Abrasive Waterjet Peening With Elastic Prestress: Effect of Boundary Conditions

2008 ◽  
Author(s):  
Balaji Sadasivam ◽  
Alpay Hizal ◽  
Dwayne Arola
Keyword(s):  
Residual Stress ◽  
Yield Strength ◽  
Boundary Conditions ◽  
Stress Fields ◽  
Abrasive Waterjet ◽  
Surface Residual Stress ◽  
Prosthetic Devices ◽  
Metal Implants ◽  
Removal Technique ◽  
Stored Elastic Energy

Abrasive Waterjet Peening (AWJP) has emerged as a potential surface treatment process for metal implants and prosthetic devices. An elastic tensile prestress has been shown to increase the magnitude and depth of residual stress that can be obtained. In the present investigation, the subsurface residual stress fields resulting from AWJ peening of Ti6Al4V with load control and displacement control elastic prestress were compared. Prestress ranged from 0 to 75% of the material’s yield strength and the subsurface residual stress distribution was quantified using the layer removal technique. Results showed that the surface residual stress was dependent on the boundary conditions for prestress levels less than 60% of the materials yield strength. The magnitude of surface residual stress and the stored elastic energy were up to 50% and 100% larger respectively when load controlled boundary conditions were used. However, the boundary condition did not affect the depth of compressive residual stress.

Abrasive Waterjet Peening With Elastic Prestress: Subsurface Residual Stress Distribution

2007 ◽  
Author(s):  
Balaji Sadasivam ◽  
Alpay Hizal ◽  
Dwayne Arola
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Stress Field ◽  
Yield Strength ◽  
Residual Stresses ◽  
Residual Stress Distribution ◽  
Abrasive Waterjet ◽  
Residual Stress Field ◽  
Surface Residual Stress ◽  
Compressive Residual Stresses

Recent advances in abrasive waterjet (AWJ) technology have resulted in new processes for surface treatment that are capable of introducing compressive residual stresses with simultaneous changes in the surface texture. While the surface residual stress resulting from AWJ peening has been examined, the subsurface residual stress field resulting from this process has not been evaluated. In the present investigation, the subsurface residual stress distribution resulting from AWJ peening of Ti6Al4V and ASTM A228 steel were studied. Treatments were conducted with the targets subjected to an elastic prestress ranging from 0 to 75% of the substrate yield strength. The surface residual stress ranged from 680 to 1487 MPa for Ti6Al4V and 720 to 1554 MPa for ASTM A228 steel; the depth ranged from 265 to 370 μm for Ti6Al4V and 550 to 680 μm for ASTM A228 steel. Results showed that elastic prestress may be used to increase the surface residual stress in AWJ peened components by up to 100%.

An Evaluation of Abrasive Waterjet Peening With Elastic Prestress

2009 ◽  
Vol 131 (1) ◽  
Author(s):  
B. Sadasivam ◽  
A. Hizal ◽  
S. Park ◽  
D. Arola
Keyword(s):  
Residual Stress ◽  
Yield Strength ◽  
Surface Texture ◽  
Surface Stress ◽  
Treatment Process ◽  
Abrasive Waterjet ◽  
Residual Stress Field ◽  
Surface Residual Stress ◽  
Stress Zone ◽  
Study Application

Abrasive waterjet peening (AWJP) has been conceived as a new surface treatment process capable of achieving desired changes in surface texture, chemistry, and residual stress simultaneously. In the present investigation, the influence of elastic prestress on the residual stress resulting from AWJP was studied. Treatments were conducted on steel, as well as nickel and titanium alloy targets subjected to an elastic prestress ranging from 0% to 75% of the material’s yield strength. The results showed that a tensile elastic prestress increases the surface residual stress and the depth of the compressive stress zone. The surface residual stress in each metal increased nonuniformly with magnitude of prestress; the maximum surface residual stress was obtained at an applied prestress between 45% and 60% of the substrate yield strength. Overall, the increases in surface stress and depth that were obtained reached 100% and 50%, respectively. There were no changes to the surface texture caused by the prestress. According to results of this study, application of an elastic prestress can serve as an effective method for improving characteristics of the residual stress field in components treated using AWJP.

Revision and extension of the standard laboratory technique for X-ray diffraction measurement of residual stress gradients

2007 ◽  
Vol 40 (4) ◽  
pp. 675-683 ◽  
Author(s):  
Cristy L. Azanza Ricardo ◽  
Mirco D'Incau ◽  
Paolo Scardi
Keyword(s):  
Residual Stress ◽  
Hole Drilling ◽  
Al Alloy ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
Surface Residual Stress ◽  
X Ray ◽  
Stress Gradients ◽  
Layer Removal ◽  
Removal Technique

A new procedure is proposed to determine sub-surface residual stress gradients by laboratory X-ray diffraction measurements at different depths using a chemical layer-removal technique. The standard correction algorithm for stress relaxation due to layer removal is improved by including corrections for X-ray absorption, and by the addition of constraints imposed by the mechanical equilibrium conditions. Besides correcting the data,i.e.providing more reliable through-thickness residual stress trends, the proposed procedure also provides an elastically compatible and plausible estimate of the residual stress inside the component, well beyond the measured region. The application of the model is illustrated for a set of Al-alloy components shot-peened at different Almen intensities. Results are compared with those given by `blind hole drilling', which is an independent and partly destructive method.

