GXY-150型工程钻机的研制          下载免费PDF全文

高铁军  崔高汉  董朝晖  张宝林 《探矿工程》2005,32(4):45-46

介绍用于小型桩基施工的GXY-150型工程钻机的设计要求、主要技术参数、结构特点及生产试验简况。  相似文献   

Enhanced alignment of plate ice crystals in a non-uniform electric field     

T.C. Foster  J. Hallett   《Atmospheric Research》2008,90(1):41-53

An atmospheric electric field exerts a torque on both column and plate ice crystals. Columns tend to align along the direction of the field. One diameter of plate crystals also aligns parallel to a field, while a non-uniform diverging field leads to further orientation and proscribes a secondary orientation along the direction of least divergence. A laboratory investigation treats the electrical orientation of thin plate ice crystals in a non-uniform field as a two-step process. In the model, the average field provides the primary torque and aligns one diameter of the plate crystal while simultaneously a spatially varying component of the field aligns the perpendicular diameter. The first element of the process, the primary torque, has been investigated previously. The complete reorientation, caused by a secondary torque, is investigated herein. Experimentally a stronger field with sufficient non-uniformity is required to demonstrate the secondary torque. The realignment caused by this torque depends also on the strength of the aerodynamic torques on the falling ice crystals. Experiments in a laboratory cold chamber with small thin plate crystals in an electric field provided by a charged rod demonstrate crystal reorientation by changing the reflections of a beam of white light. A model incorporating electrical torques is applied to the laboratory observation and used to investigate the possibility of the effects occurring in the atmosphere. Fields near lightning strokes, which are strong but of short duration, may reorient small crystals. Larger crystal aggregates like planar snowflakes are governed by the same electrical torques. It is suggested that the secondary torque realignment might be observable for aggregates large enough to be detected by radar in cases pertaining to weaker but longer duration fields associated with cloud electrification. A simplification of the model is used to investigate electrically caused crystal motion and linear aggregation, with applications to the atmosphere and to lightning initiation.  相似文献   

全断面盾构机异质岩土掘进载荷等效模型研究   总被引：2，自引：0，他引：2  

曾晓星  余海东  王皓  来新民  张凯之 《岩土力学》2010,31(4):1199-1203

由于岩土结构的变化,全断面盾构机在掘进过程中推进力和扭矩需要进行适当的顺应性设计以获得良好的掘进效率,以减少刀具磨损和损伤破坏事故的发生。针对盾构机在掘进过程中遇到的典型地质结构,建立地质结构的圆形百分比模型,分析刀盘上不同刀具在掘进过程中载荷受力,建立不同刀具及总扭转载荷的数学表述方法,基于该方法对盾构机在异质岩土结构中旋转时刀盘总扭矩随旋转角度的变化特性进行研究,结果表明,在软岩与硬岩比例大约为30%时刀盘的扭矩载荷波动最大,容易造成刀盘堵转及损伤事故,该可以解释云南上公山隧道掘进时频繁堵转产生机理,为异质岩土掘进时盾构机冗余驱动电机的顺应性设计提供指导。  相似文献   

扭矩作用下嵌岩桩桩顶内力分布的模型试验   总被引：2，自引：0，他引：2  

刘云云  陈竹昌 《岩土力学》2000,21(2):119-122

基于扭矩荷载下的 8组模型试验的实测资料 ,分析了扭矩作用下嵌岩桩基的实测桩顶内力、各桩位移抗扭力矩及转动抗扭力矩的变化及其分布规律。并讨论了试验结果同刚性承台分析结果的符合程度。  相似文献   

YCR260型旋挖钻机的研制          下载免费PDF全文

何佳鑫  解大鹏  张晓  朱小东  秦爱国 《探矿工程》2013,40(4):39-43，47

介绍了YCR260型旋挖钻机的用途、设计思想、主要性能参数、设计方案、创新点及现场使用情况。施工实践证明,YCR260型旋挖钻机稳定性好,加压力大,入岩能力强,性能稳定可靠,在同级别机型中处于领先地位。  相似文献   

Figure–figure interaction between bodies having arbitrary shapes and mass distributions: a power series expansion approach     

Pasquale Tricarico 《Celestial Mechanics and Dynamical Astronomy》2008,100(4):319-330

