A Critical Examination of Sachs’ Material-Removal Method for Determination of Residual Stress

2004 ◽  
Vol 126 (2) ◽  
pp. 234-236 ◽  
Author(s):  
Anthony P. Parker
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Critical Examination ◽  
Fatigue Lifetime ◽  
Experimental Procedure ◽  
Linear Elastic ◽  
Order Of Magnitude ◽  
Hoop Stresses ◽  
Elastic Unloading

Sachs’ method is an experimental procedure used primarily in the determination of residual stresses in autofrettaged thick cylinders. In its usual form it involves fixing axial and hoop direction strain gauges to the OD of a tube; strain readings are then obtained after each incremental removal of material from the bore. Sachs’ analysis assumes that the remaining tube unloads in linear-elastic fashion throughout the process and that superposition may therefore be employed to quantify the residual stresses within the original tube. By numerical simulation of two complete Sachs’ experimental sequences with “open end” conditions it is demonstrated that the assumption of elastic unloading is invalidated by the Bauschinger effect. Sachs’ method thereby overestimates compressive residual bore hoop stresses in a typical tube by between 24% and 43%. If used as the basis for cyclic pressurization fatigue lifetime predictions with pre-existing cracks, such discrepancies will cause overestimates in fatigue lifetime of an order of magnitude. Sachs’ experimental procedure is therefore not recommended as a reliable or conservative method for determination of residual stress.

A Critical Examination of Sachs’ Material-Removal Method for Determination of Residual Stress

2003 ◽  
Author(s):  
Anthony P. Parker
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Critical Examination ◽  
Fatigue Lifetime ◽  
Experimental Procedure ◽  
Linear Elastic ◽  
Order Of Magnitude ◽  
Hoop Stresses ◽  
Elastic Unloading

Sachs’ method is an experimental procedure used primarily in the determination of residual stresses in autofrettaged thick cylinders. In its usual form it involves fixing axial and hoop direction strain gauges to the OD of a tube; strain readings are then obtained after each incremental removal of material from the bore. Sachs’ analysis assumes that the remaining tube unloads in linear-elastic fashion throughout the process and that superposition may therefore be employed to quantify the residual stresses within the original tube. By numerical simulation of two complete Sachs’ experimental sequences with ‘open end’ conditions it is demonstrated that the assumption of elastic unloading is invalidated by the Bauschinger effect. Sachs’ method thereby overestimates compressive residual bore hoop stresses in a typical tube by between 24% and 43%. If used as the basis for cyclic pressurization fatigue lifetime predictions with pre-existing cracks, such discrepancies will cause overestimates in fatigue lifetime of an order of magnitude. Sachs’ experimental procedure is therefore not recommended as a reliable or conservative method for determination of residual stress.

Estimation of Axisymmetric Residual Stresses in a Long Cylinder

1992 ◽  
Vol 114 (2) ◽  
pp. 137-140 ◽  
Author(s):  
W. Cheng ◽  
I. Finnie ◽  
O¨. Vardar
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Plane Strain ◽  
Plane Stress ◽  
Stress Measurement ◽  
Residual Stress Measurement ◽  
Experimental Procedure ◽  
Linear Elastic ◽  
Hoop Stresses ◽  
Long Cylinder

An approach based on linear elastic equations is developed to predict axisymmetric axial and radial residual stresses in a long cylinder in plane strain from hoop stresses measured in both plane strain and plane stress. This approach, when combined with the authors’ crack compliance method for residual stress measurement, leads to a simplified experimental procedure for measurement of axisymmetric residual stresses in cylinders.

scholarly journals Determination of Residual Stresses in WCu Gradient Materials

1999 ◽  
Vol 33 (1-4) ◽  
pp. 207-217 ◽  
Author(s):  
G. Bokuchava ◽  
N. Shamsutdinov ◽  
J. Schreiber ◽  
M. Stalder
Keyword(s):  
Residual Stress ◽  
High Resolution ◽  
Elastic Behaviour ◽  
Gradient Materials ◽  
Linear Elastic ◽  
Step Functions ◽  
Order Of Magnitude ◽  
Copper Phase ◽  
Experimental Values

