Numerical and Experimental Study on Optimization of Coil Springs used in Vehicles’ Suspension System

In general, the suspension systems are used to absorb vibrations, bump, rolls, dip from shock loads due to road surface irregularities. It performs its major role without affecting the vehicles’ stability and overall handling during operation. Coil springs are used as suspension element in light vehicles to attenuate unwanted vibrations. A spring is an elastic object used to store mechanical energy and it can be twisted, pulled or extended by some force and can return to its initial position when the force is released. In this study, mild steel material was taken into consideration in designing and fabricating coil springs. Theoretical and experimental investigations were conducted to calculate springs’ stiffness and to make validation between them. Three model of springs having coils 10, 11, 14 respectively are designed which have slight stiffness difference both theoretically and experimentally. The models were analyzed to determine mechanical behaviors for randomly chosen loading conditions ranging from 29.4 N to 176.4 N which are better suited with spring size.  It is noted from both numerical and experimental investigations that deflection is high when the stiffness is less and vice-versa. In addition, shear stress formation increases with the increment of stiffness and applied load. Hence, springs having high stiffness are used in suspension system to reduce vibration and other disturbances. This study shows springs of having high stiffness are comparatively compact in size and cost economic as well.