Measurement and Prediction of the Residual Stress Field Generated by Side-Punching

2006 ◽  
Vol 128 (3) ◽  
pp. 451-459 ◽  
Author(s):  
A. H. Mahmoudi ◽  
D. Stefanescu ◽  
S. Hossain ◽  
C. E. Truman ◽  
D. J. Smith ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Residual Stresses ◽  
Measurement Techniques ◽  
Hole Drilling ◽  
X Ray Diffraction ◽  
Residual Stress Field ◽  
Surface Residual Stress ◽  
Alloy Plate ◽  
Near Surface

Side-punching is proposed as a method of introducing a well-defined residual stress field into a laboratory-sized test specimen. Such a specimen may subsequently be used to assess the influence of residual stresses on the fracture behavior of materials. Side-punching consists of simultaneously indenting opposite faces of a plate of material with rigid tools, using sufficient force to cause localized yielding over a finite-sized volume of material adjacent to the punching tools. This paper presents experimental measurements, obtained using three independent measurement techniques, of the residual stress field generated in an aluminium alloy plate after side-punching. Incremental center hole drilling is used to determine the near-surface residual stress field, while synchrotron x-ray diffraction and deep hole drilling are used to measure the through-thickness residual stress field along a path linking the two punch center points. Finite element (FE) predictions are also presented and compared to the measurements. There is very good agreement between all three sets of measurements and the FE results, which all show that the through-thickness residual stresses are compressive and attain a maximum value at the center of the plate. The results confirm the potential use of side-punching in residual stress-crack interaction studies.

Determination of the Residual Stress Field around Scratches Using Synchrotron X-Rays and Nanoindentation

2010 ◽  
Vol 652 ◽  
pp. 25-30
Author(s):  
M.K. Khan ◽  
Michael E. Fitzpatrick ◽  
L.E. Edwards ◽  
S.V. Hainsworth
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Residual Stresses ◽  
Small Scale ◽  
X Rays ◽  
X Ray Diffraction ◽  
Residual Stress Field ◽  
Fine Grained ◽  
Load Displacement

The residual strain field around the scratches of 125µm depth and 5µm root radius have been measured from the Synchrotron X-ray diffraction. Scratches were produced using different tools in fine-grained aluminium alloy AA 5091. Residual stresses up to +1700 micro-strains were measured at the scratch tip for one tool but remained up to only +1000 micro-strains for the other tool scratch. The load-displacement curves obtained from nanoindentation were used to determine the residual stresses around the scratches. It was found that the load-displacement curves are sensitive to any local residual stress field present and behave according to the type of residual stresses. This combination of nanoindentation and synchrotron X-rays has been proved highly effective for the study of small-scale residual stresses around the features such as scratches.

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%.

Measurement of Bending Residual Stress on a Hull Section of a Submarine

2012 ◽  
Author(s):  
Xavier Ficquet ◽  
Ashley Bowman ◽  
Devkumar Goudar ◽  
Manuel Körner ◽  
Ed J. Kingston
Keyword(s):  
Residual Stress ◽  
Hydrostatic Pressure ◽  
Residual Stresses ◽  
Measurement Techniques ◽  
Hole Drilling ◽  
Deep Hole ◽  
Residual Stress Field ◽  
Sheet Bending ◽  
Bending Process ◽  
Submarine Hull

