Effect of strain rate and filler size on mechanical behavior of a Cu filled elastomer based composite

This work reports the effects of strain rate on mechanical behavior of polydimethylsiloxane (PDMS)-based composites, prepared through inclusion of either micrometer or nanometer sized Cu particles into PDMS matrix. Pure PDMS and 5 vol % Cu-PDMS composites were cyclically loaded to a strain of 30% at a fixed strain rate, ranging from 1.0 × 10−3 to 5.0 × 10−1 s−1, for several loading-unloading cycles. All samples showed significant strain rate sensitivity, revealing an increase in both the flow stress and the energy absorbed per cycle with strain rate. In addition, irrespective of strain rate, Cu-PDMS composites not only showed high strength, but also absorbed more energy per cycle as compared to pure PDMS. Furthermore, both the stress bearing and the strain energy absorption capacities of the composites increased significantly with a decrease in the filler size. A simple analytical model is developed to explain experimental results.