*Article* **Finite Element Analysis of Laser Peening of Thin Aluminum Structures**

### **Kristina Langer 1, Thomas J. Spradlin 1 and Michael E. Fitzpatrick 2,\***


Received: 20 September 2019; Accepted: 2 December 2019; Published: 6 January 2020

**Abstract:** Laser shock peening has become a commonly applied industrial surface treatment, particularly for high-strength steel and titanium components. Effective application to aluminum alloys, especially in the thin sections common in aerospace structures, has proved more challenging. Previous work has shown that some peening conditions can introduce at-surface tensile residual stress in thin Al sections. In this study, we employ finite element modeling to identify the conditions that cause this to occur, and show how these adverse effects can be mitigated through selection of peen parameters and patterning.

**Keywords:** laser peening; residual stress; aluminum alloys
