Determination Of Friction Parameters Of Carbon Fiber Anchored Structure

Carbon fiber reinforced composite(CFRP)has been used in more and more buildings to replace traditional steel bars due to its light weight,high strength,corrosion resistance and excellent mechanical properties.The excellent anchoring performance of bonding type anchoring system mainly depends on the chemical bonding force and the friction force between materials,and the chemical bonding force is likely to fail with the growth of years.Therefore,the friction coefficient between materials is very important for the anchoring performance of structure.There are friction pairs composed of carbon fiber and different materials in the anchorage structure,and the law of friction coefficient variation under the action of high pressure stress is still questionable.Therefore,based on the existing basic theories and research on the coefficient of friction,a new type of friction coefficient testing device is designed to eliminate the wear caused by the constant rotation of the conventional friction machine,and realize the interaction between the materials of the carbon fiber bonded anchor structure under high pressure.The friction coefficient test,the specific research content and results of this article include:(1)The uniaxial compressive test of 50*3mm carbon fiber plate shows that the carbon fiber composite plate suffers damage when the compressive stress is 48 MPa,and micro cracks occur in the vertical fiber section.With the increase of compressive stress,the resin matrix will be damaged,leading to the dispersion of carbon fiber.(2)A new quasi-static friction coefficient testing device was designed to test the friction of carbon fiber plate-epoxy resin.The results show that the rough resin surface has a great influence on the friction coefficient.With the improvement of the smoothness of the resin surface,the friction coefficient presents a trend of first increasing and then decreasing.The maximum friction coefficient of carbon fiber plate-epoxy resin friction pair is 0.25.The friction coefficient between carbon fiber and steel has little influence on compressive stress,and the friction coefficient value is maintained at 0.20～0.25.It does not increase with increasing compressive stress.By adding iron sand into the resin,the friction coefficient between the resin and carbon fiber composite material is effectively increased under the action of no cohesive force.The test results show that the maximum friction coefficient of ferric sand resin-carbon fiber plate is 0.32,which is 0.7 higher than that of pure resin.During the test,the iron sand extruded smaller "holes" to the carbon fiber plate,which would cause permanent damage if the compressive stress continued to increase.(3)Through the Q235 steel plate-iron-containing sand resin test,it is found that the incorporation of iron sand cannot enhance the friction coefficient between the resin and the carbon fiber material,but reduces the maximum friction coefficient from 0.43 to 0.23.Due to the yield strength of metal materials,in the Q235 steel plate-steel friction test,the friction coefficient curve is relatively stable and the value is maintained at 0.22～0.25,and the friction coefficient between metal materials does not increase with the increase of compressive stress.