BUCKLING OF AUTOMATIC-TRANSMISSION CLUTCH PLATES DUE TO THERMOELASTICPLASTIC RESIDUAL-STRESSES/

The plates of multidisk automatic transmission are known to buckle und er extreme operating conditions. Axisymmetric (coning) and nonaxisymme tric (potato chip) modes can be obtained It is shown that these modes result from in-plane axisymmetric residual bending moments in the disk and the critical value for each mode is found. A numerical algorithm is then developed to determine the residual moment due to a prescribed axisymmetric thermal history. Allowance is made for the temperature d ependence of yield stress, elastic modulus, and coefficient of thermal expansion. The results show that susceptibility to buckling depends o n a dimensionless geometric shape factor, the material properties, and the magnitude of the largest thermal excursion. With steel disks and typical design values for the shape parameter; buckling is predicted f or temperature differences of about 600 degrees C between inner and ou ter radii.