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Reza Hirmand, William Tyson, Su Xu, Dash Weeks


This paper revisits previous numerical predictions and experimental measurements of tensile strain capacity (TSC) in curved wide plate (CWP) specimens. The work is motivated by the arguably surprising conclusion in (Liu, Wang, Horsley, et al. 2012) that better predictions can be made from toughness data extracted from Charpy V-notch (CVN) tests compared with fracture mechanics tests using single edge-notched tensile (SE(T)) specimens. The integral is used to describe driving and resistance forces rather than the CTOD used previously (Liu, Wang, Song, et al. 2012; Liu, Wang, Horsley, et al. 2012). Small-specimen toughness data is used to make numerical predictions of full-scale CWP specimens based on instability and initiation limit state methods. Several important factors that impact the utility of the integral approach are addressed. These include applicability of "apparent" integral in gross plasticity, consistency of the flaw constraint conditions in resistance curve measurements and CWP tests, the type of stress-strain relationships used, shape of the flaw, and mechanical properties at the flaw tip. The integral approach is shown to yield predictions that agree better with experimental measurements than previous CTOD-based calculations while avoiding the controversy over the definition of CTOD. Strain-based design using is thus validated, supporting first-principles estimation of initiation and instability strains using only small-scale SE(T) data and calculations for CWP.
Proceedings Title
Technology for Future and Ageing Pipelines
Conference Dates
October 19-21, 2021
Conference Location
Ghent, BE


Curved Wide Plate, CWP, Single Edge Notched Tension, SENT, SE(T), Charpy, CVN, tensile strain capacity, TSC


Hirmand, R. , Tyson, W. , Xu, S. and Weeks, D. (2021), �-INTEGRAL APPROACH TO ESTIMATION OF TENSILE STRAIN CAPACITY IN STRAIN-BASED DESIGN, Technology for Future and Ageing Pipelines, Ghent, BE, [online], (Accessed May 22, 2024)


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Created October 19, 2021, Updated November 29, 2022