Uneven Corrosion Research Of The Mechanical Properties Of Arch Bridge Suspender

In recent years,the engineering accidents of the arch bridge suspender fracture occurred frequently,not only caused serious economic losses,but also caused the extremely adverse social impact.From the suspender fracture accident analysis and the research achievements of many scholars,fatigue and corrosion are the two main causes.In corrosion failure forms,the harm of the corrosion pits from the pitting corrosion and erosion corrosion is much bigger than the uniform corrosion,the stress concentration near the corrosion pit accelerated the crack initiation and propagation,serious shorten the fatigue life of suspender.At present,the suspender high strength steel wire corrosion fatigue research focused on uniform corrosion determination of the mass loss,research about fatigue life caused by corrosion pit little,but in the dry-wet alternate corrosion environment,the uneven corrosion occurrence probability is higher.Based on the above background,this paper carried out the of corrosion pits which are on the suspender high strength steel wire on stress concentration coefficient and the influence of corrosion pits on fatigue damage,and discuss the influence of different forms of corrosion pits on the stress concentration factor and on the influence degree of the fatigue life.Hope for the future detection and maintenance of the suspender to provide accurate and effective experimental data.This paper made the following main research content:(1)This paper discusses the domestic and foreign research results from the corrosion pit morphology and failure behavior,the corrosion pit damage evaluation index,The influence of corrosion on mechanical properties of the suspender.There is still inadequate in uniform corrosion effect on mechanical properties,then launch a research from this Angle.(2)Application ANSYS13.0 analysis software,through different forms of equivalent corrosion pit monotonic tensile model analysis,it is concluded that there is linear relationship between the stress concentration factor and three high three dimensional size change.Stress concentration factor decreases as the length increases,increases with the decrease of the breadth and depth?The influence degree on stress concentration factor from the maximum to the minimum in the order is length,depth,width.(3)In this paper discusses the stress distribution and stress concentration factor of a single corrosion pit,then study the coupling relationship between corrosion pit.Based on the finite element analysis of the same corrosion pit in axial and radial directions,it is concluded that the axial corrosion pit has relief the stress concentration and maximum ease about 8%,the radial corrosion pit will aggravate the stress concentration degree.(4)The analysis process of the ANSYS n Code Designlife14.5 software and each parameter setting in the SN fatigue analysis are simply introduced.Analyses the influence of corrosion pits on the fatigue life of high strength steel wire,output that the fatigue life factor decreases as the length increases,increases with the decrease of the breadth and depth?The influence degree on stress concentration factor from the maximum to the minimum in the order is length,depth,width.(5)Conduct a corrosion fatigue test of suspender of full size.It is proved that the corrosion has a great influence on the fatigue life of the suspender.Corrosion resulting in a decline in the crack resistance of the derrick,rapid crack initiation,rust site of the first.Because uneven corrosion,suspender steel wire carrying capacity performance on business members of the opposite sex,and fracture in turn.This phenomenon has a obviously difference with the phenomenon that the intact suspender fracture is concentrated.Corrosion suspender fatigue fracture belongs to brittle fracture,intact suspender fracture belongs to ductile fracture.