Finite Element Analysis of Transient Thermoelastic Behavior in Multi-Disc Clutches

Characterisation of a carbon/carbon multi-plate clutch for a high energy, race car application

“…However, once the clutch plates have cooled to ambient temperature, the wear that occurred at the previous contact point results in a surface recess; contact is thus established elsewhere during the next engagement which forces the change in EFR. Zhao et al [22] and Abdullah et al [23,24] predicted a single contact pressure/temperature peak despite no wear being included in their models whereas the TCFEA only predicted a single peak when wear was included. This difference may be the result of the TCFEA simulating only a single clutch-plate pair, and hence a single friction interface, whereas Zhao et al [22] and Abdullah et al [23,24] simulated the full multi-plate aircraft clutch.…”

“…Zhao et al [22] and Abdullah et al [23,24] predicted a single contact pressure/temperature peak despite no wear being included in their models whereas the TCFEA only predicted a single peak when wear was included. This difference may be the result of the TCFEA simulating only a single clutch-plate pair, and hence a single friction interface, whereas Zhao et al [22] and Abdullah et al [23,24] simulated the full multi-plate aircraft clutch. The aggregate effect of TEI on all the friction surfaces may have resulted in a single contact area and hot band being predicted in their simulations even in the absence of any wear.…”

“…The differences in the contact pressure distributions predicted by Zhao et al [22] and Abdullah et al [23,24] may be due to the fact that their respective axisymmetric models simulated several friction interfaces and so the expansion at one friction interface may affect the expansion of another leading to single contact pressure peaks and hot bands where the material properties affect the amount of expansion and hot band location.…”

“…The simulations carried out by Zhao et al [22] predicted hot bands between the central radii and the outer radii of the clutch plates. In contrast, Abdullah et al [23,24] predicted contact pressure localisation at the centre of the friction surfaces leading to the formation of central hot bands.…”

“…Zhao et al [22] and Abdullah et al [23,24] predicted contact localisation due to TEI in carbon/carbon multi-plate clutches using axisymmetric finite element models where the friction surfaces were modelled as initially perfectly flat with the heat flux input proportional to the coefficient of friction (COF), contact pressure and sliding velocity across the friction surface. Wear was not included in the models which predicted rapid contact loss at the inner and outer radii due to radial expansion of the clutch plates.…”