板壳类金属结构健康监测的非线性调制导波理论与方法研究

项目名称： 板壳类金属结构健康监测的非线性调制导波理论与方法研究

项目编号： No.51305449

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 机械、仪表工业

项目作者： 胡海峰

作者单位： 中国人民解放军国防科学技术大学

项目金额： 25万元

中文摘要： 板壳类金属结构在各类装备和工业产品中广泛使用，疲劳裂纹是其主要损伤形式之一。采用一定的手段在线、主动地实施疲劳裂纹的早期检测、评估和定位，即结构健康监测，是确保装备安全运行的基础。板壳类结构一般面积较大，其早期疲劳裂纹的典型特点是两个断裂面相互接触而呈闭合状态、且位置具有隐蔽性，给结构健康监测带来了困难。振-声调制是近年来提出的一种非线性超声方法，对微裂纹和闭合裂纹具有很高的检测灵敏度；而超声导波由于衰减小、传播距离远的特点适合于大面积固体板结构的在线、主动损伤监测，但在检测和识别闭合裂纹方面还存在较多问题。本项目将两种方法的优点结合，以超声导波的振-声调制效应为基础，对振动-超声导波调制的物理机理、测量信号处理算法、以及在板壳类金属结构疲劳裂纹早期检测、定量评价和定位中的应用开展理论、方法和试验研究。旨在为板壳类金属结构的疲劳损伤监测和健康评估提供一新的技术途径。

中文关键词： 板壳类金属结构；结构健康监测；非线性超声；导波；振-声调制

英文摘要： Plate-like metallic structure is widely used in various engineering equipments. Fatigue cracking is one of the main damage types in such structure. To ensure structural and operational safety, it is important to research structural health monitoring (SHM) techniques to detect, assess and locate fatigue cracks at the early stage online and actively. However, plate-like structure's area is usually large, and the initial fatigue cracks in it are closed, i.e. the interfaces contact each other. Besides, these cracks are usually hidden deep in structure. These characteristics are much challenging for current SHM techniques. Vibro-acoustic modulation (VAM), which is an emerging nonlinear ultrasonic technique, has been proved highly sensitive to micro-scale and closed cracks. Furthermore, Guided ultrasonic wave has demonstrated great potential for damage monitoring of large area structures owing to its long-distance propagation, but still have some problems for closed cracks detection and identification. This research will combine VAM and guided wave techniques for fatigue crack monitoring of plate-like metallic structure. The main contents including the underlying physical mechanism of damage-induced VAM effect, signal processing approaches of testing signals, and the key techniques for early crack detection, evaluatio

英文关键词： Plate-like metallic structure；Structural health monitoring；Nonlinear ultrasonics；Guided wave；Vibro-acoustic modulation