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为了提高哑铃型钢管混凝土拱肋极限承载力的计算效率,提出了极限承载力分析的高效自适应弹性模量缩减法;根据连续条件和截面塑性承载性能,建立了钢管混凝土哑铃型构件压弯承载力相关方程,通过回归分析得到了相应的齐次广义屈服函数;采用单一组合材料梁单元建立了拱肋的线弹性有限元迭代模型,通过自适应缩减高承载单元弹性模量模拟结构在加载过程中的刚度损伤,确定拱肋的极限承载力,并与模型试验、非线性有限元法和等效梁柱法计算结果进行了对比。计算结果表明:建立的齐次广义屈服函数计算结果稳定、可靠,克服了传统广义屈服函数计算结果受荷载初始值影响的缺陷;采用自适应弹性模量缩减法只需较少的离散单元数与迭代步数即可获得稳定的极限承载力,且与模型试验结果误差小于3%,计算耗时小于16s,相对非线性有限元法具有良好的计算精度和效率;哑铃形截面拱肋相比圆形截面拱肋具有更好的承载性能,矢跨比、含钢率和荷载作用方式是影响钢管混凝土拱肋极限承载力的重要因素;随着矢跨比增大,极限承载力增速减缓;随着含钢率增大,极限承载力几乎呈线性增长;随着集中力与均布力比值增大,其对极限承载力的影响逐渐减弱;轴力与弯矩是拱肋的主要内力,随着矢跨比增大,弯矩对极限承载力的影响更加显著。
In order to improve the computational efficiency of the ultimate bearing capacity of dumbbell-shaped CFST arch rib, a highly effective adaptive elastic modulus reduction method for ultimate bearing capacity analysis is proposed. According to the continuous conditions and the plastic bearing capacity of the section, the ductile concrete filled dumbbell- Force correlation equation, the corresponding homogeneous generalized yield function is obtained by regression analysis. The linear elastic finite element iteration model of arch rib is established by using a single composite beam element. By adaptively reducing the elastic modulus of the high load bearing element, the loading process The ultimate bearing capacity of the arch rib was determined and compared with the model test, the nonlinear finite element method and the equivalent beam-column method. The calculation results show that the calculated results of the homogeneous generalized yield function are stable and reliable, and overcome the defect that the traditional generalized yield function is affected by the initial load. The adaptive elastic modulus reduction method requires only a small number of discrete elements and Compared with the model test, the error of the test results is less than 3% and the calculation time is less than 16s. The relative nonlinear finite element method has good calculation precision and efficiency. Compared with the round The cross-section arch ribs have better bearing capacity. The ratio of span to span, steel ratio and load mode are the important factors that affect the ultimate load-bearing capacity of CFST arch ribs. With the increase of ratio of span to span, the ultimate bearing capacity increases slowly, With the increase of steel content, the ultimate bearing capacity increases almost linearly. With the increase of the ratio of concentrated force and uniform force, the influence on the ultimate bearing capacity decreases gradually. The axial force and moment are the main internal forces of arch rib, With the increase of sag ratio, the influence of bending moment on ultimate bearing capacity is more significant.