玻璃纤维砂浆管动态劈裂拉伸性能试验研究

为了研究壁厚对玻璃纤维砂浆管动态劈裂拉伸性能的影响,利用直径为74 mm的分离式霍普金森压杆系统开展玻璃纤维砂浆管动态冲击试验,通过改变冲击气压得到不同加载速率下的玻璃纤维砂浆管动态特性变化规律,同时设置壁厚为2、3、4、5 mm并进行该变量下的纵向分析.试验结果表明:在玻璃纤维管的约束下,动态应力-应变曲线出现"双峰"现象,且第二个应力峰值高于第一个应力峰值;通过分离式霍普金森压杆(split Hopkinson pressure bar,SHPB)试验发现,随着壁厚的增加,动态强度-冲击速度拟合直线斜率减小,应变率效应减弱;在破坏形态方面,玻璃纤维砂浆管在0.4～0.5 MPa冲击气压下只出现一条贯穿裂缝,随着冲击气压的上升,开始出现受载面的局部破裂,但试件依然呈现完整的外形.

Experimental Study on Dynamic Splitting Tensile Properties of Concrete-Filled FRP Tubes

In order to study the influence of wall thickness on the dynamic splitting tensile properties of concrete-filled FRP tubes, a 74 diameter split Hopkinson pressure bar system was used to carry out a dynamic impact test of concrete-filled FRP tubes. The dynamic characteristics of concrete-filled FRP tubes under different loading rates were obtained by changing the impact pressure. At the same time, the wall thickness of 2mm, 3mm, 4mm, 5mm was set, and the longitudinal analysis under the variable was carried out. The results show that under the confinement of the FRP tube, the dynamic stress-strain curve appears "double peak", and the second peak is higher than the first. Through the SHPB test, it is found that with the increase of wall thickness, the slope of dynamic strength impact velocity fitting line decreases, and the strain rate effect weakens. In the aspect of failure mode, there is only one through crack under the impact pressure of 0.4 ~0.5 MPa. With the increase of impact pressure, the local fracture of the loading surface begins to appear, but the specimen still presents complete shape.