Measurement of residual stresses in T-plate weldments

2003 ◽  
Vol 38 (4) ◽  
pp. 349-365 ◽  
Author(s):  
R. C Wimpory ◽  
P. S May ◽  
N. P O'Dowd ◽  
G. A Webster ◽  
D J Smith ◽  
...  
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Plastic Zone ◽  
Residual Stresses ◽  
Plate Thickness ◽  
Welding Process ◽  
Plastic Zone Size ◽  
Hole Drilling ◽  
Stress Distributions ◽  
Premature Failure

Tensile welding residual stresses can, in combination with operating stresses, lead to premature failure of components by fatigue and/or fracture. It is therefore important that welding residual stresses are accounted for in design and assessment of engineering components and structures. In this work residual stress distributions, obtained from measurements on a number of ferritic steel T-plate weldments using the neutron diffraction technique and the deep-hole drilling method, are presented. It has been found that the residual stress distributions for three different plate sizes are of similar shape when distances are normalized by plate thickness. It has also been found that the conservatisms in residual stress profiles recommended in current fracture mechanics-based safety assessment procedures can be significant—of yield strength magnitude in certain cases. Based on the data presented here a new, less-conservative transverse residual stress upper bound distribution is proposed for the T-plate weldment geometry. The extent of the plastic zone developed during the welding process has also been estimated by use of Vickers hardness and neutron diffraction measurements. It has been found that the measured plastic zone sizes are considerably smaller than those predicted by existing methods. The implications of the use of the plastic zone size as an indicator of the residual stress distributions are discussed.

Evaluation of Through-Thickness Residual Stresses by Neutron Diffraction and Finite-Element Method in Thick Weld Plates

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
Wenchun Jiang ◽  
Wanchuck Woo ◽  
Yu Wan ◽  
Yun Luo ◽  
Xuefang Xie ◽  
...  
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Plate Thickness ◽  
Element Model ◽  
Stress Distributions ◽  
Thick Plates ◽  
Work Hardening Model ◽  
Generalized Plane Strain

Through-thickness distributions of the welding residual stresses were studied in the range of 50–100 mm thick plates by using finite-element modeling (FEM) and neutron diffraction measurements. In order to simulate the residual stresses through the thickness of the thick weld joints, this paper proposes a two-dimensional generalized plane strain (GPS) finite-element model coupled with the mixed work hardening model. The residual stress distributions show mostly asymmetric parabola profiles through the thickness of the welds and it is in good correlation with the neutron diffraction results. Both the heat input and plate thickness have little influence on the residual stress distributions due to the relatively large constraints of the thick specimen applied for each welding pass. A general formula has been suggested to evaluate the distributions of the through-thickness residual stresses in thick welds based on FEM and neutron diffraction experimental results.

Residual Stress Measurements Using the Contour, Deep-Hole Drilling and Neutron Diffraction Methods in T-Section Specimens

2016 ◽  
Author(s):  
Karim Serasli ◽  
Douglas Cave ◽  
Ed Kingston
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Complex Geometry ◽  
Contour Method ◽  
Hole Drilling ◽  
Deep Hole ◽  
Premature Failure ◽  
Deep Hole Drilling ◽  
The Wire

The presence of high magnitude residual stresses in welded components causes material degradation, local yielding and plastic deformation. Their presence provides the potential for premature failure and compromises the integrity of a structure. This paper presents a review of work carried out to ascertain the residual stresses present within T-section specimens, made from ferritic steel, in their as-welded condition. The standard and incremental deep hole drilling (DHD and iDHD) techniques, the neutron diffraction (ND) and the contour method were applied to characterise the residual stresses in the regions in and around the two fillet welds of the specimens and the surrounding parent material within which the balancing residual stresses needed to be measured. The results of these measurements are presented and compared to highlight agreements and discrepancies in the measured residual stress distributions using these different techniques. A compendium of measurements at a similar location in various T-sections and their comparison with the BS7910 standard show that the measured longitudinal distributions are similar despite the observed scatter. Finally, this paper briefly attempts to investigate and discuss the technical challenges identified when applying the contour method to complex geometry components. The constraint of the specimen during the wire electro-discharge machining (EDM) process, the quality of the wire EDM cut made and the analysis of the raw data for the conversion into residual stresses directly affect the accuracy of the contour method results. The identification and investigation of these challenges lead to continuous improvements of the contour method procedure and reduce uncertainties of the measurement.

