@misc{keller_laser_shock_2017, 
author={Keller, S.,Kashaev, N.,Klusemann, B.},
title={Laser shock peening process modelling and experimental validation for AA2198-T3 and AA2198-T8},
year={2017},
howpublished = {conference object: Weimar (D); 06.-10.03.2017},
abstract = {Laser shock peening (LSP) is a surface treatment which improves the fatigue performance,of metallic structures by inducing compressive residual stresses. A pulsed laser vaporizes,the first layer of the component and turns the solid material into plasma. Thermal,expansion of the plasma initiates high pressure shock waves within the material. Residual,stresses are the result of local plastic deformations caused by the pressure waves. The,process is highly nonlinear and difficult to optimize based on experiments alone due to the,high number of process parameters and short time events which are hard to measure (e.g.,shock wave propagation, plasma forming). Especially, the shock wave reflection at the,back side of the specimen could influence the residual stresses and, therefore, extend the,simulated time. The material under investigation is AA2198 at different temper stages,,which shows a very pronounced rolling texture. AA2198 is an aluminum-lithium-alloy,of the third generation and finds application in light weight structures (e.g. aircraft).,Aiming to an deeper understanding of the process and an optimized residual stress,profile, a finite element model is set up. A phenomenological Johnson-Cook material,model is employed to predict the strain hardening and strain rate behavior. The work,is split into two parts; at first, experiments are used to determine the requirements for,the simulation. Experiments clarify the influence of the base layer and the influence,of the initial residual stresses depending on the thickness of the specimens as well as,the aspect of the material anisotropy. The laser is characterized by 5 J laser pulses,with a squared focus of 3mm  3mm or 1mm  1mm. Residual stresses were measured,by the incremental hole drilling method using electronic speckle pattern interferometry,(ESPI). Secondly, a finite element model is employed enabling the identification of the,laser induced pressure pulse for AA2198-T3. Laser pulse impacts were simulated with,pressure boundary conditions, hence, the influence of the phase transition of the first,material layer is neglected. The validity of the model will be shown for a LSP process,simulation of AA2198-T8. Simulation and experimental measured residual stress profiles,are for both temper stages in excellent agreement. Details about the employed numerical scheme will be presented.},
note = {Online available at: \url{} (DOI). Keller, S.; Kashaev, N.; Klusemann, B.: Laser shock peening process modelling and experimental validation for AA2198-T3 and AA2198-T8. Book of Abstracts, 88th GAMM Annual Meeting 2017. Weimar (D), 2017.}}