Contact Force Formulation Based on Oilfilm Thickness Theory
The stiffness portion of the contact force between the two teeth is defined by a cubic function:
f = Stiffness * 4 / 27 / Oilfilm Thickness2 * (x - Lash + Oilfilm Thickness)3
active when:
Lash - Oilfilm Thickness < x < Lash + Oilfilm Thickness/2
The lash is adjusted according to the distance of the gear centers and the tooth profile of the gears during a Simulation. This function transitions into a linear function with a slope of stiffness:
f = Stiffness * (x - Lash)
The damping portion of the contact force between the two teeth is defined by:
f = -xvel * Damping * ( x - Lash + Oilfilm Thickness )2 / Oilfilm Thickness2
active when:
Lash - Oilfilm Thickness < x < Lash
This function transitions into a constant damping function:
f = -xvel * Damping
Total cleareance is 2 * Lash.