Explicit understanding of the residual stress field of primary submarine pressure hull induced during fabrication will improve the fidelity of numerical analysis and experimentation. Hence, supporting operational envelope and design life extension initiatives. The fatigue lifetime of a submarine hull depends on the loads generated by hull contraction under the effect of hydrostatic pressure and the residual stresses existing in the absence of external loading. The use of numerical simulation allows a straightforward calculation of the stresses induced by the hydrostatic pressure. The effect of residual stress could be determined using the current failure assessment procedures, like BS7910 and R6. However it is more intricate to determine the residual stresses resulting from the sheet bending process combined with the sheet assembly using a multipass welding process. There are several measurement techniques available to measure residual stresses. They are often classified by their level of destructiveness and their penetration.In order to compare the different measurement techniques an elastic-plastic bent beam sample has been chosen as it is very comparable to the residual stress field induced during the sheet bending process used in the submarine structure. Four bent beams have been measured using five different techniques: Incremental centre hole drilling, ring core, neutron diffraction, slitting and deep hole drilling technique. The results from measurement techniques show an excellent agreement when compared with the FEA. In order to measure a full scale Rubis class submarine hull a limited number of techniques can be used, as the technique needs to be portable. The Deep Hole Drilling (DHD) technique was chosen because the neutron diffraction would require extracting a small test sample of about 400mm × 400mm, hence redistributing the residual stresses that were intended to be measured. Six measurements were carried out at different angular positions to detect variability in manufacture on a Rubis class submarine and a probabilistic calculation was done using all six DHD measurements. The Rubis class measurement results are also compared with two other submarine types, found in the literature. Understanding the three-dimensional behaviour of residual stress in this type of structure provides a valuable resource to the numerical modelling community. The results can also support fatigue and fracture experimental work and may help increasing the operating life of 28 year old French nuclear submarine.

Assessment of non-uniform residual stress field of the thermal sprayed stainless steel coatings on aluminium substrates by the integral hole drilling method

2020 ◽  
pp. 095440622091771
Author(s):  
Harouche Mohamed Karim ◽  
Hattali Lamine ◽  
Mesrati Nadir
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Stress Field ◽  
Residual Stresses ◽  
Bond Coat ◽  
High Pressures ◽  
Hole Drilling ◽  
Arc Spraying ◽  
Residual Stress Field ◽  
Stainless Steel Coatings

Thermal spray is one of the most used techniques to produce coatings on structural materials. Such coatings are used as protection against high temperatures, corrosion, erosion and wear. The combined action of high pressures, temperatures and spraying conditions give rise to non-uniform residual stresses. The latter plays an important role in coating design and process parameters optimization. The present work highlights the influence of coatings thickness on the evolution of residual stresses in layered materials. Therefore, thick stainless steel coatings (ASTM 301) of different thicknesses are manufactured by wire arc spraying on aluminium alloy substrates (ASTM 2017A). For a better bond strength, a Ni–Al bond coat is first deposited. Furthermore, a numerically supported hole drilling strain gage method for residual stress field evaluation is proposed. Required calibration coefficients, for the strain–stress transformation formalism based on the integral method, are computed through finite element calculations using Abaqus software. The results indicate that the maximum residual stresses, for all thicknesses, are tensile and range from 140 to 275 MPa. The bond coat does not seem to affect the stress field. Also, it was found that the mean equivalent Von-Mises stress decreases with increasing coating thickness; hence reducing the interfacial adhesion energy of the sprayed materials.

Growth of surface flaws induced by the environment and machining stresses in unalloyed uranium

2005 ◽  
Vol 40 (2) ◽  
pp. 139-150 ◽  
Author(s):  
A Wallwork ◽  
G Burnell ◽  
S Morris ◽  
A Rowe ◽  
I Clarke ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Computer Modelling ◽  
Crack Nucleation ◽  
Initial Assessment ◽  
Residual Stress Field ◽  
Surface Residual Stress ◽  
Near Surface ◽  
Surface Features ◽  
Subsequent Propagation

Computer modelling techniques are used to predict the distribution of residual stresses in a machined uranium surface. The predictions are used to address the ageing of uranium exposed to inert gas based environments in terms of microcrack initiation and subsequent propagation. Metallographic observations of microcracking are used as the basis for the initial assessment of ageing behaviour. It is proposed that the near-surface residual stress field produced by machining influences the occurrence of microcracking. It is also suggested that corrosion-induced surface features act as initiation sites for microcracks, which begin to propagate by an environmentally assisted mechanism when the surface features reach a critical depth within the residual stress field of between 5 and 10 μm. However, the majority of the microcracks appear to arrest at about 150 μm. This behaviour is discussed in terms of the predicted threshold stress intensity for crack nucleation, uranium metallurgy, and the possible effects of crack coalescence on growth.

