Experimental and simulation investigation of vertical response of stepped torsion bar spring for light motor vehicle suspension system

Abstract

The straight torsion bar spring is widely used in automobile and military tankers suspension systems due to less occupation of space and high weight bearing capacity. In this present work, the vertical response of Stepped Torsion Bar Spring (STBS) in Light Motor Vehicle (LMV) suspension is investigated. The STBS consists of two segments in series. The segment-1 is larger diameter when compared to that of segment-2. Three cases of diameter ratio and length ratios combination of STBS are experimented and simulated. A 2-DOF (Degree of Freedom) quarter car model test rig is designed for the experimental work. A harmonic excitation is given as road input though a Cam. The damped and undamped vertical response and frequencies of STBS are experimented. The vertical response and its spectrum analysis are plotted and better responses of the low stiffness STBS is identified for comfort ride and the results are compared with MATLAB Simulink results. The results of the suspension parameters such as tire stiffness, damping coefficient of shock absorber, stiffness of STBS, internal damping of STBS and torsional to linear stiffness are investigated.