Supported Solvers

You can use the Altair Bushing Model with a variety of solvers including:

•	MotionSolve™

•

MATLAB™

•

Adams™

•

SIMPACK™

The table below describes the modeling elements that MotionSolve and Adams use. These elements provide equivalent functionality with the Altair Bushing Model.

Purpose	MotionSolve Element	Adams Element	Description
Apply bushing forces	FORCE_VECTOR_TWOBODY	GFORCE	Applies bushing forces and moments to the I-Body and J-Body.
Compute bushing forces	CONTROL_STATEEQN	GSE	Computes bushing forces and moments and the time derivatives of states associated with the bushing forces and moments.
Compute mount displacement and velocities	CONTROL_STATEEQN	GSE	Computes the local structural deflection and rate of change of deflection given the sum of the friction, bushing, and limit forces and moments acting between the two connecting bodies.
Compute bushing limit forces	CONTROL_STATEEQN	GSE	Computes the forces and moments due to bushing reaching the limits of its travel. This may include material contact between the connecting bodies
Compute external friction effects	CONTROL_STATEEQN	GSE	Computes the friction torque that acts in response to the relative rotational motion between the two connecting bodies.
Coordinate system	REFERENCE_MARKER	Marker	Defines a coordinate system on a body. In this context it defines the location where the forces are applied and the axes along which moments are computed.
Variable	REFERENCE_VARIABLE	Variable	Defines an algebraic state and its underlying expression. In this context they define the signals that are eventually provided as input to a GSE.
Array	REFERENCE_ARRAY	Array	A collector that collects several signals and provides them as input to a GSE.

Workflow of Solver Components

Below is an illustration of the various solver components and the data flow between them. Following the illustration are the required statements for a bushing model along with an example of a simple model:

displacement_force_signals

GFORCE Bushing

A GFORCE applies the forces and torques computed by the simulation model to parts in the MotionSolve model. The form of the GFORCE is:

! Frequency & Amplitude Dependent Bushing

GFORCE/id

, I= id-marker-I-Body,

, JFLOAT= id-floating-marker-J-body,

, RM= id-marker-J-body

, FX= ARYVAL(id-array-y-gse-bus,1) \ !FX

, FY= ARYVAL(id-array-y-gse-bus,2) \ !FY

, FZ= ARYVAL(id-array-y-gse-bus,3) \ !FZ

, TX= ARYVAL(id-array-y-gse-bus,4) \ !TX

, TY= ARYVAL(id-array-y-gse-bus,5) \ !TY

, TZ= ARYVAL(id-array-y-gse-bus,6) \ !TZ

GFORCE Attributes

The following table describes the attributes of the GFORCE:

Integer Identifier	Description
id	Integer identifying the GFORCE statement.
id-marker-i-body	ID of Marker on I-Body to which the GFORCE applies force and torque.
id-floating-marker-j-bodyUnits	ID of floating Marker on J-Body to which GFORCE applies reaction forces and torques.
id-marker-j-body	ID of Marker on J-Body used as the coordinate system for all calculations. This Marker is also used when calculating the input displacements and velocities for the simulation model.
id-array-y-gse-bus	ID of the bushing GSE Y (output) array containing the forces and torques computed by the simulation model.

GSE Bushing Force and Mount Limits

This GSE computes the output forces and torques and the derivatives of the internal states associated with the RUBBER_DAMPING or HYDROMOUNT_DAMPING formulations. The required computations are performed in the use-subroutine GSESUB_BW that is located in the .dll file or shared library file.

The example below shows the specification for a RUBBER_DAMPING formulation for all directions:

•	The number of outputs (NO) is six (6) for three forces: FX, FY, FZ; and three torques: TX, TY, TZ.

•	The number of states (NS) is eighteen (18) for 6 directions, 3 states per direction.

Example of a GSE Statement

The following is an example of the form of the GSE statement in MotionSolve:

! Rubber Damping Formulation

GSE/id

, NS = 18

, NO = 6

, U = id-array-u-gse-bus

, X = id-array-x-gse-bus

, Y = id-array-y-gse-bus

, FUNCTION = USER(

, id-str-gbs-file,

, id-array-preload,

, id-array-offset,

, id-array-scale-displacement,

, id-array-scale-force,

, id-str-doe-file,

, id-array-mount-limits ) \

, ROUTINE = AltairBushingMotionSolve::GSESUB_BW,

, AltairBushingMotionSolve::GSEXX_BW, AltairBushingMotionSolve::GSEXU_BW

, AltairBushingMotionSolve::GSEYX_BW, AltairBushingMotionSolve::GSEYU_BW

Attributes of the GSE File

The following table lists the attributes of the .gse file:

Integer Identifier

Description

id

Integer identifying the GSE statement.

id-array-u-gse-bus

ID of the ARRAY statement that provides input to this GSE. It contains a list of 12 VARIABLE ids that actually compute the required signals.

