Study On Adhesion And Rate Traction Properties Of Deep-sea Sediment

With the decrease of mineral resources on land,exploiting and using the ocean resources has been a commercial foreground strategically resource in 21 century which was focused the international attention upon.The main difficulty in the development and utilization of seabed mineral resources lies in the research and development of deep-sea mining system.As an important part of the mining system,the mining machine plays an important role in the efficient and safe operation of deep-sea mining.Because the deep-sea sediment has completely different characteristics from the terrestrial soil,such as the high water content and low shear strength of deep-sea sediment,crawled mineral collector is easy slipping in the deep-sea mining process,which not only reduces the working efficiency of the crawled mineral collector,but also affect the safety performance of the mining machine.At the same time,it was found that the grouser of the crawled mineral collector adhered to more deep-sea mining during the deep-sea mining operation,which seriously affected the working efficiency of the crawled mineral collector.Therefore,this paper studies the mechanical properties of deep-sea sediment firstly,and then the high-traction bionic grouser was designed based on the characteristics of deep-sea sediment.Finally,the adhesion characteristics of the contact between the grouser of the crawled mineral collector and the deep-sea sediment were studied and analyzed,and the roughness of the surface of the crawled mineral collector was optimized based on the roughness adhesion model.The main work of this paper is:1.In this paper,based on the unconsolidated undrained triaxial compression experiment at different loading rates,the stress-strain curves of deep-sea sediment under different loading rates were obtained.It is found that the stress first increases and then decreases slightly with the increase of strain,the yield stress of deep-sea sediment increases with the increase of loading rates,and the elastic modulus of the material increases slightly with the increase of loading rates.Therefore,based on the stress-strain curves of deep-sea sediment under different loading rates,the plastic strain rate and the yield stress ratio of the rate-dependent parameters in the finite element software are calibrated,and the rate-dependent extended Drucker-Prager constitutive model is obtained.2.The Arbitrary Lagrange-Euler finite element(LEA-FE)was used to simulate the cutting process of different bionic grousers at different speeds.the accuracy of the finite element is verified by the cutting experiments of straight grouser.By comparing the simulation of different grousers,it was found that the maximum traction of grouser is related to the grouser parameters.By analyzing the traction characteristics of different bionic grousers,the binary quadratic regression equation between maximum traction and bionic grouser parameters was established,and the best bionic grouser parameters were obtained by the optimization algorithm.Based on the rate-dependent properties of deep-sea sediment,the traction characteristics at different speeds were analyzed and the relationship between maximum traction and speeds was established,the best bionic grouser walking speed was obtained,which can provide the theoretical basis for the crawled mineral collector.3.Based on the finite element simulation between different crest spacing of metal surfaces and soil particles,the adhesion relationship between metal surface crest spacing and soil particle contact interface has been studied,and the JKR contact model has been corrected by introducing crest spacing parameters,and the roughness threshold of the adhesion of soil particles to the metal surface is obtained by the optimization algorithm,which satisfactorily reflected the surface roughness of the metal.The influence of the attached force provides a theoretical basis for the visbreaking and debonding of the metal surface.