Simulation Of Giant Fungus Grass Sawing And Optimization Of Cutter Parameters Based On LS-dyna

Giant fungus grass is a high-quality herbaceous plant that can replace forest cultivation of edible and medicinal microorganisms.With the development of the mushroom grass industry,its production mechanization level needs to be further improved.The giant fungus grass harvesting machine can achieve automated harvesting,but there are problems during operation such as high wear of the cutting saw blade,poor wear resistance,low service life,high cutting force and power consumption,and low harvesting quality and efficiency.Therefore,it is of great significance to study the working performance and wear resistance of the giant fungus grass cutter.In order to reduce the cutting power consumption and tool wear,this paper uses the methods of theoretical analysis,numerical simulation and experimental verification,and based on the finite element software LS-dyna,establishes an explicit dynamic simulation model of giant fungus stalk sawing,studies the mechanism of giant fungus stalk sawing and saw blade wear,and optimizes the cutter parameters.The main research results of the paper are as follows:(1)Analyze the organizational structure of giant fungus grass based on the LS-dyna material library 143_mat_Based on the basic theory and parameters of the wood model,combined with the current research results on the mechanical and material properties of Giant fungus grass,a geometric and material model that conforms to the mechanical properties of Giant fungus grass has been established.Referring to a cutting device similar to high stem crops,a 3D model design was carried out on the key components of the cutter and its working parameters were determined.(2)The kinematics model of giant fungus stalk sawing was established,and its non leaking cutting feed speed 2.08m/s was obtained through kinematics analysis;A mechanical model for stem sawing was established to analyze the force acting on the cutter and the wear mechanism of the saw blade.The key parameters affecting the sawing force were determined to be the sawtooth rake angle,wedge angle,saw blade thickness,and blade speed:By analyzing and comparing the Archard and Usui wear theoretical models,the integral equation of the total wear amount of the saw blade is derived from the wear model.The results show that the Archard wear model conforms to the wear mechanism of the giant fungus cutting saw blade,and is suitable for the calculation model of the saw blade material wear in the giant fungus cutting simulation.(3)Use Ansys/Workbench to conduct modal analysis on the cutter,study its first six natural frequencies and vibration modes,and obtain the influence law of the chuck diameter on the natural frequencies and vibration modes of the circular saw blade.By analyzing the critical speed of the cutter,the reasonable operating speed range of three different types of circular saw blade cutters under different diameter fixed chucks was obtained.(4)By analyzing the contact and control algorithm of Ansys/LS-dyna and setting parameters,an explicit dynamic simulation model of giant fungus stalk sawing was established,and the mechanism of giant fungus stalk sawing and tool wear was studied.The accuracy of the simulation model was verified by the results of hourglass energy and fungus sawing test.Single factor simulation was carried out for cutter parameters(front angle of saw tooth,wedge angle,rotating speed and saw blade thickness)to study the influence of each factor on the cutting power consumption(maximum cutting force)and wear resistance(maximum wear amount of saw blade)of the test target.Further,Box Behnken central assembly principle was used to design the test scheme,and multi factor simulation was carried out.The regression equation between each factor and the test target was established using mathematical statistics,Analyzed the effects of various factors and interactions on the experimental objectives,and obtained the optimal parameter combination through multi-objective optimization:sawtooth rake angle 23°,wedge angle 48°,saw blade thickness 2.6mm,rotational speed 1092r/min,the maximum cutting force of the cutter is 219N,and the maximum wear of the saw blade is 1.915μm is the smallest,and through the comparison and verification of the results of the mushroom grass sawing test,it effectively reduces cutting power consumption and saw blade wear,and improves the tool service life.