General Bushing System Files
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.
The table below describes the stiffness and damping formulations that are available
in a .gbs file. You employ different methods for force and
torque directions, but must specify for each direction only one stiffness and one
damping method. An activity table in the .gbs file tells
MotionView which bushing models are active.
| Component | Method | Description |
|---|---|---|
| Stiffness | Constant Stiffness | F=-K*x; used when the bushing’s stiffness
behavior is linear. The value x is the
deformation in the direction of interest. |
| Spline Stiffness | F=-g(x); where g(x) is a
cubic spline interpolation of static force vs. displacement data
in the .gbs file. Linear extrapolation is
used when the data is outside the range of specified
data. |
|
| Cubic Stiffness | F=-h(x); where h(x) is
defined by a pair of cubic polynomials whose coefficients are
derived from the measured force vs. displacement data in the
.gbs file. |
|
| Damping | Constant Damping | F=-c*v; used when the bushing’s damping
behavior is linear. The value v is the
deformation velocity in the direction of interest. |
| Rubber Damping | An amplitude and frequency-dependent bushing model, whose coefficients are fit to measured data using a tool such as the MotionView. | |
| Hydromount Damping | An amplitude and frequency dependent model for hydrodynamic mounts, whose coefficients are fit to measured data using a tool such as the MotionView. |