Modeling capability for realizing engineered residual stress due to mechanical surface treatment

Advanced surface treatments like laser shock peening (LSP) can significantly improve the mechanical performance of turbine engine airfoils. For example, LSP is currently in production to improve the FOD tolerance on a number of fan-blade leading edges. Success in these applications of LSP has come with a significant empirical burden. Current process development requires a determination of process effects on small blocks of material, process tuning and quantification of performance benefit on small-scale fatigue coupons, finally followed by qualification in full-scale rig tests. Significant problems often arise in moving from coupons, where benefits may be large, to full-scale components due to differences in geometry, loading, and failure mechanisms. In structures where the residual stress states have not been methodically engineered, compensatory tensile stresses may exist in areas of significant applied stresses, possibly resulting in a detrimental effect on material performance. The proposed work will develop verified computational engineering design tools for advanced surface treatments, which will eliminate the need for coupon level testing. Through the use of the engineering design tools, customers will be able to take advantage of advanced surface treatments at lower development cost and reduced risk.