厚/薄铺层混杂复合材料低速冲击损伤特征

Damage characteristics of low-velocity impact of hybrid laminates made of thick- and thin- plies

  • 摘要: 厚薄层层级混杂设计时采用多个薄铺层替代单个厚铺层,增加了界面的复杂性。为了研究低速冲击(Low-velocity Impact,LVI)下复合材料结构的厚薄层混杂效应,以准各向同性铺层为基准设计了两种厚薄层混杂层合板,开展了基准层合板和混杂层合板的LVI试验研究;采用超声C扫设备和热揭层方法对含冲击损伤的层合板分别进行了无损和有损检测,基于检测结果对冲击损伤进行了定性和定量的评估;随后,对冲击后压缩(Compression after Impact,CAI)性能和破坏模式进行了分析。试验结果表明:厚薄层混杂设计利用了薄铺层复合材料的损伤抑制特点,提高了复合材料结构的冲击损伤阻抗,减少了分层损伤投影面积和界面分层总面积,缩短了最大单一分层与中性层之间的距离,显著地提高了复合材料结构的CAI强度。该试验研究可为厚薄层混杂结构的优化设计和安全评估提供指导。

     

    Abstract: The ply level hybridization design employs multiple thin layers instead of a single thick layer, resulting in an increased complexity of the interface. To investigate the hybrid effect between thick and thin plies of laminated composites subjected to low-velocity impact loading, two hybrid laminates were designed based on the quasi-isotropic stacking sequence. The LVI tests including the baseline laminate and hybrid laminates were carried out. The ultrasonic C-scan and de-ply technology were respectively used to make a non-destructive and destructive detection on laminates with impact damages. Impact damages were qualitatively and quantitatively evaluated based on the detection results. Subsequently, the performances and failure modes of compression after impact (CAI) were analyzed. Experimental results show that hybrid design of thick- and thin- plies makes full use of the damage suppression characteristics of thin-ply composite, improves the impact damage resistance of composite structures, reduces the projected delamination area and total interface delamination area, shortens the distance between the largest single delamination and the neutral layer, and significantly improves the CAI strength of composite structures. The outputs of this experimental research serves as an indication for the optimal design and safety evaluation of hybrid structures.

     

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