Journal ArticleDOI
Fully plastic ductile tearing of HY130 steel—an analysis by J, COD, energy rate and crack opening angle
M Dagbasi,C E Turner +1 more
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TLDR
In this article, the authors examined the dependence of J-R curves on size of test piece for fully plastic DNB tests on HY130 steel, taken to large amounts of ductile crack growth (60 per cent of the ligament) for a range of initial widths at 20 mm thick and one geometrically similar size, 50 mm thick.Abstract:
The dependence of J-R curves on size of test piece is examined for fully plastic deep notch bend (DNB) tests on HY130 steel, taken to large amounts of ductile crack growth (60 per cent of the ligament) for a range of initial widths at 20 mm thick and one geometrically similar size, 50 mm thick. The object is to understand the cause of the widely different patterns of behaviour that have been reported in the literature, even within the DNB type of configuration. In the present tests, the proportion of shear lip is the same for the geometrically similar pair but the J-R curve for the 50 mm thick piece is much lower than for the similar piece, 20 mm thick. The rate of change of displacement, dq/da, is analysed using the factor, r * , that defines the instantaneous centre of rotation at each step of growth, to give a measure of crack tip opening angle (CTOA), α g . After an initial transient regime of small growth, α g and r * remain constant. The normalized load, L, rises due to work hardening during crack growth by amounts that depend on size while α g and r * vary mildly with initial width to give an appreciable variation of the combined term Lα g /r * , which is the factor that controls the behaviour of the J R curves. It is speculated that CTOA and its variation with configuration (as seen in the literature) may, for large growth, assume the role of the two parameters suggested in recent literature as controlling the variation of toughness with constraint.read more
Citations
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Journal ArticleDOI
A micro and macro approach to the energy dissipation rate model of stable ductile crack growth
C. E. Turner,O. Kolednie +1 more
TL;DR: In this article, the energy dissipation rate, D per unit area of crack growth, for plasticity and fracture combined, is presented for equilibrium crack extension in a real elastic-plastic material.
Journal ArticleDOI
A simple test method for energy dissipation rate, ctoa and the study of size and transferability effects for large amounts of ductile crack growth
C. E. Turner,O. Kolednik +1 more
TL;DR: In this paper, a simple extension to the standard deep notch bend test procedure is suggested to allow the collection of data relevant to the energy dissipation rate, D, crack opening angle, COA, and J, all for arbitrarily large amounts of growth in extensive plasticity.
Journal ArticleDOI
Application of energy dissipation rate arguments to ductile instability
O. Kolednik,C. E. Turner +1 more
TL;DR: In this paper, a macro-unstable behavior of a fully-plastic cracked component in terms of energy dissipation rate is established, and a possible relevance to brittle fracture and to a system dependence of both initiation toughness and the whole crack growth resistance curve is discussed.
Journal ArticleDOI
Translating the material fracture resistance into representations in welded tubular structures
Xudong Qian,Yang Zhang +1 more
TL;DR: In this paper, a lower bound material J-R curve was integrated into the load-deformation relationship for circular hollow section joints, and the results of a regression analysis of the experimental data for a wide range of structural steels reported in the literature were presented.
References
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Journal ArticleDOI
A Path Independent Integral and the Approximate Analysis of Strain Concentration by Notches and Cracks
TL;DR: In this paper, an integral is exhibited which has the same value for all paths surrounding a class of notches in two-dimensional deformation fields of linear or non-linear elastic materials.
Journal ArticleDOI
Family of crack-tip fields characterized by a triaxiality parameter—I. Structure of fields
Noel P. O’Dowd,C. F. Shih +1 more
TL;DR: In this article, a two-parameter fracture mechanics approach for tensile mode crack tip states in which the fracture toughness and the resistance curve depend on Q, i.e., JC(Q) and JR(Δa, Q), is proposed.
Two Parameter Characterization of Elastic-Plastic Crack Tip Fields and Associated Failure Criterion
TL;DR: In this paper, a modified boundary layer formulation based on the first two terms K and T, of the elastic field, is proposed for plane-strain elastic-plastic crack-tip fields.
Journal ArticleDOI
Two-Parameter Characterization of Elastic-Plastic Crack-Tip Fields
C. Betegón,J. W. Hancock +1 more
TL;DR: In this article, a modified boundary layer formulation based on the first two terms K and T, of the elastic field, is proposed for plane-strain elastic-plastic crack-tip fields.
Journal ArticleDOI
On the physical meaning of the J-Δa-curves
TL;DR: In this article, the authors worked out the physical meaning of these curves and derived the difference between crack-initiation toughness and crack-growth toughness from the energy balance during quasi-static crack growth.