Identification of constitutive equations at very high strain rates using shock wave produced by laser

A method coupling experiments and simulations, is developed to characterize the yield stress and strain hardening of several metals loaded at 10(6) s(-1) and < 25 ns, typically involved during Laser Shock Peening. It was applied to four materials: pure aluminum, 2024-T3 and 7175-T7351 aluminum alloys and Ti6Al4V-ELI titanium alloy. Thin foils have been irradiated with high-power laser to induce high-pressure shock wave. Plastic deformation is activated through the thickness up to the rear free-surface of the foils. These experiments have been simulated using three material constitutive equations: Elastic-Perfectly Plastic model considering static yield stress, Johnson-Cook model without strain hardening and Johnson-Cook model with strain hardening. The material parameters of Johnson-Cook law were identified by comparison of the experimental and calculated velocity profiles of the rear-free surface. Results are shown and discussed.

Automated summary

A method combining experiments and simulations has been developed to characterize the yield stress and strain hardening of several metals, including pure aluminum, aluminum alloys, and titanium alloy during Laser Shock Peening. The experiments were simulated using three material constitutive equations to identify the material parameters of the Johnson-Cook law by comparing experimental and calculated velocity profiles of the rear-free surface. Results are presented and discussed.