Soil-engaging Components Research Articles

Imitating pangolin scale structure for reducing adhesion and resistance of rotary tillage in wet-adhesive soil

The bionic design of soil-engaging components has recently received much attention in conservation tillage and is extremely important for reducing tillage resistance and increasing implement passability in wet-adhesive rice paddy soil. In this paper, to reduce adhesion and resistance of rotary tillage in wet-adhesive soil, a novel imitating pangolin scale structure is first proposed, and the bionic non-smooth surface parameters affecting the soil adhesion effect is clarified. Afterwards, based on the JKR attached Bonding contact model, an accurate discrete element interaction model of the designed rotary tillage blade -wet adhesive soil is established, and the effect of spindle speed, bump size and bump distance on the tillage resistance and soil disturbance is analyzed using the proposed model. Finally, the proposed imitating pangolin scale structure is optimized to improve the anti-adhesive and drag reduction properties using response surface method, furthermore, the corresponding model validation experiments and field tests are also conducted. Results reveal that the relative errors between the simulated and experimental values of the bionic blade rotary torque and soil adhesion mass are only respectively 4.4 % and 8.3 %. In addition, the optimal parameter combinations of anti-adhesion and drag reduction are also determined: the spindle speed is 180 rpm, the bump width is 10.6 mm and the bump distance is 17.9 mm, respectively, at the time, the effect of soil breaking of the designed blade is reduced by 9.95 % compared to that of the traditional blades but the effect of anti-adhesion and drag reduction is improved by 18.81 %.

Research on a Novel Heat Treatment Process for Boron Steel Used for Soil-Engaging Components of Tillage Machinery

To address the issue of high fracture and wear failure rates caused by the lack of toughness and abrasion resistance in the steel used for soil-engaging components of tillage machinery, a novel composite heat treatment process, “normalizing and intercritical quenching and tempering (NIQT)”, is proposed. By regulating the austenitizing heating temperature in the intercritical area (ferrite/austenite two-phase area), the type, content, and distribution of phases in the 27MnCrB5 test sample could be precisely controlled, which further influenced the mechanical properties of the material. The results demonstrated that a multiphase composite microstructure, predominantly consisting of martensite and ferrite, could be obtained in the 27MnCrB5 steel treated by the NIQT process. The results of an EBSD test indicated that the predominant type of grain boundary following the NIQT heat treatment was a high-angle grain boundary (approximately 59.5%), which was favorable for hindering crack propagation and improving the impact toughness of the material. The results of the mechanical tests revealed that, when the quenching temperature was set to 790 °C, the 27MnCrB5 steel attained excellent comprehensive mechanical properties, with a tensile strength of 1654 MPa, elongation of 10.4%, impact energy of 77 J, and hardness of 530 HV30. Compared with conventional heat treatment processes for soil-engaging components, this novel process has the potential to enhance the performance of soil-engaging components and prolong their service life.

Improved Design and Simulation of an Integrated Ridge-Breaking Earth Cultivator for Ratoon Sugarcane Fields

Ridge-breaking earth cultivation is a new agronomic technology that simplifies and efficiently cultivates ratoon sugarcane. However, traditional cultivators cannot adapt to the distribution of residual stumps, inter-row specifications, and hardened clay soil. This results in substandard soil fragmentation, poor ridge quality, and reduced operational reliability. To address these issues, this article proposes an integrated earth cultivator structure capable of breaking ridges, loosening soil, and raising ridges simultaneously. It is designed to enhance the breaking of tillage layers and the filling of ridges through the coordinated action of multiple soil-engaging components. The effects of pre-loosening by the ridge-breaking plow, high-energy crushing, and throwing by the spirally arranged dense rotary blade group, and soil gathering by the deflector are comprehensively utilized. Additionally, lateral pushing by the ridging plough is employed. Discrete element and finite element simulation results show that densely toothed blades can improve soil supply capacity and structural reliability. This is achieved by increasing the amount of soil throwback and reducing concentrated stress levels. Soil fragmentation rate (SFR) and ridge height (RH) were further used as indicators. Field experiments were conducted to study the effects of operating parameters on breaking and ridging performance. The optimal parameter solution was determined as a forward speed of 0.85 m·s−1 and rotary speed of 289.7 r·min−1. With this adaptive configuration, SFR and RH were improved by 12.4% and 38.5%, respectively, compared with conventional earth cultivators. Additionally, the RSM value of rotary tillage power (Pr) was reduced by 39.6%. Improvements in crushing hardened fields, constructing ridges, and reducing cutting energy consumption have proven effective. This study can provide a reference for the development of earth cultivators based on new agronomy and specific field characteristics.

