Design And Experimental Research Of On-line Thickness Measurement Device Based On Ultrasonic Guided Wave

In the process of chemical production,there are difficulties in the real-time detection of equipment in high and low temperature environment.Therefore,we hope to design a device that can be fixed on the equipment in harsh environment for a long time and measure the thickness of the parts prone to corrosion on line.After research,ultrasonic testing is selected as the basic principle of the device.While transmitting the guided wave by the waveguide rod,the ultrasonic transducer is isolated from the harsh environment to make the transducer work normally.For the design of on-line thickness measurement device based on ultrasonic guided wave,the problem that the addition of waveguide rod complicates the ultrasonic transmission must be solved first.According to the propagation mode of guided wave in bounded solid,the horizontal shear(SH0)wave without dispersion is excited in the waveguide rod by transverse wave straight probe as the signal source.Secondly,the shape and size of the waveguide rod need to be determined.With the help of the finite element simulation software COMSOL,the heat transfer of the waveguide rod with different shapes and materials is simulated,and the waveguide rod that can isolate the temperature most is compared.Then,the fixture used to connect the waveguide rod with the test piece is designed,which can provide appropriate pressing force to meet the needs of dry coupling between the waveguide rod and the test piece.Then,aiming at the characteristic that ultrasonic wave will change with different temperature and material propagation speed,a set of ultrasonic wave analysis and data processing method needs to be constructed.Finally,in order to verify the above research and design of the device,an experimental platform is built to verify it.The results show that the material is 316 stainless steel and the size is 0.6 × The 18 mm Rectangular Section and 300 mm long waveguide rod have good temperature isolation effect;The designed device can measure the thickness effectively in the range of 5 ～ 50 mm,and the overall error rate is less than 0.5%.The experimental device is integrated to form a prototype of thickness measuring device with network transmission function that can be used in chemical production site,which basically realizes the realtime detection of equipment in high and low temperature environment.