Vibration Characteristics And Experimental Research Of Shearer Ranging Arm Based On Strain Mode

As an important component of shearer,the ranging arm directly bears all kinds of internal and external excitations which fluctuate violently in the course of work and produces strong vibration response.In the long run,the ranging arm is more prone to overload or fatigue damage than other parts of shearer,which seriously affects the safety of underground production.Therefore,it is necessary to study its vibration characteristics.This paper takes the left cutting unit ranging arm of MG500/1180 WD type shearer as the research object,a discrete element model of the drum-coal coupling cutting is established based on EDEM which simulates the process of drum cutting to obtain the three-direction cutting load and the three-direction cutting resistance moment.Using ADAMS to establish the rigid-flexible coupling model of the shearer ranging arm for dynamic analysis to obtain its load spectrum.Based on the displacement modal analysis and strain modal analysis,the transient dynamic analysis of the ranging arm is carried out by ANSYS,which verify the feasibility of the strain modal analysis method to calculate the natural frequency.A method for analyzing the vibration characteristics of the shearer ranging arm based on strain modal analysis is proposed.Based on the effective independent method in displacement mode,the effective independent-driving point residual method suitable for strain mode is derived.The 6th-order strain modes of the primary measuring point are extracted to construct the modal matrix,and the placement of ranging arm's strain sensors are optimized through MATLAB numerical analysis.The experiment relied on the experiment platform of China Coal Zhangjiakou Coal Mining Machinery Co.Ltd.Set up the ranging arm strain data acquisition system to collect the critical section strain response of ranging arm under three working conditions of no-load straight cutting,heavy load oblique cutting and heavy load straight cutting,and analyze the experimental data in time and frequency domains.The analysis results show that the vibration mode of the ranging arm in the heavy-load oblique cutting stage is the first-order displacement mode mode,and the vibration mode of the ranging arm in the heavy-load straight-travel stage is the second-order displacement mode mode.The strain modal analysis method can effectively identify the low-order natural frequency and low-frequency excitation of the shearer ranging arm,which provides a new idea for the research of the shearer rocker arm vibration.