Measurements of Residual Stress in a Welded Compact Tension Specimen Using the Neutron Diffraction and Slitting Techniques

2010 ◽  
Vol 652 ◽  
pp. 210-215 ◽  
Author(s):  
Foroogh Hosseinzadeh ◽  
P. John Bouchard ◽  
Jonathan A. James
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Significant Contribution ◽  
Creep Crack Growth ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
Tension Specimen ◽  
Residual Stress Field ◽  
Butt Weld ◽  
Crack Driving Force

The residual stress field in a compact tension specimen blank extracted from a non-stress-relieved thick section butt weld has been measured using neutron diffraction and the slitting method. Significant triaxial residual stresses were found in the specimen that is normally assumed to be stress free. Moreover the level of stress was sufficient to make a significant contribution to the crack driving force in creep crack growth tests. The benefits of using more than one measurement technique in such investigations are demonstrated.

Measurements of Residual Stresses in 316 Stainless Steel Weldments

2010 ◽  
Author(s):  
C. M. Davies ◽  
D. Hughes ◽  
R. C. Wimpory ◽  
David W. Dean ◽  
K. M. Nikbin
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Crack Growth ◽  
Creep Crack Growth ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
Stress Distributions ◽  
Tension Specimen ◽  
Creep Crack ◽  
Term Creep

Neutron diffraction measurements have been performed to quantify the residual stresses distributions in austenitic type 316 stainless steel Manual Metal Arc (MMA) weldment sections, which are similar to those used in creep crack growth testing. Measurements have been taken along the expected crack path in these samples to determine the influence of residual stresses on high temperature crack growth. The influence of EB welding extension pieces onto the weldments sections, in order to increase specimen size, and sample cutting for compact tension specimen manufacture are also examined. Similar stress distributions have been measured in nominally identical MMA weldments sections, where peak stresses of up to 120 MPa have been shown. The effects of the EB weld used to attach extension pieces to the weldments sections dominate over the MMA weldments residual stress distributions in these samples, and increases the peak stresses by up to a factor of three. Significant stress relaxation takes place during compact tension specimen manufacture, and in addition creep strain accumulation will further relax these residual stresses. Residual stress effects are therefore considered to only influence the creep crack initiation period in short-term creep crack growth tests. However, in long-term creep crack growth tests, the residual stresses may also influence subsequent creep crack growth behaviour.

Neutron Diffraction Measurement of the Stress Field During Fatigue Cycling of a Cracked Test Specimen

1989 ◽  
Vol 166 ◽  
Author(s):  
M.T. Hutchings ◽  
C.A. Hippsley ◽  
V. Rainey
Keyword(s):  
Fracture Mechanics ◽  
Neutron Diffraction ◽  
Stress Field ◽  
Test Specimen ◽  
Maximum Stress ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
Diffraction Measurement ◽  
Tension Specimen ◽  
Neutron Diffraction Measurement

ABSTRACTThe triaxial stress field has been measured along the centre line of a compact tension specimen in the direction of cracking. The specimen had been subjected to ∼60,000 cycles at δK=31 and Kmax = 34 MPa mm½ and was bolted open at maximum stress. The field was remeasured after the stress had been fully relaxed. The results are discussed in terms of expectations from fracture mechanics calculations.

scholarly journals Estimation of C* Integral for Mismatched Welded Compact Tension Specimen

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7491
Author(s):  
Marko Katinić ◽  
Dorian Turk ◽  
Pejo Konjatić ◽  
Dražan Kozak
Keyword(s):  
Finite Element ◽  
Heat Affected Zone ◽  
Creep Crack Growth ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
Tension Specimen ◽  
Type Iv ◽  
Material Homogeneity ◽  
Severe Type ◽  
Modified Equation

The C* integral for the compact tension (CT) specimen is calculated using the estimation equation in ASTM E1457-15. This equation was developed based on the assumption of material homogeneity and is not applicable to a welded CT specimen. In this paper, a modified equation for estimating the C* integral for a welded compact tension (CT) specimen under creep conditions is proposed. The proposed equation is defined on the basis of systematically conducted extensive finite element (FE) analyses using the ABAQUS program. A crack in the welded CT specimen is located in the center of the heat-affected zone (HAZ), because the most severe type IV cracks are located in the HAZ. The results obtained by the analysis show that the equation for estimating the C* integral in ASTM E1457-15 can underestimate the value of the C* integral for creep-soft HAZ and overestimate for creep-hard HAZ. Therefore, the proposed modified equation is suitable for describing the creep crack growth (CCG) of welded specimens.

An evaluation of residual stress distribution in welded compact tension specimens using neutron diffraction

2005 ◽  
Vol 40 (2) ◽  
pp. 211-216 ◽  
Author(s):  
G. O Rading
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Neutron Diffraction ◽  
Stress Field ◽  
Fatigue Cracks ◽  
Compact Tension ◽  
Maximum Tensile Stress ◽  
Thickness Variation ◽  
Residual Stress Field ◽  
Neutron Diffraction Technique

The neutron diffraction technique was used to determine the residual stress field in welded compact tension specimens of the aluminium-lithium alloy AA 2095. The deep penetrating characteristic of neutrons was exploited to evaluate the through-thickness variation in residual stress. Moreover, insight into the redistribution of these stresses was gained by extending a fatigue crack through the residual stress field and re-examining the stress distribution. The specimen without a crack was found to have a high compressive stress (of the order of - 135MPa) ahead of the notch. This rose to a maximum tensile stress of about 50MPa, 22 mm from the notch, followed by a drop to negative values further ahead of the notch. It was observed that the magnitude of the stresses changed on moving into the thickness of the specimen. However, the form of the graph showing stress versus distance ahead of the notch remained unchanged. When fatigue cracks of different lengths were introduced, the magnitude of the stress close to the tip first increased with crack length, before decreasing and then rising again. Nevertheless, the form of the graph remained unchanged and the stress at the crack tip remained compressive. The paper concludes that any study of the response of a component to mechanical loading involving a residual stress field must take these factors (i.e. through-thickness stress variation and stress redistribution) into consideration.

Neutron Diffraction Residual Stress Measurements in Electron Beam Welded Compact Tension Specimens

2014 ◽  
Vol 777 ◽  
pp. 99-104
Author(s):  
Priyesh Kapadia ◽  
Catrin M. Davies ◽  
Thilo Pirling ◽  
David W. Dean ◽  
Kamran M. Nikbin
Keyword(s):  
Residual Stress ◽  
Electron Beam ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Crack Growth ◽  
Creep Crack Growth ◽  
Compact Tension ◽  
Diffraction Measurement ◽  
Machining Processes ◽  
Residual Stresses And Strains

In a study to investigate the effect of residual stress relaxation on Creep Crack Growth (CCG) a novel fracture mechanics specimen has been designed. Compact Tension, C(T), specimens are fabricated from blocks with Electron Beam (EB) welds such that residual stresses induced during welding are retained in the specimen. Finite element analyses of EB welding and machining processes have been developed to predict the stresses in such C(T) specimens which will drive crack growth in future CCG studies. The residual stresses and strains in these samples have been quantified using the neutron diffraction measurement technique at various stages of the fabrication process and have been used to validate numerical simulations of the fabrication processes.

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