Dynamic Mechanical Properties and Weight Optimization of Vibrated Ground Recycled Rubber

The aim in this paper is first and foremost to present an experimental method for measuring the dynamic characteristics of granular rubber. Dynamic measurements on recycled granular rubbers are performed here using dynamic mechanical thermal analysis. The Young’s modulus and loss factor of these materials are estimated by using the frequency—temperature equivalence introduced by Williams—Landel—Ferry. It allows us to describe the dynamic properties over a wide range of frequencies. An increase in the wave speed and a decrease in the loss factor were observed with an increase in the frequency for ground tire rubber (GTR) and compound particles obtained by extrusion of GTR—ethylene vinyl acetate blend. However, for recycled polyurethane particles, the loss factor increases with increasing frequency. Then, we investigate the damping efficiency of granular rubbers introduced into a metallic tube, which was subjected to vibrating bending loads. A numerical model is presented to predict the frequency response for the displacement—force function of the tube—particles system. Model prediction is hence validated through a comparison with experimental results. Second, this paper also aims at calculating the optimum weight of granular material with maximum allowable damping effects on tube subjected to bending vibrations. For this purpose, a technique is proposed from the model developed by optimizing the apparent mass of granular material and the dissipation energy of the tube—particles system. Optimization is achieved by a nondominated storing genetic algorithm (NSAG-II). From the results, this technique can be successfully used to optimize the frequency dependence of wave speed and the loss factor of granular rubber with optimized weight.