Non-destructive detection of insect attack in historically important wooden constructions.

以日本和歌山县一户传统农户住宅和普通家庭木屋为研究对象，采用声发射监测方法对白蚁侵害进行了无损检测。研制了一种专为房屋木结构构件设计的便携式声发射传感器。对传感器的性能和利用互联网的数据传输系统进行了研究。该系统由声发射传感器、用于放大、滤波和鉴别的探测器、对声发射事件进行计数的计数器（1999年已在研究项目中开发）、探测器与现场CPU的接口（称为事件适配器）以及现场CPU与中央控制CPU（或客户端CPU）之间通过局域网或互联网或电话进行数据管理的数据传输和控制程序组成。研究了神社、寺庙等具有重要历史意义的木结构建筑连续声发射监测系统的可行性。客户端可以通过PC或手机通过互联网访问服务器来获取数据。调查了九座历史上重要的木制建筑。在调查中，采用目测法检查了白蚁侵害及其他生物劣化情况。同时，利用声发射监测技术对白蚁攻击进行了无损检测。通过声发射监测发现白蚁主动攻击。然而，声发射监测在实际应用中也存在一些实际和技术问题。在室内试验中，研究了相对湿度与白蚁侵害的关系。对上述结果进行了全面审查，并发表了最终报告。

A case study on the non-destructive detection of termite attack using AE monitoring was carried out, by using a traditional Japanese farmer's house in Wakayama Prefecture and common family wooden houses. A portable AE sensor made of PVDF film was developed, which is specially designed for the wooden construction members of the houses. The performance of the sensor and the data transferring system using internet was investigated. The system consists of AE sensor, detector for amplification, filtering and discrimination, counter to count AE events (which was already developed in the research project in 1999), interface between the detector and on-site CPU (called event adapter), and the date transferring and control program for data management between on-site CPU and central control CPU (or Client CPU) using LAN or Internet, or telephones. The feasibility of the continuous AE monitoring system for the historically important wooden constructions, like shrines and temples, was investigated. The client can derive the data by accessing to the server by internet through PC or handy phones.Nine historically important wooden constructions were investigated. In the survey, the termite attack and other biological deterioration was inspected by visual inspections. At the same time, non-destructive detection of termite attack using AE monitoring was also carried out. The active termite attack was detected by AE monitoring. However some practical and technical problems were also found, whne the AE monitoring was applied.In the laboratory tests, the relationships between the relative humidity and the termite infestation was investigated.The above results were totally examined and the final reports was published.