Studies on Development of Wood Joint of High Performance

1.为了开发高性能的木材接头，研究了指底倾斜的倾斜指接接头的坡度比和胶粘剂对接头性能的影响。所用的粘合剂是间苯二酚酚醛树脂、环氧树脂和聚氨酯树脂。斜率比为0、0.5、1.0、1.5和2.0。通过静态弯曲、冲击弯曲和拉伸试验对斜指接头的性能进行了研究。1)当斜率比为1.0时，接头的抗拉强度和抗弯强度均达到饱和，超过此值，接头的抗弯强度与胶粘剂种类无关，接头效率最高可达96%。抗拉强度之间的胶粘剂，有轻微的差异，并与斜率比为1.0和聚氨酯的接头的效率显示出最大值为84%。2)在冲击弯曲的倾斜指状接头的吸收能量的效率增加的斜率比的增加，但除了聚氨酯树脂的胶粘剂的增加幅度很小。坡率为1.0且采用聚氨酯材料的接头效率最高，为62%。我们研究了斜率比和粘结剂对弯曲断裂过程中产生的声发射特性的影响。间苯二酚酚醛树脂接头的声发射事件在低载荷水平下开始发射，而环氧树脂接头的声发射事件在断裂载荷的1/2载荷水平下开始发射。聚氨酯接头声发射的引发介于间苯二酚酚醛树脂和环氧树脂之间。

1. To develop wood joint of high performance, we investigated the effect of slope ratio and adhesive on the performance of the sloped-finger joints whose bottoms of fingers were sloped. The adhesives used were resorcinol phenol formaldehyde resin, epoxy resin, and polyurethane resin. The slope ratios were o, 0.5, 1.0, 1.5, and 2.0. The performance of the sloped-finger joint was examined by static bending, impact bending, and tensile test. 1) The tensile strengths as well as the bending strengths of the joints were saturated at a slope ratio of 1.0, above which the bending strengths ded not depend upon the kind of adhesives and the maximum efficiency of the joint was 96%. There were slight differences in tensile strength among the abhesives, and the efficiency of the joint with a slope ratio of 1.0 and with polyurethane showed the maximum value of 84%. 2) The efficiencies of the absorbed energies in impact bending of the sloped-finger joints increased with an increase in slope ratio, but the extent of increase for adhesives except poly-urethane resin was small. The efficiency of the joint with a slope ratio of 1.0 and with poly-urethane showed the maximum value of 62%.2. We investigated the effect of slope ratio and adhesive on the properties of AE generated in the bending fracture process. The AE events of joint with resorcinol phenol formaldehyde resin began to be emitted at a low load level, whereas those of joint with epoxy resin did at about 1/2 load level of the breaking load. The initiation of AE generation of joint with polyurethane was intermediate between those with resorcinol phenol formaldehyde resin and with epoxy resin.