Parametric Study on Single Shot and Overlapping Laser Shock Peening on Various Metals via Modeling and Experiments

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
Yunfeng Cao ◽  
Yung C. Shin ◽  
Benxin Wu
Keyword(s):  
Experimental Data ◽  
Residual Stress ◽  
Finite Element ◽  
Element Model ◽  
Substrate Material ◽  
Laser Shock Peening ◽  
Single Shot ◽  
Laser Shock ◽  
3D Finite Element ◽  
Shock Peening

Laser shock peening (LSP) under water confinement regime involves several complicated physical phenomena. Among these phenomena, the interaction between laser and coating material during LSP is very important to the laser-induced residual stress, which has an important effect on the fatigue and corrosion properties of the substrate material. To gain a better understanding of this interaction, a series of experiments, including single shot, single-track overlapping, and multitrack overlapping LSP, has been carried out on various metals with different coatings. A 3D finite element model has also been developed to simulate the LSP process. Combining this with a previously developed confined plasma model, which has been verified by the experimental data from literature, the 3D finite element model is used to predict the residual stresses induced in the substrate material as well as the indentation profile on the substrate surface. The model prediction of indentation profiles is compared with the experimental data. The residual stresses in the depth direction are also validated against the X-ray diffraction measurement data for 4140 steel and Ti–6Al–4V, and good agreements are obtained for both predictions. The effect of process parameters on the residual stress is also investigated both experimentally and theoretically.

A Parametric Study on Overlapping Laser Shock Peening of 4140 Steel via Modeling and Experiments

2008 ◽  
Author(s):  
Yunfeng Cao ◽  
Yung C. Shin ◽  
Benxin Wu
Keyword(s):  
Experimental Data ◽  
Residual Stress ◽  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Substrate Material ◽  
Laser Shock Peening ◽  
Single Shot ◽  
Laser Shock ◽  
Shock Peening

Laser shock peening (LSP) under the water confinement regime (WCR) involves several complicated physical phenomena. Among these phenomena, the interaction between laser and coating material during LSP is very important to the laser induced residual stress, which has an important effect on the fatigue and corrosion properties of the substrate material. To gain a better understanding of this interaction, a series of experiments, including single shot, single track overlapping, and multi-track overlapping LSP, have been carried out on 4140 steel with black paint coating. A 3-D finite element model has also been developed to simulate the LSP process. Combining this with a previously developed confined plasma model, which has been verified by the experimental data from literature, the 3-D finite element model is used to predict the residual stresses induced in the substrate material as well as the indentation profile on the substrate surface. The model prediction of indentation profiles are compared with the experimental data and good agreements are obtained. The effect of process parameters on the residual stress has also been investigated both experimentally and theoretically.

Effect of Laser Shock Peening on Surface Residual Stress and Plastically Affected Depth of TC11 Titanium Alloy

2019 ◽  
Vol 943 ◽  
pp. 20-25
Author(s):  
Ran Zhu ◽  
Yong Kang Zhang ◽  
Gui Fang Sun ◽  
Pu Li
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Titanium Alloy ◽  
Finite Element Model ◽  
Element Model ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Surface Residual Stress ◽  
Shock Peening ◽  
Tc11 Titanium Alloy

The confined laser shock peening (LSP) is an innovative surface treatment technique designed to improve the fatigue performance of materials by imparting compressive residual stresses into materials. A 3D finite element model was developed to predict the surface residual stress and plastically affected depth of the TC11 titanium alloy after LSP. The modeling procedure consists of two successive explicit analysis steps. The performance of finite element model was verified by comparing simulated results with the experimental data. With the validated finite element model, the influence of the process parameters (LSP path, thickness of the sample, number of impacts) was investigated on the surface residual stress and plastically affected depth of the TC11 titanium alloy after LSP. Some simulated results can be used to mentor the optimization of the process parameters of LSP.

