Effect Of Ti On The Quality Of CFRP During Drilling Laminated Structures

During the drilling of CFRP/Ti laminated structures,there are inevitable influences between the CFRP and Ti,especially the influence of Ti on the quality of CFRP.In order to investigate the fracture damage mechanism of CFRP,the sensitivity of CFRP on temperature,the mechanical behavior of fiber-resin-volume and the fracture mode of fiber under different cutting angles were analyzed.The results show that the temperature was increased,the stiffness and cohesiveness of resin matrix was significantly decreased;its supporting capacity to the fiber was decreased,since the reduced properties of matrix,which makes the fiber-resin-volume more prone to machining damage.Additionally,the fibre cutting angle greatly influenced the depth of subsurface damage.In this paper,two kinds of machining strategies were used to machining CFRP/Ti laminated,and the influence of Ti on cutting force and cutting temperature during CFRP machining was compared and analyzed.The results show that cutting temperature increases significantly when the tool machined on the laminated interface during drilling and helical milling.However,the average axial cutting force of drilling and helical milling is a little difference.Therefore,Ti had slight influences on cutting force,and significant influences on cutting temperature.In order to investigate the effect of Ti on hole quality in CFRP during machining CFRP/Ti laminated,hole entrance and exit?hole surface and subsurface quality were compared and analyzed.A subsurface damage assessment method is also proposed.The results show that there is slightly difference in the surface damage of the hole entrance and exit and the hole wall between two strategies,but subsurface damage have greatly difference.Therefore,the change of cutting temperature caused by Ti during the machining of CFRP/Ti laminated has a significant effect on the machining quality of CFRP.The mechanical properties of CFRP with hole damage were analyzed via static tensile test.The tensile failure mechanism of CFRP was revealed by analyzing the load-displacement curve and tensile damage morphology.The effect of hole subsurface damage on mechanical properties of CFRP was investigated.The results show that the mechanical properties of CFRP are decreased,since the subsurface damage.With the damage become deepen,the mechanical properties was significantly decreased.Finally,the accuracy of subsurface damage assessment is verified by comparing the results of tensile test...