Biomimetic Design of Soil-Engaging Components: A Review.

Soil-engaging components play a critical role in agricultural production and engineering construction. However, the soil-engaging components directly interacting with the soil often suffer from the problems of high resistance, adhesion, and wear, which significantly reduce the efficiency and quality of soil operations. A large number of featured studies on the design of soil-engaging components have been carried out while applying the principles of bionics extensively, and significant research results have been achieved. This review conducts a comprehensive literature survey on the application of biomimetics in the design of soil-engaging components. The focus is on performance optimization in regard to the following three aspects: draught reduction, anti-adhesion, and wear resistance. The mechanisms of various biomimetic soil-engaging components are systematically explained. Based on the literature analysis and biomimetic research, future trends in the development of biomimetic soil-engaging components are discussed from both the mechanism and application perspectives. This research is expected to provide new insights and inspiration for addressing related scientific and engineering challenges.

Parameter calibration of discrete element simulation for the interaction between heavy soil and soil-engaging components in shellfish culture

Shellfish culture heavy soils are suitable for the cultivation of marine organisms and are essential for the development of marine fisheries. To study both the interaction between heavy soil particles and that between the soil and soil-engaging components of agricultural machinery in shellfish culture, the simulation parameters in the model were determined. To study the interaction between soil particles in the viscous soil of shellfish culture with moisture content of 26.51% ± 1%. Discrete element method is used to establish the accumulation simulation experiment; the contact parameters between soil particles were calibrated. The response surface optimization technique was used to create the accumulation angle regression model. To study the interaction between the soil and soil-engaging components, the static friction coefficient between the heavy soil and soil-engaging components was determined by static friction experiment. The contact parameters between the soil and soil-engaging components were calibrated by the slope simulation experiment; the rolling distance regression model was established by response surface optimization methodology. The findings demonstrate that the optimized soil model can simulate the actual soil, and reflect the interaction between the heavy soil particles, soil, and the soil-engaging components of agricultural machinery, which not only provides a theoretical basis for the design and optimization of soil-engaging components of agricultural machinery in heavy soil, but also provides a new way for the research and development of agricultural machinery in a complex environment.

Vibration Response of Soil under Low-Frequency Vibration Using the Discrete Element Method

The vibration response of soil is a key property in the field of agricultural soil tillage. Vibration components of tillage machinery are generally used to reduce tillage resistance and improve work efficiency, and the pressure variation under low-frequency vibration will affect the fragmentation and dispersion of farmland soil. However, the gradient of pressure variation, frequency domain response, and effective transmission range is unclear. A new method based on the DEM (discrete element method) is presented to study the vibration response and pressure transmission under low-frequency vibration. Bench test results have shown that peak pressure positively correlates with the vibration frequency and attenuates rapidly at a vibration distance of 100 to 250 mm. The resulting data were also selected to determine the simulation model’s parameters. Amplitude, vibration frequency, and soil depth were used as test factors in single-factor simulation tests, and their effects on the peak pressure, frequency domain response, and effective transmission distance were analyzed. The results showed a positive relationship between the peak pressure and the test factors. The peak pressure increased with a maximum gradient of 19.02 kPa/mm at a vibration distance of 50 mm. The amplitude, vibration frequency, and soil depth positively correlated with the dominant frequency amplitude. The main frequency was independent of amplitude and soil depth. At a vibration distance of 250 mm, the dominant frequency was approximately twice the vibration frequency at 7–11 Hz and approximately equal to the vibration frequency at 13–15 Hz. Multiple exponential functions were used to fit the peak pressure attenuation function, obtaining an effective transmission distance range of 347.15 to 550.37 mm for the 5 kPa cut-off pressure. For a soil depth of 300 mm, the vertical shear wave diffusion angle was greater than the horizontal shear wave diffusion angle. This study clarifies the vibration response of soil under low-frequency vibration, which helps to design vibration-type, soil-engaging components of tillage machinery and match vibration parameters for energy-saving and resistance reduction purposes in soil tillage.

