Low-Density, Polyurea-Based Composites: Dynamic Mechanical Properties and Pressure Effect

Abstract

In this study, we explore the fabrication, characterization and modeling of low-density polymeric composites to understand their acoustic responses. Polyurea is chosen as the matrix of the composites due to its excellent properties and advantages, i.e. blast mitigation, easy casting, corrosion protection, abrasion resistance, and various uses in current military and civilian technology. Two low-mass-density filler materials of interest are phenolic and glass microballoons. They have significant differences in their mechanical properties and chemical interactions with the matrix. Ultrasonic tests are conducted on samples with different volume fractions of fillers and variable pressure. Computational models based on the methods of dilute randomly distributed and periodically distributed inclusions are created to improve our understanding of low-density polymer-based composites and serve as tools for estimating the dynamic mechanical properties of similar composite material systems. The experimental and computational results are compared. The results are expected to facilitate the design of new elastomeric composites with desirable densities and acoustic impedances. These new composites will be useful in developing layered metamaterial structures. Furthermore, we seek to find out whether such inclusions may substantially affect the time-dependent response of the composite by introducing new resonant modes.