ABSTRACT

Rubber suspension elements suffer from oxidative ageing, resulting in a change of their mechanical behaviour. For the particular case of suspension elements of vehicles, ageing mainly increase the quasi-static and dynamic stiffness of the bushings. This influences the dynamic behaviour of the vehicle throughout its operational life, so being able to predict the changes in stiffness becomes of paramount importance. This investigation studies the influence of oxidative ageing on the mechanical properties of two natural rubber compounds that are commonly used to manufacture suspension bushings. Quasi-static and dynamic tests are conducted in tensile and compression specimens, both in non-aged and aged conditions, assessing the changes in the quasi-static stress/strain curves and in the dynamic Young’s modulus. Samples are introduced in the oven for different time spans and five ageing temperatures. Accelerated thermal-ageing test results are afterwards extrapolated by using the Arrhenius approach.