Estimation of Residual Stresses in Steel Welded Joints Using Three Dimensional Finite Element Analysis

2018 ◽  
Author(s):  
Shivdayal Patel ◽  
B. P. Patel ◽  
Suhail Ahmad
Keyword(s):  
Residual Stress ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Residual Stresses ◽  
Boundary Conditions ◽  
Welding Speed ◽  
Welded Joints ◽  
Plate Thickness ◽  
Welding Process ◽  
Element Analysis

Welding is one of the most used joining methods in the ship industry. However, residual stresses are induced in the welded joints due to the rapid heating and cooling leading to inhomogenously distributed dimensional changes and non-uniform plastic and thermal strains. A number of factors, such as welding speed, boundary conditions, weld geometry, weld thickness, welding current/voltage, number of weld passes, pre-/post-heating etc, influence the residual stress distribution. The main aim of this work is to estimate the residual stresses in welded joints through finite element analysis and to investigate the effects of boundary conditions, welding speed and plate thickness on through the thickness/surface distributions of residual stresses. The welding process is simulated using 3D Finite element model in ABAQUS FE software in two steps: 1. Transient thermal analysis and 2. Quasi-static thermo-elasto-plastic analysis. The normal residual stresses along and across the weld in the weld tow region are found to be significant with nonlinear distribution. The residual stresses increase with the increase in the thickness of the plates being welded. The nature of the normal residual stress along the weld is found to be tensile-compressive-tensile and the nature of normal residual stress across the weld is found to be tensile along the thickness direction.

Measurement and Simulation of Residual Stresses of Electron Beam Welding Joint of Pure Aluminum

2012 ◽  
Vol 184-185 ◽  
pp. 649-652
Author(s):  
Gui Fang Guo ◽  
Shi Qiong Zhou ◽  
Liang Wang ◽  
Li Hao ◽  
Ze Guo Liu
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Electron Beam ◽  
Residual Stresses ◽  
Electron Beam Welding ◽  
Pure Aluminum ◽  
Research Result ◽  
Welding Process ◽  
Hole Drilling ◽  
Longitudinal Residual Stress

The effects of electron beam welding on the residual stresses of welded joints of pure aluminum plate 99.60 are studied by through-hole-drilling and blind-hole-drilling method. Meanwhile, based on the thermal elastic-plastic theory, and making use of ANSYS finite element procedure, a three - dimensional finite element model using mobile heat source of temperature and stresses field of electron beam welding in pure aluminum is established. The welding process is simulated by means of the ANSYS software. The results show that the main residual stress is the longitudinal residual stress, the value of the longitudinal residual stress is much larger than the transverse residual stress. But the residual stress in the thickness is rather small. And in the weld center, the maximum value of residual stresses is lower than its yield strength. The simulation results about the welded residual stresses are almost identical with the experimental results by measuring. So the research result is important to science research and engineering application.

