Procedure to Realize the FEM Model of a Tubular Steel Frame for Motorcycles

During the development of a tubular steel frame for motorcycles, it is very important to make FEM calculations in order to evaluate the stress level and the stiffness of the structure. The FEM models must be light in order to reduce calculation time and precise in order to obtain reliable results that can be checked in the following experimental tests.

FEM models of tubular frame made using 1D elements (Pipe) have low precision results and are not advisable for this kind of work. It is suggested to use FEM models made using 2D elements (Shell) for sensitivity tests too. In order to obtain the best result using Shell elements, it is very important to choose the right criterion to model the welding parts: the model must represent the right inertia of the tubular welded joint and be both accurate and easy to be modeled.

In this paper, the work-flow adopted by the CAE Department of Engines Engineering for the FEM analysis of a tubular steel frame is described along with the criteria adopted to realize the model of a tubular frame by using Shell elements and those to realize a tubular welded joint also with solid elements.