基于板壳有限元理论的薄壁箱梁剪力滞效应  

Shear lag effect of thin-walled box girder based on shell finite element theory

作　　者：蔡恒[1] 卢海林[1] 汤正[1] 

机构地区：[1]武汉工程大学资源与土木工程学院,湖北武汉430074

出　　处：《铁道科学与工程学报》2017年第4期779-786,共8页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(51378404);武汉工程大学创新基金资助项目(2016036)

摘　　要：为了分析计算薄壁箱梁剪力滞效应,直接从壳体结构特点出发,由8节点曲边四边形膜单元和基于Reinssner中厚板理论的弯曲单元推导考虑剪切闭锁效应的薄壁箱梁空间壳单元刚度矩阵及相应的刚度方程,并在MATLAB上编制相应的计算程序。通过数值算例,将理论计算值与ANSYS有限元结果,模型试验的实测值进行比较,三者吻合良好,验证了理论公式推导的正确性与可靠性。本文采用8节点的等参单元和二次型位移场形函数,不仅适用于计算直线箱梁,也适用于曲线箱梁,因而更具有普遍性。最后,从平衡微分方程的角度解释剪力滞产生的真正原因,不仅仅是由于剪应力沿横向分布不均匀,其本质更在于剪应力沿横向不均匀变化。In order to compute shear lag effect of thin-walled box girder, this paper started from the characteristic of shell structure. The spatial shell element stiffness matrix and corresponding stiffness equation of thin-walled box girder considering shear locking effect were deduced by 8-nodes curve-edge-quadrangle membrane element and bending element based on Reinssner's moderately-thick plate theory. The corresponding computational procedure was programmed on MATAB. Then, a numerical analysis example was presented and the theoretical value was compared with the finite element results of ANSYS and measured value of model test. The good agreement of the results verified the correctness and reliability of the deducing theoretical formulas. In this paper, 8-nodes isoparametric element and quadric form displacement field sigmoid function are used, it is not only applied to straight box girder but also curved box girder. Therefore, this method is more universal. Finally, from the perspective of balance differential equations, the reason of shear lag is accounted for, which is not merely non-uniformed distribution of shear stress along transverse direction,but more of its non-uniformed variation.

关 键 词：板壳有限元 薄壁箱梁 剪力滞 刚度矩阵 剪切闭锁 

分 类 号：U448.42[建筑科学—桥梁与隧道工程]