基于超声二次谐波理论的混凝土无损检测研究

项目名称： 基于超声二次谐波理论的混凝土无损检测研究

项目编号： No.51308020

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 建筑科学

项目作者： 陈军

作者单位： 北京航空航天大学

项目金额： 25万元

中文摘要： 由于各种极限荷载的作用和恶劣服役环境的侵蚀，混凝土构件内部极易产生累积损伤，威胁结构服役安全。所以，研究有效可靠的结构无损探伤技术对于混凝土结构的健康状况监测和全寿命周期安全维护具有很重要的现实意义。传统超声无损检测技术如波速法、衰减法等假设受损结构保持线性本构关系，对与结构损伤高度关联的材料本构非线性缺乏研究，无法有效量化检测结构损伤早期微裂缝。本课题拟基于超声纵波在非线性介质中传播的二次谐波理论研究新的混凝土损伤表征模型和无损检测试验技术，主要内容有：（1）考虑传播衰减的超声二次谐波模型和混凝土二阶损伤参数表征式；（2）定量评估混凝土损伤的二次谐波试验系统；（3）荷载作用下混凝土损伤的二次谐波检测。研究成果将构建衰减效应下二阶损伤参数与二次谐波的理论关联，研发能有效定量检测混凝土裂缝的超声二次谐波试验系统，为混凝土结构健康监测提供具有较高灵敏度和准确度的新技术。

中文关键词： 无损检测；结构健康监测；混凝土；超声；二次谐波

英文摘要： The concrete infrastructures are internally damaged with service time owing to the frequent overloading and severe service conditions, causing a threat to the service safety of infrastructures. The research on effective and reliable nondestructive evaluation techniques for the detection of structural flaws is therefore of great importance for the accurate health condition assessment of concrete structures and for the maintenance in their remaining service life. Conventional nondestructive evaluation techniques based on ultrasonic such as the pulse velocity and amplitude method, however, assume a linear constitutive relation for the damaged structures, neglecting the material nonlinearity which is highly correlated with the structure damage. Therefore, the conventional nondestructive evaluation techniques cannot effectively quantify the microcracks formed and developed in the early phase. Based on the second harmonic generation theory of ultrasonic waves propagating in nonlinear media, this proposed research is aimed at developing a novel theoretical expression for structural damage and a new nondestructive evaluation technique for the damage detection of concrete. The main contents included in this research are: (1) Establishment of the model of second harmonic ultrasonic wave and the expression of second-order

英文关键词： nondestructive evlaluation；structural health monitoring；concrete；ultrasonic；second harmonic generation