Fatigue Life Analysis of Automotive Cast Iron Knuckle under Constant and Variable Amplitude Loading Conditions

The main aim of the present paper is to assess fatigue lifetime ductile cast iron knuckles as one critical components an automotive steering system. To this end, a real driving path, including various maneuvers, such acceleration, braking, cornering, and moving on types road roughness, was considered. Different load histories, which are applied joints component (i.e., lower control arm, linkage, Macpherson strut), were extracted through Multi-Body Dynamics (MBD) analysis full vehicle model. achievements previous studies have proved that knuckle fails from linkage due rotational motion. Therefore, only destructive history considered in future analyses study. CAD model created using Coordinate Measuring Machine (CMM) data some corrections CATIA software. Furthermore, transient dynamic performed, time von Misses equivalent stress obtained at root (which exactly location failure based laboratory well finite element simulations validated by author studies). predict life component, two different methodologies Firstly, well-known criteria employed for equalization spectrum Constant Amplitude Loading (CAL). Then, under sinusoidal loading performed. Secondly, considering Variable (VAL) predicted Critical Plane Method (CPM), employing Rain-flow cycle counting technique, utilizing Miner–Palmgren damage accumulation rule. Eventually, evaluate prediction accuracy methodologies, results compared with full-scale axial variable amplitude test performed corresponding author. indicated Finite Element (FE) domain has about 21% error reality. Additionally, relative between 20%, acceptable scattering phenomenon results, complex geometry part, complicated loading.