springs Module

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

• PELAS

• PELAST

All spring properties are SpringProperty and Property objects.

class pyNastran.bdf.cards.properties.springs.PELAS(pid, k, ge=0.0, s=0.0, comment='')

Bases: pyNastran.bdf.cards.properties.springs.SpringProperty

Specifies the stiffness, damping coefficient, and stress coefficient of a scalar elastic (spring) element (CELAS1 or CELAS3 entry).

Creates a PELAS card

Parameters

pidint

property id

kfloat

spring stiffness

geint; default=0.0

damping coefficient

sfloat; default=0.0

stress coefficient

commentstr; default=’’

a comment for the card

K()

classmethod _init_from_empty()

classmethod add_card(card, icard=0, comment='')

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

Parameters

cardBDFCard()

a BDFCard object

icardint; default=0

the index of the PELAS card that’s being parsed must be 0 or 1

commentstr; default=’’

a comment for the card

cross_reference(model: BDF) → None

ge = None

Damping coefficient, . See Remarks 5. and 6. (Real) To obtain the damping coefficient GE, multiply the critical damping ratio c/c0 by 2.0.

k = None

Ki Elastic property value. (Real)

pid = None

Property identification number. (Integer > 0)

pname_fid_map = {'GE1': 'ge', 'K1': 'k'}

raw_fields()

repr_fields()

Gets the fields in their simplified form

Returns

fieldsList[varies]

the fields that define the card

s = None

Stress coefficient. (Real)

type = 'PELAS'

uncross_reference() → None

Removes cross-reference links

class pyNastran.bdf.cards.properties.springs.PELAST(pid, tkid=0, tgeid=0, tknid=0, comment='')

Bases: pyNastran.bdf.cards.properties.springs.SpringProperty

Frequency Dependent Elastic Property Defines the frequency dependent properties for a PELAS Bulk Data entry.

The PELAST entry is ignored in all solution sequences except frequency response (108) or nonlinear analyses (129).

Creates a PELAST card

Parameters

pidint

property id

tkidfloat

TABLEDx that defines k vs. frequency

tgeidint; default=0

TABLEDx that defines ge vs. frequency

sfloat; default=0.

TABLEDx that defines force vs. displacement

commentstr; default=’’

a comment for the card

Pid()

returns the property ID of an property

Returns

pidint

the Property ID

Tgeid()

Returns the table ID for nondimensional structural damping coefficient vs. frequency (c/c0 vs freq)

Tkid()

Returns the table ID for force per unit displacement vs frequency (k=F/d vs freq)

Tknid()

Returns the table ID for nondimensional force vs. displacement

classmethod _init_from_empty()

classmethod add_card(card, comment='')

Adds a PELAST 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 identification number. (Integer > 0)

pname_fid_map = {'TKID': 'tknid'}

raw_fields()

tgeid = None

Identification number of a TABLEDi entry that defines the nondimensional structural damping coefficient vs. frequency relationship. (Integer > 0; Default = 0)

tkid = None

Identification number of a TABLEDi entry that defines the force per unit displacement vs. frequency relationship. (Integer > 0; Default = 0)

tknid = None

Identification number of a TABELDi entry that defines the nonlinear force vs. displacement relationship. (Integer > 0; Default = 0)

type = 'PELAST'

uncross_reference(model)

class pyNastran.bdf.cards.properties.springs.SpringProperty

Bases: pyNastran.bdf.cards.base_card.Property

dummy init

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