發(fā)布時間：2018-02-23 20:45

  本文關(guān)鍵詞： 月壤 月巖 PFC3D 功率 鉆探　出處：《中國地質(zhì)大學(北京)》2017年碩士論文　論文類型：學位論文

【摘要】：我國探月工程三期目標是從月球上鉆取500g的樣品返回地球。而在月球上鉆探取樣需要克服許多極端條件,比如低重力、無水、無空氣等,同時月壤具有較高的內(nèi)摩擦角和較低的內(nèi)聚力,因此在地球上進行真實環(huán)境和鉆探工藝的模擬難度較大。月球鉆探取樣要求鉆具結(jié)構(gòu)系統(tǒng)具有質(zhì)量輕、功耗低、強度大等優(yōu)點,因此通過對鉆進過程的動力學分析研究,為鉆具結(jié)構(gòu)的設(shè)計、材料的選取、鉆進工藝的設(shè)計提供理論依據(jù)。本文采用離散元方法建立鉆取月壤月巖的仿真模型,仿真分析鉆進過程中的鉆頭切削功率和鉆桿排粉功率,研究月巖對鉆進功耗的影響�；�于PFC離散元的基本本構(gòu)模型,通過模擬單軸、雙軸和直剪實驗,標定微觀參數(shù)。通過標定后的模型微觀參數(shù),得到月巖的彈性模量E 87GPa、泊松比μ0.21、單軸抗壓強度127MPa;月壤的內(nèi)聚力c 3.4kPa、內(nèi)摩擦角φ 47°、彈性模量17MPa、泊松比0.2,均符合最佳估值范圍,可保證模型的精確性。依據(jù)土力學和巖石破碎學理論,建立了鉆頭切削月壤、破碎月巖以及鉆桿排粉的理論分析模型,獲得鉆頭切削功率和鉆桿排粉功率,結(jié)果表明鉆頭切削月壤功率與鉆深為一次線性關(guān)系,排粉功率與鉆深呈二次曲線關(guān)系。由于PFC計算緩慢的問題,利用等效思想,根據(jù)鉆進過程顆粒的速度場和應(yīng)力場對模型規(guī)模進行縮減;建立無月巖塊體的淺層鉆進模型和深層等效鉆進模型,監(jiān)測鉆頭和鉆桿受到的阻力矩。監(jiān)測結(jié)果均與理論分析結(jié)果趨勢一致,印證了理論分析模型的有效性和仿真模型的真實性。最后針對月巖不同的形狀、位置、大小對鉆進過程中的功率影響進行仿真分析。結(jié)果顯示月巖體在切削齒作用范圍內(nèi),對切削功率影響呈現(xiàn)周期性4~5倍增幅,而對排粉影響較小;形狀只是會影響鉆頭力矩產(chǎn)生脈沖波動的時間,并不會影響力矩波動幅值;力矩脈沖幅值會隨著塊體體積增大而呈現(xiàn)對數(shù)函數(shù)關(guān)系。因此在鉆進過程中需要實時監(jiān)控鉆頭力矩變化,實時調(diào)節(jié)電機驅(qū)動力矩保證鉆進取樣任務(wù)的順利進行,避免發(fā)生卡鉆問題。
[Abstract]:The goal of the third phase of China's lunar exploration project is to drill 500 g samples from the moon to return to Earth. However, drilling on the moon for sampling requires overcoming many extreme conditions, such as low gravity, no water, no air, etc. At the same time, the lunar soil has higher angle of internal friction and lower cohesion, so it is difficult to simulate the real environment and drilling technology on the earth. The sampling system of lunar drilling requires the advantages of light weight, low power consumption, high strength and so on. Therefore, the dynamic analysis of drilling process provides a theoretical basis for the design of drilling tool structure, the selection of materials and the design of drilling technology. In this paper, the simulation model of drilling lunar rock is established by using discrete element method. The influence of moon rock on drilling power consumption is studied by simulation and analysis of bit cutting power and drilling pipe discharge power during drilling. Based on the basic constitutive model of PFC discrete element, the uniaxial, biaxial and direct shear experiments are simulated. Calibrated microscopic parameters. The elastic modulus E 87 GPA, Poisson's ratio 渭 0.21, uniaxial compressive strength 127 MPA, cohesion C 3.4 KPA, internal friction angle 蠁 47 擄, elastic modulus 17 MPA and Poisson's ratio 0.2 of the lunar soil are obtained. According to the theory of soil mechanics and rock fragmentation, the theoretical analysis model of cutting lunar soil, breaking moon rock and discharging powder of drill pipe is established, and the cutting power of drill bit and discharging power of drill pipe are obtained. The results show that the power of cutting lunar soil is linear with drilling depth, and the power of discharging powder is conic with drilling depth. Due to the slow calculation of PFC, the equivalent idea is used. The model size is reduced according to the velocity field and stress field of the particle during drilling, and the shallow drilling model and the deep equivalent drilling model are established. Monitoring the resistance moment of drill bit and drill pipe. The monitoring results are consistent with the theoretical analysis results, which confirm the validity of the theoretical analysis model and the authenticity of the simulation model. Finally, according to the different shapes and positions of the moon rock, The results show that the influence of lunar rock mass on cutting power is increased by 4 ~ 5 times in the range of cutting teeth, but it has little effect on powder discharge. The shape only affects the time when the torque of the bit produces pulse fluctuation, and does not affect the amplitude of the torque fluctuation. The amplitude of torque pulse will show a logarithmic relationship with the increase of bulk volume. Therefore, it is necessary to monitor the change of bit torque in real time during drilling, and to adjust the driving torque of motor in real time to ensure the smooth operation of drilling sampling. Avoid drilling problems.
【學位授予單位】：中國地質(zhì)大學(北京)
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：P634;P184.5
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本文編號：1527550