Japanese

2003

For monitoring the termite attack around the houses, containers called monitoring station buried under the ground are used for bait system. In this system, termite attacks are detected  by monitoring the wood stakes in the containers periodically using visual inspection. In this study, for monitoring the termite attack to wood stakes in the monitoring station nondestructively, using acoustic emission (AE) method, piezo-electric polymer film was applied for AE transducer in the monitoring station. Polyvinylidene fluoride (PVDF) film with the most sensitivity among piezoelectric polymers was applied for the AE transducer by inserting between the wood specimens and AEs generated by termite attack to the wood specimens were detected by the PVDF film, and the property of AE detection of PVDF film and the feasibility of AE monitoring in the station were investigated.

Fig. 1. Detection of artificial AE by PVDF film or AE transducer	Fig. 2. Inserting PVDF film between the wood specimens and attaching AE transducer on the cross section
Fig. 3. Relationship between the average amplitude of artificial AE and propagating distance	Fig. 4. Inserted PVDF film between the wood specimens and attached AE transducer on the cross section
Fig. 5. AE event rates detected by PVDF films or AE transducers at the wood specimen A or B
Fig. 6. Comparison of average of AE event rates detected by PVDF films or AE transducers at the wood specimen A or B