Numerical Investigation of Opposing Dual Sided Microscale Laser Shock Peening

2006 ◽  
Vol 129 (2) ◽  
pp. 256-264 ◽  
Author(s):  
Yajun Fan ◽  
Youneng Wang ◽  
Sinisa Vukelic ◽  
Y. Lawrence Yao
Keyword(s):  
Residual Stress ◽  
Shock Waves ◽  
Element Model ◽  
Laser Shock Peening ◽  
Time Lags ◽  
Laser Shock ◽  
Surface Residual Stress ◽  
Strain Rate Effects ◽  
Stress Profiles ◽  
Shock Peening

Laser shock peening (LSP) is an innovative process which imparts compressive residual stresses in the processed surface of metallic parts to significantly improve fatigue life and fatigue strength of this part. In opposing dual sided LSP, the workpiece can be simultaneously irradiated or irradiated with different time lags to create different surface residual stress patterns by virtue of the interaction between the opposing shock waves. In this work, a finite element model, in which the hydrodynamic behavior of the material and the deviatoric behavior including work hardening and strain rate effects were considered, was applied to predict residual stress distributions in the processed surface induced under various conditions of the opposing dual sided microscale laser shock peening. Thus the shock waves from each surface will interact in different ways through the thickness resulting in more complex residual stress profiles. Additionally, when treating a thin section, opposing dual sided peening is expected to avoid harmful effects such as spalling and fracture because the pressures on the opposite surfaces of the target balance one another and prohibit excessive deformation of the target. In order to better understand the wave–wave interactions under different conditions, the residual stress profiles corresponding to various workpiece thicknesses and various irradiation times were evaluated.

Finite Element Analysis of the Effect of Overlapping Impacts of Laser Shock Peening Within Annealed AISI 1053 Steel

2010 ◽  
Author(s):  
Rohit Voothaluru ◽  
C. Richard Liu
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Laser Shock Peening ◽  
Treatment Technique ◽  
Laser Shock ◽  
Fatigue Wear ◽  
Short Period ◽  
Shock Peening ◽  
Compressive Residual Stresses

Laser shock peening is a surface treatment technique similar to conventional shot peening. The laser induced plasma causes plastic deformations and compressive residual stresses in materials which are useful for developing improved properties in the fields of fatigue, wear or stress corrosion cracking. Finite element method is an efficient tool to predict the mechanical effects and the deformations caused due to laser shock peening, which otherwise are difficult to calculate due to the severe pressure imparted in a very short period of time. This paper presents the calculations performed using ABAQUS, for the simulation of multiple laser shock processing in order to evaluate the residual stress and the deformation of the material. A study of the effect of multiple laser shocks and their extent of overlap on the affected depths and the tensile and compressive residual stresses has been discussed. FEM calculations of residual stress fields and extent of surface deformation in annealed AISI 1053 steel has been investigated along with a study of the distribution of tensile and compressive residual stresses due to the difference in the extent of overlap of the multiple shocks.

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

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Rohit Voothaluru ◽  
C. Richard Liu ◽  
Gary J. Cheng
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Laser Shock Peening ◽  
Treatment Technique ◽  
Stress Distributions ◽  
Laser Shock ◽  
Shock Peening ◽  
The Impact ◽  
Compressive Residual Stresses

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.

Fatigue Life Recovery via Laser Shock Peening in Mechanically Damaged Aluminium Sheet; Experiments and Prediction Models

2014 ◽  
Vol 891-892 ◽  
pp. 980-985 ◽  
Author(s):  
Niall Smyth ◽  
Philip E. Irving
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Prediction Models ◽  
Load Cycle ◽  
Laser Shock Peening ◽  
Stress Fields ◽  
Hole Drilling ◽  
Laser Shock ◽  
Aluminium Sheet ◽  
Shock Peening

This paper reports the effectiveness of residual stress fields induced by laser shock peening (LSP) to recover pristine fatigue life. Scratches 50 and 150 μm deep with 5 μm root radii were introduced into samples of 2024-T351 aluminium sheet 2 mm thick using a diamond tipped tool. LSP was applied along the scratch in a band 5 mm wide. Residual stress fields induced were measured using incremental hole drilling. Compressive residual stress at the surface was-78 MPa increasing to-204 MPa at a depth of 220 μm. Fatigue tests were performed on peened, unpeened, pristine and scribed samples. Scratches reduced fatigue lives by factors up to 22 and LSP restored 74% of pristine life. Unpeened samples fractured at the scratches however peened samples did not fracture at the scratches but instead on the untreated rear face of the samples. Crack initiation still occurred at the root of the scribes on or close to the first load cycle in both peened and unpeened samples. In peened samples the crack at the root of the scribe did not progress to failure, suggesting that residual stress did not affect initiation behaviour but instead FCGR. A residual stress model is presented to predict crack behaviour in peened samples.

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