The Altair GUI Toolkit is a resource tool for coding Tcl/Tk dialogs. It contains documentation of the HyperWorks commands, demo pages that illustrate our Altair GUI standards, and sample code for creating those examples.
The Model Identification Tool, known as HyperWorks, is a profile in HyperGraph for fitting test data from frequency- and amplitude-dependent bushings to analytical models. The HyperWorks operates in conjunction with HyperGraph, MotionView and MotionSolve to provide you with a comprehensive solution for modeling and analysis.
The Altair Bushing Model is a library of sophisticated, frequency- and amplitude-dependent bushing models that you can use for
accurate vehicle dynamics, durability and NVH simulations. The Altair Bushing Model supports both rubber bushings and hydromounts.
This section provides information about using the Altair Bushing Model, also known as AutoBushFD, with MotionView. The Altair Bushing Model is a sophisticated model that you can use to simulate the behavior of bushings in vehicle
dynamics, durability and NVH simulations.
The bodies connected by the bushing are flexible and may deflect under the load being transmitted. This phenomenon
is modeled with the Mount Stiffness feature. Mount stiffness models the structural stiffness of the bodies, thus mounting
the bushing as a linear spring and damper in series with the bushing in each direction.
The Altair Bushing Model includes a Mount Limits feature, which lets you model the material contact that occurs between
the bodies that a bushing connects. The bodies are flexible and may deflect under the load being transmitted. Given
enough bushing deflection, the bodies may contact one another for negative and positive deflections in each
direction.
This section describes how preloads, offsets and scales enter into bushing force computations. You use Preloads, Offsets
and Scales to alter the operating point of a bushing. You can offset the bushing displacement in any direction, and
scale the input displacement and velocity. You can also offset the bushing force in any direction by adding
a preload or scale-output force or moment in any direction.
Coupling refers to the forces and moments generated in a bushing to oppose the overall deformation of the bushing.
These forces and moments are independent of any coordinate system that might be used to measure the deformation or
deformation velocity. Coupling is an important factor when the bushing characteristics are non-linear.
The System Performance Data file, *.spd, contains the test data used for fitting a bushing. This data should be validated to ensure that it is physically
meaningful. One test for physical consistency is that the dynamic stiffness at any amplitude of vibration must always
be greater than the static stiffness at the same amplitude.
HgTrans translates solver results files from their native file format to Altair Binary Format (ABF). This can be done using
the HgTrans GUI or via the HgTrans batch mode.
The HyperWorks Automation Toolkit (HWAT) is a collection of functions and widgets that allows an application to quickly assemble
HyperWorks automations with minimal effort and maximum portability.
HyperWorks Verification and Validation Harness (HVVH) is a tool that can be used to verify and validate HyperWorks products. End users can use this tool to quickly evaluate the software quality, performance, reliability,
scalability, and robustness, and to gain more confidence in HyperWorks products.
Uninstall HyperWorks is a tool to launch the HyperWorks uninstallation program. This program contains two options that allow you to either remove the originally installed
files, or remove all the files that resides in the installation directory.
The Model Identification Tool, known as HyperWorks, is a profile in HyperGraph for fitting test data from frequency- and amplitude-dependent bushings to analytical models. The HyperWorks operates in conjunction with HyperGraph, MotionView and MotionSolve to provide you with a comprehensive solution for modeling and analysis.
The System Performance Data file, *.spd, contains the test data used for fitting a bushing. This data should be validated to ensure that it is physically
meaningful. One test for physical consistency is that the dynamic stiffness at any amplitude of vibration must always
be greater than the static stiffness at the same amplitude.
The System Performance Data file, *.spd, contains the test data
used for fitting a bushing. This data should be validated to ensure that it is physically
meaningful. One test for physical consistency is that the dynamic stiffness at any amplitude
of vibration must always be greater than the static stiffness at the same
amplitude.
Further information about how to perform such validations in the Model Identification
Tool is included in the following sections:
Extract Relevant Dynamic Data from an SPD File
The following figure shows a section of the dynamic data block in an
.spd file. The contents of each column are described in the
header line, shown in blue.
Note the following:
Each line specifies an individual test that was performed.
The first column (D_MAG) of each line of data specifies the magnitude of the
sinusoidal input.
The third column (K_MAG) specifies the dynamic stiffness that was measured in
the test.
The sixth column (PRELOAD) specifies the preload that was applied to the bushing
before the dynamic testing was done. In the example shown, a preload of -550 N
was applied to deform the bushing. Subsequently, a dynamic test was
performed.
Extract Relevant Static Data from an SPD File
The figure below shows a section of the static data block. The contents of each
column are described in the header line, shown in blue.
Note the following:
The first column (DISP) of each line of data specifies the static displacement
provided as input.
The second column (FORCE) specifies the static force that was measured for that
input.
Static Curve Representation
Let the static data be represented with:
N displacement data points ,
i=1…N.
N force data points, , at
displacements .
An AKIMA spline is used fit this curve. Symbolically, this can be represented as:
is the displacement at which the force
is required.
Calculate the Average Static Stiffness in a Bushing for a Test
The first step is to compute the static deflection due to preload.
Designate the applied preload as P (for our example, P=-550 N).
Solve the nonlinear problem: and compute the required
displacement .
Compute the minimum and maximum values of the dynamic oscillation for each
test, j, with an amplitude .
Maximum deformation,
Minimum deformation,
Compute the average static stiffness for the range of dynamic oscillation in
test j.
Validate Bushing Dynamic Stiffness Data in an SPD File
The validation test is shown in the following plot. The test essentially consists of
verifying that the average slope of the static curve in the range of operation does
not exceed the dynamic stiffness measured in the test.
The algorithm for performing the validation is as follows:
for each dynamic test j = 1...M
get displacement magnitude, (first column of dynamic data)
get dynamic stiffness, (third column of dynamic data)
get preload, (sixth column of dynamic data)
compute using algorithm (a)
compute range of dynamic oscillations using algorithm (b)
compute average stiffness for the range using algorithm (c)
if
issue warning message