Papers by Keyword: Corrosion Fatigue Life

Abstract: Corrosion fatigue is of great significance in research of submarine structure operating in marine environment for long term since the seawater corrosion effect will reduce the resistance to fatigue failure of structure components. The paper interests on the introduction of pitting corrosion and analysis method of corrosion fatigue life. Finite element method was adopted to analyze the stress concentration factor of pitting corrosion and local corrosion fatigue of spherical-headed cylindrical shell with following conclusion. In the estimation of corrosion fatigue life of spherical-headed cylindrical shell, the proposed formula has some practical value, and only the corrosion fatigue of structure surface should be considered.

Abstract: Ther BP neural net model which is a branch of artificial neural net theory was adopted to analyse the problem of aircraft LY12CZ structure corrosion fatigue life considering the effect of stress level and corrosion environment,and Newton interpolation algorithm was used to increase the quantity and enhance the quality of BP net model training data. The application result show that the BP net model can simulate the value and development trend of corrosion fatigue life with higher precision contrast to the traditional method of exponential function fitting.

Abstract: To study life differences between pre-corrosion fatigue and corrosion-fatigue test, LY12CZ standard specimens are selected in pre-corrosion fatigue test to get the C(t) curve at first. Then, combining with Miner linear cumulative damage theory, theoretical fatigue life is calculated by simulated corrosion-fatigue interactive process. Compared with actual corrosion-fatigue interactive test, theoretical life is rather conservative. Afterwards, a modified model based on C(t) curve method and actual interactive test at different periods of specific flight strength is established. The result shows that the modified C(t) curve method is in good agreement with corrosion-fatigue interactive test.

Abstract: In order to develop a corrosion fatigue design method and estimate reliability of TMCP steel using as the material of heavy industries and plants, its electrochemical corrosion characteristics and determination of corrosion fatigue design criterion were investigated. And, a corrosion fatigue design method of TMCP steel was also investigated. From the results, the corrosion characteristic of TMCP steel is very susceptible in 3.5wt.% NaCl solution. Its susceptibility was linearly increased with the solution temperature increase. Corrosion fatigue strength in 25°C, 3.5wt.% NaCl solution is very lower than that of in air. And also, it was decreased with loading frequency decrease in the same environment. It was found that corrosion fatigue strength and life of TMCP steel is predictable by using the S-N curve of fatigue strength in air. Therefore, it is expected that the developed corrosion fatigue design method for TMCP steel will be useful for safe design and reliability assessment of the industrial facilities and structures.