平面角钢桁架模型的实验应力误差分析

Experimental Stress Error Analysis of Plane Angle Steel Truss Model

角钢桁架模型因杆件在节点处的刚性连接,荷载作用下不可避免地存在杆端弯矩,故杆件截面应力包含轴向力和节点弯矩两部分效应.在钢桁架模型的本科实验中,因采用忽略节点刚性的铰接桁架分析而导致实验值与理论值存在误差,为减小此误差,实验测点宜限定在杆件长度的一定范围内.采用有限元方法进行杆件的应力分析,确定角钢桁架模型合理的应力测试范围,以满足本科教学实验要求.

Due to the rigid connection of rods at the joints,bending moment inevitably exists at the end of rods when they are under load.Therefore,the section stress of rods includes both the axial force and the joint moment.In the undergraduate experiment of steel truss model,there is a difference between the experimental value and the theoretical value because of the analysis of hinged truss,which neglects the rigidity of the joints.In order to reduce the difference,the experimental measurement point should be within specific limits of the rods.The finite element method was used to analyze the stress of the bar,and the reasonable stress range of the angle truss model was determined to meet the requirements of undergraduate teaching experiment.