Reliability Analysis and Optimization of Hammer Rotor Vibration

In order to address the frequent resonance failures in hammer rotors during the use of tearing choppers, the finite element method was utilized for calculations in both free mode and prestress mode, along with resonance analyses of these rotors. The modal frequency distribution patterns were determined using the six sigma method, leading to the fitting of a response surface model for modal frequencies. This was done using an optimized Latin hypercube design combined with Kriging interpolation. Based on the stress-strength interference model, a performance function was developed for the hammer rotor’s resonance failure mode. The Monte Carlo method was then applied for the resonance reliability analysis of the hammer rotor, and its vibration characteristics were subsequently improved by optimization. The study yielded several findings: (1) Prior to optimization, the first-order prestress modal frequency of the hammer rotor was 148.99 Hz, with an excitation frequency of 130 Hz, resulting in an avoidance rate of 12.85%. This indicated a high likelihood of resonance, with a resonance reliability of only 24.5%. (2) Various factors were identified as significantly influencing the first-order prestress modal frequency, including the dimensions of the throwing blade, rib plate, hammer blade, hammer frame plate, as well as the number of hammer blades and frame plates, and the rotation speed. (3) Postoptimization, the avoidance rate between the first-order modal frequency of 158.31 Hz and the excitation frequency of 130 Hz improved to 21.77%, the rotor mass was reduced by 2.74%, and the vibration reliability increased to 93.2%, fulfilling the reliability requirements for essential components in general husbandry machinery. This research holds practical value in accurately predicting the vibration reliability of tearing choppers and enhancing their operational lifespan.