A bionic pulverizer cutter based on the upper jaw of monochamus alternatus and a design method thereof

Abstract

A biomimetic crusher blade based on the upper jaw of the longhorn beetle and its design method are disclosed, relating to the field of agricultural machinery and engineering bionics. The blade features an incline angle that slopes inward from both sides of the bottom surface, and biomimetic teeth evenly arranged at preset tooth spacing at both ends. Its contour is designed based on the upper jaw contour of the longhorn beetle, effectively disrupting the surface structure of rice straw. After penetrating the straw surface, it tears and cuts through a sliding action. This invention extracts the contour coordinates of the longhorn beetle's upper jaw to construct the geometry of the biomimetic blade, establishes a discrete element simulation model of the rice straw and the blade, and performs simulations to obtain the cutting resistance corresponding to different blade parameters such as tooth height, incline angle, and tooth spacing. Based on the simulation results, specific blade parameters are optimized and determined. This biomimetic blade can be applied to crushing rice straw, reducing cutting resistance and equipment power consumption, and improving straw crushing efficiency.

Description

Technical Field

[0001] This invention relates to the fields of agricultural machinery and bionics engineering, specifically to the design of blade structures for straw crushing machinery, and more particularly to a bionic crusher blade based on the upper jaw of the longhorn beetle and its design method. Background Technology

[0002] During rice harvesting, a large amount of straw resources are generated. Improper handling of this straw can easily cause environmental pollution, while appropriate processing technologies can transform it into abundant feed or biofuel, achieving efficient resource utilization. Chopping straw for use as feed not only effectively solves the environmental pollution problem caused by straw accumulation but also alleviates feed shortages in livestock farming, demonstrating significant economic and environmental benefits. As the core equipment for straw processing, the straw crusher's performance directly determines the development level of straw utilization technology. However, existing straw crushers mostly use ordinary hammer blades with flat cutting surfaces, resulting in surface contact with the straw. This leads to high resistance when penetrating the straw and the lack of a sliding cutting structure, relying solely on hard cutting, resulting in high power consumption, low straw crushing efficiency, and easy blade wear. Therefore, optimizing the crusher blades and the design of the cutting blades has become an important research topic in the development of crushers.

[0003] Bionic design offers a novel approach to tool optimization. Biomimetic tools, by replicating the unique characteristics of various organisms in nature, have proven effective in improving cutting performance, work efficiency, and material cutting quality. They also enable innovative tool design and extend tool life. Currently, numerous scholars both domestically and internationally have conducted extensive research and exploration into biomimetic tools. Studies have found that the unique geometric contours of certain organisms in nature can significantly reduce resistance during cutting and improve cutting performance in optimizing the geometric profile of cutting tools. However, current applications of biomimetic cutting tools are primarily concentrated in metal cutting and wood processing, with limited application in rice straw crushing tools. In particular, there is a lack of biomimetic straw crusher tool designs based on the upper jaw contour of the longhorn beetle, failing to leverage the unique cutting advantages of organisms in straw crushing operations and hindering the resolution of many shortcomings of existing conventional hammer blade tools.

[0004] The spotted longhorn beetle, a large longhorn beetle, possesses exceptional plant tissue cutting capabilities. While crawling on trees, it first uses its antennae to detect suitable feeding positions, then uses its powerful, sickle-shaped mandibles to grip the target plant tissue. Through the powerful contraction of its head muscles, it performs lateral cutting and biting actions, efficiently shearing plant tissue into fragments. Its unique mandible structure exhibits excellent penetration and cutting efficiency when feeding on woody fibers and other plant tissues. If the spotted longhorn beetle's superior plant tissue penetration and cutting capabilities can be combined and rationally applied to the design of shredder blades, a new method for low-power, high-efficiency straw shredding could be provided. Summary of the Invention

[0005] To address the common problems of high cutting resistance, high power consumption, and low working efficiency in existing rice straw crushers, this invention proposes a biomimetic crusher blade based on the upper jaw of the longhorn beetle and its design method.

[0006] The present invention adopts the following technical solution:

[0007] A biomimetic crusher blade based on the upper jaw of the longhorn beetle, comprising a blade body, characterized in that the blade body includes a beveled edge and biomimetic teeth;

[0008] The blade bevel angle is inclined from both sides of the bottom surface of the tool towards the inside of the tool, so that the cross-section of the tool along the width direction is an isosceles trapezoid, and the two sides of the tool body form inclined surfaces with an inclination angle of 30-40°.