Example: ARRAY/9, U, VARIABLES= 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12

Let the I Marker for the GFORCE be 1125.

Let the RM Marker for the GFORCE be 2125.

Then the 12 VARIABLES, 1-12, must have the following form:

VARIABLE/1, FUNCTION	= DX(1125, 2125, 2125)
VARIABLE/2, FUNCTION	= DY(1125, 2125, 2125)
VARIABLE/3, FUNCTION	= DZ(1125, 2125, 2125)
VARIABLE/4, FUNCTION	= VX(1125, 2125, 2125, 2125)
VARIABLE/6, FUNCTION	= VZ(1125, 2125, 2125, 2125)
VARIABLE/7, FUNCTION	= AX(1125, 2125)
VARIABLE/8, FUNCTION	= AY(1125, 2125)
VARIABLE/9, FUNCTION	= AZ(1125, 2125)
VARIABLE/10, FUNCTION	= WX(1125, 2125, 2125)
VARIABLE/11, FUNCTION	= WY(1125, 2125, 2125)
VARIABLE/12, FUNCTION	= WZ(1125, 2125, 2125)

id-array-x-gse-bus

ID of the ARRAY statement holding the GSE states.

Example: ARRAY/10, X

id-array-y-gse-bus

ID of the ARRAY statement holding the GSE outputs.

Example: ARRAY/11, Y

The GSE has the following 6 outputs:

•	Force acting at I Marker origin along the x-axis of the J Marker

•	Force acting at I Marker origin along the y-axis of the J Marker

•	Force acting at I Marker origin along the z-axis of the J Marker

•	Torque on I Marker measured about the x-axis of the J Marker

•	Torque on I Marker measured about the y-axis of the J Marker

•	Torque on I Marker measured about the z-axis of the J Marker

id-str-gbs-file

ID of the STRING statement that contains the name of the .gbs property file. The GSE reads this file to obtain all required data.

Example: STRING/12, S=/usr/people/mark/propertyFile/sample.gbs

id-array-preload

ID of the ARRAY statement containing preloads for the 3 force and 3 torque directions.

Example: ARRAY/13, NUM=100, 200, 300, 700, 800, -900

If id-array-preload is less than or equal to zero, then the preload default is zero.

id-array-offset

ID of the ARRAY statement containing the 3 translational and 3 rotational displacement offsets.

Example: ARRAY/14, NUM=0.0, 0.0, 1.3, -25D, 10D, 15D

If id-array-offset is less than or equal to zero, the offsets default to 0.0.

id-array-scale-displacement

ID of the ARRAY statement containing the 3 translational and 3 rotational displacement scales.

Example: ARRAY/15, NUM=1.0, 1.0, 1.0, 57.29578, 57.29578, 57.29578\

If id-array-scale-displacement is less than or equal to zero, then the scales default to 1.0.

id-array-scale-force

ID of the ARRAY statement containing the 3 force and 3 torque scales.

Example: ARRAY/16, NUM=9.81, 9.81, 9.81, 1.0, 1.0, 1.0

If id-array-scale-force is less than or equal to zero (0), then the force scales default to 1.0.

id-str-doe-file

ID of the STRING statement with the path name of a file containing variations of parameters in the .gbs property file. The parameter values in the doe file override those in the .gbs property file.

id-str-lim-file

If the id is positive then the software interprets the ID as the id of the STRING statement containing the path and name of a file containing impact parameters for mount limits.

Example: STRING/18, S= C:\mark\property Files\sample.gbi

-or-

id-array-mount-limits

If the id is negative then the absolute value is interpreted as the id of an ARRAY statement containing the ids of 6 other ARRAY statements containing the impact parameters for 3 translational and 3 rotational directions.

Example: ARRAY/19,NUM = 101, 102, 103, 104, 105, 106

The array contains a list of 6 ARRAY ids. Each of these ARRAY’s contains 10 parameters.

