Design and experiments of the Bouligand structure inspired bionic wear resistant soil-engaging component for the agricultural machinery

The impact of soil particles on the soil-engaging components can lead to wear and tear, even in the failure of agricultural machinery systems. The bionic Bouligand-type (twisted plywood) arrangement structure can be expected to provide new strategies in this case. This study aims to explore the wear-resistance performance of the bioinspired Bouligand structure for the soil-engaging components. A series of computational simulation experiments were also carried out on the abrasive wear using the EDEM platform. Three parameters of the geometric feature were first selected as the experimental independent variables, including the beam diameter, twist angle, and overlap distance of the Bouligand-type structure. By contrast, the abrasion loss was used as the response value. Multivariate quadratic polynomial regression models were then established for the optimization. The geometric feature parameters of the Bouligand-type structure were also optimized, according to the relationship between the independent variable and the response value. The optimization results showed that the favorable wear-resistance performance was achieved under the optimal combination of geometrical feature parameters, with a beam diameter of 1.0 mm, a twist angle of 16°, and an overlap distance of 0.13 mm. With the optimal parameters, the wear-resisting properties of the Bouligand-type structure were compared with the conventional solid ribbed surface and smooth surface. The computational results show that the abrasion losses were 2.13×10-6 g for the Bouligand-type structured surface, 2.26×10-5 g for the conventional ribbed surface, and 2.73×10-5 g for the conventional smooth surface, respectively. The bouligand-type structured surface reduced the abrasion losses by 90.6% and 92.2%, respectively, compared with the conventional ribbed surface and smooth surface, respectively. Correspondingly, the Bouligand-type structure substantially reduced the abrasion loss from the abrasive wear, particularly for better wear-resistance performance. Furthermore, the EDM-FEM coupled simulation was used to evaluate the internal deformation and strain behavior of the samples, in order to further investigate the wear-resisting enhancement from the Bouligand-type structure. In addition, the averaged deformation of the Bouligand-type structured, conventional ribbed, and smooth surface were 1.82×10-8, 7.97×10-9, and 1.62×10-9mm, respectively, where the averaged equivalent stresses were 1.16×10-6, 6.36×10-6, and 1.01×10-5 MPa, respectively. The results show that the Bouligand-type structure presented relatively higher internal deformation and strain, compared with the rest. The reason was that the Bouligand-type structure shared the better capability to absorb the impact energy from the abrasive particles for reduced abrasion loss. The rotary abrasive test bench was used to further validate the simulation. The minimum wear amount of Bouligand structural parts was 0.12 g, and the minimum standard deviation was 0.012, the wear resistance was stable compared with the conventional ribbed and smooth surface. Consequently, there were relatively stable variations in the abrasion loss of the Bouligand-type structure over the wear time. This research can also provide a new theoretical reference and technical basis for the development of promising wear-resistant materials.