Multi-State Reliability Modeling and Assessment for Corrosion of Organic Coating-Substrate Structure

Abstract

The organic coating-substrate structure suffers from corrosion reaction between the substrate material and water molecules during the storage stage. Digital twin is a promising tool for corrosion modeling and assessing the reliability of the organic coating-substrate structure. In this paper, a multi-state modelling method is proposed towards the digital twin and reliability modeling and analysis. Firstly, to analyze the physicochemical process involved in the corrosion of organic coating-substrate structures, a multi-physics simulation method is developed. Then, the degradation performance of the organic coating-substrate structure is discretized into several states, and a Markov model is utilized to model the degradation process of the structure to support the digital twine model construction. The transition intensities of the Markov model are estimated by using the multi-physics simulation data. In the proposed method, the multi-physics simulation method can incorporate the diffusion equation and the kinetic equation of the corrosion, allowing for the simulation of water molecule diffusion within the organic coating and the coupling simulation of the metal corrosion process. Subsequently, the reliability of the organic coating-substrate structure is analyzed under varying temperatures, humidity levels, and protective material parameters. The result shows that higher ambient temperatures and relative humidity levels contribute to an accelerated corrosion rate of the substrate, and the reliability decreases.