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

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

MassPerArea_structure(self)

Material(self, iply)

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

Parameters:

iply : int

the ply ID (starts from 0)

Mid(self, iply)

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

Parameters:

iply : int/str; default=’all’

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

Returns:

material_id : int

the material id of the ith ply

Mids(self)

Nsm(self)

Rho(self, iply)

TRef

Theta(self, iply)

Thickness(self, iply='all', tflag=1, tscales=None)

_adjust_ply_id(self, iply)

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:

iply : int

the ply ID

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(self, model)

Cross links the card so referenced cards can be extracted directly

Parameters:

model : BDF()

the BDF object

get_density(self, iply)

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

Parameters:

iply : int

the ply ID (starts from 0)

get_mass_per_area(self, iply='all', method='nplies')

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:

iply : str/int; default=’all’

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

method : str

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(self, rhos, iply='all', method='nplies')

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:

rhos : List[float]

the densities of each ply

iply : str/int; default=’all’

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

method : str

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(self, rhos)

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

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

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

Parameters:

rhos : List[float]

the densities of each ply

get_material_id(self, iply)

get_material_ids(self)

get_nonstructural_mass(self)

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

get_sout(self, iply)

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

Parameters:

iply : int

the ply ID (starts from 0)

get_theta(self, iply)

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

Parameters:

iply : int

the ply ID (starts from 0)

get_thetas(self)

get_thickness(self, iply='all')

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

Parameters:

iply : int/str; default=’all’

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

Returns:

thickness : float

the thickness of the ply or plies

get_thicknesses(self)

get_z_locations(self)

Gets the z locations for the various plies.

Parameters:

iply : int

the ply ID (starts from 0)

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

>>> pcomp.get_z_locations()

[0., 1., 2.]

is_symmetrical(self)

Is the laminate symmetrical?

Returns:

is_symmetrical : bool

is the SYM flag active?

material_ids

Gets the material IDs of all the plies

Returns:

mids : MATx

the material IDs

nplies

Gets the number of plies including the core.

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

sout(self, iply)

uncross_reference(self)

Removes cross-reference links

class pyNastran.bdf.cards.properties.shell.PCOMP(pid, mids, thicknesses, thetas=None, souts=None, nsm=0.0, sb=0.0, ft=None, tref=0.0, ge=0.0, lam=None, z0=None, comment='')

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

pid : int

property id

mids : List[int, …, int]

material ids for each ply

thicknesses : List[float, …, float]

thicknesses for each ply

thetas : List[float, …, float]; default=None

ply angle None : [0.] * nplies

souts : List[str, …, str]; default=None

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

nsm : float; default=0.

nonstructural mass per unit area

sb : float; default=0.

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

ft : str; default=None

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

tref : float; default=0.

reference temperature

ge : float; default=0.

structural damping

lam : str; default=None

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

z0 : float; default=None

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

comment : str; default=’‘

a comment for the card

classmethod _init_from_empty()

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

classmethod add_card(card, comment='')

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

Parameters:

card : BDFCard()

a BDFCard object

comment : str; default=’‘

a comment for the card

ft = None

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

get_ABD_matrices(self, theta_offset=0.0)

Gets the ABD matrix

Parameters:

theta_offset : float

rotates the ABD matrix; measured in degrees

get_Qbar_matrix(self, mid_ref, theta)

theta must be in radians

get_Sbar_matrix(self, mid_ref, theta)

theta must be in radians

get_z0_z1_zmean(self)

lam = None

symmetric flag - default = No Symmetry (=None)

nsm = None

Non-Structural Mass per unit Area

pid = None

Property ID

plies

raw_fields(self)

repr_fields(self)

Gets the fields in their simplified form

Returns:

fields : List[varies]

the fields that define the card

tref = None

Reference Temperature (default=0.0)

type = 'PCOMP'

update_by_pname_fid(self, pname_fid, value)

validate(self)

card checking method that should be overwritten

write_card(self, size=8, is_double=False)

