Abstract
Optimization of the laser shock peening (LSP) and LASer Adhesion Test (LASAT) processes requires control of the laser-induced target’s loading. Improvements to optical and laser technologies allow plasma characterization to be performed with greater precision than 20 years ago. Consequently, the processes involved during laser–matter interactions can be better understood. For the purposes of this paper, a self-consistent model of plasma pressure versus time is required. The current approach is called the inverse method, since it is adjusted until the simulated free surface velocity (FSV) corresponds to the experimental velocity. Thus, it is not possible to predict the behavior of the target under shock without having done the experiments. For the first time, experimental data collected in different labs with the most up-to-date laser parameters are used to validate a self-consistent model for temporal pressure-profile calculation. In addition, the parameters characterizing the plasma (temperature, thickness and duration) are obtained from the ESTHER numerical code, together with the amount of ablated matter. Finally, analytic fits are presented that can reproduce any pressure–temporal profiles in the following domains of validity: intensities, I, ranging from 10 to 500 GW cm−2 and pulse durations, T pul, between 5 and 40 ns for the direct-illumination regime at 1053 nm, I ranging from 1 to 6 GW cm−2 and T pul between 10 to 40 ns in the water-confined regime at 1053 nm, and I from 1 to 10 GW cm−2 and T pul between 7 and 20 ns in the water-confined regime at 532 nm. These temporal pressure profiles can then be used to predict the aluminum target’s behavior under laser shock using mechanical simulation software.
Highlights
Laser shock is used in several processes such as the laser shock peening (LSP) and the LASer Adhesion Test (LASAT)
The first peak is of particular interest, since it corresponds to the first emergence of the shock wave and has a direct relationship to the plasma pressure [23, 26]
By comparing the first maxima for two pulse durations (10 and 20 ns, figure 5(a) 1 and 5(b) 1) it is possible to conclude that pulse duration does not affect the respective velocity maxima (115 m s−1 for I = 16.7 GW cm−2 and 60 m s−1 for I = 8.1 GW cm−2): the maximum velocity is only influenced by applied peak intensities
Summary
Laser shock is used in several processes such as the laser shock peening (LSP) and the LASer Adhesion Test (LASAT). The propagation of shock and release waves through materials induces compression and traction zones [1, 2]. While the residual stresses arising from the compression of matter are relevant for the LSP treatment [3], the LASAT process exploits the traction peak stress that arises at the meeting point of two release waves [4, 5]. The LSP treatment, when applied to a metallic target, has already proven its capability to improve mechanical properties and fatigue performance [6,7,8,9,10]: crack initiation is inhibited and crack growth is delayed. Several studies since have shown that it can be used as an extended non-destructive test for aeronautical bonding [13,14,15]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
