复合材料夹芯梁屈曲破坏模式及极限承载

Buckling failure mode and ultimate load of composite sandwich beam

为研究复合材料夹芯梁在轴压作用下的屈曲、后屈曲特性及承载能力,进行了试验研究与有限元仿真。首先,开展了系列复合材料夹芯梁屈曲特性试验,研究了铺层比例、梁长度、表层厚度及芯层厚度等因素对其屈曲、后屈曲破坏模式及极限承载的影响;然后,基于非线性屈曲理论,采用三维内聚力界面单元模拟面芯脱粘,并引入初始预变形及材料损伤准则对复合材料夹芯梁在轴压下的屈曲特性及极限承载进行仿真研究。结果显示:界面脱粘是屈曲破坏的重要模式;仿真计算的极限承载与试验结果相比,误差控制在10%以内。所得结论表明该方法可有效预报复合材料夹芯梁的后屈曲路径、破坏模式及极限承载。

In order to investigate the buckling,postbuckling characteristics and load capacity of composite sand-wich beam under the effect of axial compression,test investigation and finite element simulation were carried out. Firstly,a series of buckling characteristic tests of composite sandwich beams were conducted.The effects of ply ra-tio angle,length of beam,face layer thickness and core layer thickness on buckling,postbuckling failure modes and ultimate load were discussed.Then,based on the nonlinear buckling theory,3D cohesive interface elements were used to simulate the debond between skin and core,and initial predeformation as well as material damage criteria were also introduced to simulate and investigate the buckling characteristics and ultimate load of composite sandwich beam under axial compression.The results show that interface debond is the important mode of buckling failure. Comparing the ultimate load calculated by simulation with the test results,the errors are controlled within 10%. The conclusions obtained prove that the method can predict the postbuckling path,failure mode and ultimate load ac-curately.