Analysis of an Intermediate Rear Axle Shaft Failure

This paper describes the failure analysis of an intermediate shaft used in a prototype, which had been failed during the trial run of the prototype. The shaft was found to be bending. The investigation was carried out in order to establish whether the failure was the cause or a consequence of the accident. A study of the bend shaft shows how vulnerable such a rotating component can be to failure by fatigue, even when operating under steady conditions, if basic preventative design actions are not taken. The analysis considers the effects of both transmission torque and weight (thus bending) upon stress levels and assesses their individual affect on the breakage and upon any subsequent modifications needed to improve the design. Results indicate that the axle shaft bends due to fatigue as a result of improper design. The drive shaft arrangement is compared with the feasible alternative of using a driven wheel arrangement rotating on a stationary axle. Findings confirm the importance of recognizing in advance the salient factors leading to fatigue and the necessity in paying adequate attention to detail during design and manufacture if long service life is to be achieved.