穹顶后张拉整体成形过程研究

Research on Shape Forming Process of a New Post-Tensioned and Shaped Dome

基于后张拉整体成形穹顶的研究,提出了一种具有新型组成形式的单弦杆平板网架张拉模型,通过试验和非线性有限元分析,对穹顶的张拉成形过程进行了研究.在有限元分析中考虑几何和材料非线性,采用节点增设梁单元方法,研究了鸭嘴半刚性连接和上弦节点域大小对穹顶成形过程的影响.结果表明:有限元计算可以很好地预测穹顶的成形形状;鸭嘴半刚性连接对穹顶成形过程中的后张拉力和成形初应力影响很大,应准确模拟其抗弯刚度;铰连或刚接处理方法均会带来很大误差.

Based on the research on the post-tensioned and shaped dome, a new forming model of a single-chorded plane space truss with tension is presented. By tests and nonlinear finite element analysis, the shape forming process is studied. The geometric and material nonlinearities are employed in the finite element analysis. By adding individual beam elements, the connector between top joints and chords in the finite element model and the factors affecting the shape forming process of dome, such as the bending stiffness of duckbilled connector and the size of top joints, are taken into account. It is shown that the method can give a good prediction for the space shape of the post-tensioned and shaped dome and that the post-tensioning forces and member forces produced in the shape forming process are influenced greatly by the bending stiffness of duckbilled connector. So the bending stiffness of duckbilled connector should be simulated accurately, otherwise, it will produce large error in dealing with pin end or rigid end of chords.