摘要
针对纤维混凝土软化过程无固定模型和Ⅰ型断裂研究较少的现状,本文利用碳纤维混凝土的机敏性捕捉到了三点弯曲梁试件的起裂荷载。引入双K断裂准则计算了碳纤维混凝土的起裂韧度KiInCi和失稳韧度KIuCn,认为利用双K断裂准则可以更有效地解释纤维对混凝土的增韧作用。通过对电阻变化率与荷载、挠度和裂缝口张开位移(CMOD)关系的分析,认为碳纤维混凝土机敏性可以较好地应用到三点弯曲梁Ⅰ型断裂的研究中,电阻变化率与荷载、跨中挠度和裂缝口张开位移(CMOD)的关系能较好地符合洛仑兹曲线的关系,该关系可以反映试件在峰值荷载前的弹性变形阶段、裂缝稳定开裂阶段和裂缝失稳开裂阶段。
According to actuality that softening process has no stable model and mode Ⅰ fracture has been investigated rarely, the smart properties of CFRC are utilized to attain the initial load of three-point bending beam. Double- K criterion is used to compute. KIC^ini and KIC^un, which can explain the toughening effect of fiber effectually. The smart properties of CFRC can be used to research mode Ⅰ fracture of three-point bending beam after analysis of the relationships .between relative variation of resistance and load, deflection and CMOD which accord with Lorentz fit. The curves of relative variation of resistance before maximum load can illustrate three stages of elastic deformation, stable fracture and unstable fracture.
出处
《水力发电学报》
EI
CSCD
北大核心
2008年第2期71-77,共7页
Journal of Hydroelectric Engineering
基金
国家自然科学基金重点项目(50438010)
国家973项目(2002CB412709)
关键词
建筑材料
双K断裂参数
试验研究
碳纤维混凝土(CFRC)
三点弯曲梁
电阻变化率
building materials
double- K fracture parameters
experimental study
carbon fiber-reinforcedconcrete（CFRC）
three-point bending beam
relative change of resistance
