Mount Limits Property File

The Mount Limits property file stores the impact parameters for mount limits. This property file is known as a General Bushing Installation file, or .gbi file.

This is the file you use to provide mount limits information to the Altair Bushing Model. Alternatively, you can specify the impact parameters in REFERENCE_ARRAYs in the solver input deck.

The .gbi file uses the TeimOrbit format organized into the following blocks:

Block Type	Description
HEADER	This is a mandatory block that provides the file type, version, and format information for use by file readers. The file type and extension for General Bushing Installation properties is .gbi.
UNITS	This is a mandatory block that provides the unit system for the parameter values used in the property file. This block enables file readers to convert the parameter values in the property file to those used in the simulation.
MOUNT_LIMITS	This block contains a parameters sub-block with twelve (12) arrays of data for the positive and negative mount parameters for each of the six (6) directions: FX, FY, FZ, TX, TY and TZ.

Note: The Header and Units block are identical in the .gbi file and .gbs file.

The following sections provide more details about blocks:

The header block contains metadata for use by file readers to identify the type, version and format of the file. This is a mandatory block. The keywords that are used in this block are:

Parameter	Type	Description
FILE_TYPE	quoted_string	The only legal value is 'gbi'
FILE_VERSION	quoted_string	The only legal value is '1'
FILE_FORMAT	quoted_string	The only legal value is 'ASCII'

The following is an example of a HEADER block:

$-----------------------------------------------------------------HEADER

[HEADER]

FILE_TYPE = 'gbi'

FILE_VERSION = '1'

FILE_FORMAT = 'ASCII'

The units block specifies the unit system used for the values in the property file. This is a mandatory block. The units must be defined for length, time, force, mass, and angle.

The table below describes the valid choices for the Units block:

Parameter

Type

Description

LENGTH

quoted_string

Valid length units are:

•

meter

•

mile

•

foot

•

inch

ANGLE

quoted_string

Valid angle units are:

•

degree

•

radian

FORCE

quoted_string

Valid force units are:

•

newton

•

kg_force

•

knewton

•	pound_force

•	kpound_force

•

dyne

•	ounce_force

MASS

quoted_string

Valid mass units are:

•

gram

•	pound_mass

•	kpound_mass

•

slug

•	ounce_mass

TIME

quoted_string

Valid time units are:

•

second

•

sec

•	millisecond

•

minute

•

hour

The following is an example of a Units block:

$--------------------------------------------------------------- UNITS

[UNITS]

LENGTH = 'mm'

ANGLE = 'degree'

FORCE = 'newton'

MASS = 'kg'

TIME = 'second'

The [MOUNT_LIMITS] block stores the parameters for mount limits. You can use commas, white spaces or tab characters to separate the data values. The solver obtains the mount limits for a model through the IMPACT function. You can specify limits in the positive and negative travel directions for all 6 directions: X, Y, Z, AX, AY and AZ. For each direction, you specify five parameters.

The following table describes the type and dimension for the input parameters. Abbreviations are [A] = angle dimension, [F] = force, [L] = length, [T] = time.

Parameter	Type	Translational Units	Rotational Units
K	Real	[F][L-1]	[F][L-1][A-1]
E	Real	-	-
CUnits	Real	[F][T][L-1]	[F][L][T][A-1]
D	Real	[L]	[A]
L	Real	[L]	[A]

Example of the Mount Limits Block

The example below shows the specification of a Mount Limits block in the .gbi file:

$----------------------------------------------------- MOUNT_LIMITS

[MOUNT_LIMITS]

$ Direction K E C D L

IMPACT_PARAMETERS_TRA_X_POS = 1000.0 1.0 0.0 1.0 1.0

IMPACT_PARAMETERS_TRA_X_NEG = 1100.0 1.1 0.0 1.0 1.0

IMPACT_PARAMETERS_TRA_Y_POS = 1200.0 1.2 0.0 1.0 1.0

IMPACT_PARAMETERS_TRA_Y_NEG = 1300.0 1.3 0.0 1.0 1.0

IMPACT_PARAMETERS_TRA_Z_POS = 1400.0 1.4 0.0 1.0 1.0

IMPACT_PARAMETERS_TRA_Z_NEG = 1500.0 1.5 0.0 1.0 1.0

IMPACT_PARAMETERS_ROT_X_POS = 20000. 1.0 0.0 1.0 1.0

IMPACT_PARAMETERS_ROT_X_NEG = 21000. 1.2 0.0 1.0 1.0

IMPACT_PARAMETERS_ROT_Y_POS = 22000. 1.3 0.0 1.0 1.0

IMPACT_PARAMETERS_ROT_Y_NEG = 23000. 1.4 0.0 1.0 1.0

IMPACT_PARAMETERS_ROT_Z_POS = 24000. 1.5 0.0 1.0 1.0

IMPACT_PARAMETERS_ROT_Z_NEG = 24000. 1.5 0.0 1.0 1.0