GFRP筋拉伸力学性能与破坏形态试验分析

对不同尺寸和纤维含量条件下的螺纹纤维筋进行研究，利用一次性拉伸和循环拉伸试验，观察筋体在受力中表观特征和应力的对应关系，对比分析玻璃纤维增强复合材料（GFRP）筋体1/2和1/4处的应力应变关系。结果表明，GFRP筋达到一定的应力时筋体出现裂纹，裂纹开展从筋体套筒附近开始，并随着应力增加而向中间扩展，在破坏前随应力减小而逐渐闭合；裂纹在筋体破坏前纵向发展，在达到破坏荷载时裂纹呈现横向参差不齐的断裂破坏特征；材料的弹性模量稳定，泊松比受加载循环影响而减小；不同纤维含量的GFRP筋会有不同的破坏荷载和破坏形态；筋体的破坏性质介于脆性破坏和塑性破坏之间；直径为20mm和直径为25mm筋体利用效率最高，是较为优化的筋体尺寸类型。

Test Analysis of Tensile Mechanical Properties and Failure Mode of GFRP Bars

Tensile mechanical properties and failure mode of GFRP bars was different from common engineering materials. By one-time tensile and cyclic tensile test on GFRP thread bars with different sizes and fiber content conditions, the relationship between apparent characteristics and the stress was observed, and stress-strain behavior of GFRP bars on the locations of 1/2 and 1/4 length was compared and analysed.It was found that cracks emerged near the sleeves when the stresses of GFRP bars reached a certain value, and developed to the central of bars with increasing stress. The cracks closed gradually as the stress decreasing before the failure of bars. Before failure, the cracks develop longitudinally and became jagged in shape.Failure property is between brittle and plastic failures.Strength analysis shows that GFRP bars with diameters of 20 and 25 mm had the maximum utilization efficiency.