基于PFC3D月球钻探功率消耗仿真分析

发布时间：2018-02-23 20:45

  本文关键词： 月壤 月岩 PFC3D 功率 钻探　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：我国探月工程三期目标是从月球上钻取500g的样品返回地球。而在月球上钻探取样需要克服许多极端条件,比如低重力、无水、无空气等,同时月壤具有较高的内摩擦角和较低的内聚力,因此在地球上进行真实环境和钻探工艺的模拟难度较大。月球钻探取样要求钻具结构系统具有质量轻、功耗低、强度大等优点,因此通过对钻进过程的动力学分析研究,为钻具结构的设计、材料的选取、钻进工艺的设计提供理论依据。本文采用离散元方法建立钻取月壤月岩的仿真模型,仿真分析钻进过程中的钻头切削功率和钻杆排粉功率,研究月岩对钻进功耗的影响。基于PFC离散元的基本本构模型,通过模拟单轴、双轴和直剪实验,标定微观参数。通过标定后的模型微观参数,得到月岩的弹性模量E 87GPa、泊松比μ0.21、单轴抗压强度127MPa;月壤的内聚力c 3.4kPa、内摩擦角φ 47°、弹性模量17MPa、泊松比0.2,均符合最佳估值范围,可保证模型的精确性。依据土力学和岩石破碎学理论,建立了钻头切削月壤、破碎月岩以及钻杆排粉的理论分析模型,获得钻头切削功率和钻杆排粉功率,结果表明钻头切削月壤功率与钻深为一次线性关系,排粉功率与钻深呈二次曲线关系。由于PFC计算缓慢的问题,利用等效思想,根据钻进过程颗粒的速度场和应力场对模型规模进行缩减;建立无月岩块体的浅层钻进模型和深层等效钻进模型,监测钻头和钻杆受到的阻力矩。监测结果均与理论分析结果趋势一致,印证了理论分析模型的有效性和仿真模型的真实性。最后针对月岩不同的形状、位置、大小对钻进过程中的功率影响进行仿真分析。结果显示月岩体在切削齿作用范围内,对切削功率影响呈现周期性4~5倍增幅,而对排粉影响较小;形状只是会影响钻头力矩产生脉冲波动的时间,并不会影响力矩波动幅值;力矩脉冲幅值会随着块体体积增大而呈现对数函数关系。因此在钻进过程中需要实时监控钻头力矩变化,实时调节电机驱动力矩保证钻进取样任务的顺利进行,避免发生卡钻问题。
[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 掳, 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.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P634;P184.5
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本文编号：1527550