球外加肋加固既有网架焊接空心球节点的非线性数值分析

Nonlinear Numerical Analysis on the Existing Welded Hollow Spherical Joints Strengthened by Rib Stiffeners outside the Ball

设置加劲肋是提高焊接空心球节点承载能力的一个有效途径,但是在球内设置加劲肋对于既有网架节点加固来说十分困难。球外设置加劲肋可能是加固既有网架结构节点的一个可能途径。本文基于数值模拟的方法对球外设置加劲肋加固网架球节点的受力变形和破坏过程进行了分析。在数值模拟中考虑了几何非线性和材料非线性两种非线性效应。以某实际工程加固为依托,研究了空心球节点在单向受力状态和空间复杂受力状态两种情况下的受力和变形特征,对焊接空心球节点的加固前后的破坏过程进行了对照分析,给出了环状肋加固球节点的承载力提高系数。

Rib stiffeners have proved to be an effective method to significantly improve the strength and stiffness of the welded hollow spherical joint. But it is very difficult to set the rib stiffener inside the hollow sphere of an existing ball grid joint system. So, an alternative method is to set the rib stiffener outside the existing hollow ball. In this paper, a nonlinear numerical analysis is presented, the deformation and failure process of the welded hollow spherical joints strengthened with outside rib stiffeners are analyzed. The numerical simulations take into account both geometric and material nonlinearity. A comparable analysis of the hollow sphere with the rib stiffener and without strengthening is presented when a hollow sphere is under the uniaxial stress state or the complex space stress state. Furthermore, the capacity increasing coefficient is derived based on the numerical simulation.