强化有限元的考虑界面滑移的组合梁数值模拟

ENHANCED FINITE ELEMENT ANALYSIS OF COMPOSITE BEAMS WITH INTERLAYER SLIPS

该文针对组合梁结构连接界面的非线性效应,采用物理区域与单元网格相独立的策略,并引入无厚度界面单元模拟界面的非连续变形,建立了基于强化有限元的考虑界面滑移的组合梁分析模型。该文所采用的物理区域与单元网格相独立的强化有限元,数学单元和物理单元在空间上重合不再是必要条件,可以根据物理单元力学描述的需要选择数学单元的大小和形状。同时一个单元内可以分成多个区域,各分区可以是不同的材料,可以具有不同的几何形状,可以具有不同的受力特点,如板、梁等,从而可以大大减少复杂结构的网格数量。该文方法可以快速便捷得到剪切连接件抗剪刚度从零变化到无穷大时所对应的挠度、界面滑移以及截面应力的变化,可以直观地确定出抗剪刚度能够充分发挥作用的区间,为实际工程设计中确定经济合理的抗剪刚度提供依据。该文方法计算效率高,可以适用于实际工程复杂变截面及空间结构的计算分析,尤其是规模庞大、受力分析繁琐的桥梁结构。

An enhanced finite element model considering interface slips of composite beams was developed in this study by separating mathematical and physical meshes and introducing zero thickness interface elements to simulate discontinuous deformation of the interfaces. With separated mathematical and physical meshes, the overlapping of mathematical and physical elements in space was no longer required, and the sizes and shapes of mathematical elements can be chosen according to the mechanical descriptions of the physical elements. In each mathematical element, the physical area can be divided into multiple sub-domains. Each sub-domain can have different materials and geometry shapes, and can also have different mechanical characteristics, thus greatly reducing the number of mesh elements. Deflections, interface slips and the stress distribution of controlling cross-sections corresponding to a slip modulus increasing from zero to infinite can be easily obtained. In addition, a slip modulus range with a maximum extent of contribution to the composite beams can be directly determined. The proposed method is of high computational efficiency, and can be used in engineering practice involving complex structures, especially large-scale bridges subject to complicated loadings.