组合肋壳非线性分析

Nonlinear analysis of composite ribbed shell

组合肋壳是一种新型组合空间结构形式,基于非线性有限元理论,利用空间梁单元和曲边壳单元,考虑结构非线性影响,推导了T.L.坐标系下结构单元刚度矩阵,采用增量迭代法和弧长法对整个受力过程进行全过程跟踪,得到组合肋壳的极限承载力,并对结构承载力影响因素进行了系统分析,最后与带肋钢筋混凝土薄壳以及光滑混凝土壳体进行了比较.分析结果表明,随着矢跨比和截面尺寸的增大、边界条件接近刚性,组合肋壳的极限承载力增大;与其它两类壳体相比,由于组合肋中钢肋的存在,使得组合肋壳整体刚度增大,承载能力提高,结构的薄膜内力分布更为合理.

The composite ribbed shell structure is a new type of spatial composite structure. Based on the nonlinear FE theory, the elemental stiffness matrix is derived by using space beam and shell element. The arc-length method is used to find the ultimate bearing capacity of the composite shell. The influence of some parameters of the composite ribbed shell are analyzed thoroughly, and then compared with those of the ribbed reinforced concrete shell and the concrete shell. It is concluded that with span ratio and dimension of composite rib section increasing, boundary condition becoms stronger and the ultimate bearing capacity is increased greatly. The global stiffness matrix and ultimate bearing of the composite shell are higher than those of the other two shell structures. The membrane forces in composite ribbed shell is more reasonable than that in the ribbed reinforced concrete shell for the steel ribs existed.