Effect of Design Parameters on Buckling Tendency of an Eccentric Drag Link Used in a Truck Steering Linkage: A DoE/RSM-Based Design Optimisation Study

Abstract

The steering system, deemed one of the most critical subsystems for ensuring the safety of a vehicle, is characterised by its pivotal role in manoeuvrability and control. The primary function of transmitting the steering input from the steering wheel to the vehicle's wheels is carried out by the drag link within the steering system. Therefore, the durability and proper functioning of the drag link in vehicles, especially carrying heavy loads, are of critical importance for both safety and efficiency. The main purpose of this study is to determine the optimal geometry of the drag link utilised in the steering system of a 4x2 truck using the Design of Experiments-Response Surface Methodology (DoE-RSM). Firstly, an idealised worst-case load model was used to determine the maximum force applied by the Pitman arm on the drag link. The stress distribution and deformation on the drag link caused by the maximum design load were deter-mined using Finite Element Analysis (FEA). Based on the results of the analyses, eccentricity, rod thickness, and fillet radius were defined as design parameters. The parameter ranges were determined by considering the volume swept by the wheel and buckling criteria under maximum load conditions. According to the DoE-RSM results, concerning the local sensitivity per-centages of the parameters on total deformation, it was observed that the eccentricity (e) parameter has the most significant impact, with an approximate positive rate of 74%.