실대재 소나무 제재목의 육안 등급 구분 특성과 휨 성능 연구

Study on the Visual Grading Characteristics and Bending Properties of Red Pine Dimensional Lumber

Although Korea has abundant red pine forests, its utilization is low. It was thought that insufficient research on the mechanical performance of red pine wood cause this situation. Therefore, in this study, the bending properties were evaluated for a red pine lumber whose production area is Gangwon-do. As a result of visual grading according to Notification on Specifications and Quality Standards of National Institute of Forest Science, grade 2, grade 1, and grade 3 were in order, and the average size of the largest knot in the red pine lumber was 47 mm. The MOR for structural design values of the grade 1, 2 and 3 were 8.4, 7.2, and 7.0 MPa, respectively. When comparing the MOR of the clear wood reported in the previous study with the average MOR of red pine lumber in this study, the average flexural strength of red pine lumber was only about 54~65%. Therefore, when designing a furniture required load capacity, it was considered that allowable strength including safe factor is appropriate to use. In addition, the MOEs according to the visual grades were presented so that size of the furniture could be calculated to be suitable for the deflection of furniture considering the user’s preference. The MOEs of grade 1, grade 2, and grade 3 were 8,915, 8,554, 7,672 MPa, respectively.