张拉成形网格结构成形过程上弦环梁位移影响分析

Displacement Analysis on Forming Process of the SFL Affected by Upper Chord Ring Beam

上弦环梁是张拉成形网格结构中心的一个重要承荷部分,各个张拉单元在此交汇,为进一步明确其对结构成形过程位移的影响特点,选用了整体分次和分批分次2种张拉成形方案,建立了上弦环梁刚度单调变化的6个张拉成形网格结构模型,利用ANSYS有限元程序,全面研究了上弦环梁对结构成形过程位移的影响规律,与整体张拉成形方案不同,采用分批张拉成形方案时,节点位移由于批次的不同而必然会产生一定的位移超前或滞后,研究表明,适当加强的上弦环梁会在很大程度上减弱这种位移的不均匀性,有利于结构顺利成形.

As a key bearing member of stretch forming lattice structure （SFL） , the upper chord ring beam is a cross center of all radiating upper chord beams. In order to deeply understand the displacement character of SFL affected by upper chord ring beam, six mechanic models about SFL, whose rigidity are monotone increasing, are established on the basis of ANSYS finite element program, which selects two tensioning method-tensioning simultaneously step by step and tensioning group by group and step by step. So the displacement rule affected by upper chord ring beam is concluded. When the construction method-tensioning group by group and step by step is chosen, the overstepping or lagging displacement on structural nodes belonging to different group inevitably comes into being, which is different from the method of tensioning simultaneously. The study shows that properly reinforced upper chord ring beam will weakens the displacement difference in a great extent, and it is favorable to SFL forming.