Coupling Fracture Mechanics Experiments and Electrochemical Modeling to Mitigate Environment-Assisted Cracking in Engineering Components

Abstract

Environment-assisted cracking (EAC) is a pertinent failure mode for many applications and industries, but the design of robust EAC mitigation strategies can be challenging due to the number of material and environmental factors that affect EAC behavior. In this study, a coupled experimental-modeling approach for designing EAC mitigation strategies in a standard panel-and-fastener geometry is presented. Fracture mechanics-based testing is executed on a high-performance steel (Pyrowear 675) immersed in 0.6 M NaCl to assess the effect of electrode potential and loading rate on EAC susceptibility. Finite element modeling (FEM) is then used to calculate the electrode potential distribution across the panel for four realistic EAC mitigation strategies (anodized fastener, fully coated panel, selectively coated panel, and bare panel/fastener). The FEM and EAC susceptibility data are synthesized to inform the efficacy of each proposed mitigation strategy. Results demonstrate that the anodized fastener and fully coated panel approaches are likely to promote EAC, while the selectively coated panel and all-bare strategies mitigate EAC. The benefits and limitations of this coupled approach for mitigating EAC are then discussed.