Y型圆钢管相贯节点轴向刚度计算模型

为获得Y型圆钢管相贯节点轴向刚度实用计算公式,基于环向模型和节点局部变形与轴向刚度的关系,建立了半圆拱模型,并导出了节点轴向刚度的理论公式;运用泰勒级数等数学手段,将理论公式中的复杂函数简化为能反映自变量间相互影响的指数函数与幂函数的乘积,并根据单参数分析结果忽略次要因素支主管壁厚比,获得了Y型节点刚度的简化计算式.研究结果表明:节点刚度与材料弹性模量、支主管平面内夹角正弦平方的倒数和主管直径成正比;支主管直径比和主管径厚比对节点刚度的影响较大;简化公式计算的刚度值与有限元计算结果和已有试验数据的相对误差基本小于8%. 

Calculation Model for Axial Rigidity of CHS Y-Type Joints

In order to establish a practical parameterization calculation formula for the axial rigidity of a circular hollow section (CHS) Y-type joint, a semicircular arch model for Y-type joint rigidity was developed based on the round-direction model and the relationship between local deformation of a joint and its axial rigidity, and a theoretical formula for the axial rigidity was established. With the help of the Taylor series, the complex theoretical formula was simplified to the product of an exponential function and a power function embodying the interaction effect between independent variables. In addition, the secondary influence factor, brace-to-chord thickness ratio, was omitted in the light of the single-parameter analysis result from finite element analyses (FEA). As a result, a practical formula for the axial rigidity of a Y-type joint was obtained through a multiple nonlinear regression analysis. The results show that the axial rigidity is directly proportional to elastic modulus of steel, reciprocal of sine-square of the angle between branch and chord in plane and chord diameter, brace-to-chord diameter ratio and chord diameter-to-thickness ratio have significant effects on the axial rigidity, and relative errors between axial rigidity values obtained by the practical formula and the FEA and existing test results are basically less than 8%.