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

Abstract

<b><sc>Abstract.</sc></b> Procambarus clarkii was found to have excellent anti-wear performance against abrasive materials. To improve the wear resistance performance of 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, 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 conventional bionic convex hull structured surface (Bionic Type 1) and surface without any structures (Smooth). Abrasive wear tests were conducted by using rotational abrasive wear testing system. The accumulative test time was 80 h and the total wear distance was 6.09x10⁵ m. By adopting the discrete element EDEM software, 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 severest 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 was ranged between 20.4% to 94.1%, as compared with 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 with the best anti-abrasive wear property, the abrasion loss was 11.5 mg. The wear morphology was observed by scanning electron microscope. Smooth surface characterized with wide, large size of grinding debris. While the bionic non-smooth surface featured with narrow and small size abrasive dust. The results obtained from EDEM simulation agreed well with those of aforementioned real scenario tests. It was revealed that the wear areas of micro-thorn and convex hull coupled structured surface mainly concentrated on the edge of convex hull and micro-thorn that facing the coming direction of particle flow. The geometric structure of convex hull had obvious effects on changing the movement behavior of particles, which means the stream of particle flow could be altered from sliding to rolling state. Consequently, the ploughing and cutting phenomenon of particles that act on the surfaces were greatly mitigated. Moreover, after coupled with micro-thorns, the anti-abrasive wear preparty of bionic convex hull geometrical structured surface was further improved. The rebound angle of particle flow that contacting with bionic micro-thorn coupled convex hull structured surface was greater than that of conventional convex hull surface. Therefore, the dispersion effect of particle flow was further enhanced. Since the movement behavior of subsequent impact particle flow was altered. As a result, the wear of 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 soil-engaging component of agricultural machinery and mitigate the problem of abrasive wear failure.