摘要
通过引入合适尺寸的低强度颗粒作为人造初始缺陷以提高PVA-ECC多重饱和裂纹破坏的性能。根据细观力学和断裂力学理论提出发生应变强化和多裂纹破坏的能量与强度准则,试验中引入与PVA-ECC中最大的固有孔洞尺寸大小相当的Norlite人造缺陷尺寸。进行了轴向受拉PVA-ECC试件中仅含有天然缺陷和引入人工缺陷后多重裂纹的对比破坏试验。结果表明,PVA-ECC材料的延性和应变强化等性能取决于基体断裂强度以及缺陷分布等特性,缺陷数量较少时裂纹数量不会达到饱和状态,纤维最大桥联应力要求只有在缺陷尺寸超过一定临界值时才能激发萌生裂纹从而导致多重饱和裂纹破坏。Norlite人造缺陷可以有效地改善水泥基复合材料的延性和应变强化性能。
Experimental investigation on multiple intrinsic and artificial flaws of prescribed size is cracking of PVA-ECC under uniaxial tension with carried out. Micromeehanics based design theory and fracture mechanics formulation leading to energy and strength criteria to achieve strain hardening and multiple cracking are described in detail. The size of introduced Norlite artificial flaws is comparable to that of the largest intrinsic void in mixtures and it is found the ductility and strain-hardening property are improved effectively.
出处
《广西大学学报（自然科学版）》
CAS
CSCD
北大核心
2010年第1期166-170,共5页
Journal of Guangxi University（Natural Science Edition）
基金
国家自然科学基金资助项目(50778115)
关键词
多重饱和裂纹
工程水泥基复合材料
人造缺陷
桥联应力
裂纹张开位移
multiple saturated crack
engineered cementitious composite
artificial flaw
bridging stress
crack opening displacement
