Crankcase and Crankshaft Coupled Structural Analysis Based on Hybrid Dynamic Simulation 2013-01-9047

This paper presents the comparison of two different approaches for crankcase structural analysis. The first approach is a conventional quasi-static simulation, which will not be detailed in this work and the second approach involves determining the dynamic loading generated by the crankshaft torsional, flexural and axial vibrations on the crankcase. The accuracy of this approach consists in the development of a robust mathematical model that can couple the dynamic characteristics of the crankshaft and the crankcase, representing realistically the interaction between both components. The methodology to evaluate these dynamic responses is referred to as hybrid simulation, which consists of the solution of the dynamics of an E-MBS (Elastic Multi Body System) coupled with consecutive FEA (Finite Element Analysis).

For this study, an in-line 6-cylinder diesel engine was selected, where the crankcase design has to be revised to withstand higher loads due to new calibration targets by keeping design changes at a minimum and taking mass and cost savings into account. As result, the crankcase fatigue design margins are presented showing clearly the benefits of the adopted methodology, which enabled fulfilling the objectives of the project through small changes in the design. The crankshaft dynamics stresses and safety margins are also presented in this paper.