碳纤维增强速生杨胶合木梁的受弯性能

Flexural behavior of fast-growing poplar glulam beams reinforced by carbon fiber

为研究碳纤维增强速生杨胶合木梁的受弯性能,考虑不同配纤率和配纤位置等因素的影响,进行梁的四点弯曲静力荷载试验,推导出梁的极限弯矩理论计算公式。研究表明:相比纯胶合木梁,碳纤维增强胶合木梁的裂缝减少、裂缝宽度减小。增强后梁的弹性模量提高了28.02%~57.93%;极限荷载提高了16.47%~50.72%;初始抗弯刚度提高了11.58%~23.37%。在受拉区配置碳纤维能提高试件的极限承载力和初始抗弯刚度,相比仅在受拉区配置碳纤维,在受拉区和受压区均配置碳纤维布时,试件的承载力反而减小,但破坏时的挠度降低。试件受拉区配纤率宜介于0.0606%~1.0311%之间,能充分利用木材的塑性抗压性能。利用推导的受弯计算公式计算得到的试件极限弯矩值与试验值吻合较好,计算结果能较好地预测此类试件受弯时的极限弯矩。

In order to study the flexural properties of the fast-growing poplar glued timber beams reinforced by carbon fiber,the influence of factors was considered,such as different fiber distribution ratios and different fiber distribution positions.A four-point bending static load test of the beam was carried out,and the theoretical calculation formula of the ultimate bending moment of the beam was deduced.The results show that,compared with the pure glulam beam,the number and width of cracks of reinforced specimens decrease,and the elastic modulus,ultimate bearing capacity and initial bending stiffness increase significantly.The elastic modulus of the beam reinforced by carbon fiber increased by 28.02%~57.93%;the ultimate load increased by 16.47%~50.72%;the initial bending stiffness of poplar beam increased by 11.58%~23.37%.The ultimate bearing capacity and initial bending stiffness of beams with carbon fiber in tension zone can be effectively improved.Compared with the specimen only with carbon fiber in the tensile zone,the load-bearing capacity of the specimen is reduced when the carbon fiber is added in the tensile zone and the compression zone,but the deflection in failure is reduced.The fiber distribution rate in the tensile zone of the specimen should be between 0.0606%and 1.0311%,which can give full play to the plastic compressive properties of wood.The bending calculation formula of the beam was obtained.The calculation results of the ultimate bending moment of the specimen are consistent with the test results,and the calculation results can predict the ultimate bending moment of this kind of specimen under bending.