옻나무 경사핑거접합재의 휨강도성능

변희섭(Hee Seop Byeon),이원희(Weon Hee Lee),홍병화(Byung Wha Hong) 한국가구학회 1999 한국가구학회지 Vol.10 No.1

The bending performances of sloped finger-jointed Rhus verniciflua were tested in order to improve the strength properties of finger-joint. Sloped finger-cur pieces were jointed with three kinds of adhesives (polyvinyl acetate, polyvinyl-aeryl acetate and oilic urethane resin). The slope ratios of finger joints were 0, 1.0, 1.5, and 2.0. The MOE, MOR and deflection to maximum load in bending of sloped finger-joints and solid wood specimen were measured.<br/> The results were:<br/> 1) The efficiencies of MOE to finger and sloped finger-joints to the solid wood were almost same in the three kinds of adhesives (polyvinyl acetate, polyvinyl-aeryl acetate and oilic urethane resin) and there were some effect of slope on the MOE in a sloped finger-joint for three kinds of resin adhesives.<br/> 2) There was the effect of slope on the MOR in sloped finger-joints in every kind of adhesive. The efficiencies of MOR in slope ratios of 0 and 2.0 ranged 65-79% and 85-94%, respectively. There was also a slight effect of the kinds of adhesives on the MOR. However, the efficiencies of deflection to the urethane resin adhesive were much less than those of polyvinyl acetate, polyvinyl-acryl acetate resin adhesives except the slope ratio of 0.<br/> 3) It might be impossible to estimate the bending strength of sloped finger-jointed Rhus vernicillua by using MOE. The correlation coefficiem(0.192) between MOE and MOR was very low and not significant at 5 % level.<br/> Keywords: Bending strength, Rhus verniciflua, sloped finger-joint, slope ratio, kind of adhesive.<br/>

핑거공차가 휨강도성능에 미치는 영향

변희섭(Hee Seop Byeon),류현수(Hyun Soo Ryu),안상열(Sang Reol An),이균필(Gyun Pil Lee),박한민(Han Min Park),김종만(Jong Man Kim) 한국가구학회 2001 한국가구학회지 Vol.12 No.2

As finger joint method has a high rate of yield and high strength and ease in working, it has been widely used as an end joint method for solid wood and wood based~material.<br/> Therefore, we end~joined the material of Pinus densiflora. Quercus variabilis and populus euramericana with polyvinyl acetate adhesive and resorcinol phenol resin adhesive. The effect of difference (0, 0.15, 0.3, 0.45mm) between the dimensions of tip width and root width of the finger (DTRW) on bending strength properties was as follows:<br/> 1. In the case of polyvinyl acetate adhesive, DTRW had no effect on bending modulus of elasticity(MOE) and modulus of rupture(MOR) of the three kinds of species, because their bonding layers were destroyed by slippage, not their woody parts.<br/> 2. In the case of resorcinol phenol resin adhesive, the material of Quercus variabilis<br/> showed an optimal result at 0.15 or 0.3 of DTRW, while the poplar did at 0 of DTRW.<br/> 3. The differences in efficiency ratio of bending MOR of populus euramericana, Pinus<br/> densiflora and Quercus variabilis species according to the kind of adhesive were 13-29%, 23-30% and 45-53%, respectively.<br/> Keywords: finger joint, dimensions of tip width and root width, bending strength.<br/>

옻나무 경사핑거접합재의 휨강도와 AE 특성

변희섭(Hee Seop Byeon),김사익(Sa Ick Kim) 한국가구학회 1999 한국가구학회지 Vol.10 No.2

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.<br/> The results were as follows:<br/> 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.<br/> The patterns of AE event count and count were very similar.<br/> 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.<br/> Keywords: AE event count, AE count, bending strength properties, sloped finger-joint, kind of adhesive, Rhus verniciflua.<br/>

목재의 음향신호전달에 미치는 함수율과 섬유방향의 영향

변희섭(Hee Seop Byeon),홍병화(Byung Wha Hong) 한국가구학회 1998 한국가구학회지 Vol.9 No.1

The estimation of the effect on the generation and propargation of acoustic signal need to evaluate the strength properties and/or detect the defect of wood, wood based-material and/or wood construction by the non-destructive testing method(acoustic emission, acousto-ultrasonic). This study was performed to clarify the effect of moisture content and grain direction on the characteristics of propagated AE wave signal using destruction of sharp pencil lead and two species of Pinus densiflora Siebold et Zuccarini and Castanea crenata Siebold et Zuccarini was used. These results indicated that, AE signal count was much more attenuate across the grain direction than along the grain direction in the both species. AE wave signal across the grain direction in a tangential section of Pinus densiflora was the most attenuate. The higher moisture content, the more effective to attenuation of AE signal, whereas the moisture content ,vas less effective across the grain direction. The charactfristics of AE wave signal count was very similar to its energy.<br/>

피아노 響板用 아가티스材의 動力學的 性質

변희섭(Hee Seop Byeon),홍병화(Byung Wha Hong) 한국가구학회 1997 한국가구학회지 Vol.8 No.1

In a piano-making, the soundboards tradionally have been made of the wood of Sitka spruce (Picea sitchensis Carr.). Recently, the wood of Agathis(Agathis alba Foxw.) has been developed and used for piano soundboards also, because of its cheap price. To clarify the characteristics of Agathls wood used in making a piano in Indonesia, we measured the the acoustic and mechanical properties of longitudinal direction strips cut from Agathis (from Indonesia) and Sitka spruce woods.<br/> The mean values of density of Agathis and Sitka spruce were 0.445 and 0.413, respectively, and the values of Agathis were distributed more widly than those of Sitka spruce. The values of dynamic modulus of elasticiy(Ed) increased with increasing density in Sitka spruce, where as the values of Agathis were distributed much more widly than those of Sitka spruce and there was not significient at 5 % Ievel between Ed and densin in Agathis. Internal fuction was found not to be related to density in both species. The mean values of acoustic converting efficiencies (√E/o³/Q-¹ ) or (1/√ pE X Q-¹) of Agathis were lower than those of Sitka spruce. These results show that the acoustic properties of Agathis were not better than those of Sitka spruce. So we need to select and use a good quality wood in using Agathis for piano soundboards.<br/> Keyword:piano, agathis alba, acoustic and mechanical propertes

