Research On The Design And Optimization Of Multi-functional Branch Shredder

As a major fruit producer in the world,China's fruit industry has contributed to regional economic development and increased farmers' income to become rich.It has become an industry model with a high degree of acceptance by farmers in China today.In this context,a large number of waste branches provide high-quality raw materials for pulp and paper,mushroom planting,and combustible gas production,to promote the use of biomass energy in China.Almost all abandoned branches need to be shredded to varying degrees before being processed and developed.Although the traditional branch crushing equipment can meet the requirements of different degrees of crushing,due to the imbalance of high-speed rotation during use,it will inevitably produce severe vibration and noise,which seriously affects the efficiency and life of the whole machine.Based on the research progress of the existing pulverizing equipment and the current situation of orchard branch pulverization in northwest China,this paper designs a multifunctional branch shredder with the goal of improving the overall vibration resistance and operating efficiency.The effects of branch diameter and moisture content on shear strength were analyzed by the branch shear test.Based on the results of the shear test,the technical route and design ideas were formulated,and the key components of the whole machine were designed and analyzed in detail.Secondly,the ABAQUS software is used to study the vibration characteristics of the entire machine component and the frame under the non-damped state based on the modal analysis.Based on this,the peak value and the change law of the amplitude of the machine under the external vibration load are calculated by harmonic response analysis,The response curve of the amplitude of each part of the whole machine within a certain range of excitation force and frequency is obtained.According to the calculation results,the crushing rotor and the frame were optimized and improved,and a vibration-damped frame with a rubber layer was designed.The distribution law and material separation characteristics of the air flow field in the discharge device were analyzed by using the CFD module of COMSOL software.Finally,the branch crushing test was carried out on the prototype,the vibration response and crushing efficiency of the whole machine operation were observed and recorded,and the validity of the simulation results was verified.The main conclusions of this study are as follows:1)Through the branch shear test,it was found that the influence of the branch radius on the shear force and shear strength is not large.When the moisture content is less than 51%,the shear strength will decrease as the moisture content increases.Therefore,when the pulverizing operation is performed,the pruned branches can be directly subjected to the pulverizing treatment,and natural air drying and drying processing are not required.2)The modal analysis shows that the low-order natural frequency of the rotor system is exactly within the range of the external excitation frequency,indicating that resonance may occur during the crushing process to produce vibration deformation and dislocation.The results of the harmonic response analysis show that the excitation force is 1500 N The maximum vibration response of the whole machine in the frequency range of 0 ~ 500 Hz is located in the rack position.When the whole machine is working,there will be obvious misalignment and deviation between the rack and the ground,which will not only affect the crushing rate,but also cause certain safety risks.Therefore the rotor system and frame need to be further optimized.3)The optimized rotor system's natural frequency increases and its amplitude decreases,effectively avoiding all external excitation frequencies.Replace the original frame with a vibration-damped frame with a rubber layer and fix it on the ground to perform a harmonic response analysis again.It is found that the peak amplitude of each observation point is significantly reduced,and there is no obvious misalignment and offset between the rack and the ground,indicating that the vibration damping rack has excellent anti-vibration performance and can effectively avoid risks.4)Through the prototype shredding test,it is found that the whole machine runs smoothly,the crushing effect is good,the average productivity is 430 kg/h,the finished product rate is about 80%,the operation process between the rack and the ground fixed good no offset and misalignment,indicating that the anti-vibration performance of the whole machine after optimization is obviously improved.