Residual stresses reconstruction in shot peened specimens containing sharp and blunt notches by experimental measurements and finite element analysis

Benedetti, M.; Fontanari, V.; Winiarski, B.; Allahkarami, Masoud; Hanan, Jay C.

doi:10.1016/j.ijfatigue.2016.01.020

Cited by 23 publications

(9 citation statements)

References 34 publications

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“…10(e) and 11(a) and (b)). Figure 12 compares the stresses measured at the surface by mechanical methods with those measured by μXRD for three The detailed analyses of the role of the RS field ahead of the notch root is beyond of the scope of this paper and can be found in the companion paper [49] and elsewhere [7]. The μXRD profile which samples over a larger depth and a wider area laterally is much smoother as one would expect.…”

Section: Surface Residual Stress Measurement Between the Notchesmentioning

confidence: 93%

“…Note: the distance along the notch bisector is measured from the root of notch notch tip is impeded by the size of the X-ray beam and/or the uncertainty on the exact location of the notch apex due to the geometry distortions produced by the peening treatment. The level of confidence whereby the RS field can be reconstructed in the vicinity of the notch tip on the base of the measurements herein presented will be discussed in the companion paper [49].…”

Section: Sub-surface Residual Stress Measurement Between the Notchesmentioning

confidence: 99%

“…A best estimate of the profile could be recovered using deconvolution methods similar to those used in [49,59]. However, given that the peak stress is broad and centred around 15 μm depth, it is likely that the RS determined by micromilling at a depth of 30 μm would be expected to be around 250 MPa.…”

Section: Shot Peening Residual Stresses Osn Plain Samplementioning

confidence: 99%

“…in 2D and 3D identified by Plasma Xe + FIB assisted large volume serial sectioning tomography, Energy-dispersive X-ray spectroscopy (EDS) and Electron Backscatter Diffraction (EBSD) maps. In our companion paper [49], the linescan measurements undertaken in the present work are used to reconstruct the RS field near the notch tips through finite element analyses.…”

Section: Introductionmentioning

confidence: 99%

“…This allowed for the first time characterize large volume (100 × 66 × 30 μm 3 ) of shot peened regions with resolution of dozens of nanometers and correlate residual stress depth profiles with 3D microstructural features. Finally, in (Benedetti et al 2016, Int. J.…”

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confidence: 97%

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High Spatial Resolution Evaluation of Residual Stresses in Shot Peened Specimens Containing Sharp and Blunt Notches by Micro-hole Drilling, Micro-slot Cutting and Micro-X-ray Diffraction Methods

et al. 2016

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The moderately high lateral RS gradients (on the order of tens of MPa/μm) near shot peened notches in conjunction with the shallow treatment depth (some hundreds of microns) limit the application of far-field and/or high resolution synchrotron diffraction residual stress measurement techniques. Recently proposed Focused Ion Beam -Scanning Elecron Microscope -Digital Image Correlation (FIB-SEM-DIC) based micro mechanical stress relaxation methods for the measurement of residual stress at the micron scale became suitable techniques for local evaluation of residual stresses and stress gradients in shot peened specimens. In this paper ultra-high resolution (~0.5-0.8 μm depth and 5-10 μm lateral resolution) mechanical relaxation stress measurements were used to evaluate the stress variation local to individual peening dimples in ceramic (60-120 μm diameter beads) shot peened Al-7075-T651 double notched samples having 0.15, 0.5 and 2.0 mm radii using Micro-Hole Drilling (μHD), Micro-Slot Cutting (μSC) and micro X-ray Diffraction (μXRD) methods. The micron-sized sampling volumes enabled the stress to be evaluated in individual impact craters (dimples) showing significant point-to-point variation (~+/−150 MPa) (with certain dimples even recording tensile stresses). After around 30 μm of layer removal the heavily deformed region had largely been removed and the stress profile became much more homogeneous. At this depth the μHD and μSC results were in good accord with those from μXRD measurements which sample over a much larger volume (~40 μm depth × 50 μm laterally) showing an in-plane compressive stress of around 150 MPa far from the notches with the residual stress rising to about 200 MPa at a blunt (2 mm) notch and 500 MPa for a sharp (0.15 mm) one. Further, these recorded variations of residual stresses were correlated with microstructural features, e.g. grains, networks of sub-surface cracks, intermetallics and highly deformed sub-surface regions, revealed by large volume Serial Sectioning Tomography using Plasma Xe + Focus Ion Beam -Scanning Electron Microscope (PFIB-SEM), EDS and EBSD maps. This allowed for the first time characterize large volume (100 × 66 × 30 μm 3 ) of shot peened regions with resolution of dozens of nanometers and correlate residual stress depth profiles with 3D microstructural features. Finally, in (Benedetti et al. 2016, Int. J. Fatigue) these RS measurements are used to reconstruct the RS field through finite element (FE) analyses.

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Section: Surface Residual Stress Measurement Between the Notchesmentioning

confidence: 93%

Section: Sub-surface Residual Stress Measurement Between the Notchesmentioning

confidence: 99%

Section: Shot Peening Residual Stresses Osn Plain Samplementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 97%

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