Modeling of the Superficial Laser Shock Peening Treatment Process: Application on a Titanium Aircraft Turbine Engine Blade

Abstract

This paper presents a numerical simulation of the Laser Shock Peening (LSP) process using Finite Element Method (FEM). The majority of the controlling parameters of the process have been taken into account. The LSP loading has been characterized by using a repetitive time Gaussian increment pressure applied uniformly at the impacted zone. The used behavior law of the treated material is supposed Johnson Cook elastic-viscous-plastic coupled with damage. The proposed model leads to obtain the surface modifications (i) the in-depth residual stresses profile, (ii) the induced plastic strains profile, (iii) the geometrical surface modification of the impacted zone and (iv) the superficial damage which can be induced in few cases, where the operating conditions are not well chosen and optimized. An aeronautical application of LSP has been carried out on aircraft turbine engine blade made by Ti-6Al-4V super alloy. This mechanical treatment is applied in order to increase the durability of titanium fan blades and decrease their sensitivity to foreign object damage (FOD). The resulting surface compressive residual stress significantly improves the high-cycle-fatigue properties of the component and greatly increases resistance to blade failure. Finally, we studied the feasibility of the influence of LSP treatment on the phenomenon of crack propagation by introducing a superficial crack defect on the edge of the studied blade structure. This is physically consistent and leads to optimize the operating conditions in order to limit the damage risks.

Review on Anti-Fatigue Performance of Gradient Microstructures in Metallic Components by Laser Shock Peening

“…Frija, M. et al [63] of the University of Sousse, Tunisia used finite element numerical simulations to simulate the effect of LSP on the resistance of Ti-6Al-4V titanium alloy blades to FOD with a square impact region and carried out experimental verification. The results showed that the surface residual compressive stress introduced by LSP significantly improved the high-cycle fatigue performance of titanium alloy fan blades.…”

Reliability prediction of high‐cycle fatigue behavior of parts treated by laser shock peening

“…The calculation of the reliability is carried out based on the "Constraint-Resistance" approach by the numerical method of Monte-Carlo random selections. For this, we used and validated the deterministic model developed in the works of Frija et al 16,17 The Crossland criterion is defined for a high cycle rate (usually taken to be equal to 10 7 cycles and for a 50% confidence level). It is defined by a linear combination of the amplitude of ffiffiffiffiffiffiffi J 2,a p and the maximum hydrostatic pressure P max .…”

“…The calculation of the reliability is carried out based on the “Constraint‐Resistance” approach by the numerical method of Monte‐Carlo random selections. For this, we used and validated the deterministic model developed in the works of Frija et al 16,17 …”