Fault Diagnosis Method On The Girder Crack Of Large-scale Vibrating Screen

Vibrating screen is one of the key equipment in washing industry. Once crack fault occurrence of its girder will make the whole production line to shut down, and result in great economic loss. Because of the girder's structure, it is very difficult to obtain its status signal and extract its crack fault feature. At present, no method can diagnose that fault effectively at home and aboard. The research findings of this paper provide theory and technique supports for that problem, have great theoretical significance and construction value.The experimental model of vibrating screen was designed and experimental platform was built in this paper. Harithm estimation of transfer function (TF) was improved, and an estimation method of TF was put forward based on cross-spectrum and average technique and the concrete estimation formula was proposed. The Regularity for changes of TF of vibrating screen's girder under various crack conditions was studied and the fault diagnosis method and route criterion on vibrating screen girder crack was put forward based on its TF. The pulse response signal of vibrating screen girder was and processed using wavelet and its power spectrum was analyzed. The fault diagnosis method and route criterion on vibrating screen girder crack was proposed based on FFT and wavelet transform, and give the means for the industry application of study results. The quick test method of vibration girder crack was discussed based on metal magnetic memory testing (MMMT) technique and eddy current testing (ET) technique and its testing system was built. The spot type approval test was carried out and 6 points vibrating screen girder early crack faults were diagnosed and detected out successfully, and which produced appreciable economic and social benefit and verified the correctness of the study results in this thesis.