dynamic_loads Module

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

• AERO
• FLFACT
• FLUTTER
• GUST
• MKAERO1 / MKAERO2

All cards are BaseCard objects.

class pyNastran.bdf.cards.aero.dynamic_loads.AERO(velocity, cref, rho_ref, acsid=0, sym_xz=0, sym_xy=0, comment='')

Bases: pyNastran.bdf.cards.aero.dynamic_loads.Aero

Gives basic aerodynamic parameters for unsteady aerodynamics.

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AERO	ACSID	VELOCITY	REFC	RHOREF	SYMXZ	SYMXY
AERO	3	1.3+		1.-5	1	-1

Creates an AERO card

Parameters:

velocity : float

the airspeed

cref : float

the aerodynamic chord

rho_ref : float

FLFACT density scaling factor

acsid : int; default=0

aerodyanmic coordinate system defines the direction of the wind

sym_xz : int; default=0

xz symmetry flag (+1=symmetry; -1=antisymmetric)

sym_xy : int; default=0

xy symmetry flag (+1=symmetry; -1=antisymmetric)

comment : str; default=’‘

a comment for the card

classmethod _init_from_empty()

_properties = ['is_anti_symmetric_xy', 'is_anti_symmetric_xz', 'is_symmetric_xy', 'is_symmetric_xz']

classmethod add_card(card, comment='')

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

Parameters:

card : BDFCard()

a BDFCard object

comment : str; default=’‘

a comment for the card

cref = None

Reference length for reduced frequency

cross_reference(self, model)

Cross refernece aerodynamic coordinate system.

Parameters:

model : BDF

The BDF object.

raw_fields(self)

Gets the fields in their unmodified form

Returns:

fields : List[int/float/str]

the fields that define the card

repr_fields(self)

Gets the fields in their simplified form

Returns:

fields : List[varies]

the fields that define the card

rho_ref = None

Reference density

safe_cross_reference(self, model, xref_errors)

Safe cross refernece aerodynamic coordinate system.

Parameters:

model : BDF

The BDF object.

sym_xy = None

The symmetry key for the aero coordinate x-y plane can be used to simulate ground effect. (Integer = -1 for symmetry, 0 for no symmetry, and +1 for antisymmetry; Default = 0)

sym_xz = None

Symmetry key for the aero coordinate x-z plane. See Remark 6. (Integer = +1 for symmetry, 0 for no symmetry, and -1 for antisymmetry; Default = 0)

type = 'AERO'

uncross_reference(self)

Removes cross-reference links

update(self, maps)

maps = {

‘coord’ : cid_map,

}

validate(self)

card checking method that should be overwritten

velocity = None

Velocity for aerodynamic force data recovery and to calculate the BOV parameter

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.aero.dynamic_loads.Aero

Bases: pyNastran.bdf.cards.base_card.BaseCard

Base class for AERO and AEROS cards.

Common class for AERO, AEROS

Attributes:

acsid : int; default=0

aerodyanmic coordinate system defines the direction of the wind

sym_xz : int; default=0

xz symmetry flag (+1=symmetry; -1=antisymmetric)

sym_xy : int; default=0

xy symmetry flag (+1=symmetry; -1=antisymmetric)

Acsid(self)

is_anti_symmetric_xy

is_anti_symmetric_xz

is_symmetric_xy

is_symmetric_xz

set_ground_effect(self, enable)

class pyNastran.bdf.cards.aero.dynamic_loads.FLFACT(sid, factors, comment='')

Bases: pyNastran.bdf.cards.base_card.BaseCard

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FLFACT	SID	F1	F2	F3	F4	F5	F6	F7
	F8	F9	etc.
FLFACT	97	.3	.7	3.5

# delta quantity approach

1	2	3	4	5	6	7
FLFACT	SID	F1	THRU	FNF	NF	FMID
FLFACT	201	0.200	THRU	0.100	11	0.1333

Creates an FLFACT card, which defines factors used for flutter analysis. These factors define either:

• density
• mach
• velocity
• reduced frequency

depending on the FLUTTER method chosen (e.g., PK, PKNL, PKNLS)

Parameters:

sid : int

the id of a density, reduced_frequency, mach, or velocity table the FLUTTER card defines the meaning

factors : varies

values : List[float, …, float]

list of factors

List[f1, THRU, fnf, nf, fmid]

f1 : float

first value

THRU : str

the word THRU

fnf : float

second value

nf : int

number of values

fmid : float; default=(f1 + fnf) / 2.

the mid point to bias the array

TODO: does f1 need be be greater than f2/fnf???

comment : str; default=’‘

a comment for the card

classmethod _init_from_empty()

classmethod add_card(card, comment='')

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

Parameters:

card : BDFCard()

a BDFCard object

comment : str; default=’‘

a comment for the card

max(self)

min(self)

raw_fields(self)

Gets the fields in their unmodified form

Returns:

fields : list[varies]

the fields that define the card

type = 'FLFACT'

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.aero.dynamic_loads.FLUTTER(sid, method, density, mach, reduced_freq_velocity, imethod='L', nvalue=None, omax=None, epsilon=0.001, comment='')

Bases: pyNastran.bdf.cards.base_card.BaseCard

Defines data needed to perform flutter analysis.

1	2	3	4	5	6	7	8	9
FLUTTER	SID	METHOD	DENS	MACH	RFREQ	IMETH	NVALUE/OMAX	EPS
FLUTTER	19	K	119	219	319	S	5	1.-4

Creates a FLUTTER card, which is required for a flutter (SOL 145) analysis.

