A Combined method of AC Impedance Measurement and BE Inverse Analysis for Detecting Corroded Rebar in Concrete Structure

交流阻抗测量与BE反演相结合的混凝土结构中钢筋锈蚀检测方法

• 批准号: 10450045
• 负责人: AOKI Shigeru
• 金额: $ 7.1万
• 依托单位: Tokyo Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10450045/
• 关键词: AC impedance method; Potential mapping method; Boundary element method; Inverse analysis; Concrete structure; Corroded rebar; Polarization curve; Non-destructive test; 鉄筋コンクリート; 鉄筋腐食位置の同定; ラプラス方程式; 精度向上; AC impedance method; Potential mapping method; Boundary element method; Inverse analysis; Concrete structure; Corroded rebar; Polarization curve; Non-destructive test; 鉄筋コンクリート; 鉄筋腐食位置の同定; ラプラス方程式; 精度向上

An effective boundary element inverse analysis method was developed to detect the corrosion location and corrosion rate of rebars in a concrete structure. This method consists of two steps. The outlines of these steps are shown below.The first step is the effective non-destractive detection of corrosion locations by combining potential measurement and boundary element inverse analysis. The boundary element inverse analysis method for this step was developed based on the boundary element direct corrosion analysis method, which had been developed before. In this inverse method, the corroded part in the rebar net was approximated as a circle, i.e., the part of the rebars in the circle is taken to be corroded. The radius r and the coordinates (x, y) are taken as design variables, and the difference between the measured and calculated values of potential is taken as the cost function robe minimized. The polarization characteristics of the corroded and non-corroded parts are assumed to be gi … More ven. The minimization is performed through use of the Simplex method. The usefulness of the method was demonstrated by solving an example problem.The second step is the identification of the corrosion rate of the corroded part which was detected in the first step. The identification of the corrosion rate is performed by improving the AC impedance method. A boundary element inverse analysis was utilized to improve the AC impedance method. At first, it was verified experimentally that the potential in the concrete domain is described with the Laplace's equation. The potential at any point in the concrete domain can be calculated by solving the Laplace's equation with the boundary element method.Then, an inverse problem was formulated in which the location and the complex impedance (corrosion rate can be obtained from the complex impedance) of corroded part on the surface of a rebar are estimated from a small number of potential data measured on the surface of a concrete structure. The cost function to be minimized in the inverse problem is a function of difference between the measured and calculated values of potential. The validity and efficiency of the proposed method were demonstrated with an example in which a prismatic concrete block specimen with an embedded piece of rebar was used. Less

开发了一种有效的边界元素逆分析方法来检测混凝土结构中钢筋的腐蚀位置和腐蚀速率。该方法由两个步骤组成。这些步骤的大纲如下所示。第一步是通过结合电位测量和边界元素逆分析来有效地检测腐蚀位置。此步骤的边界元素逆分析方法是基于以前开发的边界元素直接腐蚀分析方法开发的。在这种反方法中，钢筋净网中的腐蚀部分被近似为一个圆，即，圆圈中的钢筋部分被视为腐蚀。半径为R和坐标（X，Y）作为设计变量，并且测量值和计算的电位值之间的差异被视为成本功能的长袍最小化。假定腐蚀和非腐蚀部分的极化特性是GI…更ven。最小化是通过使用单纯形方法进行的。通过解决示例问题来证明该方法的有用性。第二步是鉴定在第一步中检测到的腐蚀部分的腐蚀速率。腐蚀速率的识别是通过改善交流阻抗方法执行的。边界元素反向分析用于改善交流阻抗方法。首先，通过实验证实了混凝土域中的电势用拉普拉斯方程描述。可以通过用边界元素方法求解拉普拉斯方程来计算混凝土域中的任何点的电势。然后，提出了一个反问题，其中从钢筋表面腐蚀部分的位置和复杂阻抗（可以从复杂阻抗中获得腐蚀速率（腐蚀速率），可以从在混凝土结构表面上测得的少量潜在数据估计。在反问题中要最小化的成本函数是测得的电位值和计算值之间的差异的函数。用一个例子证明了该方法的有效性和效率，其中使用了带有嵌入式钢筋的棱柱混凝土块标本。较少的