PREDICTING THE FATIGUE-STRENGTH OF FILLET-ROLLED CRANKSHAFTS

Since three years Darmstadt University of Technology uses finite eleme nt method for simulation of fillet rolling process. Now, together with Daimler-Benz AG, a fracture mechanics based concept has been successf ully applied predicting the fatigue strength of fillet-rolled cranksha fts. For these parts conventional assessment of fatigue behaviour show s several disadvantages. The new concept reduces time and costs for de velopment and design. It consists of three parts: a calculation of res idual stresses induced by fillet rolling and affected by crankshaft an d roller geometry, rolling load and work hardening data of material si mulation of residual stress redistribution due to cyclic load assessme nt of fatigue cracks starting from notch root and propagating under co mpressive residual stresses by means of linear-elastic fracture mechan ics.