Experimental durability assessment and life prediction of vehicle suspension components: A case study of steering knuckles

Abstract

Abstract

The recent emphasis on more reliable life predictions for fatigue-critical parts in ground vehicles would result in a reduction in costly and time-consuming traditional component testing practices. This paper aims at implementing experimental and predictive durability approaches to vehicle suspension components. Forged steel and cast aluminium steering knuckles were chosen as typical components. The fatigue behaviours of components were investigated via constant-amplitude load-controlled fatigue tests. Finite element models of the knuckles were analysed using linear and non-linear methods. Nominal stress, local stress, and local strain life prediction approaches were employed and compared with experimental results to evaluate the accuracy and validity of these approaches. The strengths and shortcomings of the applied models and the alternative analysis techniques are discussed. It is shown that among the contemporary life prediction procedures used in the automotive industry, the local strain approach in conjunction with the plasticity-corrected simple elastic analysis procedure yields reasonable life predictions that are typical of more complex and much more time-consuming non-linear analysis. A number of complexities such as material property variability, variable-amplitude and multiaxial loadings, manufacturing parameters, and environmental effects on durability assessment are also discussed.