Simulation And Experimental Study Of Double-Layer Carbon Fiber Reinforced Plastics During Laser Cutting

Carbon fiber reinforced plastics(CFRP)is a kind of composite material with carbon fiber as reinforcing material and resin as matrix material.It has high specific strength,high specific modulus,advanced design,good fatigue resistance and good seismic performance.It has been widely used in aerospace,automobile,civil engineering and many other fields.Laser cutting,as a highly efficient and flexible material processing method,is of great significance to achieve high-efficiency and high-quality processing of carbon fiber composites.Different from isotropic materials,various laser processing parameters in laser cutting process and various laying angles of carbon fiber composites have complex effects on laser cutting quality.Based on the simulation of single-layer CFRP laser cutting in our research group,aiming at the laser cutting quality problem of double-layer multi-angle carbon fiber composite sheet,the processing quality of laser cutting double-layer CFRP was studied from simulation and experiment,and the energy transfer process and characteristics of double-layer CFRP were analyzed.(1)To study the heat transfer process of double-layer CFRP laser cutting,a double-layer homogeneous model of CFRP was established based on ANSYS finite element analysis software,and the temperature field distribution of the cutting process was obtained by simulating the laser cutting process of double-layer CFRP.The temperature curves of characteristic points are extracted in the direction of scanning line,perpendicular to scanning line and material thickness respectively,and the energy transfer process during laser action is analyzed.The angle of carbon fiber laying on the surface plays a decisive role in the maximum temperature of the material under the action of laser.The simulation temperature field was validated by measuring the temperature of the heat affected zone near the scanning line directly when the thermocouple was cutting by laser.Finally,according to the simulated temperature field distribution,the width of heat affected zone(HAZ)of double-layer CFRP laser cutting with six angle combinations is predicted,and the predicted value of HAZ width of temperature field which is close to the actual HAZ width of the sample is obtained.(2)The experiment of double-layer CFRP cutting by fiber laser was carried out.The influence of laser processing parameters such as different laser power,laser scanning speed,defocusing amount,auxiliary gas pressure and various laying directions of double-layer CFRP carbon fibers on cutting quality was analyzed through observation and analysis of ultra-depth-of-field microscope and three-dimensional surface profiler.From the slit width,the slit cone angle and the width of surface heat-affected zone,the influence law of the cutting quality was discussed.The laser cutting quality of double-layer CFRP is characterized by the distribution of heat-affected zones in and between layers,crack generation and surface roughness.The distribution of heat-affected zones in cross-section is similar to that of temperature field in simulated cross-section.Find a way to improve the quality of the cutting area,reduce the heat affected zone and reduce the crack generation at the same time.(3)On the basis of fiber laser cutting double-layer CFRP,the cutting technology of holes and circular holes is studied,and the dimensional accuracy of square holes and circular holes and the distribution of heat affected zone are analyzed.By means of adjusting laser parameters and dimension interpolation,the width of heat-affected zone is reduced,the cutting quality of square and circular hole boundary is improved,and the dimension accuracy of square and circular holes is improved.To realize thin CFRP laser processing of straight,square and round holes with better quality,and to provide the corresponding experimental basis and basic research for laser cutting thick CFRP.