Early Detection of Corrosion in Steel Cables by Magnetoelastic Techniques

高强度钢丝作为单独的钢丝，或作为肌腱、电缆或绳索具有结构应用。典型的结构包括预应力和后张预应力混凝土桥梁和建筑物，地面工程中的索桥和锚固。暴露在环境中的结构和设施会恶化，最终会磨损或变得不安全。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。本研究的目的是开发一种磁弹性无损技术，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与应力状态的关系，而磁导率是用来精确测量内应力的参数。人们认识到，高振动和疲劳，加上这些电缆中现有的应力状态，是可能影响这些电缆的进展和可能开始腐蚀的因素。因此，腐蚀评估将通过腐蚀开始时磁弹性性能的变化来监测。为了确认磁弹性传感器在早期腐蚀检测中的性能，将使用两种电化学技术，直流电化学极化和电化学阻抗谱。所提议的调查的影响将是发展一种用于结构健康监测和延长寿命的无损技术。这将通过提高桥梁和其他土木结构的安全性来造福社会。

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.