Measurement of rubber properties for design

The rubber properties required for the design of engineering components are primarily concerned with stiffness, although factors such as strength and ageing resistance must be taken into account in materials selection. Calculation of static behaviour requires a shear modulus at the appropriate strain. In order to allow for the strain dependence of the shear moduli of filled rubbers, it is preferable to measure moduli over a range of strains rather than to rely on a single point measurement.

For the purposes of vibration isolation, the stiffness of the rubber is a function not only of frequency but also of the amplitude of the vibration. To allow for this, the shear moduli of the rubber at low strains, of the order of 1%, are required, over a range of frequencies.