Spall strength of polycarbonate measured using laser-driven micro-flyer impact experiments

Polymers play an increasingly large role in application areas involving extreme loadings, from polymer-bonded explosives to personnel and vehicular protection systems. However, there remain substantial gaps in our knowledge of polymer mechanics at very high strain rates, especially regarding spall strength and the underlying problem of dynamic void and crack growth. Further, the micromechanisms that control dynamic void and crack growth are not fully understood. Here we present experimental results on the spall strength of a model amorphous thermoplastic, polycarbonate, measured using laser-driven micro-flyer (LDMF) plate impact and photonic Doppler velocimetry (PDV). Our experimental method enables high-throughput testing, such that we can collect an order of magnitude more data points than traditional gas gun spall experiments. This large volume of tests allows us to generate spall strength statistics, and to estimate the uncertainty in spall strength for different impact velocities.