constraints Module

All constraint cards are defined in this file. This includes:

• Constraint

• SUPORT
• SUPORT1
• SPC
• SPC1
• SPCAX
• MPC
• GMSPC
• ConstraintADD

• SPCADD
• MPCADD

The ConstraintObject contain multiple constraints.

class pyNastran.bdf.cards.constraints.Constraint

Bases: pyNastran.bdf.cards.base_card.BaseCard

common class for:

• SUPORT / SUPORT1 / SESUP
• GMSPC
• MPC
• SPC / SPC1
• SPCAX
• SPCOFF / SPCOFF1

class pyNastran.bdf.cards.constraints.ConstraintAdd

Bases: pyNastran.bdf.cards.constraints.Constraint

common class for SPCADD, MPCADD

class pyNastran.bdf.cards.constraints.GMSPC(conid, component, entity, entity_id, comment='')

Bases: pyNastran.bdf.cards.constraints.Constraint

classmethod _init_from_empty()

classmethod add_card(card, comment='')

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

Parameters:

card : BDFCard()

a BDFCard object

comment : str; default=’‘

a comment for the card

cross_reference(self, model)

TODO: xref

raw_fields(self)

safe_cross_reference(self, model)

TODO: xref

type = 'GMSPC'

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.constraints.MPC(conid, nodes, components, coefficients, comment='')

Bases: pyNastran.bdf.cards.constraints.Constraint

Multipoint Constraint Defines a multipoint constraint equation of the form:

sum(A_j * u_j) = 0

where:

uj represents degree-of-freedom Cj at grid or scalar point Gj. Aj represents the scale factor

1	2	3	4	5	6	7	8	9
MPC	SID	G1	C1	A1	G2	C2	A2
	G3	C3	A3	…

Creates an MPC card

Parameters:

conid : int

Case Control MPC id

nodes : List[int]

GRID/SPOINT ids

components : List[str]

the degree of freedoms to constrain (e.g., ‘1’, ‘123’)

coefficients : List[float]

the scaling coefficients

classmethod _init_from_empty()

_properties = ['node_ids']

classmethod add_card(card, comment='')

Adds an MPC card from BDF.add_card(...)

Parameters:

card : BDFCard()

a BDFCard object

comment : str; default=’‘

a comment for the card

coefficients = None

Coefficient. (Real; Default = 0.0 except A1 must be nonzero.)

components = None

Component number. (Any one of the Integers 1 through 6 for grid points; blank or zero for scalar points.)

conid = None

Set identification number. (Integer > 0)

constraints

cross_reference(self, model)

Cross links the card so referenced cards can be extracted directly

Parameters:

model : BDF()

the BDF object

enforced

gids

gids_ref

node_ids

nodes = None

Identification number of grid or scalar point. (Integer > 0)

object_attributes(self, mode='public', keys_to_skip=None, filter_properties=False)

See also

pyNastran.utils.object_attributes(…)

object_methods(self, mode='public', keys_to_skip=None)

See also

pyNastran.utils.object_methods(…)

raw_fields(self)

safe_cross_reference(self, model, debug=True)

type = 'MPC'

uncross_reference(self)

Removes cross-reference links

validate(self)

card checking method that should be overwritten

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

see BaseCard.write_card``

write_card_16(self, is_double=False)

write_card_8(self)

class pyNastran.bdf.cards.constraints.MPCADD(conid, sets, comment='')

Bases: pyNastran.bdf.cards.constraints.ConstraintAdd

Defines a multipoint constraint equation of the form \(\Sigma_j A_j u_j =0\) where \(u_j\) represents degree-of-freedom \(C_j\) at grid or scalar point \(G_j\).

1	2	3	4
MPCADD	2	1	3

classmethod _init_from_empty()

_properties = ['ids', 'mpc_ids']

classmethod add_card(card, comment='')

Adds a MPCADD 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

ids

mpc_ids

raw_fields(self)

safe_cross_reference(self, model, debug=True)

type = 'MPCADD'

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

write_card_16(self, is_double=False)

class pyNastran.bdf.cards.constraints.SESUP(nodes, Cs, comment='')

Bases: pyNastran.bdf.cards.constraints.SUPORT

classmethod _init_from_empty()

type = 'SESUP'

class pyNastran.bdf.cards.constraints.SPC(conid, nodes, components, enforced, comment='')

Bases: pyNastran.bdf.cards.constraints.Constraint

Defines enforced displacement/temperature (static analysis) velocity/acceleration (dynamic analysis).

