Evolution of anodic stress corrosion cracking in a coated material
In the present paper, we investigate the influence of corrosion driving forces and interfacial toughness for a coated material subjected to mechanical loading. If the protective coating is cracked, the substrate material may become exposed to a corrosive media. For a stress corrosion sensitive substrate material, this may lead to detrimental crack growth. A crack is assumed to grow by anodic dissolution, inherently leading to a blunt crack tip. The evolution of the crack surface is modelled as a moving boundary problem using an adaptive finite element method. The rate of dissolution along the crack surface in the substrate is assumed to be proportional to the chemical potential, which is function of the local surface energy density and elastic strain energy density. The surface energy tends to flatten the surface, whereas the strain energy due to stress concentration promotes material dissolution. The influence of the interface energy density parameter for the solid–fluid combination, interface corrosion resistance and stiffness ratios between coating and substrate is investigated. Three characteristic crack shapes are obtained; deepening and narrowing single cracks, branched cracks and sharp interface cracks. The crack shapes obtained by our simulations are similar to real sub-coating cracks reported in the literature.
© The Author(s) 2010. This article is published with open access at Springerlink.com. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. Received: 11 October 2009. Accepted: 3 June 2010. Published online: 25 June 2010. C. Bjerkén was financially supported by the Swedish Research Council, (VR 50562401-02,50562402- 02). This support is greatly acknowledged. M. Ortiz would like to acknowledge the support of the United States Army Research office through the award: W911NF-06-0421 Mod/Amend#: P0001.
Published - Bjerken2010p11471Int_J_Fracture.pdf