Parameters:

sid : int

flutter id

method : str

valid methods = [K, KE,

PKS, PKNLS, PKNL, PKE]

density : int

defines a series of air densities in units of mass/volume PARAM,WTMASS does not affect this AERO affects this references an FLFACT id

mach : int

defines a series of the mach numbers references an FLFACT id

reduced_freq_velocity : int

Defines a series of either:

1. reduced frequencies - K, KE
2. velocities - PK, PKNL, PKS, PKNLS

depending on the method chosen. references an FLFACT id

imethod : str; default=’L’

Choice of interpolation method for aerodynamic matrix interpolation. imethods :

1. L - linear
2. S - surface
3. TCUB - termwise cubic

nvalue : int

Number of eigenvalues beginning with the first eigenvalue for output and plots

omax : float

For the PKS and PKNLS methods, OMAX specifies the maximum frequency, in Hz., to be used in he flutter sweep. MSC only.

epsilon : float; default=1.0e-3

Convergence parameter for k. Used in the PK and PKNL methods only

comment : str; default=’‘

a comment for the card

_get_raw_nvalue_omax(self)

_get_repr_nvalue_omax(self)

classmethod _init_from_empty()

_properties = ['_field_map', 'headers']

classmethod add_card(card, comment='')

Adds a FLUTTER 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

get_density(self)

get_mach(self)

get_rfreq_vel(self)

headers

make_flfacts_alt_sweep(self, model, mach, alts, eas_limit=1000.0, alt_units='m', velocity_units='m/s', density_units='kg/m^3', eas_units='m/s')

makes an altitude sweep

make_flfacts_mach_sweep(self, model, alt, machs, eas_limit=1000.0, alt_units='m', velocity_units='m/s', density_units='kg/m^3', eas_units='m/s')

makes a mach sweep

raw_fields(self)

Gets the fields in their unmodified form

Returns:

fields : list[varies]

the fields that define the card

repr_fields(self)

Gets the fields in their simplified form

Returns:

fields : List[varies]

the fields that define the card

safe_cross_reference(self, model)

type = 'FLUTTER'

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.aero.dynamic_loads.GUST(sid, dload, wg, x0, V=None, comment='')

Bases: pyNastran.bdf.cards.base_card.BaseCard

Defines a stationary vertical gust for use in aeroelastic response analysis.

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GUST	SID	DLOAD	WG	X0	V
GUST	133	61	1.0		1.+4

Creates a GUST card, which defines a stationary vertical gust for use in aeroelastic response analysis.

Parameters:

sid : int

gust load id

dload : int

TLOADx or RLOADx entry that defines the time/frequency dependence

wg : float

Scale factor (gust velocity/forward velocity) for gust velocity

x0 : float

Streamwise location in the aerodynamic coordinate system of the gust reference point.

V : float; default=None

float : velocity of the vehicle (must be the same as the

velocity on the AERO card)

None : ???

comment : str; default=’‘

a comment for the card

classmethod _init_from_empty()

classmethod add_card(card, comment='')

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

Parameters:

card : BDFCard()

a BDFCard object

comment : str; default=’‘

a comment for the card

raw_fields(self)

Gets the fields in their unmodified form

Returns:

fields : list[varies]

the fields that define the card

type = 'GUST'

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.aero.dynamic_loads.MKAERO1(machs, reduced_freqs, comment='')

Bases: pyNastran.bdf.cards.base_card.BaseCard

Provides a table of Mach numbers (m) and reduced frequencies (k) for aerodynamic matrix calculation.

1	2	3	4	5	6	7	8	9
MKAERO1	m1	m2	m3	m4	m5	m6	m7	m8
	k1	k2	k3	k4	k5	k6	k7	k8

Creates an MKAERO1 card, which defines a set of mach and reduced frequencies.

Parameters:

machs : List[float]

series of Mach numbers

reduced_freqs : List[float]

series of reduced frequencies

comment : str; default=’‘

a comment for the card

classmethod _init_from_empty()

classmethod add_card(card, comment='')

Adds an MKAERO1 card from BDF.add_card(...)

Parameters:

card : BDFCard()

a BDFCard object

comment : str; default=’‘

a comment for the card

mklist(self)

raw_fields(self)

Gets the fields in their unmodified form

Returns:

fields : list[varies]

the fields that define the card

type = 'MKAERO1'

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.aero.dynamic_loads.MKAERO2(machs, reduced_freqs, comment='')

Bases: pyNastran.bdf.cards.base_card.BaseCard

Provides a table of Mach numbers (m) and reduced frequencies (k) for aerodynamic matrix calculation.

1	2	3	4	5	6	7	8	9
MKAERO2	m1	k1	m2	k2	m3	k3	m4	k4

Creates an MKAERO2 card, which defines a set of mach and reduced frequency pairs.

Parameters:

machs : List[float]

series of Mach numbers

reduced_freqs : List[float]

series of reduced frequencies

comment : str; default=’‘

a comment for the card

classmethod _init_from_empty()

classmethod add_card(card, comment='')

Adds an MKAERO2 card from BDF.add_card(...)

Parameters:

card : BDFCard()

a BDFCard object

comment : str; default=’‘

a comment for the card

mklist(self)

raw_fields(self)

Gets the fields in their unmodified form

Returns:

fields : list[varies]

the fields that define the card

type = 'MKAERO2'

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