1	2	3	4	5	6	7	8
SPC	SID	G1	C1	D1	G2	C2	D2
SPC	2	32	3	-2.6	5

Creates an SPC card, which defines the degree of freedoms to be constrained

Parameters:

conid : int

constraint id

nodes : List[int]

GRID/SPOINT ids

components : List[str]

the degree of freedoms to constrain (e.g., ‘1’, ‘123’)

enforced : List[float]

the constrained value for the given node (typically 0.0)

comment : str; default=’‘

a comment for the card

.. note:: len(nodes) == len(components) == len(enforced)

.. warning:: non-zero enforced deflection requires an SPCD as well

classmethod _init_from_empty()

_properties = ['node_ids', 'constraints', 'gids_ref', 'gids']

classmethod add_card(card, comment='')

Adds an SPC card from BDF.add_card(...)

Parameters:

card : BDFCard()

a BDFCard object

comment : str; default=’‘

a comment for the card

constraints

cross_reference(self, model)

Cross links the card so referenced cards can be extracted directly

Parameters:

model : BDF()

the BDF object

gids

gids_ref

node_ids

object_attributes(self, mode='public', keys_to_skip=None, filter_properties=False)

See also

pyNastran.utils.object_attributes(…)

object_methods(self, mode='public', keys_to_skip=None)

See also

pyNastran.utils.object_methods(…)

raw_fields(self)

safe_cross_reference(self, model, debug=True)

type = 'SPC'

uncross_reference(self)

Removes cross-reference links

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.constraints.SPC1(conid, components, nodes, comment='')

Bases: pyNastran.bdf.cards.constraints.Constraint

1	2	3	4	5	6	7	8	9
SPC1	SID	C	G1	G2	G3	G4	G5	G6
	G7	G8	G9	etc.
SPC1	3	246	209075	209096	209512	209513	209516
SPC1	3	2	1	3	10	9	6	5
	2	8
SPC1	SID	C	G1	THRU	G2
SPC1	313	12456	6	THRU	32

Creates an SPC1 card, which defines the degree of freedoms to be constrained to a value of 0.0

Parameters:

conid : int

constraint id

components : str

the degree of freedoms to constrain (e.g., ‘1’, ‘123’)

nodes : List[int]

GRID/SPOINT ids

comment : str; default=’‘

a comment for the card

classmethod _init_from_empty()

_properties = ['node_ids']

classmethod add_card(card, comment='')

Adds a SPC1 card from BDF.add_card(...)

Parameters:

card : BDFCard()

a BDFCard object

comment : str; default=’‘

a comment for the card

constraints

cross_reference(self, model)

Cross links the card so referenced cards can be extracted directly

Parameters:

model : BDF()

the BDF object

node_ids

raw_fields(self)

safe_cross_reference(self, model, debug=True)

type = 'SPC1'

uncross_reference(self)

Removes cross-reference links

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.constraints.SPCADD(conid, sets, comment='')

Bases: pyNastran.bdf.cards.constraints.ConstraintAdd

Defines a single-point constraint set as a union of single-point constraint sets defined on SPC or SPC1 entries.

1	2	3	4
SPCADD	2	1	3

classmethod _init_from_empty()

_properties = ['ids', 'spc_ids']

classmethod add_card(card, comment='')

Adds a SPCADD 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

ids

raw_fields(self)

safe_cross_reference(self, model, debug=True)

spc_ids

type = 'SPCADD'

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

write_card_16(self, is_double=False)

class pyNastran.bdf.cards.constraints.SPCAX(conid, ringax, hid, component, enforced, comment='')

Bases: pyNastran.bdf.cards.constraints.Constraint

Defines a set of single-point constraints or enforced displacements for conical shell coordinates.

