Research On Online Monitoring Of Two-axle Roll-bending Of Split Sleeve Based On Acoustic Emission

As split sleeves have a wide application in the cold-expansion of the holes of the aircraft’sstructural components, their production technology is one of the key technique problems for thedevelopment of aeronautic manufacturing and maintenance. Although the technology of two-axleroll-bending to produce split sleeve with a simple structure and high precision, some problems stillexist, such as lacking of evaluation parameters and the uncontrollability of the forming process, andthe difficulty in prediction of the forming quality. This paper aimed at the shortcomings of thetechnology of the two-axle roll-bending, realizes the online monitoring of the process of two-axleroll-bending based on acoustic emission. The major work and results are as follows:1. The characteristics of the process of two-axle roll-bending are analyzed, and the method of theacquisition of the acoustic emission signal during the forming process is designed. An onlinemonitoring system for the process of two-axle roll-bending of split sleeve is completed based onLabVIEW, then the acquisition, indication, filtering spectrum analysis and storage of the acousticemission signal during the two-axle roll-bending are realized.2. The characteristics of the acoustic emission signal of0Cr15Ni7Mo2Al stainless steel in thetensile test are analyzed, and the changing laws of the amplitude, ringing count and frequency of theacoustic emission signal during the tensile test are acquired.3. The characteristics of the acoustic emission signal of friction between0Cr15Ni7Mo2Alstainless steel and45steel are analyzed, and then the phenomenon that the event count, energy countand ringing count of the acoustic emission signal changing with the friction force is observed. Theinfluence of the positive pressure, surface roughness and mutual sliding velocity on the averageenergy count rate, average ringing count rate and frequency of the acoustic emission signal isacquired.4. The characteristics of the acoustic emission signal produced from the process of two-axleroll-bending are analyzed, then the changing laws of the energy count, ringing count and frequencyduring the forming process are acquired, and the influence of the feeding distance, diameter of theelastic wheel and width of the workpiece on the average energy count rate, average ringing count rateand frequency of the acoustic emission signal are obtained. 5.The characteristics of the acoustic emission signals with different forming qualities areanalyzed, then the changing laws of the energy count, ringing count and frequency of the acousticemission signal when the split sleeve has different defects are acquired.