Effects of Simulation Parameters on Residual Stresses of Inconel Alloy 600 in Finite Element Laser Shock Peening Analysis

2012 ◽  
Author(s):  
Ju Hee Kim ◽  
Ji Soo Kim ◽  
Yun Jae Kim ◽  
Hong Yeol Bae ◽  
Joung Soo Kim
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Pulse Duration ◽  
Laser Shock Peening ◽  
Maximum Pressure ◽  
Alloy 600 ◽  
Laser Shock ◽  
Inconel Alloy ◽  
Shock Peening ◽  
Compressive Residual Stresses

Laser shock peening (LSP) is an innovative surface treatment technique, which is successfully applied to improve fatigue performance of metallic components. After the treatment, the fatigue strength and fatigue life of a metallic material can be increased remarkably owing to the presence of compressive residual stresses in the material. Recently, the incidences of cracking in Alloy 600 small-caliber penetration nozzles (CRDM (control rod drive mechanism) and BMI (bottom mounted instrument)) have increased significantly. The cracking mechanism has been attributed to primary water stress corrosion cracking (PWSCC) and has been shown to be driven by welding residual stresses and operational stresses in the weld region. For this reason, to mitigating weld residual stress, preventive maintenance of BMI nozzles was considered application of laser shock peening process. The present study is to predict the residual stresses distribution along the peening surface and the interior of the target (Inconel alloy 600 steel) induced by single and multiple LSP processes using the finite element method. The simulations were accomplished using a commercial finite element package ABAQUS, employing both explicit and implicit methodologies. Effects of parameters related to finite element simulation of laser shock peening process to determine compressive residual stresses of Inconel alloy 600 steel are discussed, in particular parameters associated with the LSP process, such as the maximum pressure, pressure pulse duration, laser spot size and number of shots. It is found that about 2HEL maximum pressure and a certain range of the pulse duration can produce maximum compressive residual stresses near the surface, and thus proper choices of these parameters are important. But plastically affected depth increase with increasing maximum pressure and pulse duration. For the laser spot size, residual stresses are not affected, provided it is larger than a certain size. Magnitudes of the compressive residual stresses and plastically affected depth are found to increase with increasing number of shots, but the effect is less pronounced for more shots. Thus, the amplitude of the initial tensile residual stresses was remarkably changed by LSP. Additionally, In order to evaluate the influence of initial residual stresses in Inconel alloy 600 steel, the initial condition option was employed in the finite element code.

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.

Numerical Analysis of Laser Shock Peening as a Process for Generation of Compressive Residual Stresses in Open Hole Specimens

2011 ◽  
Vol 681 ◽  
pp. 267-272 ◽  
Author(s):  
Goran Ivetic ◽  
Ivan Meneghin ◽  
Enrico Troiani
Keyword(s):  
Fatigue Crack ◽  
Numerical Analysis ◽  
Residual Stresses ◽  
Crack Nucleation ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Fatigue Crack Nucleation ◽  
Open Hole ◽  
Shock Peening ◽  
Compressive Residual Stresses

A numerical analysis of Laser Shock Peening (LSP) process is illustrated, applied to an open hole specimen. This specimen is representative of a section of an aircraft fuselage lap joint, typically prone to fatigue crack nucleation at the rivet holes. The effect of the residual stress field induced by LSP on the fatigue life of open hole specimens is investigated. The results show that significant compressive residual stresses can be introduced in fatigue sensitive areas using LSP, postponing fatigue crack nucleation.

Fatigue Crack Retardation in LSP and Sp Treated Aluminium Specimens

2014 ◽  
Vol 891-892 ◽  
pp. 986-991 ◽  
Author(s):  
Elke Hombergsmeier ◽  
Vitus Holzinger ◽  
Ulrike C. Heckenberger
Keyword(s):  
Fatigue Crack ◽  
Residual Stresses ◽  
Crack Propagation ◽  
Shot Peening ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Propagation Behavior ◽  
Shock Peening ◽  
Compressive Residual Stresses ◽  
Crack Propagation Behavior

