional[int]

Nsm() → float

returns the non-structural mass

Rho() → float

returns the material density

Thickness(tflag: int = 1, tscales=None)

returns the thickness of the element

classmethod add_card(card, comment='')

Adds a PSHELL 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

classmethod export_to_hdf5(h5_file, model, pids)

exports the properties in a vectorized way

get_ABD_matrices(theta_offset=0.0) → numpy.ndarray

Gets the ABD matrix

Parameters

theta_offsetfloat

rotates the ABD matrix; measured in degrees

get_Qbar_matrix(mid_ref, theta=0.0)

theta must be in radians

get_Sbar_matrix(mid_ref, theta=0.0)

theta must be in radians

get_individual_ABD_matrices(theta_offset: float = 0.0) → Tuple[numpy.ndarray, numpy.ndarray, numpy.ndarray]

Gets the ABD matrix

Parameters

theta_offsetfloat

rotates the ABD matrix; measured in degrees

http://www2.me.rochester.edu/courses/ME204/nx_help/index.html#uid:id503291

Understanding Classical Lamination Theory

get_z_locations() → List[float]

returns the locations of the bottom and top surface of the shell

property material_ids

returns the material ids

materials()

returns the material objects referenced by the shell

mid2 = None

Material identification number for bending -1 for plane strin

property mid_ref

returns the material used for mass

nsm = None

Non-structural Mass

pid = None

Property ID

pname_fid_map = {4: 't', 'T': 't', 6: 'twelveIt3', 8: 'tst'}

raw_fields()

repr_fields()

Gets the fields in their simplified form

Returns

fieldsList[varies]

the fields that define the card

t = None

thickness

tst = None

Transverse shear thickness ratio, . Ratio of the shear thickness, ts/t, to the membrane thickness of the shell, t. The default value is for a homogeneous shell.

twelveIt3 = None

Scales the moment of interia of the element based on the moment of interia for a plate

..math:: I = frac{12I}{t^3} I_{plate}

type = 'PSHELL'

uncross_reference() → None

Removes cross-reference links

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.shell.get_2d_plate_transform(theta: float) → numpy.ndarray

theta must be in radians

pyNastran.bdf.cards.properties.shell.map_failure_theory_int(ft: int) → Optional[str]