Interference Set on Wood Connecting Joint with Compressive Set and Recovery

利用木材的流变特性和形状记忆特性，对过盈联接进行了研究。在第一步骤中，在热水下压缩榫，并且在第二步骤中固定榫的压缩变形。第三步，将压榫插入榫槽后，用热水回收压榫。高含水率压榫回收后，连接接头的抗拉强度为3kN，高抗拉强度估计为紧配合。但是，当连接接头在空气干燥中干燥至含水量后，连接接头变得完全松配合。试验以失败而告终。接着，我们对榫槽尺寸沿深度方向变化的连接接头进行了研究。制作了深度方向的锥形榫（多种套式燕尾榫）和阶梯榫（T型）。榫的尺寸为深50 mm，窄边30 mm，宽边80 mm。在榫槽的插入过程中采用了压缩和恢复技术。将连接接头风干至含水量后，T型连接接头的抗拉强度为5kN，其中一种7 °斜面的锥形榫的抗拉强度为2kN，证明了这种新的连接方法的可行性。

Using rheological property and shape memory of the wood, we investigated the connecting joint with interference fit. A tenon was compressed under hot water at the first step and the compressive deformation of the tenon was fixed at the second step. At the third step, the compressed tenon was recovered with hot water after the compressed tenon was inserted into the mortise. Immediately after the compressed tenon with high moisture content was recovered, the pull strength of the connecting joint was 3kN and the high pull strength was estimated as tight fit. But, after the connecting joint was dried to moisture content in air-dry, the connecting joint became perfectly loose fit. Our trial ended in the failure.Then, we investigated the connecting joint with the tenon and mortise that their dimensions were varied in the depth direction. The taper tenon (variety housed dovetail) and the step tenon (T type) in the depth direction were made. Dimensions of the tenon were 50mm depth, narrow side 30mm, and wide side 80mm. Compression and recovery technique were utilized in the insertion of the tenon to mortise. After the connecting joint was dried to moisture content in air-dry, the pull strength of the T type connecting joint was 5kN and one of the taper tenon with 7 degrees slope was 2kN.This new connecting joint method was found the possibility.