Highly loaded aircraft components have to fulfill strict fatigue and damage tolerance requirements. For some components besides the crack initiation mainly the fatigue crack propagation behavior is the main design criteria. To improve the crack propagation behavior of a component several methods are known or have been described in literature. For thin aircraft panels i.e. the application of crenellations [1] or bonded doublers [2, 3] can be a solution. For thick structures mainly the introduction of compressive residual stresses is beneficial. In this paper the potential of compressive residual stresses obtained by Laser Shock Peening (LSP) and Shot Peening (SP) is investigated. By means of Laser Shock Peening the residual compressive stress field can extend much deeper below the treated surface than that produced by conventional Shot Peening (i.e. with steel or ceramic balls) [4, 5]. The effect of such deep compressive stress profile results in a significantly higher benefit in fatigue behavior after Laser Shock Peening or after the combination of Laser Shock Peening and Shot Peening on top. The measurement of residual stresses as a depth profile has been performed by incremental hole drilling (ICHD) and contour method. Finally crack propagation tests have been carried out to validate the process technology approach.

Fabrication and Finite Element Analysis of Micro Dents Using μ-Laser Shock Peening

2008 ◽  
Author(s):  
Michael P. Sealy ◽  
Y. B. Guo ◽  
M. F. Horstemeyer
Keyword(s):  
Finite Element ◽  
Laser Pulse ◽  
Pulse Duration ◽  
Laser Shock Peening ◽  
Direct Write ◽  
Laser Shock ◽  
Element Analysis ◽  
Element Simulation ◽  
Shock Peening ◽  
Peak Pressures

Laser shock peening (LSP) is an innovative surface treatment developed to improve surface integrity. This study explores the feasibility using LSP to direct-write surface micro dents for lubricant retention. Since LSP is a highly transient process with a pulse duration of 10 – 100 ns, a real time in-situ measurement of laser/material interaction such as transient stresses/strains is challenging. Therefore, a 3D finite element simulation of micro-scale laser shock peening was developed to determine the effect of laser pulse duration and peak pressure on the transient material behaviors of titanium Ti-6Al-4V. The simulated dent geometry is similar to the measured dent geometry in terms of morphology. The results suggested there is an optimal peening time that produces the deepest dent. The maximum transient stress in peening direction occurred at a certain laser pulse time. However, the stress along the depth and radius were drastically affected by the peak pressures.

Numerical Study of Laser Shock Peening Effects on Alloy 600 Nozzles With Initial Residual Stresses

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Ji-Soo Kim ◽  
Hyun-Suk Nam ◽  
Yun-Jae Kim ◽  
Ju-Hee Kim
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Numerical Study ◽  
Laser Shock Peening ◽  
Tensile Residual Stress ◽  
Alloy 600 ◽  
Laser Shock ◽  
Near Surface ◽  
Rate Dependent ◽  
Shock Peening

This paper investigates the effect of initial residual stress and prestrain on residual stresses due to laser shock peening for Alloy 600 using numerical simulation. For simulation, the strain rate dependent Johnson–Cook hardening model with a Mie–Grüneisen equation of state is used. Simulation results are compared with published experimental data, showing good agreement. It is found that the laser shock peening (LSP) process is more effective for higher initial tensile residual stress and for larger initial prestrain in terms of compressive stress at the near surface. However, the effective depth decreases with increasing initial tensile residual stress and initial prestrain.

scholarly journals Effect of Laser Shock Peening Parameters on Residual Stresses and Corrosion Fatigue of AA5083

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1635
Author(s):  
Jan Kaufman ◽  
Zbyněk Špirit ◽  
Vijay Krishnaswami Vasudevan ◽  
Matthew Alan Steiner ◽  
Seetha Mannava ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Corrosion Fatigue ◽  
Fatigue Testing ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Saturation Point ◽  
Compressive Stresses ◽  
Pulse Density ◽  
Shock Peening ◽  
Compressive Residual Stresses

Aluminium alloy 5083 was subjected to Laser Shock Peening both with (LSP) and without protective coating (LPwC) at multiple pulse densities. A second LPwC treatment was conducted fully submersed under water, in addition to the standard laminar water flow condition. The results show that compressive residual stresses were generated in all cases, although their character varied depending on the peening strategy and method of confinement. In all cases, higher pulse density lead to an increase in compressive stresses with a saturation point of −325 MPa at 1089 p/cm2 for the LPwC treatments. Corrosion fatigue testing of sensitized samples then showed 59% and 69% improvement in fatigue strength after the LSP and LPwC treatments, respectively.

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