复合材料薄壁方管准静态轴向压缩失效机理及吸能特性

Failure Mechanism and Energy-Absorption Characteristics of Composite Thin-Walled Square Tube Under Quasi-Static Axial Compression Load

以[±45]3s铺层的碳纤维增强复合材料薄壁方管为对象,进行准静态轴向压缩试验,研究其轴向压缩失效模式及破坏吸能特性。试验结果表明,[±45]3s方管在准静态轴向压缩载荷作用下的破坏模式为局部屈曲失效模式;在局部屈曲区,失效主要表现为纤维与基体断裂、分层以及轴向与纵向裂纹扩展,并耗散大量能量;在弹性区,能量耗散大部分由于层间分层,少部分来自于纤维与基体弹性变形。基于Puck2000基体失效准则与Yamada Sun纤维失效准则,研究建立单层壳、多层壳、层合壳3种有限元模型,对方管轴向压缩失效模式和吸能特性进行模拟。仿真结果表明,3种有限元模型能够在一定程度上复现[±45]3s方管轴向压缩失效模式及吸能特性,但层合壳模型能够更好地模拟[±45]3s方管局部屈曲的失效模式,且比吸能误差最小,仿真结果与试验结果最接近。

The quasi-static axial compression test was carried out on the composite thin-walled square tube with [±45]3s, and the axial compression failure mechanism and energy-absorption characteristics were studied. The test results show that the failure mode of [±45]3s square tube under quasi-static axial compression load is the local buckling failure mode. In the local buckling zone, the failure mainly manifests as fiber and matrix fracture, delamination, axial and longitudinal crack propagation, which dissipates a large amount of energy. In the elastic region, the energy is dissipated mainly because of the interlaminar delamination, and the elastic deformation of fiber and matrix. To simulate the axial compression failure mode and energy-absorption characteristics of the square tube, three different finite element models, i.e. single-layer shell model, multi-layer shell model and stacked shell model, were developed based on the Puck 2000 and Yamada Sun failure criteria. The simulation results show that these three finite element models can reproduce the axial compression failure mode and energy-absorption characteristics of [±45]3s square tube to some extent. But the stacked shell model can better simulate the buckling failure mode, the difference of specific energy absorption(SEA) is the minimum, and the simulation results are closest to the test results.