Advanced Evaluation Methods of Residual Stress in Bioceramics Wear Surfaces

2010 ◽  
Vol 64 ◽  
pp. 43-48
Author(s):  
Giuseppe Pezzotti
Keyword(s):  
Residual Stress ◽  
Surface Stress ◽  
Electron Probe ◽  
Stress Fields ◽  
Fluorescence Probes ◽  
Surface Residual Stress ◽  
Hip Joints ◽  
Polycrystalline Alumina ◽  
Probe Size ◽  
F Center

Photo- and electro-stimulated probes have been employed for quantitatively evaluating highly graded residual stress fields generated at the surface of alumina hip joints. Optical calibrations revealed large differences in probe size, which strongly affected the detected magnitude of residual stress. A comparison between the responses of Raman and fluorescence probes in polycrystalline alumina showed that the depth of those probes spread to an extent in the order of the tens of microns even with using a confocal probe configuration. On the other hand, the electro-stimulated luminescence emitted by oxygen vacancy sites (F+ center) in the alumina lattice represented a suitable choice for confining to a shallow volume the stress probe. The electron probe enabled confining the measurement depth to the order of the tens of nanometers. Maps of surface residual stress were collected on both main-wear and non-wear zones of an alumina femoral head. A comparison among stress maps taken at exactly the same location, but employing different probes, clarified the averaging probe effects on surface stress magnitude.

Pull-In Instability of Functionally Graded Cantilever Nanoactuators Incorporating Effects of Microstructure, Surface Energy and Intermolecular Forces

2018 ◽  
Vol 10 (08) ◽  
pp. 1850091 ◽  
Author(s):  
Mohamed A. Attia ◽  
Salwa A. Mohamed
Keyword(s):  
Residual Stress ◽  
Surface Energy ◽  
Boundary Conditions ◽  
Van Der Waals ◽  
Surface Elasticity ◽  
Van Der Waals Forces ◽  
Functionally Graded ◽  
Surface Residual Stress ◽  
Electrically Actuated ◽  
Classical Boundary

In this paper, an integrated non-classical continuum model is developed to investigate the pull-in instability of electrostatically actuated functionally graded nanocantilevers. The model accounts for the simultaneous effects of local-microstructure, surface elasticity and surface residual in the presence of fringing field as well as Casimir and van der Waals forces. The modified couple stress and Gurtin–Murdoch surface elasticity theories are employed to conduct the scaling effects of microstructure and surface energy, respectively, in the context of Euler–Bernoulli beam hypothesis. Bulk and surface material properties are varied according to the power-law distribution through the beam thickness. The physical neutral axis position for mentioned FG nanobeams is considered. Hamilton principle is employed to derive the nonlinear size-dependent governing equations and the non-classical boundary conditions. The resulting nonlinear differential equations are solved utilizing the generalized differential quadrature method (GDQM). In addition, the non-classical boundary conditions of nanocantilever beams due to surface residual stress are exactly implemented. After validation of the obtained results by previously available data in the literature, the influences of different geometrical and material parameters on the pull-in instability of the FG nanocantilevers are examined in detail. It is concluded that the pull-in behavior of electrically actuated FG micro/nanocantilevers is significantly influenced by the material distribution, material length scale parameter, surface elasticity constant, surface residual stress, initial gap, slenderness ratio, Casimir, and van der Waals forces. The obtained results can be considered for modeling and analysis of electrically actuated FG nanocantilevers.

X-Ray Diffraction Measurement of Residual Stresses in Thick, Multi-Pass Steel Weldments

1985 ◽  
Vol 107 (2) ◽  
pp. 185-191 ◽  
Author(s):  
C. O. Ruud ◽  
R. N. Pangborn ◽  
P. S. DiMascio ◽  
D. J. Snoha
Keyword(s):  
Residual Stress ◽  
Measurement Accuracy ◽  
Stress Measurement ◽  
Three Dimensional ◽  
Residual Stress Measurement ◽  
Stress Fields ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Removal Technique

A unique X-ray diffraction instrument for residual stress measurement has been developed that provides for speed, ease of measurement, accuracy, and economy of surface stress measurement. Application of this instrument with a material removal technique, e.g., electropolishing, has facilitated detailed, high resolution studies of three-dimensional stress fields. This paper describes the instrumentation and techniques applied to conduct the residual stress measurement and presents maps of the residual stress data obtained for the surfaces of a heavy 2 1/4 Cr 1 Mo steel plate weldment.

