The Method And Application Of Shaft Crack Parameters Identification Based On Zero Moment Scaling Function Finite Element

Large rotary machinery is expected to operate in high-speed, overloading, high-power,and long-term running situations, which may generate transversal cracks on rotors. Theexpanding cracks potentially fail the mechanical structure and lead to major accidents.Accordingly, identifying the parameters of structural cracks in early stage is a crucial issue onpractice of mechanical engineering. Vibration diagnostics is widely used in identifyingengineering cracks. Specifically, wavelet finite element has its unique advantages in dealingwith the singularity and large-gradient of cracks. Hence, this article applied wavelet finiteelement as the major method to identify the parameters of cracks on shafts.The authors at first calculated the values and derivative values of Daubechie waveletsacling function and Coiflet wavelet sacling function, as well as deduced the method ofcalculating connection coefficients, and then constructed Daubechies wavelet shaft unit andCoiflet wavelet shaft unit through introducing interpolation function, which was replaced bywavelet sacling function, into the finite element.While, equating cracks as massless torsion wire spring, wavelet finite element model ofshaft was built. Surface of natural frequency of shaft that changes with the depth and locationof cracks was also generated. The high degree of matching between wavelet finite elementand analytical method demonstrated the effectiveness of wavelet finite element method.The parameter sensitivity analysis on natural frequency of shaft detected the issues ofexperiments that should be noted. Then, the vibrating experiment of cantilever shaft withcrack provided a measured natural frequency. The contour method of identifying shaft crackparamters was of great effects.