芳纶纤维片材加固混凝土梁的弯曲破坏分析

Analysis on bending failure of concrete beam reinforced with aramid fiber sheet

借鉴复合材料力学的研究方法,对四点弯曲荷载作用下含裂缝的单向芳纶纤维片材加固钢筋混凝土梁的应力重新分布建立一种分层模型,从而获得了各子层的应力或位移分布。在此基础上,对现有修正的剪滞模型进行拓展,进一步研究了粘贴在梁底部的受拉伸应力作用的纤维片材由纤维束逐步断裂产生的应力集中问题;然后采用复合材料的细观统计破坏理论,求得了相应的统计强度和梁的极限承载力。所得结果与现有试验值较吻合,证实了本文模型和分析方法的正确性和可行性。

Based on the study method for mechanics of composite materials,a layering model is established for the redistribution of the stress of reinforced concrete beam strengthened by unidirectional aramid fiber sheet with crack under four-point bending load,and then the distributions of stress and displacement of all the sub-layers are obtained.On the basis of this,an existing modified shear-lag model is extended for the further study on the stress concentration induced by the fiber bundle fractures in the sheet bonded at bottom of the beam under tension;and then the corresponding statistical strength and failure load of beam are obtained by using a micro-statistical failure theory for the composite materials.The results obtained relatively coincide with the existing experimental values,thus verifying the correctness and feasibility of the present model and analytical method.