Browsers supply a great deal of view-related functionality by listing the parts of a model in a tabular and/or tree-based
format, and providing controls inside the table that allow you to alter the display of model parts.
FE geometry is topology on top of mesh, meaning CAD and mesh exist as a single entity. The purpose of FE geometry
is to add vertices, edges, surfaces, and solids on FE models which have no CAD geometry.
Tools and workflows that are dedicated to rapidly creating new parts for specific use cases, or amending existing
parts. The current capabilities are focused on stiffening parts.
The AutoBush is a bushing model that is designed to easily simulate bushings used in ground vehicles. The AutoBush entity
reads bushing stiffness (force-displacement) and damping (force-velocity) data from a file written in the TeimOrbit format.
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 Model Identification Tool (MotionView) is a utility in HyperGraph that you use to fit experimental data to various bushing models. The MotionView generates a General Bushing System file, .gbs file, which defines the bushing properties.
You can add an Altair Bushing Model, also known as AutoBushFD, a frequency-dependent bushing, to your MotionView model using the Add Auto Entity tool in MotionView.
The friction torque resists rotation of the bodies relative to one another. The friction model supports stiction and
sliding effects as well as a measured friction torque due to preload in the bushing.
Use Mount Stiffness when you want to approximate the structural deflection of the bodies that the bushing connects
due to the load that the bushing carries. Mount stiffness is modeled as a set of linear springs and dampers in series
with the bushing stiffness and damping, thus softening the connection between the bodies. Alternatively, you can use
flexible bodies to model the bodies the bushing connects.
You can activate Mount Limits to simulate material contact between the bodies that the bushing connects. This contact
limits the bushing deflection. When the deflection is sufficient in a given direction to close the gap distance, the
mount limit forces or torques become active. The forces and torque are computed using an impact function. An exponent
greater than one (1) provides increasing stiffness with penetration. The damping force is smoothed with a cubic step
function over the penetration distance.
In addition to adding a single bushing to your project, you can also add a pair of bushings such as AutoBushFD pair.
When you add a pair, MotionView automatically reflects modifications you make on the left bushing of the pair to the right bushing, unless you choose
otherwise. MotionView assumes bilateral symmetry about the global X-Z plane.
The AutoDamper entity is a force-velocity model designed to easily simulate a shock absorber used in ground vehicles.
The AutoDamper entity reads force-velocity data from a file written in the TeimOrbit format.
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 Preload/Offset/Scale tab displays the force characteristics of your bushing as
you see in the following figure:
Select the Preload/Offset/Scale tab.
Note: The Preload default value = 0; The Offset default value = 0; and the Scale
default value = 1.0. The same holds true for both translational and
rotational directions.
Enter the Preload Force X, Y and Z values as a real
value. Positive preload (Pk) values act to attract the two
bodies.
Enter the Preload Torque X, Y and Z values as a real
value. Positive preload torque values act clockwise about the given axis (that
is, x, y or z) on body 1 and counter-clockwise on body 2.
Enter the Offsets Disp X, Y and Z values as a real
value. Displacement offsets (Qk) are subtracted from the actual
displacement of body 1 with respect to body 2.
Enter the Offsets Angle X, Y and Z values as a real
value. Angle offsets are subtracted from the actual angular displacement.
Enter the Scales Disp X, Y and Z values as a positive,
real value. The displacement scale (Hk) scales both the input
displacement and velocity, but not the displacement offset. The default value is
one (1).
Enter the Scales Angle X, Y an Z values as a positive,
real value. The displacement scale (Hk) scales both the input
displacement and velocity, but not the displacement offset. The default value is
one (1).
Enter the Scales Force X, Y and Z values and
Torque X, Y Z value as positive, real values. Enter a
positive, real value. The force scale (Vk) scales the force function,
but not the preload. The default value is one (1).
The following figure shows the effect of preload and offset on a bushing:
The bushing force for the Kth direction (x, y, z, ax, ay, az) is
defined by a function:(1)
Where,
Force in the kth direction
Force function in the kth direction
Displacement input in the kth direction
Velocity input in the kth direction
Array of internal state (that is, hysteresis) in the kth
direction
Time
The displacement offset Qk and the displacement scale
Hk modify the displacement and velocity to compute new inputs to
function G as follows:
is the scaled, offset displacement.
is the scaled velocity.
So force is then
computed using the modified inputs and :(2)
Finally, the force/torque preload Pk and
force/torque scale Vk modify the output so the force computation
is:(3)