Structural Dynamic Characteristics Analysis And Experimental Research On The Traction Drum Of Mountain Orchard Rail Transport

With the continuous development and improvement of the mechanization level of orchard management in our country,Mountain orchard rail transport has become one of the most important development directions of the labor saving machinery for orchard.The traction drum is an important structure of the driving device of the orchard rail transport,and it is the direct bearing object of the load of the steel wire rope.In the working process of the rail transport,the tension of wire rope is complicated,due to the multi-curve,variable slope and variable wheel rail friction of the track,and the traction drum is subjected to complex variable loads.Under the condition of complex exciting force,the vibration and noise of the drum will be larger,which has a bad influence on the life of the drum structure and the other components of the drive system,and also harm to the physical and mental health of farmers,even leads to serious accidents in the fruits transportation process.Therefore,it is of great significance to study the structural vibration characteristics of the traction drum of orchard transport,which provides the basis for the design and optimization of the dynamic characteristics of the traction drum structure.This paper is based on the orchard rail transport driving device of the application demonstration base in Ganzhou City,Jiangxi Province,and the dynamic characteristics of the traction drum in the driving device are analyzed and studied,the results provided basis for improving the dynamic characteristics of the drum structure.The main contents and conclusions of this paper are as follows:(1)The finite element modal analysis of the drum structure was carried out by theoretical modal analysis.The geometry model of traction drum was established by using CAD software Pro/engineer,then introduced to ‘ANSYS Workbench' to establish the finite element model of the traction drum under free boundary condition.The natural frequencies and natural modes of the first 20 order modes were obtained by modal analysis,and the inherent dynamic characteristics of the traction drum structure were determined,preparing for the analysis of the influence of structure parameters on the dynamic characteristics of the drum structure.(2)The finite element model of the drums of smooth face and different wall thickness and case length were established by Pro/engineer.Then,the free modal of the drums of groove and cordless groove structure,three different wall thickness and three different case length were comparatively analyzed.The influence of the structure of the groove and the wallthickness and case length on the dynamic characteristics of the drum was studied.The conclusion can provide the basis for the design and optimization of the traction drum structure.(3)Modal test and parameter identification of the traction drum were carried out based on experimental modal analysis.The experiment adopts the hammering modal test method of multi-point excitation single point response,and after completed the steps of the layout of measuring points,three axis sensor installation,test parameter setting,data acquisition,test setting validation and modal parameter identification.And then we obtained ten modals parameters of the drum,such as natural frequency and natural vibration mode,which reflect the dynamic characteristics of the traction drum structure under actual support conditions,it provides the basis for the dynamic characteristics evaluation and life prediction of the traction drum structure.(4)The vibration test of traction drum was carried out,and the vibration signal of the traction drum unloaded was collected by setting up measuring points on the drum shaft support plate.By fast Fourier transform processing,the vibration time domain signal was transformed into frequency domain signal.Then,the vibration signal and frequency spectrum were analyzed,and obtained the main vibration direction and the peak frequency of the vibration.The results show that the vibration mainly exists in the axial direction of the drum,and the vibration peak is mainly concentrated in the frequency of 0Hz~1000Hz.The working frequency of the transmission drum drive system is only close to the natural frequencies of the first three modes,So we can focus on improving the first three order structure dynamic characteristics of the traction drum.To sum up,the research results of this paper can provide a theoretical basis for the design,evaluation,optimization of structural dynamic characteristics and the life prediction of traction drum in mountain orchard rail transport,and also provide a reference for the design of other drum structure.