Numerical Simulation of One Pulse Power Laser Shock Peening

2014 ◽  
Vol 936 ◽  
pp. 1653-1656
Author(s):  
Lei Chen
Keyword(s):  
Residual Stress ◽  
Laser Pulse ◽  
Plastic Strain ◽  
High Energy ◽  
Laser Shock Peening ◽  
High Energy Density ◽  
Stress Wave Propagation ◽  
Material Surface ◽  
Laser Shock ◽  
Shock Peening

Laser shock peening (LSP) is a novel technology of surface treatment. LSP utilizes a short laser pulse with high energy density, which induced a high pressure stress wave propagation and residual compressive stress on material surface. The effects of LSP of SAE9310 steel with a laser pulse of 14.2J at 2.9mm square beam have been studied by finite element method. The underlying formulation is based on Lagangian elastoplastic materials model. The propagation of shock wave, residual stress and plastic strain are simulated. The simulations show that the residual stress is mainly in the radial direction of the workpiece, and nearly zero in the longitudinal direction. The plastic strain remains on the processed surface dominantly. Divergences between theoretical and experimental residual stress occur due to the simplification of shock peening conditions.

scholarly journals Coupled Modeling Approach for Laser Shock Peening of AA2198-T3: From Plasma and Shock Wave Simulation to Residual Stress Prediction

Metals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 107
Author(s):  
Vasily Pozdnyakov ◽  
Sören Keller ◽  
Nikolai Kashaev ◽  
Benjamin Klusemann ◽  
Jens Oberrath
Keyword(s):  
Residual Stress ◽  
Laser Pulse ◽  
Protective Coatings ◽  
Global Model ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Coating Materials ◽  
Fe Simulations ◽  
Shock Peening ◽  
The Impact

Laser shock peening (LSP) is a surface modification technique to improve the mechanical properties of metals and alloys, where physical phenomena are difficult to investigate, due to short time scales and extreme physical values. In this regard, simulations can significantly contribute to understand the underlying physics. In this paper, a coupled simulation approach for LSP is presented. A global model of laser–matter–plasma interaction is applied to determine the plasma pressure, which is used as surface loading in finite element (FE) simulations in order to predict residual stress (RS) profiles in the target material. The coupled model is applied to the LSP of AA2198-T3 with water confinement, 3×3mm2 square focus and 20 ns laser pulse duration. This investigation considers the variation in laser pulse energy (3 J and 5 J) and different protective coatings (none, aluminum and steel foil). A sensitivity analysis is conducted to evaluate the impact of parameter inaccuracies of the global model on the resulting RS. Adjustment of the global model to different laser pulse energies and coating materials allows us to compute the temporal pressure distributions to predict RS with FE simulations, which are in good agreement with the measurements.

Laser Shock Peening on a 6056-T4 Aluminium Alloy for Airframe Applications

2014 ◽  
Vol 891-892 ◽  
pp. 974-979 ◽  
Author(s):  
Daniel Glaser ◽  
Claudia Polese ◽  
Rachana D. Bedekar ◽  
Jasper Plaisier ◽  
Sisa Pityana ◽  
...  
Keyword(s):  
Residual Stress ◽  
Laser Pulse ◽  
Fatigue Tests ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
X Ray Diffraction ◽  
Bending Fatigue ◽  
Pulse Density ◽  
Shock Peening ◽  
Compressive Residual Stresses

Laser Shock Peening (LSP) is a material enhancement process used to introduce compressive residual stresses in metallic components. This investigation explored the effects of different combinations of LSP parameters, such as irradiance (GW/cm2) and laser pulse density (spots/mm2), on 3.2 mm thick AA6056-T4 samples, for integral airframe applications. The most significant effects that are introduced by LSP without a protective coating include residual stress and surface roughness, since each laser pulse vaporizes the surface layer of the target. Each of these effects was quantified, whereby residual stress analysis was performed using X-ray diffraction with synchrotron radiation. A series of fully reversed bending fatigue tests was conducted, in order to evaluate fatigue performance enhancements with the aim of identifying LSP parameter influence. Improvement in fatigue life was demonstrated, and failure of samples at the boundary of the LSP treatment was attributed to a balancing tensile residual stress.

Application of Central Composite Design Based on Numerical Integration for Optimization of Laser Shock Peening

2012 ◽  
Vol 452-453 ◽  
pp. 1074-1078
Author(s):  
Gang Zheng ◽  
Jin Rong Fan ◽  
Shu Huang ◽  
Jian Zhong Zhou ◽  
Hong Yan Ruan
Keyword(s):  
Residual Stress ◽  
Laser Pulse ◽  
Pulse Energy ◽  
Surface Deformation ◽  
Laser Pulse Energy ◽  
Laser Shock Peening ◽  
Beam Diameter ◽  
Laser Shock ◽  
Energy Beam ◽  
Shock Peening

In order to analyze effect of processing parameters on Laser Shock Peening(LSP), a novel numerical model integrated with FEM and statistical optimization algorithm was established, and the numerical simulation of LSP process was carried out. In simulation, laser pulse energy, beam diameter and center distance were considered as control parameters, while the compressive residual stress and the deformation value as output aim parameters,. The results indicates that the laser pulse energy has the strongest impact on the surface residual stress, while the spot diameter affects the section residual stress and the surface deformation. Moreover, the response surface function was applied to predict and optimize laser parameters. Lastly the presented method was verified by experiments.

