Basic Research On Femtosecond Laser Processing Technology Of Carbon Fiber Reinforced Resin Matrix Composites

As one of the most advanced composite materials,carbon fiber reinforced resin matrix composite(CFRP)is widely used in aerospace,automobile,architecture and other fields because of its superior physical properties.The development of high-end equipment in these fields puts forward higher requirements for the processing quality of CFRP.Due to its highly uneven structure,the traditional processing methods have unavoidable defects,such as large heat affected zone,delamination,internal cracks and high wear caused by the contact of cutting tools and materials.The processing quality can not meet the demand,but also increase the cost.Laser machining is different from the traditional contact machining,which avoids the tool wear.At the same time,due to the non-contact way,some defects caused by contact are no longer produced.Continuous laser and long and short pulse laser processing still inevitably produce heat affected zone,but for ultra short pulse laser,because its action time is far less than heat diffusion time,it is called "cold processing".It can reduce the heat affected zone to a certain extent and improve the processing quality.In this paper,the interaction process between ultrashort pulse laser and CFRP is analyzed,and the coupling mechanism between femtosecond laser and CFRP is studied;the energy transfer process inside the material when femtosecond laser acts on the material;the evolution of temperature and morphology when single pulse acts on the material is studied through numerical simulation;the interaction between multiple pulses when they act on the material,changing the scanning distance,and exploring The law of its effect on the material removal rate is also discussed.The accuracy of the simulation model is verified by experiments.Secondly,based on the theoretical research and the experimental results,the causes of defects in the processing of materials are analyzed,and combined with the influence law of parameters,the measures to reduce the defects are put forward.The causes of the heat affected zone are analyzed.The influence of femtosecond laser parameters,including wavelength and pulse width,on the sizeof heat affected zone is analyzed.By analyzing the evaluation indexes of the processing quality,the processing quality and efficiency of the laser processing CFRP are characterized.The ablation threshold of CFRP under different femtosecond laser pulses was calculated by numerical method.The effects of laser energy,average power,repetition rate and scanning speed on machining quality and efficiency were studied.The influence of parameters such as scanning distance,number of processing lines,and number of single processing on material removal rate was analyzed through process experiments.The simulation results are used to optimize the process parameters,and the better process parameters and processing scheme are obtained.