Residual stress measurements were carried out on copper–tungsten gradient materials by means of neutron diffraction on the High Resolution Fourier Diffractometer on IBR-2, JINR, Dubna. The samples so far investigated had a concentration profile that approximates the gradient by step functions. The results show an averaged positive stress (stretch) in the copper phase and negative (compression) in the tungsten phase. A comparison to analytical linear elastic calculations shows that the measured values are nearly an order of magnitude too low, whereas however, a qualitative agreement of the stress distribution exists. That this quantitative discrepancy can be attributed to the model's simplifying assumption of pure elastic behaviour can be shown by recent calculations that also include plasticity and show a much better agreement with the experimental values. Single peak evaluation also strongly suggests that plasticity does indeed play a significant role.

Residual Stress Measurements by Means of Neutron Diffraction

1989 ◽  
Vol 166 ◽  
Author(s):  
H. J. Prask ◽  
C. S. Choi
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Test Specimen ◽  
Hardened Steel ◽  
Fatigue Lifetime ◽  
Near Surface ◽  
Surface Residual Stresses ◽  
Lifetime Test

ABSTRACTEnergy-dispersive neutron diffraction has been developed at the NIST reactor as a probe of sub- and near-surface residual stresses in technological samples. Application of the technique has been made to a variety of metallurgical specimens which includes the determination of tri-axial stresses as a function of depth in a number of uranium-3/4wt%Ti samples with different thermo-mechanical histories, and in two types of 7075-T6 aluminum “ogives”- of interest to the Army. Preliminary results have been obtained for an induction-hardened steel shaft, a fatigue lifetime test specimen for the SAE.

A Limiting Defect Study of an Elbow

2011 ◽  
Author(s):  
Jinhua Shi ◽  
David Blythe
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Hoop Stress ◽  
Defect Size ◽  
Welding Residual Stress ◽  
Central Section ◽  
Butt Welding ◽  
Wide Range ◽  
Stress Components ◽  
Hoop Stresses

In order to ensure the integrity of a seamless butt-welding elbow, both the central section and ends of the elbow need to be assessed, as the maximum stress is normally located at the central section of the elbow but there are no welding residual stresses. Furthermore, at the ends (welds) of the elbow, very high welding residual stresses exist if the welds have not been post weld heat treated but the primary stresses induced by the internal pressure and system moments are lower. For a 90 degree elbow welded to seamless straight pipe, both maximum axial and hoop stress components in the elbow can be calculated using ASME III NB-3685. At the ends of the elbow, axial and hoop stress components can be obtained using the stress equations presented in the paper of PVP2010-25055. In this paper, a series of limiting defect assessments have been carried out on an elbow assuming a postulated axial external defect as follows: • A number of assessments have been conducted directly using the axial and hoop stresses calculated based on ASME III NB-3685 for different system moments. • A series of assessments have been carried out using the axial and hoop stresses calculated using the stress equations presented in the paper of PVP2010-25055, a wide range of welding residual stresses and different system moments. A comparison of the assessment results in the elbow and at the ends of the elbow shows that when system moments are relatively low and the welding residual stress is high, the limiting defect size is located at the ends of the elbow; when the system moments are high and the welding residual stress is low the limiting defect size is located at the central section of the elbow. Therefore, it can be concluded that when assessing an elbow, the assessments should be carried out at both the central section and the ends of the elbow, in order to ensure the integrity of the elbow.

Characterization and Evaluation of Mechanical Properties and Residual Stress in Aluminum-Magnesium Alloys Welded by the FSW Process

2020 ◽  
Vol 1012 ◽  
pp. 349-353
Author(s):  
D.B. Colaço ◽  
M.A. Ribeiro ◽  
T.M. Maciel ◽  
R.H.F. de Melo
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Residual Stresses ◽  
Welding Process ◽  
Bending Test ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Friction Stir ◽  
Aluminum Magnesium Alloys

The demand for lighter materials with suitable mechanical properties and a high resistance to corrosion has been increasing in the industries. Therefore, aluminum appears as an alternative due to its set of properties. The aim of this work was to evaluate residual stress levels and mechanical properties of welded joints of Aluminum-Magnesium alloy AA 5083-O using the Friction Stir Welding process. For mechanical characterization were performed a uniaxial tensile test, Vickers hardness, bending test and, finally, the determination of residual stresses. It was concluded that welding by FSW process with an angle of inclination of the tool at 3o, established better results due to better mixing of materials. The best results of tensile strength and a lower level of residual stresses were obtained using a tool rotation speed of 340 RPM with welding advance speed of 180 mm/min and 70 mm/min.

