潜孔锤/声波钻钻柱动力学关键问题研究

Using the domain decomposition method, this project divides the DTH hammer drill string into several sub-domains, and changes the whole drill string dynamics problems under specific boundary constraint conditions into functional variational problems satisfying the sub-domains’ interface continuity conditions without any constraints. so we can search the boundary conditions and its kinestate of the drill string (the contact interaction between drill string and borehole, stick-slip motion, whirling) through programming and apply the load vector self-adaptively. Then we can solve the coupling vibration response of DTH hammer drill string under complicated boundary conditions. This innovative research will certainly promote the understanding/exploration of the deep well drill-string nonlinear dynamics..The Sonic vibrator frequency can be changed to active excite the Standing wave resonance of drill string, we use the mathematical analysis methods to solve the implicit function, which regard to the natural frequency equation of drill string, in order to reveal the influence of inertial boundary and other parameters on the dynamic characteristics of sonic drill string; Based on the Miner rule, we establish a sonic drill string model between the fatigue damage and variable technology parameters, in order to study the effects on the fatigue damage inherent law of the standing wave excitation stress and technological parameters of the sonic drill string. It will be helpful to improve the frame theory of standing wave resonance..DTH hammer/Sonic drill is gradually becoming a regular and efficient dynamic rock drilling method. To study the vibration utilization of sonic drill and the suppression of DTH hammer drill string coupling vibration, it is of great significance in theory research and engineering application to improve the efficient drilling performance.

项目采用区域分解法，将潜孔锤钻柱分成若干子域，把特定边界约束下钻柱动力学问题转变为子域界面位移协调的无约束泛函变分问题，能搜索钻柱边界及其运动状态（接触、粘滑或涡动），并自适应对钻柱施加载荷向量，迭代求解复杂边界潜孔锤钻柱耦合振动响应，这种创新性研究必将促进深井钻柱非线性动力学的理论认识/探索。.声波振动器改变频率以主动激励钻柱发生驻波共振，采用数学分析的方法对惯性边界钻柱固有频率的隐式函数进行求解，以揭示惯性边界等参数对声波钻柱动力学特性的影响；基于Miner法则，建立声波钻柱的疲劳损伤与变工艺参数的模型，来研究驻波激励应力、工艺参数对声波钻柱的疲劳损伤内在规律性，将有利于完善声波钻钻柱驻波共振动力学框架理论。.研究声波钻的振动利用和潜孔锤钻柱耦合振动的抑制，对于改善高效碎岩穿孔的性能具有重要的理论研究意义和工程应用价值。

针对振动与冲击机械在地质工程机械中应用广泛，但其冲击瞬态动力学问题理论研究薄弱，开展了低频行波振动和声波驻波振动的动力学系统研究。.① 驻波共振钻柱的疲劳损伤问题。声波钻惯性高频激励钻柱的驻波振动，以实现高速无扰动钻进，而钻柱内的高周交变应力易引起钻柱疲劳损伤，从而引发钻进过程中的钻杆疲劳失效。课题组通过声波激励钻柱驻波振动的建模分析，创新性建立了变长度驻波振动钻柱疲劳累积损伤的理论公式，系统研究表明：对于基频驻波共振钻进，钻柱内最大疲劳损伤点位置在距钻头上方起振长度一半的附近，与钻孔深度对应的钻柱长度无关，钻柱疲劳损伤对地层阻尼极为敏感，从理论上证明钻柱共振阶动应力是钻柱疲劳损伤的关键诱因。.② 惯性质量边界对钻柱固有频率的影响。在国际上，建立了考虑声频振动器惯性边界的声波钻固有频率的显函数公式，揭示了较大振动器质量的惯性边界对声波钻浅孔钻进时钻柱动力学的影响，通过显式频率公式求解模态频率的近似解，应用于声波钻进中，可以精确跟踪控制声波钻机浅孔钻进的振动频率，以保持声波振动器钻柱耦合驻波共振，从而提高声波钻进生产效率。.③ 振动沉入机械瞬时功率的影响因素。振动钻探或沉管／压实机械在工程中有着广泛的应用，有时会出现不明原因重启，甚至烧坏原动机的情况，项目组创新地采用阻尼力求解瞬时耗散功率，通过功率放大因子的分析，揭示了惯性振动机械吸收或耗散功率在共振区对小阻尼（阻尼比小于0.5）异常敏感，瞬时功率随着阻尼比的减小而激增，是造成振动机械功率异常增大根本原因，该结论对于振动机械的设计和施工设备的使用具有重要理论指导意义。.通过对声波钻变长度钻柱驻波振子疲劳损伤的研究，加深了对声波钻进的驻波振动钻柱疲劳损伤的关键因素及疲劳失效机制的理论认识，有利于指导声波钻机设计和声频钻进生产实践活动，同时也将促进变长度振子驻波振动疲劳损伤理论的理解和探索。