EDEM Investigation and Experimental Evaluation of Abrasive Wear Resistance Performance of Bionic Micro-Thorn and Convex Hull Geometrically Coupled Structured Surface

Abstract

Procambarus clarkii was found to have excellent anti-wear performance against abrasive materials. To improve the wear resistance performance of the soil-engaging component of agricultural machinery, in this study, the micro-thorn and convex hull coupled geometrical structured surfaces inspired from the cephalothorax exoskeleton of the Procambarus clarkii was selected as the bionic prototype. By adopting bionic engineering techniques, three types of novel geometrical structured surfaces were proposed, which were bionic single, double and triple micro-thorn coupled convex hull surfaces (Bionic Type 2, 3 and 4, respectively). The anti-abrasive wear properties of these proposed geometrical surfaces were compared with a conventional bionic convex hull structured surface (Bionic Type 1) and a surface without any structures (smooth). Abrasive wear tests were conducted by using a rotational abrasive wear testing system. The accumulative test time was 80 h and the total wear distance was 6.09 × 105 m. By adopting the EDEM software (discrete element modeling), the Archard Wear model was selected to simulate the wear behavior of five different surfaces. In addition, the wear mechanisms of different surfaces were investigated. The results showed that the smooth surface suffered the most severe abrasive were, the abrasion loss reached 194.1 mg. The anti-abrasive properties of bionic geometric structured non-smooth surfaces were greatly improved; the reduction in terms of abrasion losses ranged between 20.4% and 94.1%, as compared with the smooth surface. The wear resistance property of micro-thorn and convex hull coupled structured surfaces were greatly improved as compared with convex hull and smooth surface. Bionic Type 3 was found to have the best anti-abrasive wear property: the abrasion loss was 11.5 mg. The wear morphology was observed by a scanning electron microscope. Smooth surface was characterized with wide, large size of grinding debris, while the bionic non-smooth surface featured narrow and small size abrasive dust. The results obtained from EDEM simulation agreed well with those of the aforementioned real scenario tests. It was revealed that the wear areas of the micro-thorn and convex hull coupled structured surface were mainly concentrated on the edge of convex hull and micro-thorn that faced the coming direction of particle flow. The geometric structure of the convex hull had beneficial effects on changing the movement behavior of particles, which means the stream of particle flow could be altered from a sliding to rolling state. Consequently, the ploughing and cutting phenomena of particles that act on the surfaces were greatly mitigated. Moreover, after being coupled with micro-thorns, the anti-abrasive wear preparty of the bionic convex hull geometrical structured surface was further improved. The rebound angle of particle flow that contacted the bionic micro-thorn coupled convex hull structured surface was greater than that of the conventional convex hull surface. Therefore, the dispersion effect of particle flow was further enhanced, since the movement behavior of the subsequent impact particle flow was altered. As a result, the wear of the bionic non-smooth surface was further reduced. This biconically inspired novel micro-thorn and convex hull coupled structured surface could provide theatrical and technical references to enhance the wear resistance performance of the soil-engaging component of agricultural machinery and mitigate the problem of abrasive wear failure.