钢管混凝土拱桥极限承载力分析的自适应方法

发布时间：2018-09-10 20:04

【摘要】：针对现行钢管混凝土结构极限承载力分析的增量非线性有限元法主要依据钢管混凝土的弹塑性本构关系建立非线性迭代计算公式,其计算原理复杂、效率低,难以满足工程设计和分析要求的状况,建立了钢管混凝土拱桥结构极限承载力分析的自适应弹性模量缩减法。首先对不同受力条件下材性差异较大的圆形截面钢管混凝土构件,根据统一理论和承载力相关方程确定了构件的广义屈服函数,进而利用全面试验法在广义屈服面上设置配点,并在极值点附近加密配点,通过回归分析建立了齐次广义屈服函数,据此定义了单元承载比、承载比均匀度和基准承载比,提出了钢管混凝土拱桥高承载单元的自适应识别准则。然后,利用变形能守恒原则建立了弹性模量调整策略,通过自适应缩减高承载单元的弹性模量模拟结构在加载过程中的刚度损伤,并利用线弹性迭代分析计算钢管混凝土拱桥的极限承载力。最后讨论了离散单元数量、荷载分布方式以及广义屈服函数的齐次性对结果的影响,并将该方法与模型试验及增量非线性有限元法的计算结果开展了对比分析。研究表明:该方法能够体现钢管混凝土不同材料纤维在受力变形过程中的自适应调整能力,并通过对拱桥结构损伤演化的自适应模拟取得较高的计算精度和计算效率。
[Abstract]:Based on the elastoplastic constitutive relation of concrete filled steel tube (CFST), the incremental nonlinear finite element method (FEM) is used to analyze the ultimate bearing capacity of concrete filled steel tube (CFST) structures. The calculation principle is complex and the efficiency is low. It is difficult to meet the requirements of engineering design and analysis. An adaptive elastic modulus reduction method for ultimate bearing capacity analysis of concrete-filled steel tubular arch bridges is established. Firstly, the generalized yield function of circular concrete-filled steel tube members with different material properties under different loading conditions is determined according to the unified theory and bearing capacity equation, and then the collocation point is set on the generalized yield surface by using the comprehensive test method. The homogeneous generalized yield function is established by regression analysis in the vicinity of the extremum, and the unit bearing ratio, the bearing ratio uniformity and the reference bearing ratio are defined. An adaptive identification criterion for high bearing elements of concrete-filled steel tubular arch bridge is presented. Then, by using the principle of conservation of deformation energy, the adjustment strategy of elastic modulus is established, and the stiffness damage of structure during loading is simulated by adaptively reducing the elastic modulus of high bearing element. The ultimate bearing capacity of concrete-filled steel tubular arch bridge is calculated by linear elastic iterative analysis. Finally, the effects of the number of discrete elements, the mode of load distribution and the homogeneity of generalized yield function on the results are discussed, and the results of model test and incremental nonlinear finite element method are compared and analyzed. The results show that this method can reflect the adaptive adjustment ability of concrete filled steel tube fiber in the process of stress and deformation, and obtain high accuracy and efficiency through adaptive simulation of damage evolution of arch bridge structure.
【作者单位】：广西大学土木建筑工程学院;广西大学工程防灾与结构安全教育部重点实验室;
【基金】：国家自然科学基金项目(51478125,51469004) 广西自然科学基金重大项目(2012GXNSFEA053002)
【分类号】：U448.22

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