Experimental investigation on the tensile behavior of polyurea at high strain rates

Elastomeric polymers, like polyurea, are finding relevance in strengthening applications and as energy absorbing materials for structures and systems subjected to impulsive loadings. Understanding the dynamic behavior of these materials is essential for their application as an effective protective and retrofitting material. This paper presents the findings of a series of uniaxial tensile tests that were conducted on polyurea over the strain rate region from 0.006 to 388 s−1. The stress–strain behavior of the polyurea sample was established at different strain rates, and key mechanical properties of the material were determined. The results indicate that the stress–strain behavior of the material at high strain rates were considerably non-linear and exhibited significant rate dependency. The characteristics of the stress–strain curves at quasi-static and at higher strain rates can be described as rate-dependent linear elastic/piecewise linear strain hardening. Based on the findings of the experiments, the influence of strain rate effects on the modulus and yield stress of the polymer were analyzed and empirical correlations to describe the dynamic increase factor (DIF) of the modulus of elasticity and the yield stress at high strain rates were proposed.