Design and analysis of lower control arm of suspension system

Abstract

In automotive suspension, a control arm is a hinged suspension link between the chassis and the suspension or hub that carries the wheel. The chassis end of a control arm usually rubber busing, is attached by a single pivot. It controls the position of the tyre end in only a single degree of freedom, maintaining the radial distance from the chassis mount.The single bushing does not control the arm from moving back and forth; this motion is constrained by a separate link or radius rod. Wishbones are triangular and have two widely spaced chassis bearings, which constrain the tyre end of the wishbone from moving back and forth, controlling two degrees of freedom, and without requiring additional links. Most control arms form the lower link of a suspension with few designs using them as the upper link, usually with a lower wishbone. The lower arm should be sturdy, in many cases reported by the users of a particular vehicle, fluttering noise heard over the humps.This paper calculates the forces acting on the lower arm of a four-wheeler with critical loading conditions as the Finite Element Analysis carried for the McPherson type suspension system. The static analysis performed to determine the location of maximum deflection and stress distribution while the vehicle is stationary and moving over the hump at different speeds. The free-free and constrained modal analysis performed on the suspension arm to find the natural frequency. The fatigue analysis performed to find the life of the arm. Further, by performing topological optimization leads to reduction in the weight.