Writes the card with the specified width and precision

Parameters:

size : int (default=8)

size of the field; {8, 16}

is_double : bool (default=False)

is this card double precision

Returns:

msg : str

the string representation of the card

class pyNastran.bdf.cards.properties.shell.PCOMPG(pid, global_ply_ids, mids, thicknesses, thetas=None, souts=None, nsm=0.0, sb=0.0, ft=None, tref=0.0, ge=0.0, lam=None, z0=None, comment='')

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:

pid : int

property id

global_ply_ids : List[int]

the ply id

mids : List[int, …, int]

material ids for each ply

thicknesses : List[float, …, float]

thicknesses for each ply

thetas : List[float, …, float]; default=None

ply angle None : [0.] * nplies

souts : List[str, …, str]; default=None

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

nsm : float; default=0.

nonstructural mass per unit area

sb : float; default=0.

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

ft : str; default=None

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

tref : float; default=0.

reference temperature

ge : float; default=0.

structural damping

lam : str; default=None

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

z0 : float; default=None

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

comment : str; default=’‘

a comment for the card

GlobalPlyID(self, iply)

returns the global ply id for the specified layer

classmethod _init_from_empty()

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

classmethod add_card(card, comment='')

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

Parameters:

card : BDFCard()

a BDFCard object

comment : str; default=’‘

a comment for the card

ft = None

Failure Theory

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

lam = None

symmetric flag - default = No Symmetry (NO)

nsm = None

Non-Structural Mass per unit Area

pid = None

Property ID

plies

pname_fid_map = {}

raw_fields(self)

repr_fields(self)

Gets the fields in their simplified form

Returns:

fields : List[varies]

the fields that define the card

tref = None

Reference Temperature (default=0.0)

type = 'PCOMPG'

update_by_pname_fid(self, pname_fid, value)

validate(self)

card checking method that should be overwritten

write_card(self, size=8, is_double=False)

Writes the card with the specified width and precision

Parameters:

size : int (default=8)

size of the field; {8, 16}

is_double : bool (default=False)

is this card double precision

Returns:

msg : str

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:

pid : int

property id

mid : int

material id; MATHP / MATHE

cid : int; default=0

???

stress_strain_output_location : str; default=’GRID’

???

comment : str; default=’‘

a comment for the card

Cid(self)

Mid(self)

returns the material id

classmethod _init_from_empty()

classmethod add_card(card, comment='')

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

Parameters:

card : BDFCard()

a BDFCard object

comment : str; default=’‘

a comment for the card

cross_reference(self, model)

Cross links the card so referenced cards can be extracted directly

Parameters:

model : BDF()

the BDF object

pid = None

Property ID

raw_fields(self)

repr_fields(self)

Gets the fields in their simplified form

Returns:

fields : List[varies]

the fields that define the card

type = 'PLPLANE'

uncross_reference(self)

Removes cross-reference links

write_card(self, size=8, is_double=False)

Writes the card with the specified width and precision

Parameters:

size : int (default=8)

size of the field; {8, 16}

is_double : bool (default=False)

is this card double precision

Returns:

msg : str

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(self, tflag=1, tscales=None)

Calculates mass per area.

\[\]

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

Mid(self)

returns the material id

Thickness(self)

returns the thickness of the element

classmethod _init_from_empty()

classmethod add_card(card, comment='')

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

Parameters:

card : BDFCard()

a BDFCard object

comment : str; default=’‘

a comment for the card

cross_reference(self, model)

Cross links the card so referenced cards can be extracted directly

Parameters:

model : BDF()

the BDF object

pid = None

Property ID

raw_fields(self)

repr_fields(self)

Gets the fields in their simplified form

Returns:

fields : List[varies]

the fields that define the card

type = 'PPLANE'

uncross_reference(self)

Removes cross-reference links

write_card(self, size=8, is_double=False)

