The Study Of Corrosion Pits Impact On Steel Stress Concentration Factor And Fatigue Damage

Comprehensive corrosion and localized corrosion is the main form of corrosion ofsteel. Comprehensive corrosion caused sectional dimension thinning. The localizedcorrosion is inhomogeneous corrosion, Although the mass loss of which is smaller thanuniform corrosion, which can can cause the structure not tightly.So the localizedcorrosion is the more dangerous. Pitting and denudation which can produce corrosionpits is the most important and most dangerous form of corrosion failure. Local stressconcentration of corrosion pits can accelerated crack initiation and propagation, andpromote the destruction of components,shorten the fatigue life of the structure.Therefore, the study of corrosion pits impact on steel stress concentration factor andfatigue damage, not only can reveal the nature of the corrosion degradation on themechanical properties of steel, but also can provide basic data for the detection andreinforcemen of corrosion-service t steel works.The thesis provides an overview of corrosion pit damage parameter, exploresseveral common steel corrosion parameter variation with time and the relations betweendegradation parameters and mechanical properties. Through analyzing monotonictensile performance data of corrosion steel, and discussing the effect of steel corrosiondamage which generated stress concentration on the strength and ductility properties.The thesis analyzed monotonous stretch numerical simulation of differentcharacteristics equivalent corrosion pits by ANSYS. Studied the influence between thestress concentration factor and three dimensions, angles, distribution of primarycorrosion pits,three-dimensional geometrical characteristics of secondary corrosion pits.Established an approximate calculation model on stress concentration factor of the2 primary corrosion pits.The thesis discussed the impact on fatigue damageof corrosion pits，analyzed therelationship between three-dimensional pits and fatigue notch factor, And analyzed theeffects of corrosion pits with the three-dimensional changes on the fatigue life byANSYS nCode Designlife software.