Determination of Residual-Stress-Free State and Mapping of Residual Stress Fields Using Speckle Interferometry and Thermal Relaxation

2003 ◽  
Vol 795 ◽  
Author(s):  
Dong-Won Kim ◽  
Jong-jin Kim ◽  
Dongil Son ◽  
Nak-Kyu Lee ◽  
Kyung-Hoan Na ◽  
...  
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Speckle Pattern ◽  
Thermal Relaxation ◽  
Free State ◽  
Stress Fields ◽  
Lead Frame ◽  
Surface Residual Stress ◽  
Au Film ◽  
Stress Free State

ABSTRACTWe used an electronic speckle pattern interferometer (ESPI) for nondestructive measurement in-situ displacement fields in microsystems. A four-step phase-shift technique and magnifier with long working distance were adopted to increase displacement resolution to ∼10−2 μm and spatial resolution to ∼2 μm. A thermal vacuum chamber was designed to induce thermal treatments, including annealing. From the identification of the residual-stress-free state, we quantitatively modeled thermal strains/stress fields, relaxation stresses during annealing, and residual stress fields. Thermoelasticity theory was applied to model the relationship between the relaxation stresses and the displacements measured by ESPI during the evolution of the residual-stress-free state. We assessed the surface residual stress fields of indented bulk Cu; a Fe-Ni lead frame of 100 μm width; and 0.5 μm Au film. In the indented Cu, the normal and shear residual stresses around the indented point range from –1.7 GPa to 700 MPa and –800 MPa to 600 MPa, respectively, and the residual stress in the bending area of the Fe-Ni lead frame was estimated at 148 MPa and verified using beam-bending theory. In the Au film, tensile residual stresses are uniformly distributed from 500 MPa to 800 MPa as verified by X-ray diffraction.

Waterjet Machining and Peening of Metals

1999 ◽  
Vol 122 (1) ◽  
pp. 90-95 ◽  
Author(s):  
M. Ramulu ◽  
S. Kunaporn ◽  
D. Arola ◽  
M. Hashish ◽  
J. Hopkins
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Surface Integrity ◽  
Stress Fields ◽  
Abrasive Waterjet ◽  
Material Surface ◽  
X Ray Diffraction ◽  
X Ray ◽  
Waterjet Machining ◽  
Measurement And Evaluation

An experimental study was conducted to determine the influence of high-pressure waterjet (WJ) peening and abrasive waterjet (AWJ) machining on the surface integrity and texture of metals. A combination of microstructure analysis, microhardness measurements, and profilometry were used in determining the depth of plastic deformation and surface texture that result from the material removal process. The measurement and evaluation of residual stress was conducted with X-ray diffraction. The residual stress fields resulting from treatment were analyzed to further distinguish the influence of material properties on the surface integrity. It was found that waterjet peening induces plastic deformation at the surface layer of metals as good as shot peening. The degree of plastic deformation and the state of material surface were found to be strongly dependent on the peening conditions applied. [S0094-9930(00)00801-5]

scholarly journals The stress-strain state in the plate material, formed as a result of the movement of a heat source

2020 ◽  
pp. 194-201
Author(s):  
Евгений Евгеньевич Абашкин ◽  
Анастасия Валерьевна Ткачева
Keyword(s):  
Mathematical Model ◽  
Residual Stress ◽  
Yield Strength ◽  
Heat Source ◽  
Residual Stresses ◽  
Strain State ◽  
Stress Fields ◽  
Plate Material ◽  
Temperature Stresses ◽  
The Mathematical Model

Работа посвящена исследованию температурных напряжений в пластине из среднеуглеродистой легированной стали, по поверхности которой с определенной скоростью проходит прямолинейно источник тепла. Математическая модель строится на основе модели Прандтля - Рейса, в которой закон Гука заменен законом Дюамеля - Неймана. В качестве условия пластического течения принимается условие Мизесса, где предел текучести параболически зависит от температуры. Рассматриваются поля остаточных напряжений в зависимости от скорости прохождения источника тепла. Значения остаточных напряжений, полученные в результате расчета, сравниваются с экспериментальными напряжениями, снятыми с пластины при помощи анализатора остаточных напряжений RIGAKU. The work is devoted to the study of temperature stresses in a plate made of mediumcarbon alloy steel on the surface of which a heat source passes rectilinearly at a certain speed. The mathematical model is based on the Prandtl - Reis model, in which Hooke’s law is modified by the Duhamel - Neumann law. As a condition for plastic flow, the Mises condition is accepted, where the yield strength of the parabolic depends on the temperature. The residual stress fields are considered depending on the speed of the heat source passage. The resulting residual stresses are compared with the experimental stresses taken from the plate using the Rigaku residual stress analyzer.

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