聚乙烯醇(PVA)纤维增强水泥基复合材料单纤维拔出细观机理研究  

Micro-mechanism Study on the Single Fiber Pullout of PVA Engineered Cementitious Composite

作　　者：谷凡[1] 王凯[1] 包忠彬 胡世超 应傲 GU Fan;WANG Kai;BAO Zhongbin;HU Shichao;YING Ao(School of Civil Engineering,Shenyang Jianzhu University,Shenyang,China,110168)

机构地区：[1]沈阳建筑大学土木工程学院,辽宁沈阳110168

出　　处：《沈阳建筑大学学报（自然科学版）》2023年第6期1092-1099,共8页Journal of Shenyang Jianzhu University：Natural Science

基　　金：国家自然科学基金项目(52078309)。

摘　　要：目的 探索聚乙烯醇纤维增强水泥基复合材料(PVA-ECC)高韧性、应变硬化宏观力学行为的细观机理,为其材料特性设计奠定理论基础。方法 基于黏聚力单元和非线性弹簧连接器,建立单PVA纤维/水泥基体的ABAQUS有限元模型,对单PVA纤维拔出水泥基体的全过程进行数值模拟分析。结果 PVA-ECC单纤维拉拔力-拉拔位移曲线可细分为线弹性阶段、连续脱黏阶段、整体滑移阶段、机械咬合硬化阶段和纤维磨损断裂阶段;纤维与水泥基体之间的传力机制包括剪滞切应力和机械咬合力;随着拉拔力的增加,机械咬合力逐渐成为主要传力机制。结论 水泥基体与纤维之间的机械咬合作用以及纤维表面的磨损是导致纤维断裂的根本原因,通过对纤维表面进行适当处理,可以降低水泥基体在机械咬合硬化阶段对纤维表面的磨损,使纤维断裂模式转变为纤维拔出模式,以更好地控制水泥基体的微裂纹失稳扩展,从而进一步提高PVA-ECC的韧性。In order to explore the micro-mechanism of the high toughness and strain-hardening macroscopic mechanical behavior of polyvinyl alcohol-engineered cementitious composite(PVA-ECC),and to lay a theoretical foundation for its purposeful material property design,based on the cohesive element and nonlinear spring connector,the ABAQUS finite element model of single PVA fiber/cement matrix was established,and the whole process of single PVA fiber pullout from cement matrix was simulated and analyzed.The single fiber pullout forcedisplacement curve of PVA-ECC can be divided into linear elastic stage,continuous debonding stage,overall slip stage,mechanical interaction hardening stage,and fiber wear and fracture stage.The force transfer mechanism between fiber and cement includes shear lag stress and mechanical interaction force.With the increase of pullout force,the mechanical interaction force gradually becomes the main force transfer mechanism.The mechanical interaction effect and the surface wear of fiber are the fundamental causes of fiber fracture.By proper treatment of the fiber surface,the surface wears of fiber by cement can be reduced during the mechanical occlusal strengthening stage,and the fiber fracture mode can be changed to the fiber pullout mode,which can better control the microcrack instability propagation of the cement,and further improve the toughness of PVA-ECC.

关 键 词：PVA纤维增强水泥基复合材料 单纤维拔出 粘结界面 细观机理 

分 类 号：TU528[建筑科学—建筑技术科学]