Research on the Resistance Reduction Law of Self-Excited a Resonant Circular Arc-Surface Bulldozing Plate Based on the Discrete Element Method

We explore the mechanism and law of reducing the resistance of soil cutting tools by achieving the self-excited vibration mode through the modification of the soil-engaging surface spectrum. Around the fundamental resonance point of the soil, and superimposing geometric waveforms of different spatial frequencies and amplitudes on the basis of the circular arc surface base directrix, 18 bulldozing plate models with different soil-engaging surface spectrum structures were designed and manufactured. By conducting a discrete element method (DEM) simulation of the working process of the bulldozing plate and comparing the working resistance of the soil-engaging components with the results of the soil bin test, the microscopic process of soil disturbance was further revealed from the perspective of simulation. The results indicate that the self-excited vibrating circular arc-surface bulldozing plate could effectively improve the resistance reduction effect during the operation around the resonance point. With this model, the average error of the horizontal working resistance was 7.52%, and the average error of the vertical working resistance was 21.71%. The analysis of the soil microscopic disturbance process by DEM simulation further verified the correctness of the macroscopic test results. The research work has an important reference value for both the vibration resistance reduction design of soil cutting tools and resistance reduction design of soil-engaging surfaces’ geometric structure modification.

Research on drag reduction performance of sliding plate of rice direct seeding machine based on non-smooth structure of loach surface

Sliding plate has the problems of large sliding resistance and serious soil adhesion. Loach moves freely and flexibly in mud, has highly efficient lubrication and drag reduction effects. The sliding plate of rice direct seeding machine was selected as the research object and loach as the bionic prototype. The macroscopic and microscopic structure characteristics of loach were observed, the body surface of loach was covered by scales, which had a ridged non-smooth structure. The simulation analysis of the drag reduction performance of the non-smooth structure was carried out, the maximum drag reduction rate was 2.55% at the speed of 1 m/s. A bionic sliding plate of rice direct-seeding machine was constructed based on the non-smooth structure of loach body surface, and its working performance was simulated and analyzed. The results of orthogonal test show that the order of primary and secondary factors of bionic structure parameters affecting drag reduction rate was ribbed spacing > ribbed width > ribbed height. The optimal parameter combination was ribbing height 4 mm, ribbing width 4.5 mm, ribbing spacing, and the optimal drag reduction rate was 4.21%. The results of this study can provide theoretical support for bionic design of soil-engaging components in wet and soft paddy field.

Optimal Design of and Experiment on a Dual-Spiral Ditcher for Orchards

This study aimed to design a counter-rotating dual-axis spiral ditcher to address the problems of the lack of ditching models, low ditching quality, and high power consumption in ditching operations in hilly and mountainous orchards. By establishing a discrete element simulation model of the interaction between the dual-spiral cutter and the soil, we analyzed the effects of different operating parameters on the ditching performance and power consumption to explore the mechanism of the interaction between the soil-engaging components and the soil; meanwhile, according to the simulation data, we took the forward speed, cutter speed, and ditching depth as the experimental influencing factors, and we took the ditching qualification rate and power consumption as the experimental indicators. Then, through a three-factor and three-level orthogonal experimental analysis, we obtained the optimal parameter combination. Based on the optimized simulation results, a prototype ditcher was fabricated, and the results of a soil trough test showed that the ditcher had a stable ditching performance, an average ditching qualification rate of 91.4%, an average soil crushing rate of 72%, and a ditching adjustment structure that could adjust the ditching depth and width within the ranges of 15–25 cm and 10–20 cm, respectively. The optimized ditcher had high efficiency, stability, and energy savings during its operation, and it was able to meet the agronomic requirements for ditching operations. This study provides a design basis and technical support for dual-spiral trial ditching operations.

