Modelling corrosion effect on stiffness of automotive suspension springs

This work presents a numerical investigation that correlates the stiffness changes of corroded suspension springs with the amount of spring wire's cross section loss, the degree of surface corrosion (DSC), and corrosion spatial distribution. The aim is to provide understanding of corrosion damage characteristics and subsequent effect on the load-deflection behaviour of a helical compression spring. A 3D non-linear finite element (FE) model was developed which is used to simulate the mechanical response of the spring and to determine its ageing behaviour. The changes in stiffness (percentage loss) in relation to corrosion depth, corrosion spatial distribution and DSC were studied in great detail. Mechanical tests were conducted using a specially designed spring testing machine and the data confirmed the validity of the FE model. To the authors' knowledge limited work has been reported, especially on corroded helical springs, that present stiffness loss diagrams as a function of time.