ISSN:
1460-2695
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract— We consider the slow growth of normal tension cracks as quasi-brittle behaviour under hydrogen embrittlement conditions. Experiments show that the cracking resistance of a material in such cases is not a constant of the material, but is characterized by some function that relates the rate of crack growth to the stress intensity factor. We propose a numerical method for the calculation of opening mode crack growth when the kinetics are controlled by the gas diffusion into the material. The problems under consideration model the fracture phenomena inherent to structures (e.g. pressure vessels, pipelines) that operate in an aggressive medium and in particular a hydrogen environment.In such problems it is necessary to calculate the pressure variation inside a crack as a result of gas diffusion and crack growth under the action of this pressure. Hence it is necessary to solve problems of diffusion theory and elasticity theory for a cracked medium together with some additional conditions that provide the link between these two fundamental problems.We study the case of an infinite medium containing a crack which occupies a plane domain of arbitrary shape. To avoid difficulties related to the three-dimensionality of the problems, we reduce them to two-dimensional integro-differential equations for the crack domain. The integro-differential equation of the elasticity problem of the crack is solved on the basis of the Boundary Element Method (BEM). The crack kinetics are calculated using a scheme previously introduced by one of the authors and then the BEM is used to solve the integral equation for the diffusion-into-the-crack problem similar to the analogous problem of filtration of the fluid into a crack.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1460-2695.1997.tb01486.x
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