A bionic profiling-energy storage device based on MBD-DEM coupled simulation optimization reducing the energy consumption of deep loosening

A novel bionic profiling energy storage device was designed in this research to reduce the energy consumption of deep loosening operations. As the core technology of conservation tillage, deep loosening has always been difficult to promote on a large scale in the Phaeozem region of Northeast China due to its high energy consumption. The deep loosening mechanism is mainly composed of deep loosening shovel and energy-storage profiling device. At present, optimizing the structure of deep loosening shovel to reduce consumption was the main research method in this field, but it is still difficult to meet the production demand. At the same time, energy storage-profiling device has been neglected by researchers for a long time because of the lack of suitable mechanism innovation ideas and efficient experiment optimization methods. Based on the excellent soil excavation capability of the hare, the bionic energy storage-profiling device (BSPD) was innovatively designed by drawing the unique mechanism of its fore-upper limb, and the MBD-DEM coupled simulation technology was proposed as the experimental optimization method. It was found that BSPD has significant advantages in flexible profiling, tillage depth control, elastic energy storage and deep loosening resistance reduction capabilities compared with traditional self-excited energy storage-profiling devices (SSPD) by the analysis methods of least significant difference (LSD), Regression Analysis and Redundancy analysis (RDA), based on the results of MBD-DEM coupled simulation experiments. In addition, it was found that the torsional elastic coefficient, as the core design parameter of BSPD, also had a significant impact on the above four capabilities, and its optimal value was obtained by the established torsional elastic coefficient-deep loosening energy consumption regression model. The field experiment results showed that the deep loosening energy consumption of BSPD was 16.2% lower than that of SSPD and filed experiment results also verified the accuracy of MBD-DEM coupled simulation results. In summary, this study found a more effective new research path in addition to the traditional deep loosening consumption reduction research methods, and provided mechanism innovation design ideas and experimental optimization methods for the research and development of agricultural soil-engaging components.

The Method and Experiment of Kinetic Determination for the Rotary Soil-Engaging Components of Agricultural Machinery Using a Compacting Device in a Paddy Field as an Example

In order to explore the influence of soil force on rotary soil-engaging components during their operation, a kinetic parameter measurement system of rotary soil-engaging components was developed via the sensor strain measurement technique. By taking a single-sided compacting ridge device as an example, the kinetic experiment was carried out on the operation parameters of the compacting device and obtained the variation law of the force of the soil on the pinnae. ADAMS software was used to simulate the operation of the compacting device under different experimental factors (soil moisture content, forward speed of the ridge device, and the rotation speed of the compacting device), and the test data were obtained; the experiment was carried out with the forward speed of the soil tanker and the rotation speed of the compacting device as the experimental factors, and the average of the force of soil on the pinnae and the firmness value of the ridge were the experimental indicators. The results showed that under a moisture content of 27%, the forward speed of the device was 0.8 km∙h−1, the maximum firmness of the ridge was 1233.21 kPa, the minimum firmness of the ridge was 953.85 kPa, and the coefficient of variation of the stability of the firmness value of the ridge was 8.04; the force of the pinnae on the soil increased with an increase in the forward speed of the soil tanker, and the variation range of the force was 2838.1–5695.2 N. It was verified that the design of this operation parameter measurement system for rotary soil-engaging components meets the practical requirements and also provides an important reference for the measurement of the relevant parameters of similar rotary soil-engaging components.

Bionic Design of Liquid Fertilizer Deep Application Spray Needle, Based on Badger Claw-Toe, for Improving the Operating Performance of Liquid Fertilizer Deep Application in Northeast China

Deep application of liquid fertilizer is a technique that applies liquid fertilizer deep near the root system of crops, which has many advantages such as high fertilizer utilization rate and low environmental pollution. However, high power and high specific energy consumption caused by soil-engaging components in liquid fertilizer deep application make it difficult to popularize in northeast China. The claw-toe structure of burrowing animals has the characteristics of low resistance and low friction, which has been the focus of many scholars’ research on soil-engaging components. The claw-toe structure of the badger, a widely distributed burrowing animal in northeast China, has good characteristics of low power and low specific energy consumption. Therefore, in this research, a bionic liquid fertilizer deep application spray needle was designed, based on the claw-toe structure of the badger, to improve the operating performance of liquid fertilizer deep application. In this research, the discrete element method (DEM) was used for a computer simulation test, and the indoor soil bin verification test was carried out. The results showed that the operating angle, operating speed and fertilization depth of bionic liquid fertilizer deep application spray needle had significant effects on the power and specific energy consumption, and the optimal operating performance combination of bionic liquid fertilizer deep application spray needle was obtained as follows: The fertilization depth is 60 mm; the operating speed is 6 km h−1; the operating angle is 24.8°; the power consumption is 0.066 kW; and the specific energy consumption is 4.257 kJ m−3 under this operating condition. Through the comparison of operating performance, the operating performance of the bionic liquid fertilizer deep application spray needle is significantly better than that of other types of liquid fertilizer deep application furrow opener, with the power reduced by 9.52~40.5% and the specific energy consumption reduced by 93.9~208.6%. This research clarified the internal mechanism affecting the operating performance. Finally, based on the above findings, this research suggests that more attention should be paid to finding suitable bionic prototype and design scheme in the future design and research of soil-engaging components of liquid fertilizer deep application.

