基于向量式有限元的T单元及其在张拉索膜结构中的应用

T-ELEMENT BASED ON VECTOR FORM INTRINSIC FININTE ELEMENT AND ITS APPLICATION TO TENSILE CABLE-MEMBRANE STRUCTURES

  • 摘要: T单元是张拉索膜结构中的特殊单元,可使索和膜独立划分单元,并解决边界锯齿状问题。推导了基于向量式有限元的T单元。基于边界单元侧向刚度无穷大的假设,给出了质点质量分配和中间节点坐标插值的方法,通过虚拟逆向运动求解单元内力,并进行节点力的分配。编制了计算程序,并以一个简单算例验证了所推导的T单元静力计算的准确性。通过上海世博轴张拉索膜结构的断索算例验证了所推导T单元在结构与机构耦合动力计算中的正确性,分析结果表明数值计算结果与实际试验结果相符。

     

    Abstract: T-element is a special element for tensile cable-membrane structures. It is able to mesh the cable and membrane separately and avoid the serrate boundary by using a T-element. The T-element based on an intrinsic finite element of a vector form is proposed. Based on the infinite lateral rigidity hypothesis of a boundary element, the mass distribution and coordinate interpolation of a middle point are presented. The element internal forces are obtained through virtual reverse movements and distributed to nodes. The calculation program is also presented. The proposed T-element is proved to be effective in the static analysis by a simple example. The T-element is also applied to the cable failure analysis example of the tensile cable-membrane structure of Expo Axis in Shanghai. It is proved to be suitable and effective in the dynamic analysis combined with structural and mechanism behavior. The numerical analysis results have a good agreement with the experimental results.

     

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