Determination of Residual Stresses in Medium Density Fibreboard

Holzforschung ◽  
2000 ◽  
Vol 54 (2) ◽  
pp. 176-182 ◽  
Author(s):  
Jeroen van Houts ◽  
Debes Bhattacharyya ◽  
Krishnan Jayaraman
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Thickness Swell ◽  
Hole Drilling ◽  
Medium Density ◽  
Stress Distributions ◽  
Moisture Expansion ◽  
Hole Drilling Method ◽  
Drilling Method ◽  
Residual Internal Stress

Summary Due to the moisture and temperature gradients developed during hot pressing of medium density fibre-board (MDF), residual stresses occur within the board as it equilibrates to room conditions. It would be extremely useful to measure these residual stresses and to determine their effects on board properties such as moduli of elasticity and rupture in bending, internal bond strength and dimensional stability. In this article two methods, namely dissection and hole drilling, have been adapted to measure residual internal stress distributions in six different samples of industry produced MDF. The dissection method involves cutting several pieces of MDF perpendicular to the thickness direction at different depths. The residual stresses released by the dissection can be determined by measuring the curvatures of cut pieces and knowing their elastic moduli. The hole drilling method, on the other hand, involves mounting three strain gauges on the surface of a piece of MDF and drilling a hole to release residual stresses in close proximity. The released stresses are manifested as strains in the forms of which can be measured in three directions on the surface of the board. A theoretical model for predicting residual stresses involving various parameters has been developed and an excellent agreement with the experimental results from both the dissection and hole drilling methods has been achieved. Linear moisture expansion coefficient appears to have the greatest influence on residual stress. When compared against each other, the residual stresses measured by the hole drilling method show some shortcomings towards the centre of the board. While all six of the MDF boards exhibited similar trends in their residual stress distributions, significant differences were identified in the magnitudes of residual stress measured. Finally, some preliminary results linking the residual stress with the thickness swell of the samples and their surface densities have been presented.

Determination of Residual Stresses on a Centrifugal Compressor Impeller

2011 ◽  
Author(s):  
Hector Delgado ◽  
Jeff Moore ◽  
Augusto Garcia Hernandez
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Centrifugal Compressor ◽  
Welding Process ◽  
Hole Drilling ◽  
Residual Tensile Stress ◽  
Scanning Method ◽  
Stress Measurements ◽  
Hole Drilling Method ◽  
Compressor Impeller

This paper reports a comparison of two methods to perform residual stress measurements. The specimens tested by each method were two blades from a shrouded centrifugal compressor impeller. The first method is the conventional hole drilling strain gage method which was used to predict residual stresses across the blade surface. The residual stresses are released by drilling a hole in the blade. The second method is called the nonlinear harmonic (NLH) scanning method and is based on the principal that the magnetic domains of ferrous materials vary in a non-linear way relative to internal stress. The effects of residual stress may be either helpful or harmful, depending on the magnitude of the residual with respect to the operating stresses. If not adequately relieved by heat treatment, residual tensile stress that develops in the welding process of shrouded impellers, will add to the stress developed by rotation which moves the point to the right on the Goodman diagram and reduces allowable alternating stress. The results showed comparable residual stress measurements of the NLH method compared to the conventional hole drilling method.

Effect of Plate Thickness and Weld Position on Distortion and Residual Stress of Welded Structural Steel

2011 ◽  
Vol 689 ◽  
pp. 296-301 ◽  
Author(s):  
Muhammad Anis ◽  
Winarto
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Structural Steel ◽  
Plate Thickness ◽  
Welding Process ◽  
Diffraction Method ◽  
Longitudinal Direction ◽  
Major Effect ◽  
Angular Distortion ◽  
Vertical Position

Residual stresses are generated as a result of non-uniform temperature distribution during welding and particularly cooling process during fabrication of the welded parts. Residual stresses have a major effect on the overall performance of a component in service. In this instant, the residual stress in the form of angular distortion is primarily caused by shrinkage on longitudinal and transversal direction. Several single v-butt joints on structural steel plates of SS400 are investigated by using different plate thickness and welding positions (1G and 3G). GMAW method was used in the welding process. Measurement of residual stress was carried out on a plate with the thickness of 16 mm on longitudinal, transversal and normal direction by using neutron diffraction method. Results showed that the angular distortion of the welded plates increase with the increase of plate thickness. Welding by vertical position (3G position) resulted in a bigger angular distortion compared to flat position (1G position). The distribution of residual stress varied between tension and compression residual stress along welded area with the range of -10 mm to 10 mm. Measurement of residual stress on the longitudinal direction has the greatest value among two other directions.