Simulation of soil-tool interaction using smoothed particle hydrodynamics (SPH)

Numerical techniques in soil-tool interaction play a critical role in the applications of optimal design and optimal control of soil-engaging components. However, one of the greatest challenges in the simulation of soil-tool interaction is the complex dynamic behaviors of the soil in the regime of large deformations, and the analysis and evaluation of forces at the soil-tool interface. Recently smoothed particle hydrodynamics (SPH) has shown its advantages in modeling large deformation problems with deformable boundaries and moving interfaces. In this paper, an SPH model of soil-tool interaction based on the elastoplastic constitutive is established. Firstly, the cutting process and soil-tool interaction for both non-cohesive and cohesive soil are simulated based on a shear failure model and a contact algorithm. The simulation results for non-cohesive soil and cohesive soil in different operating conditions are discussed separately, and the results for different operating conditions are compared. In addition, interactions between soil and inclined short flat blades are also simulated to estimate the cutting force during the tillage process. The predicted soil configuration and cutting force are in good agreement with our experiments and with the results in published literature. The cutting forces for non-cohesive soil exhibit similar trends and average values throughout the process. For cohesive soil, the cutting force curve has a wavy trend and the average value in a stable state is greater than for non-cohesive soil. In order to further validate the feasibility and precision of the presented model, different tillage conditions (cutting angles and depths), internal friction angles for non-cohesive soil, different cohesion for cohesive soil, and different friction coefficient of the cutting blade are all discussed. This work has demonstrated that the proposed model is accurate in soil-tool interaction simulations and can also provide an accurate description of the shear fragmentation of cohesive soil. It helps to contribute to a better understanding of the tillage process that is fundamental and essential for the optimal design of the soil-engaging components.

Calibration and Verification Test of Cinnamon Soil Simulation Parameters Based on Discrete Element Method

To obtain the discrete element simulation model parameters suitable for the interaction between cinnamon soil and soil-engaging components, the Hertz–Mindlin with JKR contact model in EDEM simulation software was used to calibrate the relevant model parameters of cinnamon soil. Firstly, the particle size distribution, moisture content, volume density, Poisson’ s ratio, shear modulus, and other parameters of the cinnamon soil were measured with cinnamon soil as the research object. Further, taking the stacking angle as the response value, the Plackett–Burman test, the steepest climbing test, and the Box–Behnken were designed by using the Design-Expert software to calibrate and optimize the physical parameters of soil simulation. The optimal parameter combination was obtained: cinnamon soil–cinnamon soil rolling friction coefficient was 0.08, soil JKR surface energy was 0.37 J/m−2, and cinnamon soil–steel static friction coefficient was 0.64. Finally, the discrete element simulation verification test of stacking angle and cutting resistance was carried out under the calibrated parameters. The comparative calculation showed that the relative error between the simulated stacking angle and the measured stacking angle was 0.253%, and the maximum relative error between the simulated cutting resistance and the measured cutting resistance was 10.32%, which was within the acceptable range, indicating the high accuracy and reliability for the calibration parameters. The research results have important reference value for the energy-saving and consumption-reducing design of soil tillage components and provide basic data for the simulation of cutting resistance research of cinnamon-soil-engaging components.

Study on Plant Crushing and Soil Throwing Performance of Bionic Rotary Blades in Cyperus esculentus Harvesting