벗조인트를 포함한 積層材의 휨 强度性能과 Acoustic Emission 特性

변희섭(Hee Seop Byeon) 한국가구학회 1993 한국가구학회지 Vol.4 No.1

The bending strength properties and acoustic emissions of laminated wood having butt joints were investigated. the correlation coefficient between the modulus of elasticity(MOE)and the modulus of rupture(MOR) for all types of laminated wood was smaller than that of solod wood. The AE evevnt count and the generation time were related very closely to the MOR. The relationship between the load and the AE cumulative event count in the early stage can be expressed by the following equation:<br/> N=AP² + B, where N is the AE cumulative event count, P is load, and A and B are constants. The correlation coefficient between the logarithm of regression coefficient A and the MOR was much greater than that between the MOE and the MOR. The MOR for laminated wood having butt joints can be estimated using the logarithm of regresson doefficient A.

닥나무로 제조된 우드세라믹의 성질 -탄화온도의 영향-

변희섭 ( Hee Seop Byeon ),황교길 ( Kyo Kil Hwang ),이동환 ( Dong Hwan Lee ),황정우 ( Jung Woo Hwang ),오승원 ( Seung Won Oh ) 경상대학교 농업생명과학연구원(구 경상대학교 농업자원이용연구소) 2010 농업생명과학연구 Vol.44 No.4

인피섬유로 한지를 제조하고 남은 닥나무 목질부를 고부가치화 하기 위하여 닥나무 목질부로 제조된 파티클보드를 이용하여 탄화온도 변화에 따른 닥나무재료 우드세라믹을 제조하여 물성을 검토하였다. 밀도, 휨강도성능, 브리넬 경도, 압축강도 등은 탄화온도가 증가할수록 증가하였으며 밀도와 휨강도성능, 경도, 압축강도사이에는 유의성이 인정되는 밀접한 상관관계를 나타내었다. This study was carried out to investigate the properties of woodceramics made from woody part of Broussonetia Kazinoki at different carbonizing temperatures of 600℃, 800℃, 1000℃ and 1200℃. The physical and mechanical properties increased with increasing carbonizing temperature. The highest mean values of density, bending strength, Brinell hardness and compressive strength were 0.62g/cm3, 79 kgf/cm2, 203kgf/cm2 and 129kgf/cm2, respectively. There were close correlations between density and bending strength, Brinell hardness and compressive strength and MOE and MOR.

수지함침율이 닥나무 우드세라믹의 성질에 미치는 영향

변희섭 ( Hee Seop Byeon ),김재민 ( Jae Min Kim ),황교길 ( Kyo Kil Hwang ),박성철 ( Seong Cheol Park ),오승원 ( Seung Won Oh ) 한국목재공학회 2010 목재공학 Vol.38 No.3

인피섬유로 한지를 제조하고 남은 닥나무 목질부를 고부가가치화 하기 위하여 닥나무 목질부로 파티클 보드를 제조하고 페놀수지 함침율 변화에 따른 닥나무재료 우드세라믹을 제조하여 물성을 검토하였다. 밀도, 휨강도성능, Brinell 경도, 압축강도 등은 수지함침량이 증가할수록 증가하였으며 밀도와 휨강도성능, 경도, 압축강도간 및 휨탄성계수와 강도간에는 유의성이 인정되는 밀접한 상관관계를 나타내었다. This study was carried out to investigate the properties of woodceramics made from woody part of Broussonetia Kazinoki at different impregnation ratios of phenolic resin of 40, 50, 60, 70%. The physical and mechanical properties increased with increasing impregnation ratio. The highest mean values of density, bending strength, Brinell hardness and compressive strength were 0.66 g/cm3, 53 kgf/cm2, 187 kgf/cm2, 126 kgf/cm2, respectively. There were close correlations between density and bending strength, Brinell hardness and compressive strength, and between MOE and MOR.

국산재의 응용물성연구2: 잣나무 낙엽송의 수분흡착성 및 열적,전기적,음향적 성질

변희섭 ( Hee Seop Byeon ),이원희 ( Won Hee Lee ),박병수 ( Byung Soo Park ),정성호 ( Sung Ho Chong ),강호양 ( Ho Yang Kang ) 한국목재공학회 2008 목재공학 Vol.36 No.4

주요 국산 침엽수종의 평형함수율

이원희(Won-Hee Lee),박병수(Byung-Soo Park),변희섭(Hee-Seop Byeon),강호양(Ho-Yang Kang),정성호(Sung-Ho Chong) 한국가구학회 2008 한국가구학회지 Vol.19 No.1

A series of the studies on the applied physical properties of main domestic species have been conducted last three years. Equilibrium moisture content(EMC) of Pinus koraiensis, Larix kaemferi, Pinus koraiensis were investigated. The experiments for sorption property were conducted with 20- and 80-mesh wood powder and resulted in their EMC's at various sorption conditions. Amount of moisture sorption and sorption speed of Larix kaemferi were shown the most large values and very fast among three Korean main coniferous wood.