考虑损伤累积及杆件失稳效应的网壳结构极限承载力分析

ANALYSIS ON ULTIMATE BEARING CAPACITY OF RETICULATED SHELL CONSIDERING CUMULATIVE DAMAGE AND INSTABILITY OF MEMBER

为准确分析地震作用下网壳结构的极限承载力,推导了适用于网壳结构常用杆件圆钢管的考虑损伤累积的混合强化本构模型;引入了杆件失稳判别条件和杆件失稳后的力学模型;编写了考虑损伤累积和杆件失稳效应的基于有限元软件ABAQUS空间梁单元的材料子程序VUMAT-DMB。通过与理论计算结果和已有试验结果进行比较,验证了所编程序的正确性和准确性。算例分析表明:考虑损伤累积对网壳结构极限承载力影响不大,杆件失稳效应将明显降低网壳结构极限承载力。

Elastic-plastic constitutive model of circular steel tube,which is the stressed members of reticulated shell,is derived from mixed hardening considering cumulative damage.The discrimination criteria of instability and mechanical model after instability are introduced.VUMAT-DMB,the user material subroutine of ABAQUS suitable for 3D beam-column element,is compiled to apply cumulative damage model and instability of member in ABAQUS.The performance characteristics of the circular steel tube cantilever are compared with the results measured in the field to verify the theoretical analysis.The comparison indicates that VUMAT-DMB is accurate in evaluating the mechanical behavior of structure or members.The analysis results about a reticulated shell indicate that the cumulative damage has little effect on ultimate bearing capacity of structure,which decreased significantly when considering instability of member.