Finite Element Analysis of the Variation in Residual Stress Distribution in Laser Shock Peening of Steels

Abstract

Laser shock peening (LSP) is a surface treatment technique similar to conventional shot peening. The laser induced plasma causes plastic deformations and compressive residual stresses that are useful for developing improved properties in the fields of resistance to fatigue, wear or stress corrosion cracking. The actual distribution of residual stresses is extremely important while designing for improved fatigue life using laser shock peening, as fatigue cracks would initiate from the weakest point in the structure, in this paper, the variations in distribution of residual stresses due to laser shock peening are studied with a focus on two materials, annealed 1053 and hardened 52100 AISI steels. A 3D finite element model was developed to study the actual distributions of the residual stresses due to laser shock peening. The effect of hardness on the distribution of the residual stresses and the presence of tensile residual stresses in the surrounding regions of the impact is analyzed. Much larger variations in the residual stress distributions were observed in case of the 1053 steel as compared to hardened 52100 steel. A comprehensive analysis of the simulation results was performed in order to address and explain this behavior. It was observed that the extent of overlap would also affect the variations in the residual stress distributions. The tensile residual stresses present in the areas surrounding the shocked region were also analyzed based upon the extent of overlap and the hardness of the material. It was observed that the ratio of peak tensile to compressive residual stresses developed in 1053 steel was much higher as compared to that in the hardened 52100 steel.

Modeling of residual stress field induced in Ti–6Al–4V alloy plate by two sided laser shock processing

“…Thereby, the magnitude of CRS at the center of laser spot is less than that at its perimeter. This phenomenon is also called "RS hole" in some references [14,34]. Therefore, in order to avoid the effect of RS hole, the RS in thickness in Fig.…”

Laser shock processing of polycrystalline alumina ceramics

“…In this process a plasma is formed and the explosive expansion of the plasma generates shock waves which penetrate into the bulk material and induce significant compressive residual stresses in a range from 100 MPa to several GPa (Figure ). The compressive stresses can extend to a depth of more than 1 mm from the surface . A sacrificial coating protects the working materials from laser heating, which essentially remain at room temperature during processing.…”

Influence of laser shock peening on irradiation defects in austenitic stainless steels

“…The shock wave pressure is thus the origin of the plastic deformation in the near-surface of the alloy. Many studies in the literature have simulated the dynamic response of metals subjected to LSP using the finite element method [29,50,51]. It is also important to note that the compressive stress and plastic deformation generated by LSP decrease with the depth of the sample.…”

“…In the LSP process, a laser beam hits the sacrificial coating on the surface of the metal target and forms a plasma, which rapidly expands and generates shock waves into the bulk (Figure 1). The laserdriven shock waves cause significant compressive residual stresses (typically 0.1-1 GPa) that can extend to a depth of more than 1 mm from the surface [28,29]. Compared to traditional mechanical shot peening, LSP offers many advantages, such as deeper penetration of compressive stresses (typically > 1 mm, which is about ten times that of mechanical shot peening), shorter process times (typically several tens of nanoseconds), precise control, accuracy, and flexibility [30,31].…”