Evaluation of finger-jointed laminae for glulam timber by acoustic emission, 3: Examination of condition in evaluating of finger-jointed laminae with evaluation system
2010
Sato, E., Fukuoka Univ. of Education, Munakata (Japan) | Ohuchi, T. | Fujimoto, N.
In our previous study, the evaluation system for the finger-jointed laminae was constructed. This system was composed of three parts. The first part is the motive power part for the hydraulic pomp and cylinder. The second part is the AE measurement part. The third part is the data collection part which controls some devices and collects sampling data. In this study, the optimum condition needed in the evaluating test with this evaluation system was examined. In addition, the effects of the temperature and the open assembly time in finger jointing on the strength properties of the finger-jointed laminae with this evaluate system were examined. The main results are summarized as follows: The peak in the waveform of AE signals obtained by the evaluation system was recognized in the laminae with starved joint. The peak and the starved joint part were corresponded. In evaluation test of the finger-jointed laminae with this system, the necessary conditions set in this test were the deflection and the feed speed, and these optimum conditions were 3 mm and high speed (480 mm/s), respectively. The strength properties of the finger-jointed laminae with the open assembly time showed the tendency to decrease with higher the temperature in jointing. Therefore, it became clear that the high temperature in jointing was the condition that the starved joint part was caused. The MOE and MOR of the finger-jointed laminae showed the tendency to decrease with increasing the maximum value of the AE accumulated signal. Thus, it was clear that there was a high correlation between the maximum value and the strength properties. Therefore, this evaluation system was promising for the detection of the difference of the bonding performance caused by the influence of bonding conditions such as the temperature and the open assembly time in jointing.
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