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.
Displacement Offsets ans Scales
Displacement offsets change the origins of the force-deflection curves. Displacement
scales expand or contract the force-deflection curves along the deflection axis.
Let:
-
- be the displacement in the kth displacement direction (x, y,
z, ax, ay, az) between the bushing I- and J-Markers reported in the
coordinate system of the J marker.
-
- is the displacement (horizontal) scaling factor in the kth
direction.
-
- is the displacement offset in the kth direction.
Then the scaled and offset deflection,
,
is given by:
The velocity in the kth direction, is given by:
Preload and Force Scales
Preloads offset the forces or torques at zero displacement, while the force scale
applies an amplification factor to the force. If
is the function computing the force in the
kth direction, then the force in that direction is given as
follows:
Let:
-
- is the preload in the kth direction.
-
- is the force (vertical) scaling in the kth direction.
-
- is the sum of all force methods in the kth direction.
-
- is the preload in the kth direction.
Then: