• Journal of the Korean Wood Science and Technology
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• v.39 no.2
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• pp.172-178
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• 2011

Three different finger-jointed lumbers which have different geometric features and adhesives were manufactured and studied in this study. Larch and pitch pine lumbers with and without preservative treatment were used. Bending MOE was measured as the preliminary investigation for grouping the specimen. After the finger, bending MOE of two wood species without preservative treatment shows over 97% property of the control group. The tensile modulus also shows almost same property after the finger joint. And it is found out that the preservative treatment induce little effect on bending and tensile MOE. Based on this result, high performance of examined finger-jointed lumber can be found out. However, tensile strength decreased around 20% which would be induced by the crack along the root of the finger which is formed near the edge during manufacturing stage. And finger-jointed lumber with preservative treatment even shows higher decrement of the tensile strength with higher wooden part failure mode.

• Journal of the Korean Wood Science and Technology
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• v.26 no.1
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• pp.1-6
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• 1998

손가락결합부재에 대한 정적휨시험 및 초음파 비파괴시험을 실시하였다. 발신 및 수신 변환기의 상대 위치와 두 변환기 사이의 거리에 따른 음전달속도의 변화를 분석하였으며 정적 휨시험으로 부터 구한 MOE 및 MOR과 비교하였다. MOR과 음전달속도는 손가락의 경사가 증가할수록 감소하였다. MOR은 음전달속도와 매우 밀접한 상관관계를 보였으나 MOE는 손가락의 경사도나 음전달속도에 큰 영향을 받지 않는 것으로 나타났다. 음전달속도는 섬유방향이 방사방향이나 접선방향에 비하여 더 높은 값을 나타내었다. 발신 및 수선 변환기를 동일면에 부착한 경우에 직각면 또는 반대면에 부착한 경우보다 더 높은 음전달속도를 나타내었다. 변환기 사이의 거리가 증가할수록 음전달속도는 양끝면에 변환기를 부착한 경우의 속도에 수렴하는 경향을 나타내었다.

• Journal of the Korean Wood Science and Technology
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• v.22 no.4
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• pp.43-50
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• 1994

본 연구는 침엽수재를 사용한 손가락결합부재의 강도 및 감쇠특성을 측정함으로서 문창틀재로의 사용가능성을 시험하기 위하여 수행하였다. 손가락결합부 시험편의 형태는 손가락부분의 길이와 경사도에 따라서 다섯가지로 제작하였다. 하중은 4개의 하중단계를 갖는 양방향휨으로 가하였으며 각각의 하중단계는 3개의 하중주기로 구성되었다. 손가락결합부의 파괴특성을 분석하기 위하여 감쇠시험 과정에 AE신호를 측정하였다. MOE는 시험편의 형태와 뚜렷한 관련을 갖고 있지 않으나, MOR은 손가락부분의 경사도가 증가될수록 감소되는 뚜렷한 관계를 나타내었다. 감쇠비는 하중단계가 증가될수록 감소되었으나 파괴직전의 단계에서는 증가되는 경향을 나타내었다. 하중방향에 대하여 수직한 방향의 손가락결합부재가 수평방향부재보다 더 높은 강도를 나타내었다. 60dB 이상의 AE신호는 목재 또는 접착층의 파괴에 의하여 발생되는 것으로 분석되었다. 완전한 파괴가 발생하는 경우에는 100dB 이상의 AE신호가 발생하였다.

• Journal of the Korean Wood Science and Technology
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• v.28 no.1
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• pp.8-17
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• 2000

Structural glued laminated timbers were manufactured from Japanese larch(Larix leptolepis) lumber. The effect of various factors, such as finger joint, strength of lamination, on the strength properties of glulam was investigated. When only MOE of lamina was used as input variable for the estimation of strength properties of glulam, the deviations between actual and simulated results were increased with the number of lamination, because the effects of variance of lamina properties on the strength estimation of glulam were cumulated with the number of lamination. Therefore, to estimate the MOR of glulam more careful approach was needed. Besides, both MOE and MOR of lamination were used as input variable to compare the effect of input variable. In the case of finger jointed lamination was located in tension zone, MOE of glulam was some effected, because of the variation of MOE of lamination and the deficiency of information for knot. In the case of finger jointed lamination wasn't located in tension zone, more exact estimation was possible than the case of finger jointed lamination was located in tension zone. From the results, it was concluded that more exact estimation of strength properties of glulam could be obtained by considering effects of both finger joint and knot.

• Journal of Korea Foresty Energy
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• v.20 no.1
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• pp.73-80
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• 2001

This study was carried out to investigate the strength and technical feasibility of arch type laminated lumber from the domestic small lumbers(Pinus densiflora S. et Z. and Larix kampferi Catt.). Arch type lumbers manufactured with different compositions of laminae. It was designed to improve the strength and stiffness. Strength S. rt Z. U;timate load Carr. laminated lumbers were higher than that of the Pinus densiflora S. et Z. Ultimate load of 7-ply laminated lumbers were 2 times higher than the 5-ply laminated lumbers. The strength of finger jointed lumbers were found to be about 15.8% less than that of the no joint lumber. One solution for this problem is to use veneer as face lamina. The veneer laminated lumbers was considerably greater than that of the non-veneer laminated lumbers. It was suggested that this small lumber may be a candidate for high valued product member to provide the proper combination of laminae.