The scaling of laser peen forming: A two-experiment finite similitude approach

Abstract

Laser peen forming (LPF) utilizes laser-induced shock waves to bend and shape metal plates in what is effectively a non-thermal metal-forming process involving no hard tooling. A difficulty with the process, arising from the rapid localized physics involved, is the determination of process conditions for the establishment of desirable process outcomes. The nanosecond physical behaviors induced by the pulsed laser can make simulation impractical, effectively restricting investigations to experiments as the only practical recourse. This paper focuses on the use of scaled experimentation for LPF with the objective of making experimental outcomes more broadly applicable to a wider range of process conditions. Understanding how processes scale can in principle aid in the establishment of process parameters through timely and cost-effective experiments. Scaled experimentation has recently undergone a paradigm shift with the arrival of the finite similitude scaling theory. The theory provides extra degrees of freedom and facilitates the use of unlimited numbers of scaled experiments and allows for anisotropy in plate thickness. It is demonstrated in the work through experimental tests and simulation at two different scales, that geometric and loading similarities can be broken, yet the behavior of LPF can be quantified to good accuracy.