PVA-ECC动态压缩性能研究

用杆径为50mm的分离式霍普金森压杆(SHPB)试验研究了不同聚乙烯醇(PVA)纤维体积分数和不同基体强度的高延性纤维增强水泥基复合材料(PVA-ECC)在3种应变率下的动态压缩性能.结果表明:PVA纤维可有效改善PVA-ECC试件的冲击破坏程度,且体积分数越大,试件冲击破坏时的整体性越好;PVA-ECC的动态峰值应力、峰值应变和韧性均随应变率增加而明显提高,表现出较强的应变率效应;PVA纤维体积分数对PVA-ECC动态压缩性能影响明显,尤其对PVA-ECC峰后韧性的影响最为显著,但对PVA-ECC抗压强度应变率敏感性的影响较小;较高基体强度PVA-ECC具有较大的动态峰值应力,但动态峰值应变提高不明显,且其峰后韧性明显降低,不同基体强度对PVA-ECC抗压强度应变率敏感性的影响也不太显著.

Study on Dynamic Compressive Properties of PVA ECC

The dynamic compressive properties of engineered cementitious composite(PVA-ECC)with different polyvinyl alcohol(PVA)fiber contents by volume and different matrix strength subjected to three different strain rates were studied by using a 50 split hopkinson pressure bar(SHPB)apparatus.The results show that PVA fiber can effectively improve the impact damage degree of PVA-ECC specimen,and the higher the volume content is the better the integrity will be when the sample is damaged.With the increase of strain rate,the dynamic peak stress,peak strain and toughness of PVA-ECC increase remarkably,which shows an obvious strain rate effect.Different PVA fiber contents by volume have great influence on the dynamic compressive properties of PVA-ECC,especially on the post-peak toughness of PVA-ECC,but it has little influence on the strain rate sensitivity of PVA-ECC compressive strength.Higher strength PVA-ECC has higher dynamic peak stress,but the dynamic peak strain is similar and the post-peak toughness decreases significantly.Furthermore,the matrix strength also has little influence on the strain rate sensitivity of PVA-ECC compressive strength.