Study On Ablation Characteristics Of Glass Fiber Reinforced Resin Matrix Composites By CW Laser Irradiation Under Tangential Air Flow

In this thesis,the mechanical erosion effect of 1064 nm CW laser ablation of glass fiber reinforced polymer(GFRP)under the action of subsonic tangential airflow was studied.The mechanical erosion effect on the ablation was studied by both experiment and numerical simulation.An experimental device was designed to collect mechanical erosion products during the process of laser ablation of GFRP.The total mass loss and the erosion mass loss of the material were weighed and the percentage of material ablation caused by erosion was calculated.The experiments were made at different airflow velocities and different laser power densities to study the law of erosion.In the experiment,an infrared thermometer was used to measure the temperature change at the center of the light spot.The results show that the percentage of mass loss caused by mechanical erosion will increase and tend to be constant with the increase of airflow velocity.The percentage of mass loss caused by mechanical erosion will increase with the increase of laser power density.The percentage of mass loss caused by mechanical erosion will increase and tend to be constant with the increase of laser irradiation time.The mechanical erosion effect of GFRP is related to its laminated structure.The laminated structure can affect the mechanical erosion mechanism of the material surface.It will cause the regular change of the temperature of the material.A 2D axisymmetric model of laser ablation of GFRP was set up.The mechanism of laser absorption,pyrolysis of resin,melting,vaporization,and erosion of glass were considered,as well as the heat and mass transfer in the material.Then the finite element analysis is performed by COMSOL software to achieve the coupling of multiple physical fields.The temperature and ablation boundary of the composite material were calculated and compared with the experiments.The two agree well.The results of this thesis will help understand the effect of the mechanical erosion during CW laser ablation of GFRP and will help understand thermomechanical damage of CW laser ablation of GFRP under high speed airflow.