Journal ArticleDOI
Family of crack-tip fields characterized by a triaxiality parameter—II. Fracture applications
Noel P. O’Dowd,C. F. Shih +1 more
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In this paper, the J-dominance is used to define the size scale over which large stresses and strains develop while Q scales the near-tip stress distribution and the stress triaxiality achieved ahead of the crack.Abstract:
C entral to the J-based fracture mechanics approach is the concept of J-dominance whereby J alone sets the stress level as well as the size scale of the zone of high stresses and strains. In Part I the idea of a J Q annulus was developed. Within the annulus, the plane strain plastic near-tip fields are members of a family of solutions parameterized by Q when distances are normalized by J σ 0 , where σ0is the yield stress, J and Q have distinct roles: J sets the size scale over which large stresses and strains develop while Q scales the near-tip stress distribution and the stress triaxiality achieved ahead of the crack. Specifically, negative (positive) Q values mean that the hydrostatic stress is reduced (increased) by Qσ0 from the Q = 0 plane strain reference state. Therefore Q provides a quantitative measure of crack-tip constraint, a term widely used in the literature concerning geometry and size effects on a material's resistance to fracture. These developments are discussed further in this paper. It is shown that the J Q approach considerably extends the range of applicability of fracture mechanics for shallow-crack geometries loaded in tension and bending, and deep-crack geometries loaded in tension. The J Q theory provides a framework to organize toughness data as a function of constraint and to utilize such data in engineering applications. Two methods for estimating Q at fully yielded conditions and an interpolation scheme are discussed. The effects of crack size and specimen type on fracture toughness are addressed.read more
Citations
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Journal ArticleDOI
Numerical evaluation of the effect of the weld metal on the constraint factor in bi-metal C(T) specimens
TL;DR: In this article, the effect of the weld metal on the out-of-plane constraint in C(T) bi-material specimens was studied using the Common Format Equation and its associated constraint factor, Ω∗, as a function of the thickness-to-ligament ratio, B/b.
Book ChapterDOI
2 – Constraint fracture mechanics: test methods
K.A. Macdonald,E. Østby,B. Nyhus +2 more
TL;DR: In this paper, the authors outline the basis of the current guidance for the use of SENT testing and how it is applied in practice, including consideration of the development of the SENT test for use in fracture control of pipelines.
Proceedings ArticleDOI
Deterministic and Probabilistic Fracture Mechanics Analysis of Pipeline Weld Flaws Accounting for Crack Tip Constraint Effects
Jens P. Tronskar,Zhang Li +1 more
TL;DR: The acceptability of weld defects during line pipe manufacture and pipeline construction is governed by international codes and standards such as the DNV OS-F101 or API1104 as discussed by the authors.
Book ChapterDOI
Transferability of Fracture Toughness with Constraint
TL;DR: In this paper, the plastic constraint in the material failure master curve (MFMC) and the material transition temperature (MTTMC) was examined for transferability of fracture toughness.
Journal ArticleDOI
A novel unified constraint parameter based on plastic strain energy
TL;DR: In this article , a unified constraint parameter λ based on the plastic strain energy was proposed to characterize the constraint of C(T) and SEN(B) specimens but is effective in characterizing the multi-axiality effect while traditional constraint parameters failed to do so.
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
Plane strain deformation near a crack tip in a power-law hardening material
James R. Rice,G. F. Rosengren +1 more
TL;DR: In this paper, the authors investigated the C rack-tip strain singularities with the aid of an energy line integral exhibiting path independence for all contours surrounding a crack tip in a two-dimensional deformation field of an elastic material (or elastic/plastic material treated by a deformation theory).
Journal ArticleDOI
Singular behaviour at the end of a tensile crack in a hardening material
TL;DR: In this paper, a total deformation theory of plasticity, in conjunction with two hardening stress-strain relations, is used to determine the dominant singularity at the tip of a crack in a tension field.
Journal ArticleDOI
On the relationship between critical tensile stress and fracture toughness in mild steel
TL;DR: In this paper, the critical value of tensile stress (a) for unstable cleavage fracture to the fracture toughness (K,,) for a high-nitrogen mild steel under plane strain conditions.
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.
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Family of crack-tip fields characterized by a triaxiality parameter—I. Structure of fields
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Plane strain deformation near a crack tip in a power-law hardening material
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