基于ANSYS的木桁架齿连接应力状态分析

Analysis of the Stress State for Cogging Joints in Timber Trusses Based on ANSYS

通过有限元分析了木结构齿连接的工作特性,目前,齿连接的设计简化了接触表面的应力分布,而忽略了压杆与弦杆夹角α对接触面应力分布的影响。这样的假设,与现实不符,也不能客观地评估应力应变状况。因此采用数值模拟的方法以更客观地评估齿连接节点的工作性能,优化节点的几何形态。应用Ansys软件,模拟不同的夹角α,发现了压杆和弦杆在不同夹角α情况下,压杆端承面和剪力面应力分布的特点,同时接触表面的摩擦作用也影响弦杆的剪切强度,揭示了压杆与弦杆夹角α是接触面应力分布的决定因素。

Based on the finite element analysis, the working characteristics of cogging joints in timber structures was discussed. At present, the design of these joints is conducted by using simplifying assumptions of the stress distribution on the contacting surfaces, and neglecting the effect of angle between the rafter and the tie. Based on this hypothesis, stress and strain condition can not be objectively evaluated in fact. A more realistic approach is presented in this paper by conducting a numerical simulation of the behaviour of carpentry joints,which enables optimisation in the geometric definition of this type of joints. The behavior of joints with different angles was simulated by using Ansys software, making us discover the characteristics of stress distribution in the bearing plane of notch and shear plane in different angle between the rafter and the tie. It was also found that the function of friction on the contact surfaces also influences the shear strength of tie. In conclusion, the angle between the rafter and the tie is the deciding factor of the stress distribution on the contacting surfaces.