Structural Technology Evaluation Analysis Program (STEAP). Delivery Order 0025: Laser Peening for Reliable Fatigue Life

摘要

Laser peening (LP) is an advanced mechanical surface enhancement technique used to increase the fatigue life of metallic components. To reduce costs and make the technique available on a large-scale basis for industrial applications, simulation of the LP process is required. One of the objectives of this research is to make advancements in the simulation of LP-induced residual stresses by validating various material models for use in simulation and design. An inverse optimization-based methodology is developed, which involves optimizing the model constants for one load case and using the same constants for other load cases. The second aspect of this research is to develop a framework for uncertainty quantification of the residual stress field induced by the LP process by propagation of regression uncertainty. Development methodology includes identification of regression uncertainty as a source of input uncertainty and using the bootstrap method to verify the multivariate normality assumption of the model constant estimates. The propagation of the input uncertainty is performed using Taylor series expansion and sensitivity analysis. A confidence band for the entire residual stress field is obtained and validated using the Monte Carlo analysis.