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.

Fabrication and Characterization of Micro-Dent Produced by Laser Shock Peening on Zr-Based Bulk Metallic Glass

2016 ◽  
Vol 849 ◽  
pp. 14-21
Author(s):  
Yun Hu Zhu ◽  
Jie Fu ◽  
Chao Zheng ◽  
Zhong Ji
Keyword(s):  
Plastic Deformation ◽  
Laser Pulse ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Pulse Energy ◽  
Laser Pulse Energy ◽  
Laser Energy ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Shock Peening

A Zr41.2Ti13.8Cu12.5Ni10Be22.5 (vit1) bulk metallic glass was processed by Nd: Glass laser pulses with duration 30ns and energy in the range 20 to 30J. The surface morphology and surface micro-hardness of the vit1 metallic glass, treated with varying laser energy, had been studied in detail. Laser shock peening induced plastic deformation and caused a micro-dent to be generated on the vit1 surface. The optical profiling tests showed that laser pulse energy greatly influenced the diameter and depth of the micro-dents. The surface roughness which was caused by various laser pulse energy was assessed and characterized. The three-dimensional surface topography of the laser treated region on vit1 surfaces had been characterized. In addition the plastic deformation features were also studied.

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.

Study on Characteristics of Stress and Parameters Influence in Microscale Laser Shock Peening

2011 ◽  
Vol 464 ◽  
pp. 336-339 ◽  
Author(s):  
Yu Jie Fan ◽  
Jian Zhong Zhou ◽  
Shu Huang ◽  
W. Wang ◽  
Deng Hui Wei ◽  
...  
Keyword(s):  
Residual Stress ◽  
Shape Factor ◽  
Influence Factor ◽  
Laser Energy ◽  
Laser Shock Peening ◽  
Beam Diameter ◽  
Laser Shock ◽  
Asymmetrical Distribution ◽  
Shock Peening ◽  
Distribution Of Stress

Microscale laser shock peening (μLSP) can generate beneficial compressive stress distribution in the targets, as the used beam diameter in μLSP is at the order of micron equivalent with grain size, the treated material must be considered as anisotropic and inhomogeneous, this causes an asymmetrical distribution of residual stress. In this paper, shape factor σSF was introduced and defined to characterize the asymmetrical distribution of stress, optimum conditions of factors and the influence degree were explored based on Taguchi design with the optimal object of stress characterization values. The results show that shape factor is a significant characteristic of residual stress induced by μLSP, crystal orientation is the most important influence factor, but laser energy and peening number have significant influence on stress characterization values.

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.

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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