Fatigue Based Optimization of Cast Iron Bracket depends on Proving Ground Data

Nowadays, a light weight component design plays a significant role in both cost of a vehicle and fuel efficiency in competitive automobile industry. This paper describes the optimum design of an anti-roll bar bracket which is used in a Ford Cargo heavy vehicle according to road load data (RLD) . In order to find forces acting on brackets, calibration process of road load data (RLD) should be initially performed. To reduce body roll pitch, anti-roll bars are supported to cast brackets via links in which the dominant forces are along vertical direction during cornering. In order to measure real forces acting on anti-roll bar links, calibration is performed in laboratory conditions. Once the links are instrumented with full bridge strain gages which are sensitive to measure only tension and compression on links. The forces are applied to anti-roll bar links in special test rig and strain data is collected to get the coefficient of micro strain versus force. According to this study, measured strains are correlated with theoretical strains. Road load data collection is performed at Lommel Proving Ground with calibrated anti-roll bar links in test vehicle considering number of measurements taken of the same event to obtain statistical distribution. nCode software is contracted to provide the necessary signal processing and force calculation. Together with the pre-defined total durability cycles, the optimization study can be performed by considering fatigue life. Finally, topology optimization is used in design process of anti-roll bar bracket made of cast iron. With sufficient packaging volume, design space, optimization and fatigue subcase parameters are defined with the die direction to take into account the manufacturability of component. Compared with initial design of anti-roll bar bracket, the weight of anti-roll bar bracket is reduced 15% and it is still durable according to fatigue life considerations.

The Author

Mr. Mehmet Burak Yegin
Mechanical Engineer
Ford Otosan A.S