平纹铺层及三维角联锁复合材料热氧老化后低速冲击及剩余弯曲性能

以平纹铺层和三维角联锁碳纤维/环氧树脂复合材料为研究对象,探究其在180℃高温下分别老化4、8、16和32 d后的低速冲击响应,并结合其冲击后弯曲性能,比较两种结构复合材料抗冲击性能随老化时间的变化规律。结果表明:随着老化时间的增加,冲击加载下平纹铺层和三维角联锁纤维环氧树脂两种复合材料试件的最大冲击载荷减小,能量吸收率增大,承载性能退化;相同老化条件下,三维角联锁结构试件的剩余模量和强度保留率均高于平纹铺层试件。两者微观形貌的分析表明:平纹铺层结构试件易在热氧老化过程中形成连续的层间裂纹,并在外加载荷作用下扩展造成层间失效;三维角联锁结构试件因厚度方向的接结纱作用,界面裂纹扩展受阻,从而缓解热氧老化引起的界面性能退化。

Low-Velocity Impact and Residual Flexural Behaviors of Plain Laminates and 3D Angular Interlock Woven Composites after Thermal Oxidative Ageing

Taking plain-woven laminate and three-dimensional angular interlock carbon fiber/epoxy resin composites as research objects,the low-velocity impact response after aging at 180℃ for 4,8,16 and 32 days was investigated,and the impact resistance of the two structural composites was compared with the aging time by combining their post-impact bending properties.The results show that with the increase of aging time,the maximum impact load of the two structural composites decreases while the energy absorption rate increases,indicating the degradation of bearing capacity.Under the same aging condition,the residual modulus and strength retention rate of three-dimensional angular interlock specimens are higher than those of plain-woven specimens.The microscopy morphologies reveal that continuous interface cracks are formed in aged plain laminates,which can cause delamination easily under external loading.However,the binding yarns along thickness direction of 3D woven composites restrain the formation of continuous interface cracks,alleviating the degradation of interfacial property caused by thermal oxidative ageing.