Research On Acoustic Emission Detection Technology Of Aeroengine Titanium Alloy Materials

With the continuous development of the titanium industry,the application of titanium alloy materials in aviation has become more and more popular,and the requirements for material properties are getting higher and higher.This paper studies the titanium alloy materials used in aviation engines,which have the advantages of high specific strength,low density,good corrosion resistance and good thermal stability.However,the working environment of various components in the aviation engine is complex,and it may cause crack damage in the long-term work under high temperature environment.In order to ensure the normal and safe operation of the diffuser,it is necessary to detect it by means of non-destructive testing.And acoustic emission detection method has advantages in real-time and dynamic monitoring of materials in the non-destructive testing method,it could find the damaged part and take countermeasures timely.In order to study the characteristics of titanium alloy material in the event of damage,the tensile test and three-point bending test of titanium alloy material are carried out,monitor the acoustic emission behavior during the experiment and analyze its signal characteristics.In order to improve the accuracy of the damage source localization,the acoustic emission detection technology is used to perform time reversal positioning on the titanium alloy test block.The tensile test of the titanium alloy test block is carried out to study whether the different factors have an effect on the acoustic emission behavior during the tensile test.In this paper,the defect-free test block and the linear defect test block are carried out under different loading rate conditions respectively.The mechanical curves and acoustic emission behaviors of the linear and non-defective specimens under different tensile rates were analyzed,and the mechanical properties and corresponding acoustic emission characteristics were summarized.Three-point bending test was carried out on the titanium alloy test block under three loading rates,and the three-point bending test was performed on the defect-free and linear defect test blocks respectively.According to the mechanical curve and acoustic emission characteristic parameter signals obtained from the experiment,the effects of different loading rates on the mechanical properties during bending test and the effects on acoustic emission behavior are analyzed.The mechanical properties and corresponding acoustic emission characteristics are summarized.Since many signals of the positioning points appear during the test,in order to determine the specific position of the acoustic emission source,this paper improves the time-reversed positioning method.Through the time reversal focusing process of the acoustic emission source signal,the monitoring area is divided into a plurality of pixel points,each pixel point corresponds to the fluctuation amplitude of the mass point,and the point with the largest amplitude is the position of the acoustic emission source.Using the actual experimental data to verify the improved time-reversed positioning method,the experimental results show that the time reversal positioning algorithm can effectively improve the positioning accuracy of the acoustic emission source.