Each of these referenced ARRAY's has the following form:

ARRAY/id, NUM = KN, EN, CN, DN, LN, KP, EP, CP, DP, LP

The 10 parameters have the following meaning:

•	KN : Stiffness Negative

•	EN : Exponent Negative (left)

•	CN : Damping Negative

•	DN : Penetration for full damping Negative

•	LN : Gap Negative (left)

•	KP : Stiffness Positive

•	EP : Exponent Positive (right)

•	CP : Damping Positive

•	DP : Penetration for full damping Positive

•	LP : Gap Positive (right)

Note: If the ID is zero or omitted, then mount limits are inactive.

GSE Mount Stiffness

The mount GSE computes the combined local structural deflection and rate-of-change-of-deflection of I-Body and J-Body due to the forces and moments across the bushing. The input to the mount GSE is the sum of the forces and moments due to the bushing, friction, and limits acting between the I-Body and J-Body that the bushing connects.

Example of Mount Stiffness

The following is an example of the form of the mount CONTROL_STATEEQN:

GSE/id-gse-mou

, NS = 6

, NO = 6

, U = id-array-u-gse-mou

, X = id-array-x-gse-mou

, Y = id-array-y-gse-mou

, FUNCTION = USER(id-array-mou-k, id-array-mou-c, id-array-mou-act)\

, ROUTINE = boucwen_gse::GSESUB_MOUNT,

, boucwen_gse::GSEXX_MOUNT

, boucwen_gse::GSEXU_MOUNT

, boucwen_gse::GSEYX_MOUNT

, boucwen_gse::GSEYU_MOUNT

The attributes of the mount GSE are described below:

Integer Identifier

Description

id-gse-mou

Integer identifying the GSE statement.

id-array-u-gse-mou

ID of the ARRAY statement that provides input to this GSE. The U ARRAY holds the identifiers of VARIABLEs statements whose values are the forces.

Example: ARRAY/51, U, VARIABLES= 51, 52, 53, 54, 55, 56

Let the I Marker for the GFORCE be 1125.

Let the J-FLOAT Marker for the GFORCE be 2124.

Let the RM Marker for the GFORCE be 2125.

Then the 6 VARIABLES, 51-56, must have the following form:

•	VARIABLE/51, FUNCTION = FX(1125, 2124, 2125)

•	VARIABLE/52, FUNCTION = FY(1125, 2124, 2125)

•	VARIABLE/53, FUNCTION = FZ(1125, 2124, 2125)

•	VARIABLE/54, FUNCTION = TX(1125, 2124, 2125)

•	VARIABLE/55, FUNCTION = TY(1125, 2124, 2125)

•	VARIABLE/56, FUNCTION = TZ(1125, 2124, 2125)

id-array-x-gse-mou

ID of the ARRAY statement containing the internal states for this GSE.

Example: ARRAY/52, X

id-array-y-gse-mou

ID of the ARRAY statement that provides the GSE outputs . The outputs are the 6 components combined I-Body and J-Body structural deflections and the 6 components of the structural velocities.

Example: ARRAY/53, Y

The contents of the Y ARRAY are:

•	Combined l- & J-Body structural deflection along XJ

•	Combined l- & J-Body structural deflection along YJ

•	Combined l- & J-Body structural deflection along ZJ

•	Combined l- & J-Body rotational structural deflection about XJ

•	Combined l- & J-Body rotational structural deflection about YJ

•	Combined l- & J-Body rotational structural deflection about ZJ

•	X-velocity of structural deflection along XJ

•	Y-velocity of structural deflection along YJ

•	Z-velocity of structural deflection along ZJ

•	WX-velocity of structural deflection about XJ

•	WY-velocity of structural deflection about YJ

•	WZ-velocity of structural deflection about ZJ

id-array-mou-k

ID of the ARRAY containing the combined local structural stiffness of I-Body and J-Body. The stiffness coefficients (kx, ky, kz, ktx, kty, ktz) must be positive real numbers. An example is shown below.

Example: ARRAY/54, IC, NUM = 123.3, 234.5, 345.6, 987.6, 876.5, 765.4

id-array-mou-c

ID of the REFERENCE_ARRAY statement giving the combined local structural damping of I-Body and J-Body. The camping coefficients (cx, cy, cz, ctx, cty, ctz) must be positive real numbers. An example is shown below.

Example: ARRAY/55, IC, NUM = 1.233, 2.345, 3.456, 9.876, 8.765, 7.654

id-array-mou-act

ID of the ARRAY specifying the activity of local structural deflection per direction. The activity coefficients (act-x, act-y, act-z, act-rx, act-ry, act-rz) must be zero (0) or one (1). A value of zero (0) turns off the structural deflection, while a value of one (1) turns on the structural deflection.

Example: ARRAY/56, IC, NUM = 1, 1, 0, 0, 1, 1