[0009] The contour curve of the biomimetic blade is the best fitting curve obtained by fitting the contour coordinates of the anterior third of the upper jaw of the longhorn beetle with a polynomial of degree three to eight, and the tooth height of the blade is 1.2-2 mm.

[0010] Furthermore, the cutter body is a crusher hammer, and the crusher hammer has two mounting through holes symmetrically distributed around the center point of the cutter.

[0011] Furthermore, the bionic cutting teeth are symmetrically distributed on the inclined surfaces at both ends of the cutting tool body and are evenly arranged according to a preset tooth spacing of 1.5-2.5 mm.

[0012] A design method for a biomimetic crusher blade based on the mandible of the longhorn beetle, characterized by the following steps:

[0013] Step 1: Based on the performance requirements of the cutting tool, the spotted longhorn beetle is selected as the biomimetic object. The image of the spotted longhorn beetle's upper jaw is obtained. After digital image processing of the image, the contour coordinates of the first third of the upper jaw of the spotted longhorn beetle are extracted. The extracted contour coordinates are fitted with polynomials of order 3 to 8. By comparing the smoothness and geometric feature fit of the polynomial fitting curves of each order, the best polynomial fitting curve is selected.

[0014] Step 2: Import the best polynomial fitting curve into the 3D modeling software environment, construct a complex curve using the spline curve function of the software, optimize the accuracy of the curve segment by adjusting the spline control points, reconstruct the obtained curve into a simulated tooth curve, and perform modeling operations in combination with the geometry of the crusher hammer to establish the geometric model of the bionic crusher blade.

[0015] Step 3: Based on the physical properties of rice straw, such as diameter, wall thickness, Poisson's ratio, density, and shear modulus, a discrete element model of rice straw is constructed. Combined with the geometric model of the biomimetic crusher blade determined in Step 2, a discrete element model of the blade is constructed. The boundary conditions, initial conditions, and material properties of the discrete element models of rice straw and blade are defined respectively. Through discrete element analysis, the contact process between the blade and rice straw is simulated, and the cutting process of the blade on the rice straw is simulated.

[0016] Step 4: Design a single-factor experiment. By setting different cutter parameters such as tooth height, blade angle, and tooth spacing, obtain the cutting resistance of the cutter on rice straw under different cutter parameters, analyze the influence of different cutter parameters on the cutting resistance, and determine the optimal value of the cutter parameters that minimizes the cutting resistance.

[0017] Furthermore, in step one, a high-precision microscopic image of the mandible of the longhorn beetle is acquired using a scanning electron microscope, and the digital image processing includes image binarization processing and mathematical morphology processing.

[0018] Furthermore, in step four, the single-factor experiment uses the tooth height, cutting edge angle, and tooth spacing as single-factor variables in a discrete element simulation experiment to analyze the influence of each variable on the cutting performance of the tool.

[0019] As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following beneficial effects:

[0020] The biomimetic crusher blade inspired by the mandible of the longhorn beetle, as studied in this invention, is a novel type of biomimetic crusher blade. By setting the blade angle to create an inclined surface, and machining biomimetic teeth on the inclined surfaces at both ends of the blade to form biomimetic teeth that mimic the mandible contour of the longhorn beetle at a preset tooth spacing, the blade achieves point contact during the straw cutting process, significantly reducing resistance during insertion. After insertion, the straw is torn and cut through a sliding cutting action, replacing the traditional hard cutting method, further reducing cutting resistance and equipment power consumption. Simultaneously, through discrete element simulation experiments, the blade parameters such as tooth height, blade angle, and tooth spacing are successively optimized to determine the optimal values, effectively reducing energy consumption in the process of crushing agricultural waste rice straw, and solving the technical problems of high energy consumption and poor tearing effect of existing crusher blades when cutting straw. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is an electron microscope image of the mandible of the longhorn beetle *Spodoptera litura*, the biomimetic object of this invention.

[0023] Figure 2 This is a three-dimensional structural diagram of the bionic cutting tool of the present invention.

[0024] Figure 3 This is a front view schematic diagram of the bionic cutting tool of the present invention, where h is the tooth height, p is the tooth spacing, and α is the cutting edge angle.

[0025] Figure 4 This is a schematic diagram of the biomimetic tool design method of the present invention.

[0026] In the diagram: 1 is the blade bevel angle, 2 is the biomimetic cutting tooth, 3 is the tooth spacing, and 4 is the through hole of the cutting tool. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to specific embodiments and the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0028] See Figures 2 to 3A biomimetic crusher blade based on the upper jaw of the longhorn beetle includes a blade body. The blade body is provided with a cutting bevel angle 1 and biomimetic teeth 2. The biomimetic teeth are evenly arranged on the inclined surfaces at both ends of the blade according to the tooth spacing 3. The blade body is provided with two through holes 4 symmetrically distributed with respect to the center point of the blade.

