Thickness Measurement and Process Optimization of CFRP Based on Laser Ultrasonic Pulse Reflection Method
In order to improve the thickness measurement accuracy of carbon fiber composite(CFRP),a thickness measurement method of CFRP based on laser ultrasonic pulse reflection method was designed,and the process parameters were optimized.The results show that the relative error can be less than 5.2%when measuring the thickness with convex lens.When the outer diameter of spot is increased,the ultrasonic signal with lower amplitude is formed.The spot area formed by convex lens focusing is smaller than that formed by cylindrical lens gathering,which improves the energy density,promotes the excitation of ultrasonic signal with larger value,and significantly enhances the laser thermoelastic effect.In the absence of external light sources,a reflected signal with a stable frequency is formed.When the power of the light source is increased,more noise frequency and amplitude are generated in the signal.Background noise also causes multiple reflection echo to drown.When the power is 0.45MW and0.60MW,the relative effective signal frequency is larger,and the reflected signal is also significantly affected.This research can be extend-ed to the thickness measurement of other microscopic materials and has a good precision control standard.
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