Tensile Performance of Machine-Cut Dovetail Joint with Larch Glulam

낙엽송집성재를 이용한 기계프리커트 주먹장접합부의 인장성능

Members used for the Korean traditional joints have been processed by handicraft, especially with domestic red pine species. Dovetail joint is most commonly used in woodworking joinery and traditional horizontal and vertical connections. It is able to be processed much easier to cut by handicraft and machines. However, although it is processed straight forwards, it requires a high degree of accuracy to ensure a snug fit. Also, tenons and mortises must fit together with no gap between them so that the joint interlocks tightly. A few scientific studies on the dovetail joints have been conducted so far. For the effective applications of traditional joints and domestic plantation wood species, dovetail joints were assembled by larch glulam members processed by machine pre-cut. To identify the tensile properties of through dovetail joints, larch glulam with 150 150mm in cross section were prepared. Furthermore, various geometric parameters of dovetai joints such as width, length, and tenon angle, were surveyed. The ends in the mortise was cracked mainly at a low strength level in the control specimens without reinforcements. The maximum tensile strengths of reinforced specimens considering real connections such as capital joint and headpiece on a column, increasedby handicraft, especially with domestic red pine species. Dovetail joint is most commonly used in woodworking joinery and traditional horizontal and vertical connections. It is able to be processed much easier to cut by handicraft and machines. However, although it is processed straight forwards, it requires a high degree of accuracy to ensure a snug fit. Also, tenons and mortises must fit together with no gap between them so that the joint interlocks tightly. A few scientific studies on the dovetail joints have been conducted so far. For the effective applications of traditional joints and domestic plantation wood species, dovetail joints were assembled by larch glulam members processed by machine pre-cut. To identify the tensile properties of through dovetail joints, larch glulam with 150 150mm in cross section were prepared. Furthermore, various geometric parameters of dovetai joints such as width, length, and tenon angle, were surveyed. The ends in the mortise was cracked mainly at a low strength level in the control specimens without reinforcements. The maximum tensile strengths of reinforced specimens considering real connections such as capital joint and headpiece on a column, increased by two times with shear failures on the tenon than the control specimens. The maximum tensile strength was obtained in the specimen of 25 degrees, and no difference was observed in the changes of neck widths.

전통공법에서는 주로 소나무를 수가공하여 구조부재로 사용하고 있다. 주먹장 접합(이음, 맞춤)은 일반 가구나 구조부재의 접합에 사용되고 있으며, 수가공이나 간단한 기계가공에 의해 쉽게 가공할 수 있는 이점이 있다. 비록 외관상 선형적인 가공이 주를 이루지만, 손쉬운 짜맞춤이 될 수 있어야 하는 고도의 가공정밀성이 요구된다. 더욱이, 장부와 장부받이는 틈새없는 긴결한 접합이 이루어져야 한다. 주먹장접합부에 대한 과학적인 연구는 체계적으로 수행된 예가 많지 않으므로 전통공법과 국산재 활용이라는 관점에서 낙엽송집성재를 기계가공하여 이용하였다. 통주먹장이음 접합부의 인장성능을 파악하기 위하여 150 mm 정각 낙엽송 집성재를 사용하였으며, 내력성능에 영향을 끼치는 주먹장의 다양한 기하학적 요소(장부 너비, 길이, 각도)에 대해 조사하였다. 보강목을 설치하지 않은 시험편은 장부받이(장부홈)의 모서리부에서 할렬이 발생하며 내력도 낮게 나타났다. 기둥머리의 화통맞춤 및 주두와 같은 상황을 고려한 보강시험편은 최대인장내력에서 2배 이상의 성능을 발휘하였다. 장부의 적정각도는 25도 수준이었으며, 어깨폭의 변화와는 상관성이 없는 것으로 나타났다.