A Shockless Plate-Impact Spalling Technique, Based on Wavy-Machined Flyer-Plates, to Evaluate the Strain-Rate Sensitivity of Ceramic Tensile Strength

Silicon carbide ceramics are widely used for armor protection due to their high compressive strength, high hardness and low density. In the present study, an experimental technique based on the plate-impact technique is developed to measure the tensile strength of ceramic materials. As the strength of ceramics under dynamic loading is highly sensitive to the strain rate, the effort was made to maintain a constant strain rate loading at the failure location. Numerical simulations were used to design several geometries of wavy-machined flyer-plates, which generate a pulse-shaped compressive wave upon impact, with smoothed rising and falling times ranged from 0.65 to 1 $$\upmu$$ s. Such shockless plate-impact experiments were performed on a SiC ceramic at impact velocities set between 200 and 450 m/s. Thanks to laser interferometry analysis, the target rear face velocity provides a measurement of the material spall strength at a given strain-rate loading. The strain rate in the failure zone was evaluated via elasto-plastic numerical simulations, using the pulse loading and spall strength determined experimentally. With an appropriate design of the flyer-plate, the plate-impact technique is found to properly allow a well-controlled strain-rate loading around 10 $$^4$$ -10 $$^5$$ s $$^{-1}$$ with relatively long rising time to be reached. This work is expected to provide a suitable tool to investigate the high strain-rate behavior of ceramic materials.