Research On The Lunar Dust Rising By Lunar Rover Wheel And Adhesion And Friction Characteristics Of Lunar Particles

With the proposal of the "Artemis" plan of the United States,China will also carry out key technological breakthroughs in manned moon landing.The Apollo mission report once pointed out that lunar dust is the main factor affecting human lunar landing activities.The particle size of lunar dust is less than 20?m,mainly sharp and angular fragments,and has high hardness and more adhesion.The movement of the astronauts and the lunar rover is very easy to produce dust.The spread lunar dust floats and adheres to the surface of the detection equipment,causing wear and tear to it,and even causing the space agency to get stuck,which seriously damages the orderly development of the spacecraft’s lunar surface exploration.Therefore,the exploration of the characteristics of the lunar wheel dust and lunar dust is a necessary condition to ensure the steady progress of lunar exploration.Firstly,the adhesion between simulated lunar dust particles and the surface of common spacecraft materials are studied from the microscopic point of view.Through the self-made colloidal probe with lunar dust particles at the tip of the cantilever,the adhesion characteristics between a single lunar dust and the material are analyzed,and the influence law of the surface roughness of the material on the adhesion characteristics of lunar dust is revealed.The test results show that the adhesion force is closely related to the surface roughness of the material,and the adhesion generated by the small particle size moon dust(30μm)is 6 orders of magnitude higher than that of the large particle size moon dust(70μm).Greater than the adhesion caused by large particle size moon dust.The adhesion value of carbon fiber and single moon dust in non-metallic materials is only 0.0328,which is 1 order of magnitude smaller than other materials and relatively small,while the adhesion force of polyimide is 16.4 times that of carbon fiber.Among metal materials,the minimum adhesion value of magnesium alloy and titanium alloy is only 0.0462,and the maximum adhesion value of copper alloy is 5.8 times that of magnesium alloy.Secondly,based on the adhesion test,three typical metal materials are selected,and the friction and wear test are carried out with UMT-3 testing machine.The friction and wear characteristics between simulated lunar dust and typical metal materials are analyzed.The test results show that aluminum alloy is the most serious wear of the three materials by lunar dust,followed by copper and finally stainless steel,and the friction coefficient of test sample has no significant relationship with its inherent properties of materials.The wear of small particle size lunar dust on the surface of metal materials is larger,and the particle size is more serious,and the coefficient of friction is about 0.04 higher.Thirdly,the dust emission of different toothed lunar rover wheels under vacuum is experimentally studied,and a dust emission test-bed simulating the lunar environment is built.Among them,the peak dust concentration and range value of helical gear are the smallest.The maximum concentration at high speed is 41% of that of pinion gear,and the range value is 37.1% of that of pinion gear.Finally,to further study the dust phenomenon,the discrete element software EDEM is used to simulate and analyze the dust spread of lunar rover,and the wheel dust height and dust size under different wheel thorn height,width,quantity and different tooth shape are analyzed.The results indicate that the dust amount of herringbone gear is the minimum and that of pinion gear is the maximal,and the dust amount augments with the increase of tooth height and reduce with the improve in the number of wheel thorns,the dust volume under the moon’s gravity is about 2-4 times that of the earth’s state.Summary,through the self-made colloidal probe technology and the construction of friction and wear test device,this thesis analyzes the adhesion and friction and wear characteristics between lunar dust and common materials,reveals the adhesion and wear law between lunar dust and common materials,and provides a reference for the selection of key parts and materials for subsequent spacecraft.In addition,the dust emission characteristics of four kinds of toothed wheels are analyzed through the selfdesigned and built wheel dust emission test device,and the relationship between vehicle speed and dust emission is revealed.The effects of microgravity and other wheel parameters on dust characteristics are studied by discrete element simulation analysis.