We derive an expression for the mutual gravitational force and torque of two bodies having arbitrary shapes and mass distributions, as an expansion in power series of their products of inertia and of the relative coordinates of their centres of mass. The absolute convergence of all the power series developed is rigorously demonstrated. The absence of transcendental functions makes this formalism suitable for fast numerical applications. The products of inertia used here are directly related to the spherical harmonics coefficients, and we provide a detailed analysis of this relationship.  相似文献   

HDD挤压式扩孔钻头拉力-扭矩模型建立及验证          下载免费PDF全文

邱玲玲  乌效鸣  孟凡威 《探矿工程》2010,37(3):59-61

在水平定向钻进中,作用在钻头上拉力和扭矩是设计钻进和施工的重要依据。通过对挤压式钻头的力学分析,提出了挤压式钻头的拉力－扭矩模型并较全面地分析了影响模型结果的因素。还结合现场施工数据对模型进行实践验证,结果与现场数据较为吻合。因此,该模型对挤压式钻头水平定向钻进施工设计优化起到了很重要的指导作用。  相似文献   

地球主磁场电磁转矩导致的地球差异旋转     

邹润莉 《地球物理学进展》2012,27(3):977-987

为探索驱动地球系统差异旋转的力源,选择整个地球作为研究对象,应用经典电磁学理论,分析地球固体介质中的电荷在地球主磁场中的运动特点,发现存在一个与地球自转方向相反的切向洛伦兹力.通过电荷与介质间的相互作用,切向洛伦兹力传递至介质迫使介质西漂.为探索地球差异旋转的规律,建立了地球薄圆筒圈层模型.应用经典物理学理论和方法推导出了地球主磁场电磁转矩及其产生的角加速度公式.研究得到四点主要结论:1)作用于半径不同的地球薄圆筒圈层的地球主磁场电磁转矩及其产生的角加速度绝对值不同:地轴及赤道附近圈层的小,其自转相对较快;半径等于3～(1/2)倍地球半径的薄圆筒圈层及其相邻圈层的大,其自转相对较慢.2)同一薄圆筒圈层中的差异旋转缘于介质的介电常数、阻力系数及质量密度的差异.3)地球差异旋转缘于地球的自转、正负电荷的非对等分布及介质的介电常数、阻力系数、质量密度的差异.4)地球差异旋转导致地壳运动,孕育地震,地球主磁场是地球差异旋转和地震孕育的敏感因子.  相似文献   

季节性层结对孤立内波作用于圆柱载荷的影响   总被引：1，自引：0，他引：1  

CAI Shuqun  XU Jiexin  CHEN Zhiwu  XIE Jieshuo  DENG Xiaodong  LV Haibin 《海洋学报(英文版)》2014,33(7):21-26

On the basis of Morison＇s empirical formula and modal separation method in estimating the force and torque exerted by internal solitary waves （ISWs） on a cylindrical pile, it is found that the loads exerted by the ISWs change largely in different seasons at the same site of the continental shelf in the South China Sea （SCS） even under the condition that the amplitudes of ISWs are the same. Thus, the effect of a seasonal water stratification variation on the force and torque exerted by the ISWs is investigated, and a three-parameter stratification model is employed. It is shown that the loads exerted by the ISWs depend largely on the wa- ter stratification. The stronger the water stratification, the larger the force and the torque; when the depth where the maximum thermocline appears is deepened, the force decreases but the torque increases; when the width of the thermocline is narrowed, the force increases but the torque decreases. The seasonal varia- tion of the force and the torque exerted by the ISWs in four seasons in the SCS is thus explained. Key words： internal solitary waves, force, torque, water stratification, South China Sea  相似文献   

Research on the unsteady hydrodynamic characteristics of vertical axis tidal turbine   总被引：1，自引：0，他引：1  

张学伟  张亮  王峰  赵东亚  庞程燕 《中国海洋工程》2014,28(1):95-103

The unsteady hydrodynamic characteristics of vertical axis tidal turbine are investigated by numerical simulation based on viscous CFD method. The starting mechanism of the turbine is revealed through analyzing the interaction of its motion and dynamics during starting process. The operating hydrodynamic characteristics of the turbine in wave-current condition are also explored by combining with the linear wave theory. According to possible magnification of the cyclic loads in the maximum power tracking control of vertical axis turbine, a novel torque control strategy is put forward, which can improve the structural characteristics significantly without effecting energy efficiency.  相似文献