The Design Of Shock Isolation System For Apple Orchard Track Transport Case Based On Computer Simulation

In China,hilly region is very important planting base for fruits industry.Limited by topography,rail transport is generally used at home and abroad for transportation of the fruits mechanization.However,the fruits need frequent handling operation in the process of transportation,leading to transport brake and start for high frequency.The adding rate in the process of transportation produced large inertial impact,which makes fruits to impact injuries.In this study,Shandong red Fuji apple was taken as the research object,the conditions of the fruit reaching the national standard damage degree was studied.Due to the research results,a buffer mechanism was designed to achieve the purpose of slowing down the fruit damage in the process of apple orchard rail transportation.(1)Develop a set of fruit impact test device,which is used for impact damage test of fruit.The device consists of stepper motor,controller,the dynamic fruit clamping mechanism,high precision S type pressure sensors,pressure transmitter,etc,and can realize automatic fruit in the process of the collision impact signal acquisition,through to the impact velocity and impact of distance,holding the adjustment of the parameters such as diameter,applicable to test the impact of different fruit injury.(2)Taking Shandong red Fuji apple as the research object,the impact damage test of the fruit was carried out.The damage area of the fruit under different impact conditions was studied.The impact damage threshold of red Fuji apple was obtained to be 30 N.The data of impact force and damage area of fruit were analyzed.(3)Using EDEM software,the stress situation of apples in the box during braking or starting in orchard rail transit was simulated and analyzed.The contact impact force between fruits in the box under different acceleration values was studied,and the acceleration value when the fruit reached the damage threshold was 0.5m/s2.It was found that the impact force between fruits increased when the acceleration value increased,which provided a theoretical basis for the design of buffer mechanism.(4)In order to mitigate the impact damage of apples in the process of orchard rail transport,a buffer mechanism for apple orchard rail transport box is designed,which is mainly composed of rubber vibration isolator.The vehicle body,box body and buffer mechanism are simplified into undamped single-degree-of-freedom foundation excitation model,and the model formula is imported into MATLAB for calculation.The response acceleration and response displacement of the box body under different stiffness conditions of the buffer mechanism are obtained,and the stiffness coefficient satisfying the design requirements is selected according to the maximum acceleration value of the box body obtained from the previous research.According to the large mass method,the ABAQUS simulation verification was carried out,the particle-elastic element model was established,and the simulation calculation was carried out.The simulation results were consistent with the MATLAB calculation results,the stiffness coefficient of the buffer mechanism was determined,and the parameter value of the rubber isolator in the buffer mechanism was obtained according to the design requirements.Through the explicit dynamic analysis of the buffer mechanism designed by ABAQUS,the simplified model of the railcar and buffer mechanism is established,and the acceleration and displacement of the box unit are obtained by applying acceleration load on the car body,which verifies that the buffer mechanism of apple orchard rail transport box meets the design requirements.