Measuring the Variation of Residual Stress with Depth: A Validation Exercise for Fine Incremental Hole Drilling

2006 ◽  
Vol 524-525 ◽  
pp. 531-537 ◽  
Author(s):  
A. Tony Fry ◽  
Jerry D. Lord
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Hole Drilling ◽  
X Ray Diffraction ◽  
Surface Residual Stress ◽  
Near Surface ◽  
X Ray ◽  
Treatment Processes ◽  
Incremental Hole Drilling ◽  
Significant Interest

Hole drilling along with X-Ray diffraction, is one of the most widely used techniques for measuring residual stress, but the conventional approach is limited in the near surface detail that can be resolved. Because of concerns regarding the levels of induced residual stress that might develop during machining and surface treatment processes, there is significant interest in developing a technique that can obtain near surface residual stress information by the application of fine increment hole drilling. Through a cross comparison with X-ray diffraction and neutron diffraction the procedure of fine incremental drilling has been validated, and the advantages of this technique demonstrated.

Numerical Analyses of Residual Stress Fields in Welded Components

2009 ◽  
Author(s):  
Dieter Siegele ◽  
Marcus Brand ◽  
Igor Varfolomeev ◽  
Jo¨rg Hohe
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Residual Stresses ◽  
Base Metal ◽  
Stress Fields ◽  
X Ray Diffraction ◽  
Residual Stress Field ◽  
Temperature Dependent ◽  
Compressive Stresses ◽  
Core Shroud

Residual stresses in welded components can influence the lifetime significantly. Besides experimental methods of residual stress measurements numerical methods of welding simulation are an important tool to determine the whole residual stress field in a component as a basis for lifetime prediction. As examples, the residual stresses in a core shroud of a boiling water reactor (BWR) and in a cladded plate have been investigated. In case of the core shroud postulated cracks in the residual stress field of the weld have been assessed with respect to possible crack corrosion cracking. For the cladded plate, the numerical simulation of the cladding and heat treatment process was accompanied by measurements of temperature, distortions and residual stresses. In the analysis, the temperature dependent material properties as well as the transformation behavior of the ferritic base metal were taken into account. The calculated residual stresses show tensile stresses in the cladding followed by compressive stresses in the base metal that are in agreement with measurements with X-ray diffraction technique.

Measuring Residual Stresses by Hole-Drilling and Coherent Optics Techniques: A Numerical Calibration

1991 ◽  
Vol 113 (1) ◽  
pp. 41-50 ◽  
Author(s):  
F. M. Furgiuele ◽  
L. Pagnotta ◽  
A. Poggialini
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Residual Stresses ◽  
Strain Gage ◽  
Displacement Component ◽  
Hole Drilling ◽  
Residual Stress Field ◽  
Relaxation Data ◽  
Coherent Optics ◽  
Fringe Patterns

Hole-drilling is a widely accepted method for determining residual stresses from the relaxation data obtained by a strain-gage rosette. Several researchers have recently investigated the alternative of employing interferometric techniques to reveal the displacement field produced by hole-drilling. As in the case of the standardized hole-drilling strain-gage method, proper calibration constants must be assessed so that this procedure can be effectively employed. This paper reports the displacement calibration constants derived from the results of an extensive numerical analysis. The constants proposed enable a uniform residual stress field to be determined, whatever the displacement component detected. The most commonly employed coherent optics techniques have been considered; computer-generated fringe patterns are reported and criteria are suggested to derive the stress field from fringe readings taken around the edge of the hole.

