基于ABAQUS的深水连接器连接性能分析     

曹博  蔡志杰  石中玉  张玉龙  段梦兰 《海洋工程》2020,38(3):132-139

为解决现有深水连接器连接性能研究中力学分析建模不准确,且缺乏抗弯抗扭能力分析的问题,基于ABAQUS有限元分析软件对深水连接器进行三维模型动态仿真分析,对连接器的受力、密封性能以及在实际工程需求中不同内压下的抗弯及抗扭性能进行深入研究。结果表明:在安装及生产两种工况下,深水连接器各部件除密封环外受力均满足其强度设计要求,密封环接触表面发生合理塑性变形,满足密封要求;随着内压的增加,深水连接器的抗弯能力逐渐下降,抗扭能力则呈现增加的趋势;极限弯矩分别在0 MPa与35 MPa内压下的判定依据为密封失效,在14 MPa与52 MPa内压下的判定依据为下毂座屈服,而极限扭矩在不同内压下的判定依据均为密封失效。  相似文献   

钢管脐带缆扭转平衡设计     

牛学超  祝庆斌  潘盼  邵鹏进  胡明  谢书鸿 《海洋工程》2020,38(6):151-157

钢管脐带缆包含多种螺旋缠绕的功能单元，其在外力载荷下会发生相对运动，而且钢管的刚度较大对扭转平衡有重要影响，因此，相对于普通电缆，钢管脐带缆在扭转平衡设计时更加困难。根据扭转平衡理论公式，采用控制变量法，以第二层铠装钢丝的绞合角度为变量进行扭转平衡设计。首先建立脐带缆缆芯有限元模型，对其施加拉伸载荷，结果显示缆芯出现了扭转，这证明不能将脐带缆缆芯视为一实心圆柱。其次建立不同绞合角度的脐带缆有限元模型，设置各功能单元的材料属性和摩擦系数，分析模型在拉伸载荷下的扭转角度，并将相同拉伸载荷下的扭转角度拟合为直线，从而得到钢管脐带缆在扭转平衡状态时的最优绞合角度。最后，采用试验方法对实物钢管脐带缆进行扭转平衡测试，测试结果显示在拉伸载荷下脐带缆单位长度扭转角度十分微小，这表明缆是扭转平衡的。因此验证了使用的有限元方法在钢管脐带缆扭转平衡设计中的有效性。  相似文献   

Equilibria of a satellite subjected to gravitational and aerodynamic torques with pressure center in a principal plane of inertia     

V. A. Sarychev  S. A. Mirer  A. A. Degtyarev 《Celestial Mechanics and Dynamical Astronomy》2008,100(4):301-318

Attitude motion of a satellite subjected to gravitational and aerodynamic torques in a circular orbit is considered. In special case, when the center of pressure of aerodynamic forces is located in one of the principal central planes of inertia of the satellite, all equilibrium orientations are determined. Existence conditions of all equilibria are obtained and evolution of domains with a fixed number of equilibria is investigated in detail. All bifurcation values of the system’s parameters corresponding to the qualitative change of these domains are determined. Sufficient conditions of stability are obtained for each equilibrium orientation using generalized integral of energy.  相似文献   

大直径气举反循环成套钻具的研制          下载免费PDF全文

袁志坚 《探矿工程》2014,41(12):44-48

介绍了大直径气举反循环成套钻具的研制背景、设计原则、结构尺寸和主要技术参数。该套钻具不仅强度大,连接便捷,而且充分考虑了通气、通泥浆、泥浆补给三大通道面积等因素,采用内平设计。经生产试验,完全能满足大直径工程井气举反循环钻进的需要。  相似文献   

Correction and update to 'The earth's C₂₁ and S₂₁ gravity coefficients and the rotation of the core'     

John Wahr 《Geophysical Journal International》1990,101(3):709-711

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The coupled rotation of the inner core   总被引：1，自引：0，他引：1  

