A schematic of a clutch-testing machine is shown. The steel shaft rotates at a constant speed ω. An axial load is applied to the shaft and is cycled from zero to P. The torque T induced by the clutch face onto the shaft is given by

T = f P(D + d)/4

Where D and d are defined in the figure and f is the coefficient of friction of the clutch face. The shaft is machined with Sy = 120 kpsi and Sut = 145 kpsi. The theoretical stress-concentration factors for the fillet are 3.0 and 1.8 for the axial and torsional loading, respectively. Assume the load variation P is synchronous with shaft rotation. With f = 0.3, find the maximum allowable load P such that the shaft will survive a minimum of 106 cycles with a factor of safety of 3. Use the modified Goodman criterion.

Determine the corresponding factor of safety guarding against yielding.

Transcribed Image Text:

R 0.1 in d 1.2 in Friction pad