scholarly journals Cross-Sectional Mapping of Residual Stresses by Measuring the Surface Contour After a Cut

2000 ◽  
Vol 123 (2) ◽  
pp. 162-168 ◽  
Author(s):  
M. B. Prime
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Measurement ◽  
Superposition Principle ◽  
New Method ◽  
Contour Method ◽  
Stress Profile ◽  
Relaxation Methods ◽  
Cross Sectional ◽  
Residual Stress Profile

A powerful new method for residual stress measurement is presented. A part is cut in two, and the contour, or profile, of the resulting new surface is measured to determine the displacements caused by release of the residual stresses. Analytically, for example using a finite element model, the opposite of the measured contour is applied to the surface as a displacement boundary condition. By Bueckner’s superposition principle, this calculation gives the original residual stresses normal to the plane of the cut. This “contour method” is more powerful than other relaxation methods because it can determine an arbitrary cross-sectional area map of residual stress, yet more simple because the stresses can be determined directly from the data without a tedious inversion technique. The new method is verified with a numerical simulation, then experimentally validated on a steel beam with a known residual stress profile.

Residual Stress Mapping in Welds Using the Contour Method

2005 ◽  
Vol 490-491 ◽  
pp. 294-299 ◽  
Author(s):  
Ying Zhang ◽  
S. Pratihar ◽  
Michael E. Fitzpatrick ◽  
Lyndon Edwards
Keyword(s):  
Residual Stress ◽  
Stress Measurement ◽  
Contour Method ◽  
Welding Parameters ◽  
Stress Profile ◽  
Efficient Manner ◽  
Cross Sectional ◽  
Stress Evaluation ◽  
Residual Stress Profile ◽  
Stress Mapping

The contour method, a newly-invented sectioning technique for residual stress measurement, has the potential to measure the cross-sectional residual stress profile of a weld in a simple and time-efficient manner. In this paper we demonstrate the capability of the contour method to measure cross-sectional residual stress profiles, which are compared with neutron diffraction measurements and show excellent agreement. The results provide useful information for safetycritical design of welded components and optimization of welding parameters, and also illustrate the potential of the contour technique as a powerful tool for residual stress evaluation.

Residual Stress Profiles of Pipe Girth Weld Using a Stress Decomposition Method

2014 ◽  
Author(s):  
Huaguo Teng ◽  
Steve Bate
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Measurement ◽  
Heuristic Method ◽  
Measurement Data ◽  
Stress Profile ◽  
Residual Stress Profile ◽  
Stress Components ◽  
Stress Profiles ◽  
Girth Welds

The application of procedures such as R6 or BS7910 for the structural assessment of defects in pressurised components containing residual stresses requires knowledge of the through-wall residual stress profile. Currently there is much interest in improving the residual stress profiles that are provided in the procedures. In this paper we present an improved analysis of residual stresses of the pipe girth welds by applying the developed heuristic method to one set of extended residual stress measurement data. The through-thickness residual stress is decomposed into three stress components: membrane, bending and self-equilibrating. The heuristic method was applied to the three components separately, so that the residual stress profile was a combination of the three stress components. This form provides not only a clear physical basis for the residual stress profile, but is also convenient for defect assessment where only the membrane and bending stress components are important.

scholarly journals On the Accuracy of Finite Element Models Predicting Residual Stresses in Quenched Stainless Steel

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1308 ◽  
Author(s):  
Israel Medina-Juárez ◽  
Jeferson Araujo de Oliveira ◽  
Richard J. Moat ◽  
Francisco Alfredo García-Pastor
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Contour Method ◽  
Stress Profile ◽  
304L Stainless Steel ◽  
Fem Model ◽  
Residual Stress Profile ◽  
Industry Applications

Prediction of residual stress profiles after quenching is important for a range of industry applications. Finite element method (FEM) models have the capability of simulate the cooling and stress evolution during quenching; however, they are very dependent on the heat transfer coefficient (HTC) imposed on the surface. In this paper, an analysis of the HTC effect on the accuracy of the residual stress profile after quenching a 304L stainless steel Jominy sample was conducted. The FEM model was validated in its thermal accuracy using thermocouples and the residual stress profile was measured using the contour method. The results show that a thermally validated FEM model may yield results which overestimate the tensile residual stress and underestimates the compressive residual stress maxima while accurately calculating the maxima positions from the quenched edge. The FEM model accuracy was not improved by modifying the HTC or by using a different thermal expansion coefficient. The results are discussed in terms of the effect of plasticity due to twinning in the residual stresses calculated by the FEM model.

