玻璃纤维增强聚氨酯基复合材料圆管弯曲性能试验研究

Experimental study on bending property of glass fiber reinforced polyurethane(GFRP)composite circular tube

玻璃纤维增强聚氨酯基(GFRP)复合材料是一种轻质高强的新型材料,GFRP圆管是输电钢塔筒、通讯钢塔筒和钢制路灯杆的有效替代材料,可承受水平荷载作用下的弯剪作用。组成GFRP圆管的材料是玻璃纤维和聚氨酯,配比为(0.60~0.65)∶(0.40~0.35),通过拉挤缠绕方式成型。对GFRP圆管进行直接弯曲试验,研究其弯曲性能,试验结果表明:GFRP圆管在荷载较小时基本保持整体变形,荷载—位移(应变)曲线保持线性增长;荷载达到45 kN后,GFRP圆管在加载点和支点处发生局部屈服,荷载—位移(应变)曲线增长速度加快;荷载达到50 kN后,GFRP圆管出现强化现象,荷载—位移(应变)曲线增长速度减慢;最终破坏模式为复合材料层间剪切分层的局部屈服褶皱破坏,但卸载后屈服变形可以恢复,表明GFRP圆管具有较强的恢复能力。根据美国ANSI/AISC 360-10和澳大利亚AS4100规范对GFRP圆管的局部屈服抗弯承载力进行计算,发现规范计算值和试验值相差小于10%。

Glass fiber reinforced polyurethane(GFRP)composite is a new type material with lightweight and high strength,GFRP circular tube is an effective substitute for transmission steel tower,communication steel tower and steel light pole,which should have bending and shearing capacity under action of horizontal force.GFRP tube is made of glass fiber and polyurethane with ratio of(0.60~0.65)∶(0.40~0.35),which is formed by pultrusion and winding.Direct bending test of GFRP tube was carried out to study bending property.The experimental results show that,GFRP tube kept the whole deformation basically,and load-displacement(strain)curves kept linear growth at a small level of test load.With test load increasing to 45 kN,GFRP tube yielded locally at loading point and bearing points,and load-displacement(strain)curves were accelerated.When test load reached 50 kN,GFRP tube was strengthened,which made growth rate of load displacement(strain)curves slow down.GFRP tube final failure mode is local yield fold failure with shear delamination in interlaminar of GFRP composite.Local yield bending capacity of GFRP tube was calculated according to American ANSI/AISC 360-10 and Australian AS4100 codes,and it was found that the difference between calculated bending value and test bending value is less than 10%.