一种焊接管结构动力性能分析简化模型

Simplified Model for Analyzing Dynamic Behavior of Welded Tubular Structures

在焊接管结构有限元分析中,常采用刚接杆件体系对结构进行简化分析。刚接杆件模型由于忽略了管节点部位的局部柔度,会对结构整体刚度和承载力估计偏高。为了解决这个问题,在管节点处引入一种虚拟梁单元(FBE)来模拟管节点局部柔度,并给出了确定FBE截面和材料性质的原理和方法。分别采用3D实体模型、刚接杆系模型和引入FBE模拟节点局部柔度的杆系模型对承受动力荷载的T型管桁架和含T、Y、K节点管桁架模型进行了有限元分析,结果显示:刚接杆系模型会过低地估计管结构振动幅值,而考虑节点柔度的简化杆系模型与3D实体模型的计算结果吻合很好,说明基于FBE模拟节点局部柔度的简化杆系模型在分析焊接管结构的动力性能上是可行的。

In the finite element analysis for welded tubular structures,rigid beam-column system is frequently used to carry out simplified analysis. In the beam-column system,local joint flexibility is not considered,which overestimates the structural stiffness and load carrying capacity. To overcome this problem,a kind of fictitious beam element(FBE) is introduced to simulate the local joint flexibility,and definitions on the cross section and on the materials are provided. Finite element analyses on dynamic behavior of a T-joint tubular model and a complex tubular model consisted of T-,Y-and K-joints are conducted by using 3D solid elements, rigid beam-column elements and beam-column elements considering local joint flexibility with FBE respectively. The results indicate that the dynamic response of the two tubular models analyzed with simplified beam-column system by considering local joint flexibility with FBE agrees quite well with corresponding result of 3D model while the rigid beam-column system overestimates the structural stiffness. Hence,the presented simplified model is efficient and accurate in analyzing the dynamic behavior of welded tubular structures.