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.

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.

Numerical Simulation on Nanoparticles Integrated Laser Shock Peening of Aluminum Alloy

2009 ◽  
Author(s):  
Chang Ye ◽  
Gary J. Cheng
Keyword(s):  
Numerical Simulation ◽  
Particle Size ◽  
Laser Shock Peening ◽  
Particle Orientation ◽  
Stress Wave Propagation ◽  
Stress And Strain ◽  
Laser Shock ◽  
The Matrix ◽  
Final Stress ◽  
Shock Peening

In this paper, numerical simulation of nanoparticle integrated laser shock peening of aluminum alloys was carried out. A “tied constraint” was used to connect the matrix and nanoparticle assembly in ABAQUS package. Different particle size and particle volumes fraction (PVF) were studied. It was found that there is significant stress concentration around the nanoparticles. The existence of nanoparticle will influence the stress wave propagation and thus the final stress and strain state of the material after LSP. In addition, particle size, PVF and particle orientation all influence the strain rate, static residual stress, static plastic strain and energy absorption during the LSP process.

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