三维五向编织复合材料的冲击压缩特性及破坏机制

Impact compression characteristics and failure mechanism of 3D five-directional braided composites

利用分离式霍普金森压杆(split Hopkinson pressure bar,SHPB)实验系统和高速摄像技术对三维五向碳/环氧编织复合材料的动态压缩特性进行研究。通过对编织角为22.3°的试样分别进行沿纵向和横向方向的冲击压缩实验,得到材料在200~1200 s^(-1)应变率范围内的应力应变曲线,并结合高速摄像记录的动态压缩过程,对不同应变率下材料在高速变形下的渐进破坏规律进行分析。同时,综合试样的宏观破坏特征和微观断口形貌特征,进一步分析材料的破坏模式及破坏机理。结果表明:随着应变率的增加,材料在纵向和横向均具有一定的应变率强化效应,在横向方向的应变率强化效应更为显著;不同加载方向下材料的渐进破坏过程、应力应变曲线特征以及破坏方式均具有明显差异,且随着应变率的增加而发生改变。

The dynamic compressive properties of 3D five-directional braided composites were investigated by using the Split Hopkinson pressure bar(SHPB)and the high-speed photography device.Through the impact compressive tests along the longitudinal and transverse directions of the sample with the braided angle of 22.3°,the stress-strain curves within the range of 200~1200/s strain rate were obtained respectively.And combined with the dynamic compressive process,the progressive failure law of the materials under high-speed deformation under different strain rates were analyzed.Meanwhile,the failure mode and failure mechanism of the material were further analyzed by combing the macroscopic failure characteristics and microscopic fracture morphology characteristics of the sample.The results show that the material is sensitive to strain rate in both longitudinal and transverse directions,among which the strain rate strengthening effect in transverse directions is more significant.The progressive failure process,stress-strain curve characteristics and the failure modes of the material under different loading directions are obviously different,and change with the increase of strain rate.