Finite Element Model Generator for Assessment and Optimization of Crankshaft Design

This paper describes the concept of model generator for structural assessment of crankshaft design, its application and methodology in the design optimisation of crankshaft. The model generator saves to a great extent the time required for iterative design process. It is developed on the ANSYS general purpose finite element programme and makes use of symmetry and repeatability of crankshaft geometry.

This model generator software uses 12 parameters which include fillet radius, web thickness and overlap as design iteration parameters. Using these parametric studies of the crankshaft have been carried out. Two stage analysis has been used for computation of fillet stresses. In the first stage 3 dimensional coarse model is analysed to compute stresses and displacements. Next stage uses 3D zoomed model of the critical fillet zone. Zoomed model is refined to give maximum possible accuracy of computation using submodelling techniques. The displacements of the boundary nodes from the coarse model are applied as forced displacements to the corresponding nodes of the zoomed model.

Experimental verification of model generator has been carried out by strain gauging the crankshaft and the difference between results has been found within 3% which is generally considered acceptable. The concept of modeller has been extended for analysis of shaft with oil hole.