X-Ray Diffraction Analysis of Steel with Oxidised Surface Layer

2016 ◽  
Vol 368 ◽  
pp. 99-102
Author(s):  
Lukáš Zuzánek ◽  
Ondřej Řidký ◽  
Nikolaj Ganev ◽  
Kamil Kolařík
Keyword(s):  
Residual Stress ◽  
Surface Layer ◽  
Residual Stresses ◽  
Diffraction Analysis ◽  
Oxide Surface ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrolytic Polishing ◽  
Small Depth

The basic principle of the X-ray diffraction analysis is based on the determination of components of residual stresses. They are determined on the basis of the change in the distance between atomic planes. The method is limited by a relatively small depth in which the X-ray beam penetrates into the analysed materials. For determination of residual stresses in the surface layer the X-ray diffraction and electrolytic polishing has to be combined. The article is deals with the determination of residual stress and real material structure of a laser-welded steel sample with an oxide surface layer. This surface layer is created during the rolling and it prevents the material from its corrosion. Before the X-ray diffraction analysis can be performed, this surface layer has to be removed. This surface layer cannot be removed with the help of electrolytic polishing and, therefore, it has to be removed mechanically. This mechanical procedure creates “technological” residual stress in the surface layer. This additional residual stress is removed by the electrolytic polishing in the depth between 20 and 80 μm. Finally, the real structure and residual stresses can be determined by using the X-ray diffraction techniques.

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.

The Bauschinger and Hardening Effect on Residual Stresses in an Autofrettaged Thick-Walled Cylinder

1986 ◽  
Vol 108 (1) ◽  
pp. 108-112 ◽  
Author(s):  
P. C. T. Chen
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Closed Form Solution ◽  
High Strength ◽  
Form Solution ◽  
Residual Stress Distribution ◽  
Hardening Effect ◽  
Reverse Yielding ◽  
Walled Cylinder ◽  
Elastic Unloading

Most of the earlier solutions for residual stresses were based on the assumption of elastic unloading and only a few considered reverse yielding. In this paper a new theoretical model for a high strength steel is proposed and a closed-form solution of residual stresses in autofrettaged tubes has been obtained. The new results indicate that the influence of the combined Bauschinger and hardening effect on the residual stress distribution is significant.

Wheel Rim Axial Residual Stress and a Proposed Mechanism for Vertical Split Rim Formation

2011 ◽  
Author(s):  
Cameron Lonsdale ◽  
John Oliver
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Measurement ◽  
Axial Stress ◽  
X Ray Diffraction ◽  
X Ray ◽  
Axial Residual Stress ◽  
Railroad Wheels ◽  
Hoop Stresses ◽  
Future Work

Railroad wheels are manufactured with beneficial residual compressive hoop stresses, which are imparted by rim quenching and tempering. Hoop and radial residual stresses for wheels have been studied in detail by various organizations over the years and are relatively well characterized. However axial residual stresses, in the orientation across the rim width from back rim face to front rim face, have not been extensively investigated. This paper describes a failure mode known as a vertical split rim (VSR) and describes efforts to measure the axial residual stresses in, 1) new wheels, 2) service worn wheels and 3) wheels that have failed from VSRs. Initial axial residual stress measurement efforts, using core drilling and x-ray diffraction from the tread surface, are briefly reviewed. Further more extensive work using x-ray diffraction to measure axial residual stress on radial wheel slices is described and data are presented, focusing on differences between the three wheel types. The concept of Axial Stress Amplification (ASA) is outlined, and the relationship of axial residual stress to VSRs is discussed. A proposed mechanism for VSR formation is described. Future work, with a goal of reducing or eliminating VSRs in service, is considered.

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