Early Detection of Corrosion in Steel Cables by Magnetoelastic Techniques

高强度钢丝具有结构应用，如单独的钢丝，或作为钢筋束，电缆或绳索。典型的结构包括预张和后张混凝土桥梁和建筑物，缆索支撑桥梁和地面工程中的锚。暴露在环境中的结构和设施会恶化，最终磨损或变得不安全。了解何时更换它们以及如何延长它们的使用寿命是一个关键问题。本研究的目的是发展一种磁弹性无损检测技术，可以早期检测腐蚀，并量化其进展，磁弹性技术是基于结构钢的磁性能对应力状态的依赖性，磁导率是被用作精确测量内应力的参数的属性。人们认识到，高振动和疲劳，再加上这些电缆中现有的应力状态，是可能影响这些电缆中腐蚀进程和可能引发腐蚀的因素。因此，腐蚀评估将通过磁弹性性能如何被腐蚀的开始改变来监测。为了确认早期腐蚀检测的磁弹性传感器的性能，两个电化学技术，直流电化学极化和电化学阻抗谱，将被使用。拟议的调查的影响将是一个非破坏性的技术，结构健康监测和寿命延长的发展。这将通过提高桥梁和其他土木结构的安全性而造福社会。

High tensile steel wires have structural applications as individual wires, or as tendons, cables or ropes. Typical structures include pre-tensioned and post-tensioned concrete bridges and buildings, cable-supported bridges and anchors in ground engineering. Structures and facilities exposed to the ambient deteriorate and eventually wear out or become unsafe. Understanding when to replace them and how to prolong their useful lifetimes is a critical issue. The objective of this investigation is to develop a magnetoelastic nondestructive technique that would detect corrosion early, and quantify its progress.The magnetoelastic technique is based upon the dependence of the magnetic properties of structural steels on the state of stress and the magnetic permeability is the property that has been used as the parameter to precisely measure the internal stresses. It is recognized that high vibrations and fatigue, coupled with the existing stress state in these cables, are factors that can influence the progress and perhaps the initiation of corrosion in these cables. Hence the corrosion assessment will be monitored by how the magnetoelastic properties are altered by the onset of corrosion. To confirm the performance of the magnetoelastic sensor for early corrosion detection, two electrochemical techniques, DC electrochemical polarization and electrochemical impedance spectroscopy, will be used. The impact of the proposed investigation will be the development of a nondestructive technique for structural health monitoring and life extension. This will benefit society by improving the safety of bridges and other civil structures.