Study Of Metal Corrosion Damage And Microeracks Evolution Process

The metal material react chemically and electrical-chemical reaction with environmental media in corrosive environment,and corrosion damage is formed on the surface of the structure.Under the exterior loads,the micro cracks are easily formed at the corrosion damage area and they influence each other,then forming macro cracks.The propagation of macro cracks will lead to structure failure.In the corrosive environment,the process of metal structure failure includes corrosion damage,micro cracks initiation and propagation,macro cracks formation and propagation and failure.The stages of corrosion damage and micro cracks initiation and propagation account for 70%?90%of the total damage failure life of metal material.Aiming at the failure process,this paper first uses the cellular automata method and comebine with the MATLAB programming to simulate the multi-point corrosion pits of metal material,and the pit-tings image of corrosion damage evolution along with time in corrosion environment is obtained.Then,the metal cellular in the cellular automata model is reduced to molecular dynamics model with multiple cracks.Choosing appropriate potential function,equaions of motion and ensemble,programming C++program to simulate the evolution process of multiple cracks which are formed at the bottom of multi-point corrosion pits under the exterior loads,and the laws of impaction of micro cracks under different conditions is obtained.The main content of the paper as follows:1.The corrosion damage failure process of metal material in corrosive environment is introduced in detail,and expounds the researches about corrosion damage,micro cracks initiation and propagation,macro cracks propagation at home and abroad.2.The cellular automata method is introduced,then using the cellular automata method to simulate the multi-points corrosion damage and the evolution process of corrosion pittings on the surface of metal structure in corrosive environment,the pittings image of multi-points corrosion damage evolution along with time is obtained.3.The fundamental theory,boundary conditions,potential function,motion equation,integration algorithm,ensemble and control technique of molecular dynamics method are introduced in detail.The molecular dynamics method is used to simulate the micro cracks initiation and evolution process of mul-tiple cracks which are formed at the bottom of multi-point corrosion pits under the exterior loads on the basis of using the cellular automata method to simulate the multi-points corrosion damage and the evolu-tion process of corrosion pittings,and the laws of impaction of micro cracks under different conditions is obtained.