An efficient method for calculating the nonlinear stiffness of progressive multi-leaf springs

Abstract

An efficient method for calculating the nonlinear stiffness of a progressive multi-leaf spring is developed and evaluated. This method utilises the interaction between the main and help springs that induces the nonlinearity. The main and the help springs are modelled as multi-leaf cantilever beams, and are then integrated as one by connecting the models for each side of the progressive multi-leaf spring at the centre-bolt. The results from the developed model are evaluated by comparison with those from the commercial FEA programme, ABAQUS. The nonlinear spring coefficients calculated by FEM analysis are very close to those calculated using the developed method. From the comparative evaluations, the developed method is shown to quickly evaluate the nonlinear spring behaviour of progressive multi-leaf springs with acceptable accuracy. Finally, comparison of the model results with those from an experiment measuring the stiffness of a progressive multi-leaf spring show that the model captures the mechanical characteristics of the spring to an accuracy acceptable for design use.