Characteristics of Residual Stress Profiles in Hard Turned Versus Ground Surfaces With and Without a White Layer

2008 ◽  
Author(s):  
A. W. Warren ◽  
Y. B. Guo
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Compressive Residual Stress ◽  
Hard Turning ◽  
Stress Measurement ◽  
White Layer ◽  
Stress Profile ◽  
Residual Stress Profile ◽  
Mechanical Products ◽  
Stress Profiles

Hard turning and grinding are competitive processes in many cases for manufacturing various mechanical products. Product performance is highly dependent on the process induced residual stresses. However, there exist some inconsistence regarding the true residual stress profiles generated by hard turning and grinding with and without the presence of a white layer. This study aims to clarify the pressing issues via an extensive residual stress measurement for five surface types: hard turned fresh (HTF), hard turned with a white layer (HTWL), ground fresh (GF), ground with a white layer (GWL), and as heat treated. The x-ray diffraction data revealed distinct differences in the residual stress profiles between the turned and ground surfaces. Specifically, the key findings are: (i) HTF surfaces generate a “hook” shaped residual stress profile characterized by surface compressive residual stress and maximum compressive residual stress in the subsurface, while GF surfaces only generate maximum compressive residual stress at the surface; (ii) HTWL surfaces generate a high tensile stress in the white layer, but has highly compressive residual stress in the deeper subsurface than the HTF surface; (iii) GWL surfaces only shift the residual stress to more tensile but does not affect the basic shape of the profile; (iv) Tensile residual stress in the HTWL surface is higher than that for the GWL one. However, the residual stress for the ground white layer does not become compressive and remains tensile in the subsurface; (v) Elliptical curve fitting is necessary for measuring residual stress for the HTWL surface due to the presence of shear stress induced severe Ψ splitting; (vi) Residual stresses by grinding show more scattering than those by hard turning; and (vii) Machining is the deterministic factor for the resulting residual stress magnitudes and profiles compared with the minor influence of initial residual stress by heat treatment.

scholarly journals The Contour Method: Simple 2-D Mapping of Residual Stresses

2000 ◽  
Author(s):  
Michael B. Prime
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Superposition Principle ◽  
Measured Data ◽  
New Method ◽  
Contour Method ◽  
Inversion Process

Abstract An entirely new method for measuring residual stress that is extremely simple to apply yet more powerful than existing techniques is presented. In this method, a part is carefully cut in two. The contour of the resulting new surface is measured, which gives the displacements caused by the release of the residual stresses. By Bueckner’s superposition principle, analytically forcing the surface back to its original flat state gives the residual stresses that originally existed normal to the plane of the cut. The main advantage of this method is that the measured data can be used to solve directly for the stresses, whereas other methods require a complex inversion process.

Assessment of Weld Residual Stress Measurement Precision: Mock-Up Design and Results for the Contour Method

2015 ◽  
Vol 1 (3) ◽  
Author(s):  
Mitchell D. Olson ◽  
Michael R. Hill ◽  
Eric Willis ◽  
Artie G. Peterson ◽  
Vipul I. Patel ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Measurement ◽  
Measurement Techniques ◽  
Repeated Measurements ◽  
Residual Stress Measurement ◽  
Contour Method ◽  
Stress Profile ◽  
Residual Stress Profile ◽  
Stress Measurements ◽  
Reproducibility Study

Recent experimental work has shown residual stress measurements in welded material to be difficult. To better assess the precision of residual stress measurement techniques, a measurement article was designed to allow repeated measurements of a nominally identical stress field. The measurement article is a long 316L stainless steel plate containing a machine-controlled eight-pass slot weld. Measurements of weld direction residual stress made with the contour method found high tensile stress in the weld and heat-affected zone, with a maximum near 450 MPa and compressive stress away from the weld, a typical residual stress profile for constrained welds. The repeatability standard deviation of repeated contour method residual stress measurements was found to be less than 20 MPa at most spatial locations away from the boundaries of the plate. The repeatability data in the weld are consistent with those from a previous repeatability experiment using the contour method in quenched aluminum bars. A finite-element simulation and neutron diffraction measurements were performed for the same weld and provided results consistent with the contour method measurements. Much of the material used in the work remains available for use in assessing other residual stress measurement techniques, or for an interlaboratory reproducibility study of the contour method.

The Mechanics Basis of Residual Stress Profiles in Proposed API 579 Appendix E

2006 ◽  
Author(s):  
P. Dong ◽  
Z. Cao
Keyword(s):  
Residual Stress ◽  
Heat Input ◽  
Stress Measurement ◽  
Measurement Data ◽  
Stress Profile ◽  
Continuous Change ◽  
Parametric Function ◽  
Residual Stress Profile ◽  
Stress Profiles ◽  
Pipe Geometry

