碳布补强含裂纹梁的断裂特性实验

Experiment of the fracture behaviour of cracked beams strengthened with carbon fiber cloth

为了解采用纤维复合材料加固含裂纹结构的断裂机理,通过光学焦散线方法对碳纤维布加固含裂纹梁进行3点弯荷载下的断裂实验,研究了其补强效果及断裂特性。实时记录了不同载荷状态下裂纹尖端应力集中引起的焦散斑光学图像,确定了不同初始裂纹长度的试件在粘贴加固不同长度碳布的情况下裂纹尖端的应力强度因子演化规律,分析了初始裂纹和粘贴碳布两种因素对加固效果的影响。实验结果表明:加固碳布可以大幅度地提高含裂纹梁强度,在该文实验中强度最大增加了近2倍。

Fiber composites are now widely used to strengthen concrete structures. To improve understanding of the effect of fiber composites on cracked structures the strength and fracture characteristics of cracked beams strengthened with carbon fiber cloth were investigated experimentally with three-point bending loading. Different sizes of carbon cloth were used to strengthen beams with initial cracks of various lengths. The strength characteristics and stress intensity factors were measured. Empirical equations for the stress intensity factors were obtained from the experimental results. The relationships between the mechanical characteristics of the beams and the initial crack lengths and the carbon cloth thickness were also analyzed. The crack beams strength is greatly improved by the carbon fiber cloth. The strength of some strengthened beams is almost twice the strength without the carbon fibers.