内压作用下CFRP/钢复合管受力性能试验研究

Experimental Study on the Mechanical Performance of CFRP/Steel Composite Pipes Under Inner Pressure

为研究内压作用下碳纤维增强复合材料(carbon fiber reinforced plastic, CFRP)/钢复合管的受力性能,进行了8根CFRP/钢复合管及1根普通钢管的内压荷载试验.试验中考虑的变量有碳纤维布层数、碳纤维布轴向及环向搭接长度.试验结果表明:外贴单层碳纤维布时,CFRP与钢管的协同变形效应随碳纤维布轴向及环向搭接长度的增加而增强,当轴向及环向搭接长度分别达到50mm及200mm时CFRP与钢管变形趋于一致;内压作用下CFRP/钢复合管的荷载-应变曲线呈近似双线性的变化规律,其刚度、屈服强度及极限强度均随碳纤维布层数的增加而增大,试件典型破坏形态为CFRP环向受拉断裂.最后,基于试件典型破坏特征,提出了适用于CFRP/钢复合管的强度计算模型.

To study the mechanical performance of carbon fiber reinforced plastic(CFRP)/steel composite pipes, eight CFRP/steel composite pipes and one steel pipe were tested under inner pressure.The variables involved in the experiment were layer number of carbon fiber sheet, longitudinal and hoop lap lengths of carbon fiber sheet.The experimental results demonstrated that the difference between strains of CFRP and pipe-wall was decreasing with the increase of the longitudinal and the hoop lap lengths when one layer of carbon fiber sheet was applied.When the longitudinal and the hoop lap lengths were reached 50 mm and 200 mm, the CFRP and pipe-wall showed almost the same strains in the longitudinal and the hoop directions respectively.Besides, for CFRP/steel composite pipes, an approximately bi-linear load-strain relationship was observed and the typical failure mode was CFRP rupture along the hoop direction.Moreover, the stiffness, yield strength and ultimate strength of CFRP/steel composite pipes were increased with the increase in the number of carbon fiber sheet.At last, a theoretical model was proposed to calculate the strength of CFRP/steel composite pipes under inner pressure based on their typical failure mode.