编织角和承载方向对三维四向编织复合材料动态压缩性能的影响

Influence of braid angle and bearing direction on dynamic compressive properties of 3D four directional braided composites

利用分离式霍普金森压杆(SHPB)装置对三维四向编织碳纤维增强树脂基复合材料的动态压缩性能进行了研究。通过对编织角为20°、30°和45°的试验件分别进行沿纵向、横向和厚度方向的动态压缩试验,得到材料在800~2 000/s应变率范围内的应力-应变曲线,并与准静态压缩试验结果进行对比,研究了应变率、压缩方向及编织角对材料极限强度和弹性模量的影响。结合高速摄影记录的动态压缩过程,进一步分析了不同情况下材料的破坏模式与破坏过程。结果表明:应变率越高,材料的极限强度和弹性模量越大,材料在受压的三个方向上均具有一定的应变率强化效应,且高应变率下表现出比准静态压缩时更明显的脆性;编织角的改变对材料在三个方向上的动态压缩性能均有影响,其中对纵向的影响最为明显;不同方向受压时材料的失效形式不同,且准静态和高应变率下的失效形式也有区别。

The dynamic mechanics properties of 3D four directional braided carbon fiber reinforced resin matrix composites were investigated using split Hopkinson pressure bar（SHPB）.Conducting experiments on specimens of different braid angles in longitudinal,transverse and thickness directions,the stress-strain curves of the composites were obtained at strain rate ranging from 800/s to 2000/s,and the quasi-static compression test results were also included.The influence of strain rate,compressive direction and braid angle on ultimate strength and elastic modulus was discussed.And the processes of experiments were recorded by high-speed camera,thus the effect of strain rate and compressive direction on the failure mode can be further analyzed.The results show that the 3D four directional braided composite is sensitive to strain rate in all three compressive directions,with ultimate strength and elastic modulus both increasing as strain rate rises,and it becomes more fragile in high strain rate compared with quasi-static conditions.The braid angle has influence on dynamic compressive properties,which is the most when it comes to the longitudinal direction.The failure mode of the composite changes in different compressive directions and strain rates.