Differential evolution based identification of automotive hydraulic enginemount model parameters

Hydraulic engine mounts are commonly used in automotive applications, and n umerical models exist for performing full-vehicle noise, Vibration and hars hness (NVH) studies by means of multibody simulation. The parameters of the se models are usually determined by the manufacturer from first-principle n umerical calculations, or by means of direct testing of the individual comp onents. This paper describes, instead, a four-step identification method de veloped to determine the parameter values of a specific hydromount numerica l model, the Freudenberg hydromount equations, a set of highly non-linear p iecewise-continuous differential equations. The identification procedure is based on two concepts, the first being the use of the differential evoluti on algorithm for determining optimal parameter values, while the second is the use of data obtained from a series of experimental tests of progressive ly higher displacement amplitude. Identified parameters provide models whos e mean square errors between the calculated output force time history and t he experimentally measured force time history are typically of the order of 1-2 per cent.