A deep rolling finite element analysis procedure for automotive crankshafts

Abstract

Deep rolling is performed on crankshafts since the 1960s, yet there is still a knowledge gap regarding residual stress generation. Until this moment, there is no consolidated and widespread procedure to predict such stresses during the crankshaft design cycle. This study establishes an analysis procedure and correlates it with experimental results. An explicit finite element model with real boundary conditions is developed together with a converged mesh for the fillet radius. Simulation nodal displacement and strain output are compared to geometrical measurements using a coordinatemeasuring machine. Outputs in terms of residual stresses are related to X-ray diffraction measurements taken along fillet depth. The experimental results attest to the accuracy of the model and correctness in predicting the process outcomes.

Numerical modelling of deep rolling influence over crankshaft bending and correlation with fatigue behaviour

“…The stress output was quantitatively compared to RS measurements using the XRD technique. The model's results for hoop and axial stress directions, shown in Figure (b), agreed both in tendency and magnitude with the experimental data for the particular process condition described in Fonseca and Faria . Surface compressive RS was found, along with a subsurface peak, followed by a smooth transition to a tractive state.…”

“…The present investigation intends to further develop an ABAQUS® model created by and thoroughly described in Fonseca and Faria . A summarized workflow of the model development can be found in Figure and will be briefly explained as follows.…”

“…Fonseca and Faria focused on the development and the validation of a crankshaft deep rolling finite element model. Although the process can be considered quasi‐static, an explicit formulation was used because of its robustness.…”

“…A total simulation time of 62 hours was considered feasible for engineering design requirements. The results presented in Fonseca and Faria explored the energy balance output from the simulation, illustrated in Figure (e), which gave insight into the model's capabilities on representing the process dynamics. The model validation was made through the comparison of the simulation's nodal displacements (Figure (f)) and residual stress outputs (Figure g) with geometrical and X‐ray diffraction measurements respectively, performed on real components.…”

“…It is encompassed in a broader research topic whose main objective is the understanding of the effects of DR parameters over the fatigue life of cast iron crankshafts. The investigation published in Fonseca and Faria brought the first results obtained from the deep rolling numerical model under development, which will be expanded here. A holistic comprehension on the process parameters can enable its optimization aiming for fatigue strength enhancement.…”