Influence of Surface Treatements on Fatigue Life of a Free Piston Linear Generator Engine Components Using Narrow Band Approach

This paper describes finite element based vibration fatigue analysis techniques to predict fatigue life using the narrow band frequency response approach. The life prediction results are useful for improving the component design at a very early development stage. The approach is found to be suitable for periodic loading but requires very large time records to accurately describe random loading processes. The focus of this paper is to investigate the effects of surface treatments on the fatigue life of the components of free piston linear engine. The finite element modeling and frequency response analysis have been performed using a computer-aided design and a finite element analysis commercial code, respectively. In addition, the fatigue life prediction was carried out using a finite element fatigue analysis commercial code. The Narrow band approach is specially applied to predict the fatigue life of the free piston linear engine cylinder block. It is observed that there is a significant variation between the surface treatments and untreated cylinder block of free piston engine. The obtained results indicate that the nitrided treatment produces the longest life. This approach is capable of determining premature products failure phenomena. Therefore, it can reduce time to market, improve product reliability and customer confidence.