Asymptotic analysis of steady dynamic crack growth in an elastic-plastic material

In this paper a finite element analysis of steady-state dynamic crack growth under mode I plane strain small scale yielding conditions has been performed in a power law hardening rate dependent plastic material, characterized by the Perzyna over stress model. A modified version of the rate tangent modulus method has been used to update the stress. The main objective of the work is to obtain a quantitative relationship between dynamic fracture toughness ratio (K/Kss) and crack speed. A plastic strain criteria proposed by McClintock (1968) has been applied to obtain this relationship. It is found that dynamic stress intensity factor increases with velocity for all values of βˆ (a normalized viscosity parameter). At a low value of βˆ, which corresponds to high rate sensitivity, the fracture toughness ratio (K/Kss) increases with hardening. On the other hand, at a higher βˆ, the ratio increases initially and falls subsequently, with increasing hardening.

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Crack growth in an elastic-plastic material and effects on near tip constraint

Computational Materials Science ◽

10.1016/0927-0256(94)90134-1 ◽

1994 ◽

Vol 3 (2) ◽

pp. 207-217 ◽

Cited By ~ 1

Author(s):

Noel P. O'Dowd

Keyword(s):

Crack Growth ◽

Plastic Material ◽

Elastic Plastic ◽

Elastic Plastic Material

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A Finite Element Analysis of Mode III Quasi-Static Crack Growth at a Ductile-Brittle Interface

Journal of Applied Mechanics ◽

10.1115/1.2787199 ◽

1996 ◽

Vol 63 (1) ◽

pp. 204-209 ◽

Cited By ~ 2

Author(s):

S. Omprakash ◽

R. Narasimhan

Keyword(s):

Finite Element ◽

Crack Growth ◽

Power Law ◽

Plastic Material ◽

Bimaterial Interface ◽

Mode Iii ◽

Elastic Substrate ◽

Elastic Plastic ◽

Static Crack ◽

Elastic Plastic Material

Steady-state quasi-static crack growth along a bimaterial interface is analyzed under Mode III, small-scale yielding conditions using a finite element procedure. The interface is formed by an elastic-plastic material and an elastic substrate. The top elastic-plastic material is assumed to obey the J2 incremental theory of plasticity. It undergoes isotropic hardening with either a bilinear uniaxial response or a power-law response. The results obtained from the full-field numerical analysis compare very well with the analytical asymptotic results obtained by Castan˜eda and Mataga (1991), which forms one of the first studies on this subject. The validity of the separable form for the asymptotic solution assumed in their analysis is investigated. The range of dominance of the asymptotic fields is examined. Field variations are obtained for a power-law hardening elastic-plastic material. It is seen that the stresses are lower for a stiffer substrate. The potential of the bimaterial system to sustain slow stable crack growth along the interface is studied. It is found that the above potential is larger if the elastic substrate is more rigid with respect to the elastic-plastic material.

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