新型竹—木—GFRP夹层梁的受弯性能试验

为研究竹—木—GFRP夹层梁的受弯性能,设计以泡桐木作为芯材,竹、GFRP作为面层的夹层梁试件,对夹层梁试件进行了等芯材厚度和等梁高两组四点弯静载试验,得出各试件的破坏现象、破坏荷载并绘制荷载—位移曲线。研究结果表明:竹材部分替代GFRP作为面层的一部分,可降低成本,防止加载点处局部破坏;设置泡桐木纤维沿梁长度方向有利于提高夹层梁的受弯性能;芯材厚度不变的情况下,竹材加固夹层梁有极高的性价比,而使用GFRP面层则能显著提高夹层梁的弯曲刚度;梁高不变的情况下,夹层梁的弯曲刚度、极限荷载分别随竹材与GFRP厚度的增加而增大。竹—木—GFRP夹层梁跨中截面应变分布基本满足平截面假定。换算截面法可作为竹—木—GFRP夹层梁应力计算依据,使用考虑剪切变形的铁木辛柯梁理论计算竹—木—GFRP夹层梁的跨中挠度有着不错的精度。

Experimental study on the flexure property of bamboo-wood-GFRP sandwich beams

In order to study the flexure property of bamboo-wood-GFRP sandwich beams,some specimens with paulownia wood as the core,and bamboo and GFRP as the face were designed.Four-point bending tests on the specimens of equal core thickness or equal height were carried out in order to acquire failure phenomenon and ultimate load of each specimen,and to draw load-deflection curves.The results showed that cost could be reduced and local damage could be prevented by using bamboo partly instead of GFRP as the face;that bending performance of sandwich beams could be improved by allowing the fiber of paulownia wood parallel to the longitudinal direction of the specimens;that for the same core thickness,strengthening sandwich beams with bamboo could result in high cost-efficiency and the bending stiffness of the sandwich beams could be improved obviously with GFRP face;that for the same beam height,bending stiffness and ultimate load of sandwich beams were increased with the thickness of bamboo and GFRP.Strain distributions in the midspan sections of bamboo-wood-GFRP sandwich beams roughly met the plane-section assumption.Transformed-section method could be used to calculate stresses of bamboo-wood-GFRP sandwich beams.The midspan deflection of bamboo-wood-GFRP sandwich beams given by Timoshenko beam theory had satisfying precision.