In this paper, the mechanics basis underlying the parametric through-thickness residual stress profiles proposed for the revised API 579 Appendix E are presented. The proposed residual stress profiles are governed to a large extent by a unified parametric function form valid for a broad spectrum of pipe and vessel welds. The functional relationship is established based on the comprehensive knowledge base developed within a recent major international joint industry project (JIP) under the auspice of Pressure Vessel Research Council (PVRC) and a large amount of residuals stress measurement data from recent literature. One of the most important features associated with the proposed revision is that residual stress profile is uniquely determined by two important sets of governing parameters: (1) parameters relevant to pipe geometry, i.e., r/t and t; (2) a parameter related to welding linear heat input Q (J/mm), referred to as the characteristic heat input Qˆ which has a dimension of J/mm3. As a result, the corresponding through-wall residual stress distribution exhibits a continuous change as a function of r/t, t, and Qˆ, instead of falling into a few discrete and unrelated profiles, as seen in the current Codes and Standards.

A Numerical Study on the Redistribution of Residual Stress After Machining

2017 ◽  
Author(s):  
Kunyang Lin ◽  
Wenhu Wang ◽  
Ruisong Jiang ◽  
Yifeng Xiong
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Residual Stresses ◽  
Numerical Study ◽  
Cutting Speed ◽  
Machining Process ◽  
Stress Profile ◽  
Residual Stress Field ◽  
Machining Processes ◽  
Residual Stress Profile

Machining induced residual stresses have an important effect on the surface integrity. Effects of various factors on the distribution of residual stress profiles induced by different machining processes have been investigated by many researchers. However, the initial residual, as one of the important factor that affect the residual stress profile, is always been ignored. In this paper, the residual stress field induced by the quenching process is simulated by the FEM software as the initial condition. Then the initial residual stress field is used to study the residual stress redistribution after the machining process. The influence of initial stress on the stress formation is carried out illustrating with the mechanical and thermal loads during machining processes. The effects of cutting speed on the distribution of residual stress profile are also discussed. These results are helpful to understand how initial residual stresses are redistributed during machining better. Furthermore, the results in the numerical study can be used to explain the machining distortion problem caused by residual stress in the further work.

Residual Stress in Plain Carbon Steel Induced by Laser Hardening

2015 ◽  
Vol 812 ◽  
pp. 321-326 ◽  
Author(s):  
A. Filep ◽  
Márton Benke ◽  
Valéria Mertinger ◽  
Gábor Buza
Keyword(s):  
Heat Transfer ◽  
Residual Stress ◽  
Residual Stresses ◽  
Plain Carbon Steel ◽  
Laser Hardening ◽  
Manufacturing Processes ◽  
Stress Profile ◽  
Multiple Sources ◽  
Residual Stress Profile ◽  
Hardening Treatment

Technological residual stresses have great importance in the manufacturing processes and the lifetime of components. The residual stresses formed by quenching can be very diverse because of its multiple sources. Alternative quenching processes such as laser hardening have a great potential for different applications. The direction of heat transfer during laser hardening is the opposite compared to conventional quenching. This further increases the complexity of the developed stress state. The residual stress profile and the microstructure formed by laser hardening treatment are investigated in the present manuscript.

Experimental/Modelling Study of Residual Stress in Al/SiCp Bent Bars by Synchrotron XRD and Slitting Eigenstrain Methods

2008 ◽  
Vol 571-572 ◽  
pp. 277-282 ◽  
Author(s):  
Xu Song ◽  
Solène Chardonnet ◽  
Giancarlo Savini ◽  
Shu Yan Zhang ◽  
Willem J.J. Vorster ◽  
...  
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Residual Strain ◽  
Numerical Models ◽  
Front Face ◽  
Stress Profile ◽  
X Ray Diffraction ◽  
Element Analysis ◽  
X Ray ◽  
Residual Stress Profile

The aim of the study presented here was to evaluate the residual stresses present in a bar of aluminium alloy 2124-T1 matrix composite (MMC) reinforced with 25vol% particulate silicon carbide (SiCp) using X-ray diffraction and 3D profilometry (curvature measurement using Mitutoyo/Renishaw coordinate measurement machine) and comparing these results with numerical models of residual strain and stress profiles obtained by a simple inelastic bending model and Finite Element Analysis (FEA). The residual strain distribution was introduced into the test piece by plastic deformation in the 4-point bending configuration. At the first stage of this study the elasticplastic behaviour of the MMC was characterized under static and cyclic loading to obtain the material parameters, hardening proprieties and cyclic hysteresis loops. Subsequently, synchrotron Xray diffraction and CMM curvature measurements were performed to deduce the residual stress profile in the central section of the bar. The experimental data obtained from these measurements were used in the inelastic bending and FEA simulations. The specimens were then subjected to incremental slitting using EDM (electric discharge machining) with continuous back and front face strain gauge monitoring. The X-ray diffraction and incremental slitting results were then analysed using direct and inverse eigenstrain methods. Residual stresses plots obtained by different methods show good agreement with each other.

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