Design Of High Temperature Internal Friction Detection Dystem For Metal Materials Based On Ultrasonic Guided Wave

In the development,production and industrial applications of materials(such as hightemperature heat treatment,high-temperature smelting and high-temperature furnaces,etc.),high-temperature internal friction testing of metal materials is particularly important.Internal friction refers to the process of converting mechanical energy into thermal energy dissipation.It can describe the microscopic changes of matter from a macroscopic perspective.Traditional internal friction measurement methods include static mechanical experiment method and lowfrequency torsion pendulum measurement method,audio mechanical spectrum and ultrasonic pulse method.However,the static mechanics experiment method,the low frequency torsion pendulum measurement method and the audio mechanical spectrum measurement temperature range are limited,while the ultrasonic pulse method can measure the internal friction in the high temperature environment,and can achieve long-distance measurement.It is suitable for samples of various shapes and sizes,and the sample is small.,Save material.Based on the detection principle of ultrasonic guided wave resonant sensor,combined with the advantages of magnetostrictive ultrasonic guided wave detection technology and resonant sensor,a metal material high temperature internal friction detection system based on ultrasonic guided wave is developed.Using the remote resonance characteristics of the ultrasonic guided wave resonance sensor,a resonant frequency automatic tracking drive circuit is designed to realize the excitation and reception of the ultrasonic resonance echo signal;by tracking the attenuation section of the resonator radiation signal and the oscillation source Established a loop integral control model;designed an FPGA-based control acquisition system to control the emission of excitation pulses,pulse frequency measurement,A/D acquisition of ultrasonic resonance echo signals,and USB data transmission;developed Lab VIEW host computer to send parameter settings,data acquisition,display and storage.The half-wavelength guided wave resonant sensor is made of iron-chromium alloy wire,and the designed high-temperature internal friction detection system for metal materials is used to do a temperature rise test in the temperature range from room temperature to 1000 ℃.In the experiment,the natural frequency of the resonator was measured,the ultrasonic echo signal was collected,and the internal friction-temperature curve of the iron-chromium alloy was obtained.The curve shows that it is consistent with the change in the material properties of Fe-Cr alloy.The results show that the system can realize ultrasonic signal transmission,automatic tracking of resonance frequency,pulse frequency measurement and acquisition of ultrasonic resonance echo signals.The system can be used as a means of analyzing and evaluating the internal friction of metal materials at high temperature.