Self-repairing Efficiency And Mechanical Properties Of Hollow Fiber Composites

Fiber reinforced composites are increasingly used in aerospace,automotive and other fields due to their high specific strength and stiffness.But its basic structural form is mostly laminated structure,and there are many problems between the layer process,such as the lack of reinforced.When the laminate is subjected to external loads,it is easy to crack,so as to reduce the overall stiffness and strength of the structure,and even damage laminates,so that its application is limited.Therefore,it is very important to repair the crack and the damaged parts by the self-healing method,and then to prolong the service life of the material.The hollow glass tube with outer diameter of 0.9mm is arranged in the carbon fiber reinforced epoxy resin matrix composite laminate,and the epoxy resin is used as the repair agent.After curing,it is cut into three point bending standard test specimen.After Quasi-Static Indentation Test on some specimens,the specimens were repaired by thermal stimulation then all the specimens were tested by three point bending test.By analyzing and calculating the experimental results,it is showed that ① the hollow glass tube in laminated plates using cross placed way will not reduce the mechanical properties of the laminated plates;②Quasi static indentation experiment,the damage degree increases with the increase of the loading load.When the quasi-static indentation load is 1700N,the bending resistance of the specimen is the maximum reduction of 37%;③ The hollow glass tube in laminated plywood is destroyed by quasi-static indentation test.The repair agent in the pipe can quickly flow to the damaged part of the laminate,repair the crack,bonded crack,and repair the damage.The bending strength of the damaged specimen can be restored to the original strength of 109%.Referring to the placement of "Z-pin" in the compo-site laminate,the hollow glass tube with outer diameter of 0.9mm was implanted in the thickness direction,and the ENB was used as the repair agent to construct the self-healing system.The prepreg laminates curing after processed into double cantilever beam specimens and three point bending specimens.By means of pressure damage test,three point bending test and double cantilever beam experiment,it is showed that ① In the indentation test,8KN pressure can bring damage to the test piece,and the bending resistance of the test piece can be reduced by 11.91%;② The repair system composed of ENB and Grubbs catalysts can repair any layer crack and bonded crack in the laminate,and the bending strength of the damaged specimen is restored to 96.63%of the original strength;③In the experiment of double cantilever beam,the hollow glass tube with longitudinal structure can play the role of toughening the laminate plate,and the toughening effect increases with the increase of the distribution density of the hollow glass tube.The maximum fracture load value is increased by 33.26%.Using epoxy resin as repair agent,according to composite laminates of "Z-pin" in place,using the above method and the experimental process of quasi static indentation test and three point bending test.By analyzing and calculating the experimental results,it is showed that ① Hollow glass tube in the laminated plate using vertical placement method can improve the flexural performance of the laminate,the bending resistance of the specimen under the same conditions was improved by 32.24%;② Quasi static indentation experiment,the damage degree increases with the increase of the loading load.When the quasi-static indentation load is 5KN,the bending resistance of the specimen is the maximum reduction of 57.83%;③ The epoxy resin repair system can fix any layer crack and bonded crack,and the repair efficiency increases with the increase of the distribution density of the hollow glass tube.The bending strength of the damaged specimen can be restored to the original strength of 66.85%.