Study On The Properties And Applications Of Carbon Nanofiber FRP Materials

At present,the monitoring methods commonly used in the engineering field are mainly sound emission technology,optical fiber monitoring,ultrasonic testing,laser holographic nondestructive testing and carbon fiber intelligent concrete structure,etc.,but these traditional monitoring methods also have disadvantages such as high maintenance cost and short monitoring period.The Carbon Nanofibers Reinforced Plastic(CNFRP)is a new intelligent structural material.Due to its excellent mechanical and electrical properties,it is capable of responding to external stimuli,providing a new way of thinking for the monitoring of stress,deformation and structural damage in modern engineering structures.The structural properties of CNFRP are closely related to the distribution of CNFs in the matrix.In order to broaden the application of CNFRP in structural diagnosis and safety monitoring,a series of studies on strain sensing performance of CNFRP with different distribution conditions are carried out in this paper.The influence of fiber content,temperature and humidity on the resistivity of CNFRP is discussed.The results show that the CNFRP shows more obvious percolation without magnetic field.The influence of temperature on the resistivity of CNFRP without magnetic field is more obvious than that of CNFRP without magnetic field.Humidity has little influence on CNFRP.CNFRP also has good ohmic properties.The mechanical properties of CNFRP are also studied in the paper.The results show that the tensile and flexural properties of the magnetic field-induced CNFRP are obviously better than those of the non-magnetic field-induced CNFRP,which also proves that the magnetic field makes the CNFs present an ordered distribution in the matrix.The interlaminar shear properties of CNFs modified Basalt Fiber(BF)reinforced composite(BF-CNFRP)under the action of magnetic field perpendicular to the axial direction of the specimens were further studied.The results showed that the interlaminar shear strength of BF-CNFRP under magnetic field induction was higher than that of BF-CNFRP without magnetic field induction.In addition,the sensing performance of CNFRP to strain under static and cyclic tensile loads is studied.The results showed that the sensing performance was the best when the mixture of CNFs was 0.75wt%,and the magnetic field induced CNFRP to have higher mechanical properties and still have good response to strain.Moreover,by attaching CNFRP to the bottom of concrete beam,the impact response of CNFRP to concrete beam is studied.Under the impact load,CNFRP shows a good response.The results show that CNFRP has the potential to be applied in engineering structure monitoring,and it has important practical application value to grasp the service state of the structure.