FINITE ELEMENT BASED VIBRATION FATIGUE ANALYSIS OF A NEW TWOSTROKE LINEAR GENERATOR ENGINE COMPONENT

This paper presents the finite element analysis technique to predict the fatigue life using the narrow band frequency response approach. Such life prediction results are useful for improving the component design at the very early stage. This paper describes how this technique can be implemented in the finite element environment to rapidly identify critical areas in the structure. Fatigue damage is traditionally determined from the time signals of the loading, usually in the form of stress and strain. However, there are scenarios when a spectral form of loading is more appropriate. In this case the loading is defined in terms of its magnitude at different frequencies in the form of a power spectral density (PSD) plot. A frequency domain fatigue calculation can be utilized where the random loading and response are categorized using power spectral density functions and the dynamic structure is modeled as a linear transfer function. This paper investigates the effect of mean stress on the fatigue life prediction by using a random varying load. The obtained results indicate that the Goodman mean stress correction method gives the most conservative results compared with Gerber, and no mean stress correction method. The proposed analysis technique is capable of determining premature products failure phenomena. Therefore, it can reduce cost, time to market, improve product reliability and customer confidence