Study on Multi-Point Random Contact Characteristics of Metal Rubber Spiral Mesh Structure

Metal rubber (MR) is a porous damping material, which achieves the damping energy consumption by the contact friction between the internal wires. Complex wire structure makes explanation of energy dissipation mechanism by the traditional theoretical models limited to comparison with equivalent models or microcell models, which cannot truly reflect the spatial multi-point contact characteristics of each wire. This work demonstrates numerical modeling based on actual preparation process parameters of annular MR. Using the penalty function to solve the complex contact that is difficult to predict between the internal spiral wires, the variation laws for equivalent stress and strain recorded during the loading-unloading process of MR, were obtained. The small-ball algorithm and the Tabu search algorithm were used to realize the accurate assessment of contact points between the wires and the hyper dimension matrix was used to track the friction state of the contact points in real time, thereby obtaining a proportional relationship between various friction forms during the loading-unloading process. It is found that sliding friction accounts for the majority of the total number of contact points, which is about 81.38%, consistent with the equivalent plastic strain law of stepwise change. It becomes further clarified from the microscopic point that MR accomplishes macroscopic energy dissipation mechanism through the fretting slip friction between the internal wires. In order to verify the authenticity of the simulation, a quasi-static loading-unloading experiment of MR was carried out under identical parameters, and the experimental macroscopic results were in excellent agreement with the simulation results. The research indicates that the MR finite element model established in this paper can precisely describe the dynamic contact of the internal structural features of MR materials, for providing a theoretical basis for guiding the preparation and application of MR.