Research On Surface Characteristics And Stochastic Constitutive Model Of Corroded Steel In General Atmosphere And Offshore Atmosphere

Steel structures exposed to the general atmospheric and offshore atmospheric corrosion environments for a long period of time are extremely susceptible to corrosion damage,and corrosion is one of the main factors that cause the deterioration of the durability of steel structures.Due to the influence of factors such as structure type,service environment and protective measures,the surface morphology and mechanical properties of the steel after corrosion have significant random characteristics.In this paper,through statistical analysis of the surface morphology characteristic parameters of corroded steel in the general atmospheric and offshore atmospheric environments,a random field model of rust depth and a random distribution model of rust pits are established to achieve the overall corrosion and pitting surface shape of the general atmosphere and offshore atmosphere Appearance simulation.Combined with the finite element,large-scale numerical simulation and parametric analysis were carried out to study the correlation between the mechanical property parameters of the corroded steel plate and the volume loss rate,and the random constitutive models for general corrosion and pitting corrosion of the general atmosphere and offshore atmosphere were established.The service performance and reliability evaluation of the service steel structure laid the foundation.The main research contents of this article are as follows:(1)According to the surface scan results of the corroded steel plate,based on MATLAB software programming,the surface characteristic parameters such as the pit depth,diameter-to-depth ratio,rust pit volume of the corroded steel plate at different corrosion ages were extracted,and the distribution of the corroded steel plate surface characteristic parameters was studied using probability statistical methods The law reveals the change between the mean value of the average corrosion depth and other characteristic parameters.A random field model of rust depth and a random distribution model of rust pits are proposed to realize the surface feature simulation of the corroded steel plate and the three-dimensional reconstruction of the finite element model.(2)Using the random depth field model of corrosion depth,a large number of general corrosion surface morphology models of general and offshore atmospheres with different degrees of corrosion are generated to study the effect of comprehensive corrosion on the degradation of mechanical properties of steel plates.Therefore,a probabilistic model and a random constitutive model of the law of mechanical properties degradation of fully corroded steel under two environments are established respectively.(3)Using the random distribution model of rust pits,a large number of pitting morphology models of the general atmosphere and offshore atmosphere with different degrees of rust were generated to study the effect of pitting on the degradation of mechanical properties of steel plates.Therefore,a probabilistic model and a random constitutive model of the mechanical degradation of pitting steel under two environments are established.