Determination of Optimal Shot Peen Forming Patterns Using the Theory of Non-Euclidean Plates

We show how a theoretical framework developed for modeling nonuniform growth can model the shot peen forming process. Shot peen forming consists in bombarding a metal panel with multiple millimeter-sized shots that induce local bending of the panel. When applied to different areas of the panel, peen forming generates compound curvature profiles starting from a flat state. We present a theoretical approach and its practical realization for simulating peen forming numerically. To achieve this, we represent the panel undergoing peen forming as a bilayer plate, and we apply a geometry-based theory of non-Euclidean plates to describe its reconfiguration. Our programming code based on this approach solves two types of problems: it simulates the effect of a predefined treatment (the forward problem) and it finds the optimal treatment to achieve a predefined target shape (the inverse problem). Both problems admit using multiple peening regimes simultaneously. The algorithm was tested numerically on 200 randomly generated test cases.