Local Ratcheting Response in Dissimilar Metal Weld Joint: Characterization Through Digital Image Correlation Technique

Paul, Surajit Kumar; Roy, Satish; Sivaprasad, Sobha; Bar, H. N.; Tarafder, S.

doi:10.1007/s11665-017-2919-9

Cited by 10 publications

(10 citation statements)

References 21 publications

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“…DIC technique can be effectively used to measure axial strain at the necked region. 33 DIC technique is adopted in this work to measure local strain at necked region.…”

Section: Resultsmentioning

confidence: 99%

Fundamental aspect of stretch-flangeability of sheet metals

Paul

2018

Proceedings of the Institution of Mechanical Engineers, Part B:

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Stretch-flangeability of sheet metal is normally represented by hole expansion ratio. Hole expansion ratio cannot be determined from uniaxial tensile test though uniaxial tensile deformation occurs at the hole’s edge, because of fundamental difference in deformation and damage processes present between hole expansion test and uniaxial tensile test. It is proposed that only localized necking is observed in hole expansion test; however, diffuse necking followed by localized necking is observed in uniaxial tensile test of sheet metal. It is noticed that the hole expansion ratio is marginally higher than maximum diffuse neck strain determined from uniaxial tensile test with local strain measurement by digital image correlation technique. The absence of diffuse neck in hole expansion test with defect-free central hole (i.e. electrical discharge machined hole) results far higher hole expansion ratio than uniform elongation of the material.

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“…DIC technique can be effectively used to measure axial strain at the necked region. 33 DIC technique is adopted in this work to measure local strain at necked region.…”

Section: Resultsmentioning

confidence: 99%

Fundamental aspect of stretch-flangeability of sheet metals

Paul

2018

Proceedings of the Institution of Mechanical Engineers, Part B:

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“…For example, yield strength (YS) is not normally determined during CWTT due to the expected gradient in mechanical properties across the joint [1][2][3]. Cross weld tensile loading results in heterogenous strain responses in the various weldment regions, which conventional physically attached extensometers are not normally capable of measuring [1,[9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. This leads to additional requirements for the quali cation of welding procedures in applications such as pipelines [2,3].…”

Section: Introductionmentioning

confidence: 99%

“…However, SBD requirements are not well de ned in the design standards. Additionally, methods to determine the applicable properties in materials for SBD may be cumbersome to obtain using traditional physically mounted extensometers [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. This is especially true in welds where straining is localized due to materials properties differences across the welded joint.…”

Section: Introductionmentioning

confidence: 99%

Quantification of the Local Mechanical Behaviour in Dissimilar Metal Welds using Digital Image Correlation Instrumented Cross Weld Tensile Testing

Siefert,

Buehner,

Alexandrov

2023

Preprint

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The local yielding behavior in base metal, heat affected zone, fusion boundary region, and weld metal of low alloy steel / Alloy 625 filler metal welds was quantified using digital image correlation instrumented cross weld tensile test. The tested welds exhibited undermatching, matching, or overmatching weld metal yield strength with significant gradients in the local yielding behavior. An undermatching weld yielded at 69 MPa below the base metal yield stress, accumulating to 0.72% total strain. The base metal in an overmatching weld had 110 MPa lower yield strength than the weld metal. The strong strain hardening response in the Alloy 625 weld metal, within the uniform elongation range, and its constraining effect on the fusion boundary region and heat affected zone, led to extensive strain accumulation, necking, and final failure in the base metal of all tested welds. The yielding behavior of the tested welds was compared to stress-based criteria, utilizing minimum specified and as-delivered yield and ultimate tensile strength, and to strain-based criteria. The capability of digital image correlation instrumented cross weld tensile testing to quantify local yielding and strain accumulation demonstrates potential application in proving conformity to stress-based and strain-based design criteria of dissimilar and matching filler metal welds.

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“…Compared with bulky BM, the weld joint is usually more vulnerable to in-service repetitive and fluctuating loading, which can induce progressive deformation accumulation. Such heterogeneous deformation leads to a significant local strain concentration and may act as a source of localized damage, resulting in an early crack initiation and subsequent catastrophe. , As the structural safety is governed by the weakest region, weld joints are often the weak points in structures. Consequently, it is imperative to monitor heterogeneous local strain accumulation in weld joints.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, these techniques could not provide clear and direct visible local strain distribution. In recent years, the digital image correlation (DIC) method could visualize large-scale heterogeneous stress/strain distribution in weld joints by postprocessing a series of digital photographs at different elongations. , Results showed that the local strain accumulated inhomogeneously in the stretched weld joints because of the different hardness in different regions. Nevertheless, DIC is still an indirect visible technique, which needs a high-speed camera and intensive computation to provide real-time monitoring.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Visible Monitoring of Heterogeneous Local Strain Response through an Organic Mechanoresponsive AIE Luminogen

Zhang

Cao

Zhang

et al. 2020

ACS Appl. Mater. Interfaces

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Local strain concentration is critically important for damage formation of structural components. Therefore, it is of particular interest in developing the structural health monitoring (SHM) method for large-scale, full-field, and on-site monitoring of local strain response in complicated structural components in service. The present work investigated a SHM method based on a pure organic mechanoresponsive luminogen (MRL), 1,1,2,2-tetrakis(4-nitrophenyl)ethane, for heterogeneous local strain concentration. Invisible heterogeneous local strain response in complicated weld joints is transformed into visible fluorescence under monotonic tension and cyclic stress loading. The local strain (<15%) calculated by fluorescence intensity has a good agreement with the results obtained by the conventional digital image correlation method, indicating good measurement accuracy of the calibrated organic MRL method. The heterogeneity of local strain in complicated weld joints increases along with elongation and number of stress cycles. Moreover, the higher mean stress and stress amplitude can induce significantly higher accumulated local strain in the relatively soft fusion zone region. Compared with conventional strain measurement methods, the present organic MRL method opens up new possibilities for large-scale, full-field, and on-site monitoring of local strain concentration and damage in complicated structural components.

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Local Ratcheting Response in Dissimilar Metal Weld Joint: Characterization Through Digital Image Correlation Technique

Cited by 10 publications

References 21 publications

Fundamental aspect of stretch-flangeability of sheet metals

Fundamental aspect of stretch-flangeability of sheet metals

Quantification of the Local Mechanical Behaviour in Dissimilar Metal Welds using Digital Image Correlation Instrumented Cross Weld Tensile Testing

Dynamic Visible Monitoring of Heterogeneous Local Strain Response through an Organic Mechanoresponsive AIE Luminogen

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