Soil blocking and plant entanglement are the main challenges in Cyperus esculentus harvesting and excavating. The structure of the rotary blade is one of the critical factors affecting plant crushing and soil throwing performance. Inspired by the composite motion of longitudinal soil cutting and lateral soil throwing of the oriental mole cricket, a bionic rotary blade was designed with the contour curve of the excavation edge and excavation surface of its forefoot claw toe. The bionic rotary blade’s mechanical and kinematic analysis revealed its cutting mechanism. A flexible plant soil, bionic, rotary blade discrete element model was developed to simulate the Cyperus esculentus digging process. The optimal excavation edge and excavation surface were selected by a single factor experiment, and the optimal operating parameters of the bionic rotary blade were obtained by quadratic regression orthogonal rotational combination design. The results showed that the bionic rotary blade, based on the excavation edge and excavation surface of mole cricket first claw toe, had the longest throwing distance and the largest number of broken bonds. The best combination of operating parameters of the bionic rotary blade was 11.16 mm for blade spacing, 0.66 m/s for forward speed, and 300 rpm for shaft speed. The field experiment was carried out according to the best parameters. The results showed that the bionic rotary blade’s average soil throwing distance and plant crushing rate were 632.30 mm and 81.55%, respectively; thereby, not only meeting the requirements of Cyperus esculentus harvesting, but proving superior to the operation performance of the Chinese standard rotary blade IT245 and rotary blade with optimized cutting edge (IT245P). The results of this study can provide bionic design ideas and methods for the design of soil-cutting-based tillage machinery’s soil-engaging components, such as the rotary blade and returning blade.

Bioinspired Imbricated Microthorn Scale Surfaces and their Abrasive Wear Performance

HighlightsImproving the wear resistance of soil-engaging components is an urgent need for the agricultural machinery industry.Sandfish (Scincus scincus) epidermis with exceptional wear resistance was selected as a bionic prototype.By adopting a bionic engineering approach, a novel bioinspired microthorn scale surface was designed and prepared.Numerical simulations were performed with EDEM to investigate the wear resistance mechanism.Abstract. To solve the problem of abrasive wear failure of the soil-engaging components of agricultural machinery, the imbricated microthorn scale structure of the sandfish (Scincus scincus) epidermis surface was selected as a bionic prototype. By adopting a bionic engineering approach, nine bionic microthorn scale surface specimens with different geometric structure parameters were designed and prepared. Wear resistance tests were performed in a rotating abrasive wear testing system. The results of the wear tests showed that the imbricated microthorn scale structured surfaces had substantially less abrasion loss than a conventional smooth surface. The influence of the geometric structure parameters on the wear performance was also identified. Numerical simulations were performed to explore the wear resistance mechanism of the imbricated microthorn scale structured surfaces. The abrasion of the bionic surfaces mainly occurred at the edge of the microthorn that faced the abrasive particle flow. The trajectory of subsequent abrasive particle flow was modified by the large dispersion of particle flow; hence, the number of particles that impacted the surface decreased. Therefore, the wear resistance performance of the bionic surfaces was enhanced. This bioinspired surface can provide a technical reference to mitigate the abrasive wear failure of the soil-engaging components of agricultural machinery. Keywords: Abrasive wear, Archard wear, Bionic design, Discrete element method, Scale surface.

Effects of vibration parameters on the interfacial adhesion system between soil and metal surface

In actual preparation of arable lands, the soil easily adheres to soil-engaging components of tillage machinery and affects the plowing efficiency and quality, thus leading to low traction efficiency and high power consumption. It has been proposed that vibration can effectively reduce the adhesion of soils to the soil-engaging components in field operation. Here, in order to explore the vibration response characteristics of soils and the mechanism for soil detachment under sine wave vibration, a vibration detachment measurement system of soils was assembled with an acceleration sensor, an electric vibration generator, a power amplifier and a data acquisition system. The measurement system was then used to study the effects of three vibration characteristic parameters (amplitude, frequency and time) on the interfacial adhesion system between soil and metal surface (ASSM) in both tangential and normal directions. Taking the soil detachment rate as a representative characteristic of ASSM, the effect of each factor was analyzed through single-factor experiments. The optimal interval of each vibration parameter was determined based on the experiment results. According to the orthogonal experimental design and analysis, we established a mathematical model for the relationship between the vibration soil detachment rate and the vibration parameters, as well as identified their primary and secondary order and interaction effect on the soil detachment rate. As determined by response surface analysis, the optimal combination of parameters for soil detachment rate in the tangential direction is vibration amplitude of 7.99 g, vibration frequency of 42.87 Hz and vibration time of 26.03 s, and that in the normal direction is vibration amplitude of 9.00 g, vibration frequency of 59.76 Hz and vibration time of 88.20 s. The relative errors of the optimization results are 1.05% and 2.65%, respectively, which are generally consistent with the prediction results of regression equation. These results indicate that the mathematical model can be used to predict and evaluate soil adhesion under vibration. Therefore, the soil detachment performance of ASSM can be enhanced by a reasonable setting of vibration parameters, which may be of great significance for improving the working quality and efficiency of tillage machinery.

