复合材料多墙盒段弯扭耦合下的屈曲和后屈曲

Buckling and Post Buckling of Composite MultiWall Box Section under Bending-Torsion Coupled Loads

针对复合材料典型多墙盒段,采用试验和有限元分析相结合的方法,研究了弯扭耦合载荷作用下的稳定性、承载能力及损伤起始、扩展情况.试验采用数字图像相关(Digital Image Correlation,DIC)测量方法捕捉试验件屈曲模态的变化过程,通过载荷-应变曲线获得屈曲和后屈曲破坏载荷.数值仿真基于ABAQUS/Explicit模块,采用Hashin准则结合刚度降的VUSDFLD子程序模拟复合材料的屈曲和后屈曲行为.研究结果表明,多墙盒段在弯扭载荷组合作用下发生屈曲时,扭矩会改变屈曲模态的分布形式和对称性,屈曲鼓包依然保持波峰、波谷交替出现;多墙盒段后屈曲阶段历程较长,屈曲模态由一阶向高阶逐渐发展,直到结构发生过大变形,彻底破坏而失去承载能力.

In this paper,a research on the typical multi-wall box section of composite materials is carried out.The stability,loadbearing capacity,damage initiation and propagation under the bending-torsional coupled loads were studied by experimental tests and finite element analysis.Using(Digital Image Correlation,DIC)method,the change of buckling mode of the test piece was captured.The buckling and post-buckling strengths were determined from the load-strain curves.In the numerical simulations,the buckling and post buckling behaviors were investigated using the Hashin criterion combined the VUSDFLD subroutine incorporating the stiffness reduction based on the ABAQUS/Explicit module.The results show that when the multi-wall box section buckles under the bending-torsional coupled loads,the torque will change the distribution and symmetry of the buckling mode,with the peaks and troughs appearing alternately.The multi-wall box section has a long post-buckling stage,with the buckling mode gradually developed from first-order to high-order,until the structure is completely destroyed and loses its loadbearing capacity due to excessive deformation.