Crack-tip plastic zones in glassy polymers under small-scale yielding

The KIII-stress intensity factor in an edge-cracked plate submitted to antiplane shear may be evaluated by the reflected caustic created around the crack tip, provided that a purely elastic behavior exists at the crack tip [1]. For a work-hardening, elastic-plastic material, when stresses at the vicinity of the crack tip exceed the yield limit of the material, the new shape of caustic differs substantially from the corresponding shape of the elastic solution. In this paper the shape and size of the caustics created at the tip of the crack, when small-scale yielding is established in the vicinity of the crack tip, were studied, based on a closed-form solution introduced by Rice [2]. The plastic stress intensity factor may be evaluated from the dimensions of the plastic caustic. Experimental evidence with cracked plates made of opaque materials, like steel, corroborated the results of the theory.

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Estimation of K in Ductile CT and SENB Specimens under LEFM and SSY Regimes by J Integral Method: A Review

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.275-277.242 ◽

2013 ◽

Vol 275-277 ◽

pp. 242-246

Author(s):

Bhimsen Karadin ◽

Nilesh Satonkar ◽

Sunil Bhat

Keyword(s):

Integral Method ◽

Crack Tip ◽

Small Scale ◽

J Integral ◽

Small Scale Yielding ◽

Critical Limit ◽

Ductile Materials ◽

Ductile Mode ◽

Scale Yielding ◽

Material Fracture

Stress intensity factor (K) is the measure of severity of stress at the crack tip. When K exceeds the critical limit (i.e., the material fracture toughness), the crack grows. K is valid in brittle materials (LEFM) and to some extent in ductile materials also provided there is small scale yielding (SSY) at the crack tip. The paper reviews the numerical methodology to obtain KI of ductile, Mode I cracked, CT and SENB test specimens in LEFM and SSY regimes with the help of J integral method. The numerical values are successfully compared with the theoretical values.

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Small-scale yielding interfacial crack-tip fields

Journal of the Mechanics and Physics of Solids ◽

10.1016/0022-5096(92)80002-8 ◽

1992 ◽

Vol 40 (3) ◽

pp. 511-536 ◽

Cited By ~ 34

Author(s):

E. Zywicz ◽

D.M. Parks

Keyword(s):

Interfacial Crack ◽

Crack Tip ◽

Small Scale ◽

Small Scale Yielding ◽

Crack Tip Fields ◽

Scale Yielding

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Small Scale Yielding at a Crack Normal to the Interface Between an Elastic and a Yielding Material

MRS Proceedings ◽

10.1557/proc-239-585 ◽

1991 ◽

Vol 239 ◽

Cited By ~ 3

Author(s):

Ming Y. He ◽

R. M. McMeeking ◽

Ning T. Zhang

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Brittle Material ◽

Crack Tip ◽

Asymptotic Solutions ◽

Ductile Material ◽

Small Scale ◽

Small Scale Yielding ◽

Element Analysis ◽

Scale Yielding

ABSTRACTBy using the elastic singular field as a prescribed loading condition, small scale yielding solutions are obtained for a crack normal to the interface between a brittle and a ductile material. Results for both a crack in the brittle material and one in the ductile material are obtained by finite element analysis. The crack tip fields obtained by the finite element analysis are compared with the asymptotic solutions. It is found that near the tip the stress fields approach the asymptotic solutions. If the crack is in the brittle material, the high triaxial stresses are developed near the interface ahead of the crack tip.

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