Reduction of Friction and Soil Adhesion of Medium Carbon Steel via Hard Coating and Surface Texture

Rapid development of mechanical cultivation demands satisfactory wear performance and lower soil adhesion on the soil-engaging components of terrain machinery. A thick 2Cr13 hard coating was used in conjunction with surface textures in this sector. The results showed that 2Cr13 coating and surface texture decreased the friction coefficient and wear rate enormously. The surface wettability of the coating was reduced by a dimpled-surface texture. The adhesion test suggested that dimples greatly decreased the adhesion force by decreasing the friction component and the decrement increased with the increase of dimple size. The adhesion force increased with the soil moisture and then decreased when exceeding the moisture content threshold.

Analysis of the Wear-Resistance Characteristics of Bionic Ridge Structures

HighlightsBionic technology can be applied to resolve agricultural engineering problems.Pangolin Squama and Chlamys Farreri shells possess excellent wear-resistance.Bionic ridges can improve sample wear-resistance.Abstract. Consistent soil contact rapidly wears the soil-engaging components of agricultural machinery, such as ploughs and subsoilers. A bionic method was applied to their structural design to improve component wear resistance. Some animal organs possess excellent wear-resistant structures which can provide design inspiration for improving the wear-resistance of agricultural mechanical parts. Previous research found that many ridges exist on Pangolin squama and Chlamys Farreri shell surfaces. Those ridges cause Pangolin squama and Chlamys Farreri shells to exhibit excellent wear-resistance. Therefore, these ridge structures were applied to the design of experimental subsoiler samples (bionic samples) to enhance their wear-resistance. An abrasive wear tester was utilized to conduct abrasive wear experiments under special experimental conditions. These experimental conditions involved sliding speed, soil particle size, moisture content, and space between the ridges. Finally, nine experiments were conducted that subjected the bionic and flat surface samples to different experimental conditions, and their respective mass-loss quantities were measured. Results show that bionic sample mass loss was less than that of the flat surface samples under the same experimental conditions; bionic sample wear-resistance improved by 77%, 73.8%, 66.9%, 45.4%, 58.9%, 65.5%, 33.1%, 66.4%, and 42.6% when compared with flat surface samples under the same experimental conditions. Orthogonal test results reveal that the soil particle size most significantly affected sample wear-resistance, followed by the space between bionic ridges and the sliding speed. One reason that bionic samples exhibited excellent wear-resistance is that the soil particles underwent a “guiding effect” and a “rolling effect” over the bionic ridge surface, thereby reducing the “micro-plowing” that soil particles generated when moving over the contact surface. Mutual interference among soil particles also reduced wear. Part of the soil particles rushing over the bionic sample surface rebounded back; the rebounded soil particles collided with incoming soil particles, then the speed and kinetic energy of all of the particles decreased and sample surface abrasion declined. Moreover, “vortexes” generated by sample surface air and ridges lead to an “air cushion” effect which can lessen the number of sample surface soil particles, and bionic ridge sample abrasions can be significantly reduced. Abrasion experiment results analysis indicates that bionic ridges distributed on subsoiler sample surfaces can significantly improve wear-resistance. The bionic design method provides a new approach for increasing the wear-resistance of the soil-engaging components of agricultural machinery. Keywords: Abrasive wear, Bionic ridge, Optimal design, Wear-resistance.

Research on the drag reduction mechanism of antlion (Myrmeleon sagax) larvae nonsmooth structural surface.

Antlion (Myrmeleon sagax) larvae live in sandy soil and possess the ability to enter soil quickly. In this article, the hierarchical structure of the nonsmooth surface of antlion larvae was obtained using a scanning electron microscope (SEM). Based on the results, a bionic nonsmooth structure model was established to investigate the friction and movement of soil particles above it. Then the relationship between drag reduction characteristics and the antlion larvae's nonsmooth structural surface was discussed, which would be helpful to design soil-engaging components. When the height of each nonsmooth structure is proportional to the square of their interval distance, and is proportional to the velocity of movement, it is shown that a nonsmooth structural surface contributes to improving the bulk coefficient of granular materials, which leads to substantial drag reduction.