Research On Thermal Damage Of Carbon Fiber Reinforced Plastics Induced By High Power Laser

Carbon Fiber Reinforced Plastics(CFRP)is a new kind of high strength and high corrosion resistance materials.Traditional machining methods are used to cut and drill CFRP materials,which are easy to produce faults and burrs and affect the processing quality.At present,the modern industry needs a new method to deal with CFRP materials.Laser is a non-contact method for processing materials based on thermal effect,which is especially suitable for the processing of composite materials.Therefore,it is of great theoretical and practical significance to study the thermal damage law of CFRP materials caused by the laser.In this thesis,the thermal damage of CFRP materials with different physical parameters(fiber structure and thickness)irradiated by high power lasers is studied both theoretically(including simulations)and experimentally.On the theoretical research side,based on high power laser irradiation of CFRP materials heat conduction theory,thermal elastic-plastic mechanics theory.Considering the physical properties of carbon fiber and matrix,the anisotropy of carbon fiber,and the structural characteristics of carbon fiber layer,the theoretical model of CFRP materials irradiated by high power laser is established.On the simulation research side,the corresponding simulation model is established based on the theoretical model of CFRP materials with different physical parameters(fiber structure and thickness)irradiated by high power laser.The composite materials was simulated by COMSOL finite element analysis software.The temperature of the center point,radial and axial on the surface of the composite,and the radial and axial stress were analyzed.The variation of the temperature field and stress field of the composite with the laser power density was obtained.On the experimental research side,point thermometer was used to measure the temperature change of CFRP materials during laser damage in real-time.A three-dimensional surface measuring instrument was used to measure the surface damage morphology,damage area,and damage depth after laser action.The relationship between the temperature,damage area,damage depth,and laser parameters and materials thickness of two kinds of structural CFRP materials under the action of a high power laser,and the change law of damage threshold of two kinds of structural CFRP materials under the action of high power laser are obtained.Finally,combined with the simulation results and experimental results,the thermal damage law of CFRP materials irradiated by high power laser is analyzed,which provides a theoretical basis for laser processing of composite materials.