옻나무 경사핑거접합재의 휨강도와 AE 특성

The Bending Strength and Acoustic Emissions Properties of Sloped Finger-Jointed Rhus Verniciflua

This paper describes the relationship between the bending strength properties of sloped fingerjointed woods and the acoustic emissions (AEs) generated during the test. Rhus vernieilIua pieces were cut in sloped-finger types and glued with three kinds of adhesives (polyvinyl acetate, polyvinylacetate and oille urethane resin). The slope ratios of finger joints were 0, 1.0, 1.5, and 2.0. The AE cumulativeevent count and cumulative count were measured during the bending test. The results were as follows: The lower the bending strength(load) was, the earlier the generation time of AE event count got and the higher the increasing rate of AE event count became in the sloped finger-jointed specimens bonded with polyvinyl acetate, polyvinyl-acryl acetate and oillc urethane resin adhesives. Therefore, the slope from load-AE cumulative event count curve was very steep. The patterns of AE event count and count were very similar. The relationship between the MOR and the AE parameter from load and AE cumulative event count in the early stage of the sloped finger-jointed specimens bonded with polyvinyl acetate, polyvinyl-aeryl and oillc urethane resin adhesives was much greater than that betWeen the MOE and the MOR. Therefore, the AE signals obtained during bending test are useful for estimating the strength of sloped finger-jointed Rhus verniciflua specimens.