Fatigue failure mechanism of coal mining machine cutting gearbox housing
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(2020) 42:273
TECHNICAL PAPER
Fatigue failure mechanism of coal mining machine cutting gearbox housing Rui Zhang1 · Yimin Zhang2 · Lisha Zhu2 · Jing Huang3 Received: 13 August 2018 / Accepted: 20 April 2020 © The Brazilian Society of Mechanical Sciences and Engineering 2020
Abstract The cause of fatigue fracture in gearbox housing of coal mining machine cutting part (CPGH) is analyzed in this paper. Considering the effects of low-frequency external excitation caused by coal cutting and high-frequency internal excitation caused by gear meshing, systematic studies of force analysis and local resonance analysis are employed. Force analysis is proposed to obtain the region of stress concentration and stress values are calculated by finite element analysis. Field testing and modal analysis are employed to get the resonance frequencies and main vibration modes under internal excitation. Further investigation including the influence of key design parameters on stress amplitude and natural frequencies of CPGH is proposed for avoiding the resonance frequencies and reduce stress concentration. The results indicate that fatigue failure is caused by internal and external excitations. Internal vibrations excite the 15th, 23rd and 27th resonance modes, and the superposition of these vibration modes causes beat phenomenon and results in excessive stress and increases the likelihood of exceeding fatigue limits in the failure region which is induced by external excitation. Fatigue fracture failure of CPGH was caused by both stress concentration and local resonance. The influence of some design parameters on stress amplitude and natural frequencies is analyzed, and some advices for reducing stress concentration and avoiding local resonance are provided. Keywords Fracture failure · Field test · Modal analysis · Local resonance · Beat phenomenon
1 Introduction Coal is the leading energy at present and will be China’s dominant energy for a long time. The proportion of coal in the whole energy consumption was 10% in 2016. The main coal mining technology is the fully mechanized coal mining with long coal wall in China, as shown in Fig. 1. Coal mining machine whose main task is cutting the coal from the coal wall and transport them to the scraper conveyor is one of the key equipments of fully mechanized coal mining and is the core productivity in the process of coal production. Technical Editor: Wallace Moreira Bessa, D.Sc. * Yimin Zhang [email protected] 1
School of Mechanical Engineering and Automation, Northeastern University, Shenyang 110819, China
2
Equipment Reliability Institute, Shenyang University of Chemical Technology, Shenyang 110142, China
3
Shenyang Engine Design Institute of China Aero Engine, Shenyang 110000, China
Coal mining is forced to be in deep and complex geological condition coal seams with the depletion of the shallow coal resources, and deep mining will cause inconvenience in equipment maintenance. Therefore, the reliability of coal mining machine is one of the most concerned problems of
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