斜胶接CFRP的冲击损伤容限研究

首先,提出了复合材料胶接修补结构与胶接装配结构的冲击损伤容限问题,指出该类结构冲击后拉伸承载能力需要关注。然后,选用基于中心差分法的显式有限元和基于D-B模型的内聚力单元法,以二次名义应力准则为胶层损伤起始准则,并采用混合型幂准则形式的能量释放率准则作为胶层破坏准则。对无损斜胶接CFRP的拉伸基准进行了确定,指出破坏位置、破坏形式和破坏载荷。另外,选取5个典型位置进行损伤容限敏感性的位置研究。在敏感性最高的位置,用不同能量级别的冲击进行胶层损伤分析,并将冲击损伤引入拉伸模型,进行冲击后剩余承载能力规律研究。

三维正交机织复合材料的冲后压缩性能

为揭示纱线张力对三维机织复合材料抗冲击及冲后压缩性能的影响规律,基于多剑杆织造工艺,配置不同接结纱张力(25、50、100 cN)织造三维正交机织物,通过真空辅助树脂传递模塑成型工艺制备复合材料,并在室温下进行低速冲击及冲后压缩性能测试。结果表明:当接结纱张力为100 cN时,试样在冲击载荷下发生表层树脂大面积破裂和剥离并使纬纱失去支撑,同时,试样表层纬纱发生较大卷曲,促使压缩载荷发生屈曲失效;接结纱张力为100 cN试样的压缩性能相比接结纱张力为25 cN试样下降约50%;接结纱张力较高时易导致纬纱卷曲增大和树脂富集,并由此降低试样的弯曲刚度和冲后压缩性能。

Progressive damage behaviors of woven composite laminates subjected to LVI, TAI and CAI

This paper seeks to deal with progressive damage behaviors of woven composite laminates subjected to low-velocity impact(LVI),tension-after-impact(TAI)and compression-afterimpact(CAI).The LVI,TAI and CAI tests were conducted on woven carbon fibre lamina3238 A/CF3052 and woven glass fibre lamina 3238 A/EW250 F,and the time-dependent LVI contact force and deflection curves,static TAI and CAI load versus displacement curves were determined and discussed.A modified progressive damage model was presented for explicit dynamic LVI and implicit static TAI and CAI analysis by using basic material properties and geometrical dimensions,and progressive damage LVI,TAI and CAI behaviors of woven composite laminates were simulated,demonstrating a good correlation between simulations and experiments.