Comparison Between Shrinkage Strain and FEM Thermo-Mechanical Method for Estimation of Welding Induced Residual Stresses

2021 ◽  
Author(s):  
Sachin Bhardwaj ◽  
R. M. Chandima Ratnayake
Keyword(s):  
Residual Stress ◽  
Plastic Zone ◽  
Residual Stresses ◽  
Welded Joints ◽  
Structural Integrity ◽  
Welding Process ◽  
Shrinkage Strain ◽  
Computational Time ◽  
Transient Temperature ◽  
Strain Method

Abstract Residual stress estimation in structural integrity procedures plays an important role during the fitness-for-service (FFS) assessment of girth welds. Various FFS codes and standards, such as API 579 and BS 7910, recommend predetermined residual stress profiles based on finite element modeling (FEM) coupled with experimental results. Nonlinearity associated with non-uniform temperature gradients’ distribution during welding can develop residual stress up to the yield strength of the material, in weld shrinkage and plastic zones. Plastic zone size, shape, and locations are critically important in reducing or controlling final distortions, decreasing the residual stress according to length scale, and defining the optimum sequence of the welding process. However, in practice, estimation of finally developed residual stresses is used in structural integrity procedures for determining the FFS of welded joints. Various FEM models employed in its assessment require large computational time in solving the complex thermo-mechanical phenomenon involved in the welding process. Shrinkage strain models have been found to be fast and effective in determining final residual stresses, once the size, location and shape of the plastic zone can be predetermined. This manuscript demonstrates a comparison between the shrinkage strain method and the moving heat source method, based on transient temperature development as a function of time. The results (or findings) reveal a high compromise between FEM thermo mechanical model and shrinkage strain method in determining final residual stresses with later consuming less computational time. The findings provide significantly important feedback to welded joints’ structural integrity assurance practitioners.

Neutron Diffraction Studies of Residual Stresses Around Gouges and Gouged Dents

2012 ◽  
Author(s):  
Lynann Clapham ◽  
Vijay Babbar ◽  
Thomas Gnaeupel-Herold ◽  
Remi Batisse ◽  
Mures Zarea
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Neutron Diffraction ◽  
Stress Field ◽  
Residual Stresses ◽  
Wall Stress ◽  
Outer Wall ◽  
Stress Distributions ◽  
Wall Surface ◽  
Residual Stress Field

The residual stress pattern surrounding gouges is complex and, to date, has not been accurately modeled using stress modeling software. Thus measurement of these stress distributions is necessary. Neutron diffraction is the only experimental method with the capability of directly evaluating residual strain throughout the entire thickness of a pipe wall, in and around dent or gouged regions. Neutron diffraction measurements were conducted at the NIST reactor on three gouged dents in X52 pipeline sections. These were part of a larger sample set examined as part of the comprehensive MD4-1 PRCI/DOT PHMSA project. Gouges contained in pipeline sections were termed BEA161 (primarily a gouge with little denting), and BEA178 (mild gouging, very large dent). Measurements were also conducted on a coupon sample – P22, that was created as part of an earlier study. For the moderate gouges with little or no associated denting (BEA161 and P22) the residual stress field was highly localized around the immediate gouge vicinity (except where there was some denting present). The through wall stress distributions were similar at most locations — characterized by neutral or moderate hoop and axial stresses (50–100MPa) at the outer wall surface (i.e. at the gouge itself) gradually becoming highly compressive (up to −600MPa) at the inner wall surface. The other sample (BEA178) exhibited a very mild gouge with significant denting, and the results were very different. The denting process associated with this kind of gouge+dent dominated the residual stresses, making the residual stress distribution very complex. In addition, rather than having a residual stress field that is localized in the immediate gouge vicinity, the varying stress distribution extends to the edge of the dented region..

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