混杂纤维增强应变硬化水泥基复合材料的压缩本构关系

Compression constitutive relation of hybrid fiber reinforced strain hardening cementitous composites

混杂纤维增强应变硬化水泥基复合材料(HyF/SHCC)的力学性能是近年来的研究热点问题之一,但是目前依然欠缺HyF/SHCC压缩本构关系的深入探讨。本文研究了钢纤维(SF)-聚乙烯醇(PVA)纤维增强SHCC (SF-PVA/SHCC)的压缩应力-应变全曲线,分析了纤维对HyF/SHCC抗压强度、压缩应变以及压缩韧性的影响。研究发现,在本文研究工况下混杂纤维的引入对材料的抗压强度无明显影响,但是提高了压缩峰值应变。钢纤维对HyF/SHCC压缩韧性的影响较为显著,且随着钢纤维掺量的增大,HyF/SHCC的压缩韧性逐渐提高。基于损伤力学理论,从能量的角度提出了一种新的单轴压缩本构模型,通过与试验曲线的对比,发现该模型可以较好地预测SF-PVA/SHCC的压缩应力-应变关系。

Mechanical properties of hybrid fiber reinforced strain hardening cementitious composites(HyF/SHCC)have been one of the hot topics in recent years. However, there is still a lack of in-depth discussion on the constitutive relationship of HyF/SHCC in compression. In this paper, the full compressive stress-strain curve of HyF/SHCC containing steel fiber(SF) and polyvinyl alcohol(PVA) fiber was investigated. The compressive strength, strain and toughness of SF-PVA/SHCC were discussed. The results indicate that the introduction of hybrid fibers has no significant effect on the compressive strength of SF-PVA/SHCC in this case, but it increases the corresponding strain at peak stress. The effect of SF on the compressive toughness of SF-PVA/SHCC is significant. The compressive toughness increases gradually with the increase of SF content. Based on the theory of damage mechanics, a new uniaxial compression constitutive model was proposed from the perspective of energy. Through the comparison with the experimental curves, it was found that the proposed model could well predict the compressive stress-strain relationships of SF-PVA/SHCC.