考虑局压效应的榫卯节点力学性能研究

The mortise-tenon joint is usually in a local compression state. In this paper, the compressive behavior of three kinds of stress regions, including the middle local compression, the end local compression and the full section compression, were studied along two grain directions of the wood, respectively. The corresponding wood properties were obtained. To study the whole process of strain evolution of mortise-tenon joints under local compression, three different forms of separated one-way straight mortise-tenon joints, including rigid mortise-wood tenon, wood mortise-rigid tenon, wood mortise-wood tenon, were tested under monotonic loading. On the basis of test results, the analytical model of one-way straight mortise-tenon joint considering the local compression effects was established. The results indicate that the compressive strength of the local section perpendicular to the grain of wood is higher than that of the whole section. The elastic modulus of wood in compression perpendicular to the grain is ten times of that of wood in compression parallel to the grain. Meanwhile, the strain generated in the tenon is much larger than that in the mortise. The deformation of the joint is mainly caused by the tenon, hence, the deformation of the mortise could be ignored. Furthermore, the calculated initial stiffness is much more likely to agree with test results with the consideration of the local compression effects.