Corrosion Initiation and Crack Propagation in Wires of Cable Suspension Bridges

9901378本研究项目源于前人对高强桥梁钢丝环境劣化的研究结果和结论，重点研究了腐蚀过程的开始，以及随后的裂纹形成和扩展机制及其与机械应力的相互作用。这项工程主要是为了回答悬索桥主缆在运营状态下为什么会出现断丝这一难题？研究项目将集中在1)桥梁钢丝腐蚀过程的开始和位置，2)残余应力及其与服役应力的叠加的影响和重要性，3)钢丝可承受的服役荷载水平及其与腐蚀过程的相互作用，以及4)镀锌工艺和钢丝制造。将特别关注1)裂纹的形成和残余应力的分布，2)腐蚀萌生和点蚀及其与微裂纹、残余应力和材料缺陷的关系，3)机械应力、腐蚀萌生和扩展与氢脆的基本关系，以及4)线材制造对残余应力分布的影响。

9901378This research project stems from the results and conclusions of a previous study on the environmental deterioration of high-strength bridge wires and it focuses on the initiation of the corrosion process and on the subsequent crack formation and propagation mechanism and their interaction with the mechanical stresses. The main purpose of this project is to answer the difficult question of "why are there broken wires in the main cables of suspension bridges in service conditions"? The research project will focus on 1) the initiation and location of the corrosion process in bridge wires, 2) the effects and importance of residual stresses and their superposition with service stresses, 3) the lever of service loads that wires can carry and their interaction with the corrosion process, and on 4) the galvanizing process and wire manufacturing. Particular attention will be given to 1) crack formation and distribution of residual stresses, 2) corrosion initiation and pitting and their relation to microcracks, residual stresses and material flaws, 3) the fundamental interrelation between mechanical stresses, corrosion initiation and propagation and hydrogen embrittlement, and 4) the effects of wire manufacturing on the distribution of residual stresses.