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.

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.

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.

Finite Element Validation of the over-Coring Deep-Hole Drilling Technique

2011 ◽  
Vol 70 ◽  
pp. 291-296 ◽  
Author(s):  
Sayeed Hossain ◽  
Ed J. Kingston ◽  
Christopher E. Truman ◽  
David John Smith
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Field ◽  
Residual Stresses ◽  
Stress Measurement ◽  
Residual Stress Measurement ◽  
Hole Drilling ◽  
Deep Hole ◽  
Residual Stress Field ◽  
Deep Hole Drilling

The main objective of the present study is to validate a simple over-coring deep-hole drilling (oDHD) residual stress measurement technique by utilising finite element simulations of the technique. A number of three dimensional (3D) finite element analyses (FEA) were carried out to explore the influence of material removal and the cutting sequence during the deep-hole drilling (DHD) residual stress measurement process on the initial residual stress field. Two models were considered in the study. First, the residual stress field predicted in a rapid spray water quenched solid cylinder was used as the initial stress field for the DHD FE model. The DHD reconstructed residual stresses were compared with the initial FE predicted stresses. Different cutting sequences and different dimensions were systematically simulated before arriving at an optimum solution for the oDHD technique. The oDHD technique significantly improved the spatial resolution and was applied in a second model consisting of a 40mm thick butt-welded pipe. The DHD reconstructed residual stresses compared very well with the initial FE predicted weld residual stress thereby validating the oDHD technique.

scholarly journals Residual stresses in thermite welded rails: significance of additional forging

2020 ◽  
Vol 64 (7) ◽  
pp. 1195-1212
Author(s):  
B. Lennart Josefson ◽  
R. Bisschop ◽  
M. Messaadi ◽  
J. Hantusch
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Residual Stresses ◽  
Weld Metal ◽  
Welding Process ◽  
Surface Zone ◽  
Fe Model ◽  
Uneven Surface ◽  
Residual Stress Field ◽  
High Dynamic

Abstract The aluminothermic welding (ATW) process is the most commonly used welding process for welding rails (track) in the field. The large amount of weld metal added in the ATW process may result in a wide uneven surface zone on the rail head, which may, in rare cases, lead to irregularities in wear and plastic deformation due to high dynamic wheel-rail forces as wheels pass. The present paper studies the introduction of additional forging to the ATW process, intended to reduce the width of the zone affected by the heat input, while not creating a more detrimental residual stress field. Simulations using a novel thermo-mechanical FE model of the ATW process show that addition of a forging pressure leads to a somewhat smaller width of the zone affected by heat. This is also found in a metallurgical examination, showing that this zone (weld metal and heat-affected zone) is fully pearlitic. Only marginal differences are found in the residual stress field when additional forging is applied. In both cases, large tensile residual stresses are found in the rail web at the weld. Additional forging may increase the risk of hot cracking due to an increase in plastic strains within the welded area.

The Effects of Loadings on Welding Residual Stresses and Assessment of Fracture Parameters in a Welding Residual Stress Field

2011 ◽  
Author(s):  
Liwu Wei ◽  
Weijing He ◽  
Simon Smith
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Residual Stresses ◽  
Path Dependence ◽  
Welding Residual Stress ◽  
Assessment Procedure ◽  
Fe Model ◽  
J Integral ◽  
Residual Stress Field ◽  
Growing Crack

The level of welding residual stress is an important consideration in the ECA of a structure or component such as a pipeline girth weld. Such a consideration is further complicated by their variation under load and the complexity involved in the proper assessment of fracture mechanics parameters in a welding residual stress field. In this work, 2D axi-symmetric FEA models for simulation of welding residual stresses in pipe girth welds were first developed. The modelling method was validated using experimental measurements from a 19-pass girth weld. The modeling method was used on a 3-pass pipe girth weld to predict the residual stresses and variation under various static and fatigue loadings. The predicted relaxation in welding residual stress is compared to the solutions recommended in the defect assessment procedure BS 7910. Fully circumferential internal cracks of different sizes were introduced into the FE model of the three-pass girth weld. Two methods were used to introduce a crack. In one method the crack was introduced instantaneously and the other method introduced the crack progressively. Physically, the instantaneously introduced crack represents a crack originated from manufacturing or fabrication processes, while the progressively growing crack simulates a fatigue crack induced during service. The J-integral values for the various cracks in the welding residual stress field were assessed and compared. This analysis was conducted for a welding residual stress field as a result of a welding simulation rather than for a residual stress field due to a prescribed temperature distribution as considered by the majority of previous investigations. The validation with the 19-pass welded pipe demonstrated that the welding residual stress in a pipe girth weld can be predicted reasonably well. The relaxation and redistribution of welding residual stresses in the three-pass weld were found to be significantly affected by the magnitude of applied loads and the strain hardening models. The number of cycles in fatigue loading was shown to have little effect on relaxation of residual stresses, but the range and maximum load together governed the relaxation effect. A significant reduction in residual stresses was induced after first cycle but subsequent cycles had no marked effect. The method of introducing a crack in a FE model, progressively or instantaneously, has a significant effect on J-integral, with a lower value of J obtained for a progressively growing crack. The path-dependence of the J-integral in a welding residual stress field is discussed.

Macro-Residual Stress Field Retrieval for Predicting the Machining Deformation of Non-Prestretched Plate

2011 ◽  
Vol 317-319 ◽  
pp. 386-392
Author(s):  
Yin Fei Yang ◽  
Ning He ◽  
Liang Li
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Large Scale ◽  
Hole Drilling ◽  
Residual Stress Field ◽  
Hole Drilling Method ◽  
Machining Deformation ◽  
Stress Changes ◽  
Drilling Method ◽  
And Control

The unknown and uneven macro-residual stresses in blanks will cause deformation on large-scale component, especially in non-prestretched plates. Based on the retrieval of stress field by measuring stress changes due to the rebalance of stresses after machining, a new idea is proposed in this paper to predict and control the machining deformation of large-scale components. It consists of analysis of the machining deformation, retrieval of macro-residual stress field, and finally optimization of following cutting process. In the retrieval process, the stresses are measured with an improved hole-drilling method and the measured data are then interpolated to 3D stress field.

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.

The Effect of Residual Stresses on the Fracture Resistance of Ductile Steels

2002 ◽  
Author(s):  
Noel P. O’Dowd ◽  
Yuebao Lei
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Residual Stresses ◽  
Crack Opening ◽  
Stress Distributions ◽  
Residual Stress Field ◽  
Element Analysis ◽  
Fatigue And Fracture ◽  
Negative Effect ◽  
Fracture Performance

Tensile residual stresses, such as those generated by welding, act as crack opening stresses and can have a negative effect on the fatigue and fracture performance of a component. In this work the effect of representative residual stress distributions on the fracture behaviour of a ferritic steel has been examined using finite element analysis. A Gurson-type void growth model is used to model the effect of ductile tearing ahead of a crack. For the cases examined it is seen that a tensile residual stress field may lead to a reduction in the toughness of the material (as represented by the J-resistance curve). The observed difference in toughness can be linked to the different constraint levels in the specimens due to the introduction of the residual stress field and can be rationalised through the use of a two parameter, J–Q approach.

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