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

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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.