Micro-slotting technique for reliable measurement of sub-surface residual stress in Ti-6Al-4V

2018 ◽  
Vol 53 (6) ◽  
pp. 389-399 ◽  
Author(s):  
Elizabeth Burns ◽  
Joseph Newkirk ◽  
James Castle
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Image Correlation ◽  
X Ray Diffraction ◽  
Surface Residual Stress ◽  
Near Surface ◽  
X Ray ◽  
Measurement Volume ◽  
Surface Residual Stresses

Micro-slotting, a relaxation residual stress measurement technique, has recently been shown to be an effective method for measuring local residual stresses in a variety of materials. The micro-slotting method relies on a scanning electron microscope–focused ion beam system for milling and imaging, digital image correlation software to track displacements due to residual stress relaxation after milling, and finite element analysis for displacement–stress correlation and calculation of the original stress state in the imaged region. The high spatial resolution of the micro-slotting method makes it a promising technique for obtaining near-surface residual stress data in Ti-6Al-4V components for input into fatigue life models and crack growth simulations. However, use of the micro-slotting method on this alloy has yet to be evaluated against more established measurement techniques. In this study, spatially resolved sub-surface residual stress measurements were obtained on shot peened and low-stress surface-machined Ti-6Al-4V planar coupons using the micro-slotting method and were compared to measurements obtained using the conventional X-ray diffraction depth profiling technique. The sub-surface measurements were in good agreement for the shot peened sample. Observed differences in the measured near-surface residual stresses on the surface-machined sample were attributed to the larger measurement volume of the X-ray diffraction method, suggesting that the micron-sized measurement volume of the micro-slotting method may be more suitable for capturing shallow stress profiles and steep stress gradients. Prior to performing the micro-slotting measurements, finite element modeled displacements were used to verify the measurement procedure and to address uncertainties in the milled slot geometries. The results of this study demonstrated the validity of the micro-slotting procedure and established the technique as a reliable method for measuring sub-surface residual stresses in Ti-6Al-4V.

scholarly journals Intermethod Comparison and Evaluation of Measured Near Surface Residual Stress in Milled Aluminum

2021 ◽  
Author(s):  
C. R. Chighizola ◽  
C. R. D’Elia ◽  
D. Weber ◽  
B. Kirsch ◽  
J. C. Aurich ◽  
...  
Keyword(s):  
Residual Stress ◽  
Material Removal ◽  
Flat Surface ◽  
Cutting Speed ◽  
Hole Drilling ◽  
X Ray Diffraction ◽  
Surface Residual Stress ◽  
Near Surface ◽  
X Ray ◽  
Milled Surface

Abstract Background While near surface residual stress (NSRS) from milling is a driver for distortion in aluminum parts there are few studies that directly compare available techniques for NSRS measurement. Objective We report application and assessment of four different techniques for evaluating residual stress versus depth in milled aluminum parts. Methods The four techniques are: hole-drilling, slotting, cos(α) x-ray diffraction (XRD), and sin2(ψ) XRD, all including incremental material removal to produce a stress versus depth profile. The milled aluminum parts are cut from stress-relieved plate, AA7050-T7451, with a range of table and tool speeds used to mill a large flat surface in several samples. NSRS measurements are made at specified locations on each sample. Results Resulting data show that NSRS from three techniques are in general agreement: hole-drilling, slotting, and sin2(ψ) XRD. At shallow depths (< 0.03 mm), sin2(ψ) XRD data have the best repeatability (< 15 MPa), but at larger depths (> 0.04 mm) hole-drilling and slotting have the best repeatability (< 10 MPa). NSRS data from cos(α) XRD differ from data provided by other techniques and the data are less repeatable. NSRS data for different milling parameters show that the depth of NSRS increases with feed per tooth and is unaffected by cutting speed. Conclusion Hole-drilling, slotting, and sin2(ψ) XRD provided comparable results when assessing milling-induced near surface residual stress in aluminum. Combining a simple distortion test, comprising removal of a 1 mm thick wafer at the milled surface, with a companion stress analysis showed that NSRS data from hole-drilling are most consistent with milling-induced distortion.

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