1	2	3	4	5	6
SPCAX	SID	RID	HID	C	D
SPCAX	2	3	4	13	6.0

Creates an SPCAX card

Parameters:

conid : int

Identification number of a single-point constraint set.

ringax : int

Ring identification number. See RINGAX entry.

hid : int

Harmonic identification number. (Integer >= 0)

component : int

Component identification number. (Any unique combination of the Integers 1 through 6.)

enforced : float

Enforced displacement value

classmethod _init_from_empty()

classmethod add_card(card, comment='')

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

Parameters:

card : BDFCard()

a BDFCard object

comment : str; default=’‘

a comment for the card

component = None

Component identification number. (Any unique combination of the Integers 1 through 6.)

conid = None

Identification number of a single-point constraint set.

cross_reference(self, model)

enforced = None

Enforced displacement value

hid = None

Harmonic identification number. (Integer >= 0)

raw_fields(self)

ringax = None

Ring identification number. See RINGAX entry.

safe_cross_reference(self, model)

type = 'SPCAX'

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.constraints.SPCOFF(nodes, components, comment='')

Bases: pyNastran.bdf.cards.constraints.Constraint

1	2	3	4	5	6	7	8	9
SPC	G1	C1	G2	C2	G3	C3	G4	C4
SPC	32	3	5

classmethod _init_from_empty()

classmethod add_card(card, comment='')

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

Parameters:

card : BDFCard()

a BDFCard object

comment : str; default=’‘

a comment for the card

constraints

cross_reference(self, model)

Cross links the card so referenced cards can be extracted directly

Parameters:

model : BDF()

the BDF object

node_ids

raw_fields(self)

safe_cross_reference(self, model, debug=True)

type = 'SPCOFF'

uncross_reference(self)

Removes cross-reference links

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.constraints.SPCOFF1(components, nodes, comment='')

Bases: pyNastran.bdf.cards.constraints.Constraint

classmethod _init_from_empty()

classmethod add_card(card, comment='')

Adds a SPCOFF1 card from BDF.add_card(...)

Parameters:

card : BDFCard()

a BDFCard object

comment : str; default=’‘

a comment for the card

constraints

cross_reference(self, model)

Cross links the card so referenced cards can be extracted directly

Parameters:

model : BDF()

the BDF object

node_ids

raw_fields(self)

safe_cross_reference(self, model, debug=True)

type = 'SPCOFF1'

uncross_reference(self)

Removes cross-reference links

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

write_card_16(self, is_double=False)

class pyNastran.bdf.cards.constraints.SUPORT(nodes, Cs, comment='')

Bases: pyNastran.bdf.cards.constraints.Constraint

Defines determinate reaction degrees-of-freedom in a free body.

1	2	3	4	5	6	7	8	9
SUPORT	ID1	C1	ID2	C2	ID3	C3	ID4	C4

Creates a SUPORT card, which defines free-body reaction points. This is always active.

Parameters:

nodes : List[int]

the nodes to release

Cs : List[str]

compoents to support at each node

comment : str; default=’‘

a comment for the card

classmethod _init_from_empty()

_properties = ['node_ids']

classmethod add_card(card, comment='')

Adds a SUPORT 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

node_ids

raw_fields(self)

safe_cross_reference(self, model, debug=True)

type = 'SUPORT'

uncross_reference(self)

Removes cross-reference links

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.constraints.SUPORT1(conid, nodes, Cs, comment='')

Bases: pyNastran.bdf.cards.constraints.Constraint

Defines determinate reaction degrees-of-freedom (r-set) in a free body-analysis. SUPORT1 must be requested by the SUPORT1 Case Control command.

1	2	3	4	5	6	7	8
SUPORT1	SID	ID1	C1	ID2	C2	ID3	C3
SUPORT1	1	2	23	4	15	5	0

Creates a SUPORT card, which defines free-body reaction points.

Parameters:

conid : int

Case Control SUPORT id

nodes : List[int]

the nodes to release

Cs : List[str]

compoents to support at each node

comment : str; default=’‘

a comment for the card

classmethod _init_from_empty()

_properties = ['node_ids']

classmethod add_card(card, comment='')

Adds a SUPORT1 card from BDF.add_card(...)

Parameters:

card : BDFCard()

a BDFCard object

comment : str; default=’‘

a comment for the card

add_suport1_to_set(self, suport1)

cross_reference(self, model)

Cross links the card so referenced cards can be extracted directly

Parameters:

model : BDF()

the BDF object

node_ids

raw_fields(self)

safe_cross_reference(self, model, debug=True)

type = 'SUPORT1'

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