| Abrasive wear of soil on engaging components of agricultural machinery can result in decreased service life and diminished performance.Furthermore,soil adhesion to these components can directly lead to reduced production efficiency,compromised work quality,and increased production consumption.The objective of this study was to evaluate the efficacy of the Bouligand-type structure in mitigating wear and soil adhesion.This study focused on the Bouligand-type structure,employing the principles of bionics engineering.By examining the non-smooth surface and the internal spiral laminated Bouligand-type structure,this investigation sought to optimize its geometrical parameters.Wear and adhesion tests were conducted,and the results were analyzed through simulation techniques.The research was conducted from the following perspectives:（1）Bouligand-type structures,commonly found in the exoskeletons of animals such as Procambarus clarkii,were examined.Geometrical model development was achieved using the 3D software UG,with reference to the principles of convergent evolution.A macro-scale Bouligand-type structural model specimen was designed and incorporated into the structural design of the soil-engaging component.（2）The adhesive properties of the bionic Bouligand-type specimens were analyzed.The optimal combination of parameters was obtained using a universal tensile testing machine in conjunction with a central composite test.The minimum adhesion force for the bionic Bouligand structure was achieved when the diameter of the structural unit was 3.5 mm,the helical angle between layers was 33°,and the overlap distance between layers was 0.06 mm.The maximum adhesion force for the smooth specimens was 13.23N,for the ribbed specimens it was 9.56 N,and for the Bouligand specimens it was 8.63N.The simulation test demonstrated that the adhesion force trend during the three stages of the sample desorption process was consistent with the actual test results.The maximum adhesion force for the smooth specimens was 12.61 N,for the ribbed specimens it was 8.76 N,and for the Bouligand specimens it was 7.36 N.The discrepancy between the adhesion force of the simulation test and the actual test ranged from 4.69%to 14.72%,which falls within the acceptable margin of error for engineering applications.（3）An analysis of the wear resistance properties of bionic Bouligand-type samples were conducted.Wear samples were designed to determine the geometrical composition parameters corresponding to the smallest wear volume through a central composite test.Specifically,the diameter of the structural unit was 1.03 mm,the spiral angle between layers was 16.48°,and the overlapping distance between layers was 0.13 mm.Abrasion tests were performed using an abrasive wear tester.Results indicated that the bionic Bouligand structure exhibited greater wear resistance than both the ribbed and smooth structures.Scanning electron microscopy（SEM）was employed to observe the wear morphology on the specimen surface after wear.The Bouligand-type surface displayed a fish-scale pattern with a minimal presence of white abrasive particles and shallow wear marks.In the simulation comparison test,the wear values were 2.73×10-5 g for the smooth sample,2.26×10-5 g for the ribbed sample,and 2.13×10-6 g for the Bouligand-type sample,respectively.Comparing the surface accumulative contact energy with the surface accumulative contact force of the three specimens,it was observed that the surface energy of the Bouligand-type structure was significantly reduced,contributing to a decrease in wear volume.The internal stress-strain of the three samples was analyzed using a DEM-FEM coupling simulation.The Bouligand-type specimens exhibited not only a greater amount of deformation but also a higher value of equivalent stress.This finding suggests that the non-smooth structures on the surface are responsible for reducing the number of impacts by the particle flow,while the internal spiral structures play a role in absorbing the impingement forces and diminishing the wear volume of the samples.（4）Field experiments demonstrated that when the working speed increased from 3km/h to 5 km/h,in comparison with the conventional rolling soil-engaging components,the resistance and adhesion of the rolling component of ribbed structure decreased by8.66%to 10.27%and 17.69%to 20.17%,respectively.The resistance and adhesion of that with the bionic Bouligand-type structure were reduced by 12.82%to 13.23%and26.56%to 27.88%,respectively.When the soil moisture content increased from 20%to40%,in comparison with the conventional rolling component,the traction resistance and adhesion of the rolling components of ribbed structure decreased by 8.53%to 10.27%and 16.54%to 20.28%,respectively.The traction resistance and adhesion of the bionic Bouligand-type rolling soil-engaging components were reduced by 12.79%to 13.53%and 23.00%to 29.30%,respectively.The above research provides new bionic methods for the soil adhesion and abrasive wear of the agricultural machinery soil-touching components,which provides theoretical basis and technical basis for improving the service life,operating efficiency and quality of agricultural machinery soil-touching work components. |
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