古建筑木结构燕尾榫节点力学模型研究

Research on mechanical model of dovetail joint for Chinese ancient timber structures

在古建筑木结构中,燕尾榫节点广泛用于水平构件与柱头相交的部位。为了研究古建筑木结构中燕尾榫节点的弯矩-转角(M-θ)力学模型,在分析燕尾榫节点构造特点和受力机理的基础上,建立其数值模型,采用已有的燕尾榫节点试验数据验证了数值模型的正确性。根据受力分析的结果,建立以屈服点、极限点为特征点的双折线多参数M-θ力学模型,给出了考虑模型尺寸和材料特性的特征点计算式,其计算结果与大量试验数据吻合,并将该力学模型应用于木构架的受力分析中。研究结果表明:燕尾榫节点的挤压变形主要集中在榫头处,而卯口变形可忽略;提出的M-θ力学模型反映了燕尾榫节点的整个受力过程,适用于木构架的受力分析,其加载点荷载-位移曲线与试验结果基本吻合。研究成果可为中国古建筑木结构的维修与保护提供参考。

Dovetail joints are widely used in the intersection between the horizontal members and column heads in Chinese ancient timber structures. To build the moment-rotation(M-θ) mechanical model of dovetail joints, based on the structural characteristics and mechanical mechanism of devotail joints, a numerical model was established and verified through previous test results of dovetail joints.According to the force analysis, a two-stage multi-parameter M-θ mechanical model was proposed, which considers yield point and ultimate point as the characteristic points. An equation reflecting model dimensions and material properties was proposed. The mechanical model was verified against extensive previous test results and then applied to the numerical analysis of a timber frame. The results show that the deformation of the devotail joints mainly occurs at the joint zone, whereas that of the mortise is negligible. The M-θ mechanical model reflects the mechanical properties of the dovetail joints and can be applied to the force analysis of the timber frame.The numerical model of timber frame is proved to be in good agreement with the previous test results. The obtained load-displacement curve also agrees well with the previous test results. The model can serve as a reference for the maintenance and protection of ancient timber structures.