Su Xu  & Szeto 《Geophysical Journal International》1998,133(2):279-297

The rotation of the inner core (IC) is influenced by the rest of the Earth through a number of coupling mechanisms. Among four possible coupling mechanisms, gravitational, pressure, viscous and electromagnetic, the first two torques are dominant. Numerous existing IC gravitational torque estimates have been shown to agree very well with one another Xu & Szeto 1996 ). It is shown in this paper that different estimates of the IC pressure torque are also in good agreement.
The coupled rotation of the IC has been investigated in the frequency domain by several research groups (Mathews et al. 1991a,b; De Vries & Wahr 1991 ; Dehant et al. 1993; Jiang 1993 ). Not all of these efforts obtained two IC-related rotational modes, the inner-core wobble (ICW) and the free-inner-core nutation (FICN). We investigate this problem in the time domain and confirm the existence of the two modes. The periods of ICW and FICN are in good agreement with those obtained by other researchers. In studying the effects of coupling torques on the IC rotational modes we have found that depending on whether the IC net torque is 'restoring' or otherwise, an increased torque magnitude will respectively shorten or lengthen the ICW period. We have also found that the sense of FICN is determined by the orientation of the net coupling torque on the IC.  相似文献   

1980-2010年冬季北极涛动季节内振荡的成因分析          下载免费PDF全文

沈新勇  王涛  赵南  黄伟  王乙舒  崔妍 《大气科学学报》2016,39(1):1-7

采用NCEP/NCAR日平均再分析资料,对冬季热带外低频振荡(大气角动量收支及地形力矩)与AO(Arctic Oscillation)指数进行计算,通过功率谱和统计分析发现,它们都存在30~60 d的周期,大气角动量收支与山脉力矩的变化为正相关,且显著响应AO变化。通过动力学诊断分析初步认为,北半球两大地形的山脉力矩作用于纬向大气角动量,副热带纬向西风发生变化,改变南北西风偶极子结构,使得AO产生变化,而且在两大地形中以喜马拉雅山脉地形作用为主。通过对喜马拉雅山脉地区的动力学诊断发现,在高(低)AO指数阶段,喜马拉雅山脉地区激发准定常行星波并作用于副热带西风,导致副热带西风偏弱(偏强),高纬西风偏强(偏弱),因而AO偏强(偏弱),平流层极涡偏强(偏弱),极涡强(弱)中心偏向东北亚。  相似文献   

Lunisolar torque on the atmosphere and Earth's rotation     

C. Bizouard  S. Lambert 《Planetary and Space Science》2002,50(3):323-333

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矩形高层建筑扭转动力风荷载解析模型   总被引：4，自引：0，他引：4  

梁枢果  刘胜春  张亮亮  王奇志  罗永宁  付晓丽 《地震工程与工程振动》2003,23(3):74-80

本文通过研究不同长宽比、高宽比的矩形棱柱体在边界层风洞中典型攻角下的扭矩，提出了矩形高层建筑扭矩功率谱密度、均方根扭矩系数和Strouhal数的经验公式，并对相干函数作了一定的探讨，建立了完整的扭转动力风荷载解析模型。该模型和试验结果吻合较好，证明它是合理有效的，可在此基础上建立高层建筑扭转动力响应频域计算方法。  相似文献   

Axial poloidal electromagnetic core-mantle coupling torque: A re-examination for different conductivity and satellite supported geomagnetic field models     

H. Greiner-Mai  J. Hagedoorn  L. Ballani  I. Wardinski  D. Stromeyer  R. Hengst 《Studia Geophysica et Geodaetica》2007,51(4):491-513

We investigate the temporal behaviour of the axial component of the electromagnetic core-mantle coupling torque that is associated with the poloidal part of the geomagnetic field observable at the Earth surface. For its computation, we use different models of the geomagnetic field, expanded into spherical harmonics (Wardinski and Holme, 2006; Sabaka et al., 2004), and the mantle conductivity. The geomagnetic field, which we have to know at the core-mantle boundary for the associated computations, will be inferred from the field at the Earth surface by the non-harmonic field continuation through a conducting mantle shell. The aims of this investigation are (i) to check how sensitive is the computation of the torque with respect to the different geomagnetic field models, (ii) to check its dependence on the spherical harmonic degree n, and (iii) to determine the difference between the mechanical torque derived from the observed length-of-day variations (atmospheric influence subtracted) and the poloidal electromagnetic torque in dependence on the assumed conductivity. To use the non-harmonic field continuation for the torque calculation and to obtain an insight into the influence of the different geomagnetic field models on the EM torques are the major aspects of this paper. grm@gfz-potsdam.de  相似文献