lubrication
regime undergoes a transition from the hydrodynamic regime to the
mixed or boundary lubrication regime. The time scale of the first
stage of the engagement process is typically on the order of one
second during which the squeeze action is of paramount importance
(cf. Jang and Khonsari, 1999a). The research aims at investigating
the effect of operating conditions on wet clutches dynamic, thermal
and thermoelastic behavior, and the underlying frictional process.
The goal is to develop designs that minimize failure, improve smoothness
of operation, and extend component life. Preliminary 2D and 3D simulations
of the dynamic and heat transfer behavior have been carried out
based on FEM model (cf. Mansouri et. al., 2001), and systematic
analyses have been developed, in order to quickly and accurately
predict key performance parameters, such as developed energy, maximum
power requirement, maximum temperature rise, engagement time, and
maximum brake torque (cf. Mansouri et al., 2002). In order to investigate
the failure phenomenon of coning, preliminary simulations of the
thermoelastic problem have been carried out. As illustrated in Figure
2, temperature gradients developed in the separator disc during
engagement produce deformation, which, under severe engagement condition
and after many cycles of use, can lead to coning and fatigue failure
as thermoelastic loading builds up, and stress reversal takes place.
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