کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
771366 897626 2008 14 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Characteristic crack-tip distances in fracture criteria: Is crack propagation discontinuous?
موضوعات مرتبط
مهندسی و علوم پایه سایر رشته های مهندسی مهندسی مکانیک
پیش نمایش صفحه اول مقاله
Characteristic crack-tip distances in fracture criteria: Is crack propagation discontinuous?
چکیده انگلیسی

The present paper describes a possible mechanism for discontinuous crack advance in which surface separation occurs initially not at the crack-tip itself but within the crack-tip plastic zone of size rp, at the mid-point of the crack-tip characteristic distance d (identified here with the finite growth step Δa), i.e., at the region of maximum opening tensile stress, spreading towards (and also away from) the crack-tip. The crack extension occurs when the crack-tip is reached and full opening over the distance d is completed.Finite element analyses show that this mechanism causes the formation of a rippled crack face surface in elastic–plastic materials in which irreversible plastic deformations take place during each growth step, in sharp contrast with the smooth surface created in ideal elastic materials in which all deformations are fully reversible. Some pictorial evidence of void formation ahead of the crack tip and of ripples during propagation, found in the literature, is presented.Although the present analysis is from a continuum standpoint it is acknowledged that micro structural features and mechanisms can condition the fracture events taking place in the process zone.The implication to the brittle-ductile transition of the dependence of the energy release rate, GΔΞ, on the ratio q (=Δa/rp) is also discussed.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Engineering Fracture Mechanics - Volume 75, Issue 7, May 2008, Pages 1815–1828
نویسندگان
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