A study on the diagnosis system using the rotary hammering sound based on the structural vibration and acoustic theory

基于结构振动与声学理论的旋锤声诊断系统研究

基本信息

批准号：
21360215
负责人：
SONODA Yoshimi
金额：
$ 10.98万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2009
资助国家：
日本
起止时间：
2009 至 2011
项目状态：
已结题

项目摘要

Recently, it becomes very important to maintain the existing(aging) reinforced concrete structures in Japan. In order to minimize their life-cycle cost, many researches on the nondestructive evaluation technique have been conducted. However, most of nondestructive tests have problems related to their expense or measurement condition. Thus, visual inspection and conventional hammering sound test are usually applied as an effective method. But, the hammering sound test requires a high degree of skill to evaluate hammering sound and theoretical investigation has not well conducted on the acoustic mechanism of the hammering sound test. Therefore, this study appraises the capabilities of conventional hammering test and the rotary hammering test by means of the experiment using mortar specimens and existing bridges. Furthermore, acoustic analysis based on finite element method is conducted in order to grasp influences of defect on the hammering sound. The following results are obtained in this study.1)It is recognized that maximum sound pressure increase due to the existence of inner defect.Whereas,damping performance decrease due to the effect of defect.2)We confirmed the results of rotary hammering sound test shows clear adn significant influence of inner defect on their impact sounds. Therefore as for the diagnostic capability, the rotary hammering test is superior to conventional hammering test.3)Identification of defect condition by sound pressure information was attempted using the Self-Organizing Map algorithm and it is confirmed that the size of defect was clearly identified using the result of SOM.4)In addition,combination use of sound pressure and frequency information by time-frepuency analysis could evaluate precise defect conditions.

最近，维持日本现有的（老化）钢筋混凝土结构变得非常重要。为了最大程度地降低其生命周期成本，已经进行了许多关于非破坏性评估技术的研究。但是，大多数无损测试都有与其费用或测量条件有关的问题。因此，通常将视觉检查和常规锤击声测试作为有效方法应用。但是，锤击声音测试需要高度的技巧来评估锤击声音，理论研究并未在锤击声音测试的声学机制上进行。因此，本研究通过实验使用砂浆标本和现有桥梁来评估常规锤击测试和旋转锤击测试的能力。此外，为了理解锤击声音的缺陷的影响，进行了基于有限元方法的声学分析。在这项研究中获得以下结果。1）人们认识到，由于缺陷的存在，由于缺陷的影响，阻尼性能下降。因此，至于诊断能力，旋转锤击测试优于常规的锤击测试。3）使用声音压力信息鉴定缺陷条件，使用自组织图算法识别缺陷，并确认使用SOM的结果清楚地识别出缺陷的大小。4）在其他时间压力和频率的结合使用时，可以通过时间限制进行频率进行评估。