High-speed micro-scale laser shock peening using a fiber laser (Conference Presentation)

2017 ◽  
Author(s):  
Chenfei Zhang ◽  
Leimin Deng ◽  
Shiding Sun ◽  
Yongfeng Lu
Keyword(s):  
Fiber Laser ◽  
High Speed ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Micro Scale ◽  
Shock Peening

Numerical Investigation of Opposing Dual Sided Micro Scale Laser Shock Peening

2006 ◽  
Author(s):  
Yajun Fan ◽  
Youneng Wang ◽  
Sinisa Vukelic ◽  
Y. Lawrence Yao
Keyword(s):  
Residual Stress ◽  
Shock Waves ◽  
Laser Shock Peening ◽  
Time Lags ◽  
Laser Shock ◽  
Surface Residual Stress ◽  
Strain Rate Effects ◽  
Micro Scale ◽  
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 micro scale 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.

scholarly journals Grain boundary response of aluminum bicrystal under micro scale laser shock peening

2009 ◽  
Vol 46 (18-19) ◽  
pp. 3323-3335 ◽  
Author(s):  
Siniša Vukelić ◽  
Jeffrey W. Kysar ◽  
Y. Lawrence Yao
Keyword(s):  
Grain Boundary ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Micro Scale ◽  
Shock Peening

scholarly journals A Novel Micro-Scale Plastic Deformation Feature on a Bulk Metallic Glass Surface under Laser Shock Peening

2013 ◽  
Vol 30 (3) ◽  
pp. 036201 ◽  
Author(s):  
Yan-Peng Wei ◽  
Bing-Chen Wei ◽  
Xi Wang ◽  
Guang-Yue Xu ◽  
Lei Li ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Glass Surface ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Micro Scale ◽  
Deformation Feature ◽  
Shock Peening

Spatially Resolved Characterization of Residual Stress Induced by Micro Scale Laser Shock Peening

2004 ◽  
Vol 126 (2) ◽  
pp. 226-236 ◽  
Author(s):  
Hongqiang Chen ◽  
Y. Lawrence Yao ◽  
Jeffrey W. Kysar
Keyword(s):  
Residual Stress ◽  
Cell Structure ◽  
Fem Analysis ◽  
Dislocation Cell ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
X Ray ◽  
Micro Scale ◽  
Spatially Resolved ◽  
Shock Peening

Single crystal aluminum and copper of (001) and (110) orientation were shock peened using laser beam of 12 micron diameter and observed with X-ray micro-diffraction techniques based on a synchrotron light source. The X-ray micro-diffraction affords micron level resolution as compared with conventional X-ray diffraction which has only mm level resolution. The asymmetric and broadened diffraction profiles registered at each location were analyzed by sub-profiling and explained in terms of the heterogeneous dislocation cell structure. For the first time, the spatial distribution of residual stress induced in micro-scale laser shock peening was experimentally quantified and compared with the simulation result obtained from FEM analysis. Difference in material response and microstructure evolution under shock peening were explained in terms of material property difference in stack fault energy and its relationship with cross slip under plastic deformation. Difference in response caused by different orientations (110 and 001) and active slip systems was also investigated.

Experimental Study of Micro-Scale Laser Shock Peening on Copper Foils

2011 ◽  
Vol 464 ◽  
pp. 506-509 ◽  
Author(s):  
W. Zhu ◽  
Jian Zhong Zhou ◽  
M Wang ◽  
Shu Huang ◽  
Deng Hui Wei ◽  
...  
Keyword(s):  
Laser Energy ◽  
Mechanical Test ◽  
Test System ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Micro Scale ◽  
Copper Foils ◽  
Typical Experiment ◽  
Shock Peening ◽  
Reliability Performance

Micro-scale laser shock peening (μLSP) is a flexible and precise process that can potentially be applied to metallic structures in micro devices to improve strength and reliability performance. In order to understand the mechanism of μLSP process, a typical experiment was carried out for copper foils specimen with various process parameters. Surface morphology, deformation and hardness of the specimens were observed and characterized by 3D microscope system and situ nano-mechanical test system respectively. It was found that overlapping rate of laser spot has a little effect on microscopic deformation depth which increases slowly with the increasing of laser energy, and micro-hardness of the laser treated specimens was improved significantly.

