An Approach to Identification and Simulation of the Nonlinear Dynamics of Anti-Vibration Mounts

摘要

This paper addresses the characterization of the amplitude-dependent stiffness of common vibration mounts. Anti-Vibration Mounts (AVMs) are very common passive vibration isolation devices used in a variety of engineering applications. These are, in most cases, off-the-shelf items which engineers select on the basis of the manufacturer's specifications (in particular their natural frequency). This value is then used for modelling and prediction purposes during the design stage. However, in many cases the nominal value is (very) different from the stiffness value in operational conditions. It is a standard practice to perform dynamic tests on the mounts in order to extract an experimental value for the stiffness. It is well known that the stiffness of rubber AVMs is dependent on a number of factors, amongst which the most important are amplitude and frequency of excitation, as well as temperature. In particular, this work considers only the amplitude-dependency of the stiffness. The approach proposed here is to identify the nonlinear stiffness from a dynamic test and use the extracted stiffness function for nonlinear prediction using a commercial-off-the-shelf (COTS) solution. It is shown that by input the nonlinear stiffness function (identified with experiments) into the numerical model of the installation, it is possible to predict the effect of different excitation amplitudes with good accuracy. This method allows engineers taking a first step towards a more complex and refined model. However, it falls short of including frequency and temperature effects, which are objects of future work.