Research On The Mechanism Of Banana Profiling Cutting Based On Vibration Cut

Banana is one of the most important fruit in tropical and subtropical regions.It is also the fruit with the largest consumption of fresh fruit and the largest trade volume in the world.There are 133 countries and regions producing and selling banana.In 2017,the planting area of banana is about 56.375 million hectares,and the annual output is about 114 million tons.In China,the planting area of banana is about 407.9 million hectares,accounting for 7.24 % of the world,and the annual output is about 11.1698 million tons,accounting for98 % of the world.Banana industry has become one of the most important economic industry in tropical and subtropical regions of China.Banana crown cutting is an important part of banana harvesting and processing.However,at present,both domestic and foreign,banana crown cutting is processed by manual method,which have some shortcomings such as low mechanization,high labor intensity,low efficiency and low quality of operation.As a result,the chain of banana harvesting and processing is interrupted,thus the whole mechanization of banana production cannot be realized.Mechanization of banana crown cutting is an effective way to solve these problems,which can effectively realize the mechanization of banana crown cutting segment,and thus make up for the shortcomings in the banana harvesting and processing chain.However,the lack of research on banana crown cutting machine has become a bottleneck restricting its mechanized development.China’s banana industry is currently in an important stage of transformation from traditional to modern production mode.Mechanized operation can effectively improve production efficiency and guarantee banana quality,thus creating favorable conditions to compete in the international market.Exploring the way of mechanization on banana crown cutting is of great significance for stabilizing and promoting the development of banana industrial production.Therefore,it is of great practical significance,theoretical value and application value to research on key technologies and mechanism of banana cutting mechanism in depth.In this paper,the basic physical and geometric characteristics of banana crown,crown handle and crown fibers of main banana varieties in Guangdong Province were experimented.The multi-constraint coupling of banana crown cutting mechanical workspace was constructed,under this condition,the banana crown profiling cutting mechanism,which is the key component in the cutting process,was parameterized designed.In order to reduce the cutting resistance,improve the quality of cutting incision and also for ascertain the principle and characteristics of vibration cutting,the vibration cutting characteristics and cutting process of banana crown were researched experimentally by selecting various factors,and the optimum values of each influencing factors were obtained.In order to research the breaking mechanism of banana crown fibers during cutting process,the numerical simulation of the breaking process was carried out by used the method of coupling the DEM with FEM.The main contents of this paper include:(1)The structure and characteristics of banana crown and fibers were experimented.Such as the spacing,the rotation angle on fruit axis,the thickness,the arc length,the envelope angle on fruit axis,the density and the water content were researched.Through cutting and measuring statistics of the crown,the structure and characteristics of crown fibers,such as layered distribution,cluster characteristics,flow direction and section microstructure,were researched.The parameters of biological and physical properties of banana crown and crown fibers were obtained respectively,which provide basic parameters for future research.(2)Based on the measured characteristic parameters,parametric design and experiment of banana crown profiling cutting machine under multi-constraints were conducted.The workspace of mechanism formed by coupling constraints of various parameters was analyzed.The design of deployable arc profiling cutting mechanism based on deployable mechanism was researched.The parametric design of all the core components of the mechanism was carried out,and the parametric equations with wide generality and applicability were obtained.The obtained parameter equations were analyzed by the value of the variable parameters,and the influence of the value of variable parameters on the whole mechanism was obtained.It was proved by experiments that the profiling precision of the mechanism is maintained above 96.425 %.The experiments prove that the mechanism has a good effect of profiling cutting,and the quality of cutting incision has been greatly improved,which is obviously better than that of the unused profiling mechanism.(3)The experimental research was carried out by using the vibration profiling cutting mechanism of banana.The influence of slip angle on cutting process was analyzed,and the change of slip cutting edge angle with various factors was obtained.The principle of vibration cutting was analyzed,and the experiment device of vibration cutting was introduced.Taking the peak cutting force,forced vibration amplitude of the crown and the cutting quality of the crown as the experiment indexes,the single-factor experiments were carried out on whether the vibration cutting was applied,the vibration frequency,the cutting feed speed,the thickness of the crown cutting tool,the type of the cutting edge,the width of the cutting edge and the diameter of the profiling envelope were carried out,and the influence of each singlefactor on experiments were obtained.Then the main influencing factors were selected for response surface experiments.Through the analysis and fitting of the regression equations,the functional relationship between the influencing factors and the response values were obtained,and the optimal combination of parameters were obtained.(4)The cutting mechanism of banana crown was researched by used the method of coupling the DEM with FEM.The reason of selecting coupling method,the basic theory of DEM and FEM were expounded.The discrete element model and finite element model of banana crown fibers were derived,and a large number of related model equations were obtained.The direct coupling method was selected to coupled calculate the discrete element model with the finite element model,the coupled models of structural and equations,and the calculation equations of the coupled models were obtained.The DEM-FEM coupling model equations of banana crown fibers was simulated numerically.The change of fibers,the force of cutting tool and the state of fibers breaking during the process of cutting were obtained.Finally,the mechanism of banana crown cutting was clarified.