Spatially Resolved Characterization of Geometrically Necessary Dislocation Dependent Deformation in Micro-Scale Laser Shock Peening

2008 ◽  
Author(s):  
Youneng Wang ◽  
Sinisa Vukelic ◽  
Jeffrey W. Kysar ◽  
Y. Lawrence Yao
Keyword(s):  
Scale Effects ◽  
Fem Simulation ◽  
Target Material ◽  
Material Point ◽  
Laser Shock Peening ◽  
Lattice Rotation ◽  
Length Scale ◽  
Laser Shock ◽  
Micro Scale ◽  
Shock Peening

As the laser spot size in micro-scale laser shock peening is in the order of magnitude of several microns, the anisotropic response of grains will have a dominant influence on its mechanical behavior of the target material. Furthermore, conventional plasticity theory employed in previous studies needs to be reexamined due to the length scale effect. In the present work, the length scale effects in microscale laser shock peening have been investigated. The crystal lattice rotation underneath the shocked surface was determined via Electron Backscatter Diffraction (EBSD). From these measurements, the geometrically necessary dislocations (GND) density that the material contains has been estimated. The yield strength increment was then calculated from the GND distribution by using Taylor model and integrated into each material point of the FEM simulation. Finite element simulations, based on single crystal plasticity, were performed of the process for both with and without considering the GND hardening and the comparison has been conducted.

Study on the Numerical Simulation and Statistical Optimization of Micro-Scale Laser Shock Peening

2012 ◽  
Vol 9 (9) ◽  
pp. 1399-1403 ◽  
Author(s):  
Wei Zhu ◽  
Jianzhong Zhou ◽  
Min Wang ◽  
Shu Huang ◽  
Yujie Fan ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Statistical Optimization ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Micro Scale ◽  
Shock Peening

Effect of Laser Shock Peening on Fatigue Life at Stress Raiser Regions of a High-Speed Micro Gas Turbine Shaft: A Simulation Based Study

2019 ◽  
Vol 45 ◽  
pp. 15-27
Author(s):  
Jan G. Pretorius ◽  
Dawood A. Desai ◽  
Glen C. Snedden
Keyword(s):  
Fatigue Life ◽  
Gas Turbine ◽  
High Speed ◽  
Stress Raiser ◽  
Element Model ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Residual Stress Field ◽  
Shock Peening ◽  
Stress Raisers

Fatigue failure due to stress raiser regions on critical rotating components in gas turbine engines, such as the shaft, is a crucial aspect. Methods to reduce these stresses and improve fatigue life are a source of ongoing research. Laser shock peening is a method where compressive residual stresses are imparted on the stress raisers of such components. However, numerical based studies on multiple laser shock peening applied to stress raisers is under-researched. Hence, this study will attempt to predict the fatigue life at fillet radii step induced stress raiser regions on a high-speed gas turbine engine shaft by utilization of laser shock peening. The objective of this study was achieved by developing a more computational efficient finite element model to mimic the laser shock peening process on the fillet radii step induced stress raiser regions of a shaft. A modified laser shock peening simulation method for effective prediction of the residual stress field was introduced. Furthermore, the fatigue life improvement due to laser shock peening was predicted by employing Fe-safe fatigue software. From the results, the modified laser shock peening simulation method provided accurate prediction of the residual stress field with a reduced computational time of over 68% compared to conventional methods. The fatigue life revealed an improvement of 553% due to laser shock peening, which is comparable to similar findings in the literature. Hence, from the findings and results achieved, the developed finite element model can be an appropriate tool to assist in the fatigue life estimation of laser shock peening applied to stress raisers.

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