Non Dimensional Graphs for the Vibration Analysis of C.V. Driveshafts

In previous papers, the authors have shown, by comparison with experimental results [1],[2], that the simply supported beam model can be used in the representation of vibration phenomenon that can occur in half shafts of front wheel drive vehicles, when one of its flexural natural vibration frequencies matches the excitation coming form the engine. Once obtained this reliable model, the physical variables that influence the phenomenon are investigated and a non dimensional analysis is conducted with the aim to obtain non-dimensional design graphs to help the work of the design engineer. A dimensional analysis is carried out on two beam models based on the simply supported beam model as described in references [1] and [3], and the results are used to obtain the non-dimensional design graphs. Model I represents a half-shaft with a detuner and model II is a half-shaft with a vibration absorber. This graphs are constructed with non-dimensional parameters that relate the main variables involved in the phenomenon of interest. Based on these graphs a procedure for the verification and design of shafts and half-shafts is defined, obtaining a very simple and easy way to make dynamic analysis, even for the non experienced design engineer. By means of these design graphs, the designer has the possibility to investigate various design options before the construction of physical prototypes, without the need of fully understand the underlying theory. The results of the calculations with this graphical method are also compared with published experimental and numerical results, showing very good agreement. The main advantage of the graphical method is the possibility of doing parametric studies in an easy and straightforward manner, helping to shorten the process of design and quotation of the half shaft project