不同长径比聚乙烯醇(PVA)/高延性纤维增强水泥基复合材料(ECC)动态压缩性能

Dynamic compression property of polyvinyl alcohol (PVA)/engineered fiber reinforced cementitious composite (ECC) with different length-diameter ratios

  • 摘要: 基于杆径为50 mm的分离式霍普金森压杆装置(SHPB)研究了不同长径比和不同聚乙烯醇(PVA)纤维体积掺量的高延性纤维增强水泥基复合材料(PVA/ECC)在4种应变率下的动态压缩性能。结果表明:长径比较大(l/D>1.0)的PVA/ECC试件冲击压缩后更易产生方向性明显的滑移破坏,其应力-应变曲线平台期的长度明显缩短,且曲线所包围的面积也明显减小;PVA/ECC的动态峰值应力、峰值应变和冲击韧性均随长径比增加而降低,存在一定的尺寸效应,且应变率越高、PVA纤维体积掺量越小,长径比的影响更明显;长径比较大的PVA/ECC试件其应变率效应有所减弱但PVA纤维的强化效应有所提升,尤其是对冲击韧性的影响程度最显著。

     

    Abstract: The dynamic compression properties of engineered fiber reinforced cementitious composite (PVA/ECC) with different length-diameter ratio and different polyvinyl alcohol (PVA) fiber contents by volume subjected to four different strain rates were investigated by using a 50 mm diameter split Hopkinson pressure bar (SHPB). The results show that PVA/ECC specimens with larger length-diameter ratio (l/D>1.0) are more prone to directional slip failure after impact compression damage. Furthermore, the length of plateau period of stress-strain curve is obviously shortened and the area surrounded by the curve is also significantly reduced. The dynamic peak stress, peak strain and impact toughness of PVA/ECC decrease significantly with the increase of length-diameter ratio, which reveals the existence of a certain size effect, and that the higher the strain rate or the smaller PVA fiber contents by volume is the more obvious the influence of length-diameter ratio will be. The strain rate effect of PVA/ECC specimens with larger length-diameter ratio may become not obvious, but the strengthening effect of PVA fiber become more obvious, which effect is the most significant on impact toughness.

     

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