A Physics-based Model for the Prediction of Laser Shock-Induced Spallation

In this SBIR phase-I proposal, a physics-based modeling approach is proposed to predict the spallation in Ti-6Al-4V coupons induced by laser shock peening (LSP). Although LSP can dramatically improve the fatigue strength, life and resistance to crack propagation in materials and parts, small subsurface flaws due to spallation can be induced in certain conditions, which are considered extremely undesirable and may affect the full functionality of the particular component. No physics-based approach is available today for the robust prediction of LSP-induced material failure. Motivated by this knowledge gap, we propose to 1) establish a physics-based model for the shock pressure generated by LSP and 2) develop a nonlinear damage-based constitutive material model that is capable of describing the key physics associated with LSP spallation. By incorporating the models into the commercial nonlinear finite element code (ABAQUS), extensive parametric study will be performed on processing parameters (pulse input energy, pressure, spot size, duration) and coupon configurations (size, shape, boundary conditions) implementation includes modeling of the LSP-induced shock pressure. The results obtained will be correlated to the experimental data to establish a comprehensive understanding of the relationship among the process parameters, stress evolution, and material failures.