Stiffness of simple bonded elastomer bushes Part 1 - Initial behaviour

This work examines the stiffness of cylindrical elastomer bush mountings in different modes of deformation. Stiffness predictions in different deforma tion modes obtained using published analytical relationships are compared w ith finite element analysis (FEA) and with experimental measurements made o n a range of elastomer bush geometries. The results for the torsional and a xial stiffness from all three methodologies agree reasonably well. However, existing analytical approaches predict values that are clearly incorrect f or both the conical and the radial stiffness. Both a revised analytical and a graphical approach are proposed, which predict the radial stiffness more reliably. The work also demonstrates that to predict the initial stiffness of bushes manufactured from filled elastomers, a neo-Hookean stored energy function implemented in a FEA package is sufficient. Hence a single measur e of shear modulus taken over the correct strain range is all that is requi red to characterise the elastomer behaviour for this purpose.