[0029] The biomimetic cutting tool has an inclination angle that slopes inward from both sides of the bottom surface, resulting in an isosceles trapezoidal cross-section along its width. The inclination angle is 30-40°, preferably 35°. The contour curve of the biomimetic cutting teeth is the optimal fitting curve obtained by fitting the contour coordinates of the anterior third of the upper jaw of the longhorn beetle using a third to eighth-order polynomial. The tooth height is 1.2-2 mm, preferably 1.5 mm. The biomimetic cutting teeth are distributed on the inclined surfaces at both ends of the tool, symmetrically distributed on both sides of the inclined surfaces, and evenly arranged at a preset tooth spacing of 1.5-2.5 mm, preferably 2 mm.

[0030] A biomimetic crusher blade based on the upper jaw of the longhorn beetle, wherein the blade body is a crusher hammer, and the design method steps are as follows:

[0031] Step 1: Based on the performance requirements of the cutting tool, the *Spodoptera litura* was selected as the biomimetic model. A high-precision microscopic image of the beetle's upper jaw was acquired using a Regulus 8220 scanning electron microscope. The acquired images of the beetle's upper jaw were preprocessed using binarization algorithms, erosion, dilation, opening, and closing operations in MATLAB. The outer contour points on the anterior third of the tooth profile curve of the *Spodoptera litura* upper jaw were extracted using GetData coordinate extraction software to obtain the outer contour data points. The obtained discrete coordinate points of the beetle's upper jaw were then imported into Origin plotting software, and polynomial fitting from cubic to octave was performed. By comparing the smoothness and geometric feature fit of the polynomial fitting curves of each order, a sixth-order polynomial fitting curve was selected, with a goodness of fit of R0. 2 =0.9878, the model achieves the optimal balance between geometric fidelity and numerical stability;

[0032] Step 2: Import the sixth-order polynomial fitting curve into the SolidWorks software environment, construct complex curves using the spline curve function, optimize the accuracy of the curve segments by adjusting the spline control points, reconstruct the simulation tooth profile curve and the geometry of the crusher hammer based on the obtained curve, and then perform solid modeling operations such as extrusion cutting to complete the establishment of the tool geometry model.

[0033] Step 3: The average diameter of the rice straw was measured to be 5 mm and the wall thickness to be 0.8 mm. Using EDEM discrete element simulation software, a discrete element simulation model of the rice straw was established. A large cylinder with dimensions of 70 mm × 10 mm was created in the EDEM using the coordinate positioning method. 5 mm, another small cylinder has dimensions of 70 mm × A 3.4 mm thick material, with its property set to "physics," is used to encapsulate and store particles. A discrete element model of the tool is constructed using a biomimetic tool geometry model. Boundary conditions, initial conditions, and material properties are defined for both the rice straw discrete element model and the tool discrete element model. The Poisson's ratio of the rice straw is set to 0.4, and the straw density to 196 kg / m³. 3 The shear modulus of straw is 1×10⁻⁶. 6 Pa, the normal stiffness per unit area of ​​straw is 5×10 9 N / m 3 The tangential stiffness per unit area of ​​straw is 5×10. 9 N / m 3 The critical normal stress of straw is 5×10 9 Pa, the critical tangential stress of straw is 5 × 10 9 Pa, the Poisson's ratio of the tool steel is 0.3, and the density of the tool steel is 7865 kg / m³. 3 The shear modulus of the tool steel is 7.9 × 10⁻⁶. 9 Pa. The simulation fixed time step is set to 5.72054 × 10⁻⁶. −7 s, the data target storage interval is 1×10 −5 When generating the simulation mesh, the minimum mesh size was set to 2.5 Rmin according to the software's recommended standard, the total duration was 0.02 s, 12 CPU solvers were set, and the contact between the cutter and the rice straw was simulated and the cutting process was simulated through discrete element analysis.

[0034] Step 4: Simulation experiments were conducted with tooth heights of 1, 2, 3, and 4 mm, cutting edge angles of 30°, 40°, 50°, and 60°, and tooth spacing of 1, 2, 3, and 4 mm. The effects of tooth height, cutting edge angle, and tooth spacing were investigated sequentially using a single-factor experimental method. Three sets of experiments were conducted to determine the optimal tooth height, cutting edge angle, and tooth spacing. In the second and third sets of experiments, the optimal tooth height value obtained from the first set was applied. In the third set of experiments, the optimal cutting edge angle value obtained from the second set was applied. Discrete element simulation was used to obtain the cutting resistance of the cutter cutting rice straw under different cutter parameters. The influence of different cutter parameters on the cutting resistance was analyzed to determine the optimal cutter parameter values ​​that minimized the cutting resistance: tooth height of 1.5 mm, cutting edge angle of 35°, and tooth spacing of 2 mm.

