M. P. Sealy, Y. Guo, The University of Alabama, Tuscaloosa, AL; S. Chen, University of Texas at Austin, Austin, TX
Laser Shock Peening (LSP) is a mechanical process where pressure waves caused by expanding plasma plastically deform the surface of a material. Typically, LSP is applied to metals as a form of surface treatment. As a result, the mechanical properties on the surface are enhanced to improve the performance of fatigue, wear, and foreign object damage (FOD).Titanium Ti-6Al-4V is a widely used engineering material in aerospace, automotive, and biomedical industries. Surface integrity induced by LSP of Ti-6Al-4V components is critical for product performance. However, the surface deformation and mechanical behavior in peening a Ti-6Al-4V surface has not been well understood. The research aims to understand the laser/ Ti-6Al-4V interaction, surface dent, and the related mechanical phenomena. A 3D finite element model has been developed to simulate micro scale laser shock peening of Ti-6Al-4V. The 3-dimensional Spatial and Temporal Shock Pressure Load was modeled using a developed load user subroutine. The dynamic mechanical behavior at high strain rates has been modeled using an internal state variable (ISV) plasticity model via a material user subroutine VUMAT which was coded into finite element software ABAQUS. Surface dent profile was simulated and favorably agrees with the measured geometry in terms of dimension and shape. Two simulation schemes at constant peak peening pressure and constant peening time were performed. Surface material behavior including stresses, strains, and strain rates along the peening or depth direction and along the radial direction were examined. A few interesting difference in mechanical phenomena between the surface and subsurface have been identified. Keywords: laser shock peening, surface dent, titanium, dynamic mechanical behavior, finite element analysis
Summary: Laser Shock Peening (LSP) is a mechanical process where pressure waves caused by expanding plasma plastically deform the surface of a material. Typically, LSP is applied to metals as a form of surface treatment. As a result, the mechanical properties on the surface are enhanced to improve the performance of fatigue, wear, and foreign object damage (FOD).
Titanium Ti-6Al-4V is a widely used engineering material in aerospace, automotive, and biomedical industries. Surface integrity induced by LSP of Ti-6Al-4V components is critical for product performance. However, the surface deformation and dynamic mechanical behavior at high strain rates in peening a Ti-6Al-4V surface has not been well understood. The research provides an insightful understanding on laser/ Ti-6Al-4V interaction, surface dent, and related mechanical phenomena.
