端部增强方式对CFRP管轴压力学性能的影响

端部局部破坏严重制约CFRP(Carbon Fiber Reinforced Polymer)管轴压承载力的发挥,对采用金属加强箍-金属端帽增强与碳纤维-金属内衬增强两种端部增强方式的CFRP层合管进行了轴压试验,得到了试件受力过程和破坏形式。基于Hashin失效准则,利用有限元模型分析两种端部增强方式下CFRP管首层失效模式和承载力,并解释了增强机理。研究表明:与未施加端部增强的试件相比,端部增强可改变试件失效模式并提高承载力;端部增强时,外部增强约束刚度不宜过大,增强件与试件较大的刚度差会导致变形不一致,易在增强端边缘处发生剪切破坏;采用碳纤维-金属内衬的端部增强方式可有效防止端部发生"开花式"破坏和剪切破坏,可使层合管发生整体破坏,轴压承载力提高了46.37%。

EFFECT OF END ENHANCEMENT ON MECHANICAL PROPERTIES OF CFRP TUBES

The CFRP (carbon fiber reinforced polymer) tube is used to control the axial load bearing capacity of the CFRP (carbon fiber reinforced polymer) pipe,and the CFRP laminates are reinforced with the metal reinforcing hoop-metal end cap and the carbon fiber-metal lining reinforcement.The stress test and the failure form of the specimen are obtained by axial compression test.Based on the Hashin failure criterion,the finite element model was used to analyze the failure mode and bearing capacity of the CFRP pipe under the two end enhancement modes,and the enhancement mechanism was explained.The results show that the end enhancement can change the failure mode of the specimen and increase the bearing capacity compared with the specimen with no end reinforcement.When the end is strengthened,the external reinforcement stiffness should not be too large,and the reinforcement and the specimen are larger.The difference in stiffness will lead to inconsistent deformation,easy to occur at the edge of the enhanced edge of the shear damage.The use of carbon fiber-metal as the enhanced way of the end can effectively prevent the end of the "flowering" damage and shear damage.The overall bearing damage and axial load capacity increased by 46.37％.