Fatigue life evaluation of suspension knuckle using multibody simulation technique

Suspension is part of automotive systems, which provides vehicle control and passenger comfort. Knuckle is an important part within the suspension system, constantly facing cyclic loads subjecting it to fatigue failure. This paper presents to evaluate the fatigue characteristics of knuckle using the multibody simulation (MBS) techniques. Load time history extracted from MBS is used for stress analysis. The actual road profile of the road bumps was used as input to MBS. The stress luctuations for fatigue simulations are considered with the road profile. Strain-life method is utilized to assess the fatigue life. The instantaneous stress distributions and maximum principal stress are used for fatigue life predictions. The mesh sensitivity analysis has been performed. The results show that steering link in the knuckle is found to be the most susceptible region for fatigue failure. The number of times knuckle can face the road bump at 40 km/hr is found to be 371 times approximately with 50% certainty of survival. The proposed method of using the loading time history extracted from MBS simulation for fatigue life estimation is found to be very promising to evaluate the performance of suspension system components accurately