[0035] Based on the above optimization design, the geometry of the bionic cutting tool, as well as the height, bevel angle, and spacing of the cutting teeth, were determined. A prototype bionic cutting tool was fabricated using 65Mn steel as the material, and a comparative experiment was conducted on cutting three rice straws with the bionic cutting tool. The experimental results show that compared to a conventional crusher hammer, the peak resistance of the bionic cutting tool when cutting three rice straws was reduced by 46.62%, verifying that the bionic cutting tool has a significant drag reduction effect during rice straw cutting.

[0036] The above are merely specific embodiments of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial modifications made to the present invention using this concept shall be considered as infringing upon the protection scope of the present invention.

Claims

1. A biomimetic crusher blade based on the mandible of the longhorn beetle, comprising a blade body, characterized in that, The cutter body includes a beveled edge and biomimetic cutting teeth; The blade bevel angle is inclined from both sides of the bottom surface of the tool towards the inside of the tool, so that the cross-section of the tool along the width direction is an isosceles trapezoid, and the two sides of the tool body form inclined surfaces with an inclination angle of 30-40°. The contour curve of the biomimetic blade is the best fitting curve obtained by fitting the contour coordinates of the anterior third of the upper jaw of the longhorn beetle with a polynomial of degree three to eight, and the tooth height of the blade is 1.2-2 mm.

2. The biomimetic crusher blade based on the mandible of the longhorn beetle according to claim 1, characterized in that, The blade body is a crusher hammer, and the crusher hammer has two mounting through holes, which are symmetrically distributed around the center point of the blade.

3. The biomimetic crusher blade based on the mandible of the longhorn beetle according to claim 1, characterized in that, The bionic cutting teeth are symmetrically distributed on the inclined surfaces at both ends of the cutting tool body and are evenly arranged according to a preset tooth spacing of 1.5-2.5 mm.

4. A design method for a biomimetic crusher blade based on the upper jaw of the longhorn beetle, characterized in that, Includes the following steps: Step 1: Based on the performance requirements of the cutting tool, the spotted longhorn beetle is selected as the biomimetic object. The image of the spotted longhorn beetle's upper jaw is obtained. After digital image processing of the image, the contour coordinates of the first third of the upper jaw of the spotted longhorn beetle are extracted. The extracted contour coordinates are fitted with polynomials of order 3 to 8. By comparing the smoothness and geometric feature fit of the polynomial fitting curves of each order, the best polynomial fitting curve is selected. Step 2: Import the best polynomial fitting curve into the 3D modeling software environment, construct a complex curve using the spline curve function of the software, optimize the accuracy of the curve segment by adjusting the spline control points, reconstruct the obtained curve into a simulated tooth curve, and perform modeling operations in combination with the geometry of the crusher hammer to establish the geometric model of the bionic crusher blade. Step 3: Based on the physical properties of rice straw, such as diameter, wall thickness, Poisson's ratio, density, and shear modulus, a discrete element model of rice straw is constructed. Combined with the geometric model of the biomimetic crusher blade determined in Step 2, a discrete element model of the blade is constructed. The boundary conditions, initial conditions, and material properties of the discrete element models of rice straw and blade are defined respectively. Through discrete element analysis, the contact process between the blade and rice straw is simulated, and the cutting process of the blade on the rice straw is simulated. Step 4: Design a single-factor experiment. By setting different cutter parameters such as tooth height, blade angle, and tooth spacing, obtain the cutting resistance of the cutter on rice straw under different cutter parameters, analyze the influence of different cutter parameters on the cutting resistance, and determine the optimal value of the cutter parameters that minimizes the cutting resistance.

5. The design method of a biomimetic crusher blade based on the upper jaw of the longhorn beetle according to claim 4, characterized in that: In step one, a high-precision microscopic image of the mandible of the longhorn beetle is acquired using a scanning electron microscope. The digital image processing includes image binarization and mathematical morphology processing.

6. The design method of a biomimetic crusher blade based on the upper jaw of the longhorn beetle according to claim 4, characterized in that: In step four, the single-factor experiment uses the tooth height, cutting edge angle, and tooth spacing as single-factor variables in a discrete element simulation experiment to analyze the influence of each variable on the cutting performance of the tool.

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