Writes the card with the specified width and precision

Parameters:

size : int (default=8)

size of the field; {8, 16}

is_double : bool (default=False)

is this card double precision

Returns:

msg : str

the string representation of the card

class pyNastran.bdf.cards.properties.shell.PSHEAR(pid, mid, t, nsm=0.0, f1=0.0, f2=0.0, comment='')

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:

pid : int

property id

mid : int

material id

t : float

shear panel thickness

nsm : float; default=0.

nonstructural mass per unit length

f1 : float; default=0.0

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

f2 : float; default=0.0

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

comment : str; default=’‘

a comment for the card

MassPerArea(self, tflag=1, tscales=None)

Calculates mass per area.

\[\]

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

Mid(self)

returns the material id

Rho(self)

returns the material density

Thickness(self)

returns the thickness of the element

classmethod _init_from_empty()

classmethod add_card(card, comment='')

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

Parameters:

card : BDFCard()

a BDFCard object

comment : str; default=’‘

a comment for the card

cross_reference(self, model)

Cross links the card so referenced cards can be extracted directly

Parameters:

model : BDF()

the BDF object

mid = None

Material ID

pid = None

Property ID

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

raw_fields(self)

type = 'PSHEAR'

uncross_reference(self)

Removes cross-reference links

write_card(self, size=8, is_double=False)

Writes the card with the specified width and precision

Parameters:

size : int (default=8)

size of the field; {8, 16}

is_double : bool (default=False)

is this card double precision

Returns:

msg : str

the string representation of the card

class pyNastran.bdf.cards.properties.shell.PSHELL(pid, mid1=None, t=None, mid2=None, twelveIt3=1.0, mid3=None, tst=0.833333, nsm=0.0, z1=None, z2=None, mid4=None, comment='')

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:

pid : int

property id

mid1 : int; default=None

defines membrane material defines element density (unless blank)

mid2 : int; default=None

defines bending material defines element density if mid1=None

mid3 : int; default=None

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

mid4 : int; default=None

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

twelveIt3 : float; 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.

nsm : float; default=0.0

non-structural mass per unit area

z1 / z2 : float; 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

comment : str; default=’‘

a comment for the card

MassPerArea(self, tflag=1, tscales=None)

Calculates mass per area.

\[\]

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

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

Calculates mass per area.

\[\]

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

MassPerArea_structure(self)

Calculates mass per area without considering non-structural mass.

\[\]

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

Mid(self)

returns the material id used for mass

Mid1(self)

returns the extension material id

Mid2(self)

returns the bending material id

Mid3(self)

Mid4(self)

Nsm(self)

returns the non-structural mass

Rho(self)

returns the material density

Thickness(self, tflag=1, tscales=None)

returns the thickness of the element

classmethod add_card(card, comment='')

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

Parameters:

card : BDFCard()

a BDFCard object

comment : str; default=’‘

a comment for the card

cross_reference(self, model)

Cross links the card so referenced cards can be extracted directly

Parameters:

model : BDF()

the BDF object

classmethod export_to_hdf5(h5_file, model, pids)

exports the properties in a vectorized way

get_ABD_matrices(self, theta_offset=0.0)

Gets the ABD matrix

Parameters:

theta_offset : float

rotates the ABD matrix; measured in degrees

get_Qbar_matrix(self, mid_ref, theta=0.0)

theta must be in radians

get_Sbar_matrix(self, mid_ref, theta=0.0)

theta must be in radians

get_z_locations(self)

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

material_ids

returns the material ids

materials(self)

returns the material objects referenced by the shell

mid2 = None

Material identification number for bending -1 for plane strin

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(self)

repr_fields(self)

Gets the fields in their simplified form

Returns:

fields : List[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(self)

Removes cross-reference links

write_card(self, size=8, is_double=False)

Writes the card with the specified width and precision

Parameters:

size : int (default=8)

size of the field; {8, 16}

is_double : bool (default=False)

is this card double precision

Returns:

msg : str

the string representation of the card

pyNastran.bdf.cards.properties.shell.get_2d_plate_transform(theta)

theta must be in radians