Prediction of Residual Stress Random Fields for Selective Laser Melted A357 Aluminum Alloy Subjected to Laser Shock Peening

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Mohammad I. Hatamleh ◽  
Jagannathan Mahadevan ◽  
Arif Malik ◽  
Dong Qian ◽  
Radovan Kovacevic
Keyword(s):  
Residual Stress ◽  
Random Fields ◽  
Joint Probability ◽  
High Energy ◽  
Laser Shock Peening ◽  
Model Parameters ◽  
Laser Shock ◽  
Near Surface ◽  
Numerical Predictions ◽  
Shock Peening

Abstract Residual stress (RS) is a major processing issue for selective laser melting (SLM) of metal alloys. Postprocessing by way of heat treatment or hot isostatic pressing is usually required for acceptable mechanical properties. In this work, laser shock peening (LSP) treatment on both SLM and cast aluminum A357 alloys are compared with regard to the development of beneficial near-surface compressive RS. Experiments are conducted using high energy nanosecond pulsed laser, together with a fast photodetector connected to a high-resolution oscilloscope and high-speed camera to identify detailed temporal and spatial laser pulse profiles to improve numerical predictions. Constitutive modeling for SLM A357 alloy is performed using finite element simulation and data obtained from X-ray diffraction (XRD) measurements. Since XRD-RS measurements are accompanied with significant machine-reported error, an effective method is introduced to quantify the material constitutive model uncertainty in terms of a joint probability mass function. Conventionally, most constitutive behavior research for LSP involves deterministic material modeling. Predicted RS using deterministic approaches fail to reflect real-world variations in the materials, laser treatment, or RS measurements. A discretized Bayesian inference is used to quantify the rate-dependent plasticity material model parameters as a joint probability function. RS are then characterized as random fields, which provides far greater insight into the practical ability to attain desired residual stresses. Moreover, for identical LSP treatments, it is determined that the material models are significantly different for the SLM and the conventional cast A357 aluminum alloys, resulting in much lower magnitude of compressive RS in the SLM alloy.

Effect of Post Laser Shock Peening on Microstructure and Mechanical Properties of Inconel 718 by Selective Laser Melting

2019 ◽  
Author(s):  
Kuldeep Singh Sidhu ◽  
Yachao Wang ◽  
Jing Shi ◽  
Vijay K. Vasudevan ◽  
Seetha Ramaiah Mannava
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Inconel 718 ◽  
Compressive Residual Stress ◽  
High Energy ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Laser Melting ◽  
Heat Treated ◽  
Shock Peening

Abstract This study investigates the effects of laser shock peening (LSP) on residual stress, near surface modification, and hardness of Inconel 718 (IN718) specimens manufactured by selective laser melting (SLM) technique. Optical microscope and electron backscattered diffraction (EBSD) is used to characterize the microstructures of both heat-treated and as-built specimens. A nanoindentation test is performed to determine the properties such as the hardness of as-built and heat-treated specimens. Afterward, the hardness along the distance from the LSP treated surface is also defined. To investigate the effect of LSP energy on the mechanical properties of specimens, two levels of LSP energy, e.g., low energy LSP (6.37 GW/cm2) and high energy LSP (8.60 GW/cm2), are carried out on selected samples. With the increase in laser energy density, it is found that both compressive residual stress and hardness increase after LSP treatment. The as-built specimens after high energy LSP treatment show the compressive residual stress of −875 MPa, and the surface hardness increases from 468 HV to 853 HV.

Laser Shock Peening of Nanoparticles Integrated Alloys: Numerical Simulation and Experiments

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
Chang Ye ◽  
Gary J. Cheng
Keyword(s):  
Residual Stress ◽  
Wave Propagation ◽  
Experimental Studies ◽  
Deformation Energy ◽  
Laser Shock Peening ◽  
Stress Wave Propagation ◽  
Laser Shock ◽  
Properties Of Materials ◽  
Shock Peening ◽  
Integrated Structures

Nanocomposite and multiphase structures have become more important nowadays to enhance the mechanical properties of materials. Laser shock peening (LSP) is one of the most efficient ways to increase component fatigue life. In this paper, numerical and experimental studies have been carried out to study the effects of nanoparticles integrated structures during the laser shock peening of aluminum alloys. The LSP experiment of aluminum samples with different particle densities was carried out. The effect of nanoparticle on shock wave propagation, plastic deformation, energy absorption, and residual stress magnitude was studied. A qualitative agreement is found between experiment and simulation. The existence of nanoparticles affects the stress wave propagation and increases the ratio of absorbed energy to total energy and thus the magnitude of residual stress of the material after LSP.

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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