Laser Shock Peening Pressure Impulse Determination via Empirical Data-Matching with Optimization Software
Technical Report,01 Sep 2016,30 Sep 2016
AIR FORCE INSTITUTE OF TECHNOLOGY WRIGHT-PATTERSON AFB OH WRIGHT-PATTERSON AFB United States
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Laser shock peening LSP is a form of work hardening by means of laser induced pressure impulse. LSP imparts compressive residual stresses which can improve fatigue life of metallic alloys for structural use. The finite element modeling FEM of LSP is typically done by applying an assumed pressure impulse, as useful experimental measurement of this pressure impulse has not been adequately accomplished. This shortfall in the field is a current limitation to the accuracy of FE modeling, and was addressed in the current work. A novel method was tested to determine the pressure impulse shape in time and space by optimization driven data-matching. FE model development and material model verification was completed in Abaqus. A 2D and 3D model type study was conducted. A proof of concept data-matching optimization tool was developed and verified. This tool was then applied to match experimentally collected residual stress measurements from single LSP treated spots in 2024-T351 aluminum specimens. Validation of this best-fit pressure impulse was attempted in a 6Al-4V titanium material model for the LSP treatment.
- Fabrication Metallurgy