碳纤维增强聚合物 重组竹复合材的弯曲力学性能

重组竹已广泛应用于室内高档装饰、园林景观、室外防腐地板等领域,但重组竹的弹性模量比较小,为钢材的1/7~1/5,应用于建筑领域时难以充分发挥其自身高强度的特性。针对重组竹刚度较小的问题,提出一种重组竹板和碳纤维增强聚合物(CFRP)厚板嵌合粘接的新型重组竹复合材料,采用三点弯曲试验和有限元仿真方法,对CFRP 重组竹复合试件的失效模式、荷载 位移关系、应变曲线、胶层界面剥离影响等进行了研究。结果表明:重组竹试件失效模式是跨中位置处拉伸区域竹纤维断裂,且出现若干水平分层破坏,CFRP 重组竹复合试件的失效模式是CFRP与重组竹层间胶层出现大面积剥离;CFRP 重组竹复合试件的变形过程分为线弹性阶段和界面破坏阶段;CFRP可以明显提高重组竹梁的弹性模量和静曲强度,复合试件弹性模量是重组竹试件的2.33~2.94倍,静曲强度是重组竹试件的1.49~1.58倍;胶层界面剥离是CFRP 重组竹复合试件失效的重要因素,胶层界面剥离对复合试件的应变分布和挠度都有较大影响,完全剥离后试件的挠度是未剥离时的3.09倍。

Flexural mechanical properties of carbon fiber reinforced polymer bamboo scrimber composite

Bamboo scrimber is a reorganized bamboo plate or square material with a bamboo bundle or fiberized bamboo veneer as a component.Its raw material is a kind of natural renewable resource that can be used as structural components after harvest and degradable after being abandoned.It requires low energy consumption during processing,which is 1/3 of wood,1/8 of the reinforced concrete,and 1/50 of steel.The bamboo scrimber has been widely used in the fields of interior decoration,garden landscape,outdoor anticorrosive flooring,etc.However,the elastic modulus of bamboo scrimber is relatively small,being about 1/7 to 1/5 of steel,which is difficult to fully take advantage of its own high strength characteristics in the construction application.For the low stiffness problem of bamboo scrimber,this study proposed a new structure composite made up of bamboo scrimber and carbon fiber reinforced polymer(CFRP).Three-point bending test and finite element simulation were conducted to study the failure mode,load-displacement relationship,strain curve and the effect of adhesive debonding,etc.The results were shown as follows:1)The failure mode of the bamboo scrimber specimen was that the bamboo fiber was broken at the middle position of tensile region,and there were several failures of horizontal delamination,but no local bending or breaking was detected at the compression area.The failure mode of the CFRP-bamboo scrimber composite specimens was the large-scale debonding of the adhesive between CFRP and the bamboo layer.2)The deformation process of bamboo scrimber specimens could be divided into linear elasticity stage,stiffness degradation stage and failure stage.The deformation process of CFRP-bamboo scrimber composite specimens could be divided into linear elasticity stage and interface failure stage.3)Under the same cross-section conditions,CFRP could significantly improve the elastic modulus and static bending strength of the bamboo scrimber specimens.The modulus of elasticity of the CFRP-bamboo scrimber composite specimens were 2.33 to 2.94 times higher compared with that of the bamboo scrimber specimens.The static bending strength of the CFRP-bamboo scrimber composite specimens were 1.49 to 1.58 times higher compared with that of the bamboo scrimber specimens.4)The adhesive debonding was an important factor for the failure of the CFRP-bamboo scrimber composite specimens,which had a great influence on the strain distribution and deflection of the composite specimens.After being completely debonded,the deflection of the specimen was 3.09 times higher compared with that of the undebonded specimens.