Modelling and identification of a wire-cable vibration isolator via a cyclic loading test Part 1: experiments and model development

A cyclic loading test was carried out on a wire-cable vibration isolator to obtain experimentally its hysteretic behaviour in shear, roll and tension- compression respectively. In shear and roll modes, the isolator exhibits sy mmetric soft-hardening hysteresis loops under cyclic loading, namely the hy steresis loops display a softening stiffness in relatively small deformatio ns and diverge to exhibiting a hardening stiffness at large deformation lev els. In the tension-compression mode, the isolator exhibits asymmetric hyst eresis loops, which constitute a segment of a hardening overlapping envelop e in the loading curves. In recognizing the inapplicability of existing hys teretic models, two improved Bouc-Wen models are proposed within the framew ork of the mathematical Duhem hysteresis operator, to represent the symmetr ic soft-hardening hysteresis loops and the asymmetric hysteresis loops with a hardening overlapping envelope respectively.