坚定信心 创新思路 努力提升全省矿产资源勘查开发管理水平 全省矿管工作暨地质找矿改革发展大讨论动员会在郑州召开

4月20日,全省矿产资源勘查开发管理工作暨地质找矿改革发展大讨论动员部署会议在郑州召开。副省长张大卫出席会议并作重要讲话。会议由省国土资源厅党组书记、厅长张启生主持。省政府副秘书长张庆义,厅领导唐全国、郭公民、杨士海出席会议。     

U型半潜式起重铺管平台水动力分析

采用理论分析和模型试验相结合的方法,对一U型半潜式起重铺管平台进行了运动性能与气隙分析,为该平台的主尺度确定和作业能力评估提供了参考依据。同时,对半潜式起重铺管平台水动力分析的方法和流程进行了归纳与总结。     

Simplified Prediction Model for Vortex-Induced Vibrations of Top Tensioned Risers

According to the characteristics of deepwater top tensioned risers, a simplified model is presented to predict the multi-modal response of vortex-induced vibration （VIV） in non-uniform flow based on energy equilibrium theory and the exporimental data from VIV self-excited and forced oscillations of rigid cylinders. The response amplitude of each mode is determined by a balance between the energy fed into the riser over the lock-in regions and the energy dissipated by the fluid damping over the remainders. Compared with the previous prediction models, this method can take fully account of the intrinsic nature of VIV for low mass ratio structures on lock-in regions, added mass and nonlinear fluid damping effect, etc. Moreover, it is the first time to propose the accurate calculating procedure for VIV amplitude correction factor by solving energy equilibrium equation and a closed form solution is presented for the case of a riser of uniform mass and cross-section oscillating in a uniform flow. The predicted values show a reasonable agreement with VIV experiments of riser models in stepped and sheared currents.     

Nonlinear Dynamic Analysis of Deepwater Drilling Risers Subjected to Random Loads

Excited by ocean currents, random wave and vessel motion, deepwater drilling risers exhibit significant dynamic response. In time domain, a method is proposed to calculate the nonlinear dynamic response of deepwater drilling risers subjected to random wave and dynamic large displacement vessel motion boundary condition. Structural and functional loads, external and internal pressure, free surface effect of irregular wave, hydrodynamic forces induced by current and wave, as well as wave and low frequency (drift) motion of the drilling vessel are all accounted for. An example is presented which illustrates the application of the proposed method. The study shows that long term drift motion of the vessel has profound effect on the envelopes of bending stress and lateral displacement, as well as the range of lower flex joint angle of the deepwater riser. It can also be concluded that vessel motion is the principal dynamic loading of nonlinear dynamic response for the deepwater risers rather than wave force.     

Design Methods for Geotextile Tubes Application in Dike Construction

The technique of geotextile tubes used to construct dikes for land reclamation has been widely used. The tubes are usually filled with slun＇y of soil, such as sand, silt or clay. The tensile stress developed in the geotextile during filling the tube is the dominant factor for construction of a safe dike. The existing design methods are good for designing sausage shaped tubes and can not be directly applied for designing fiat tubes, which are commonly used in dike construction. This paper presents a procedure that can detenmine the relatiorrship among the tube size, the pumping pressure, the unit weight of the slurry, and the tensile stress developed in the geotextile during the tube filing. When the tubes are piling up to form the dike, the tubes in the bottom will sustain the load from the weight of the upper ones. A procedure is also developed to calculate the changes of the mechanical and geometrical behavior of the tubes under the load with a similar method. All these approaches have been programmed, which can help dike designers to select the suitable geotextile and determine the profile of the dike.     

基于OrcaFlex的钢悬链立管疲劳损伤预报

涡激振动是钢悬链立管疲劳损伤的重要诱导因素之一,因此涡激振动分析在钢悬链立管设计中占据重要地位。OrcaFlex在海洋工程领域功能强大、应用广泛,能够提供两种涡激振动疲劳损伤预报方法,分别是基于模态叠加法的频域预报方法和基于Iwan-Blevins尾流振子模型的时域预报方法。OrcaFlex的涡激振动时域预报模型只考虑了横流向涡激振动造成的疲劳损伤,基于OrcaFlex的时域预报方法开发了双自由度涡激振动尾流振子模型的接口,考虑了浮式平台运动对钢悬链立管的涡激振动激励作用,实现了钢悬链立管双自由度涡激振动疲劳损伤预报。     

海洋纤维增强柔性管压溃失效特性研究及参数敏感性分析

以一种黏结型的纤维增强柔性管作为研究对象,基于ABAQUS建立纤维增强柔性管的实体单元模型。根据二维 Hashin失效判据判断柔性管失效情况,充分考虑管道内外护套层塑性及纤维增强层复合材料渐进失效,建立纤维增强柔性管的压溃数值模型。将特征值法与弧长法相结合,计算得到了较为精准的纤维增强柔性管临界压溃压力及对应的外压—椭圆度曲线;并对影响柔性管临界压溃压力的几个敏感性参数如椭圆度、纤维缠绕角度、直线度进行分析。研究结果表明椭圆度和直线度偏差的增大及纤维缠绕角度的降低均会使柔性管的临界压溃压力下降,该结果对纤维增强柔性管的设计与使用均具有一定的参考意义。     

层间摩擦系数对非黏结柔性管抗拉铠装层轴压屈曲失效模式的影响研究

在柔性管运输、铺设安装和服役过程中,由于其抗拉铠装层钢带为柔性细长螺旋结构,当外部载荷超过临界值时,抗拉铠装层钢带容易发生屈曲失效。考虑非线性材料、几何大变形、层间接触和摩擦等非线性效应的影响,运用ABAQUS有限元软件建立了63.5 mm典型非黏结柔性管8层完整结构模型,研究了在抗拉铠装层不同层间摩擦系数的情况下,非黏结柔性管在轴向压缩载荷作用下的力学性能和屈曲失效模式。研究结果表明,层间摩擦系数对非黏结柔性管的抗压刚度和抗拉铠装层屈曲失效模式有较大影响,层间摩擦系数以0.1和0.2为分界点,抗压刚度和屈曲失效模式均呈现出“三段式”变化规律。研究成果可为海洋非黏结柔性管的结构设计和屈曲失效评估提供技术参考。     

内压载荷下输氢复合柔性管力学性能研究

中国氢能产业正随着碳中和愿景的不断推进而快速发展,由于氢气在钢管中容易引发“氢脆”现象,使用钢管输送氢气存在较大挑战,纤维增强复合柔性管作为一种非金属管道在氢气输送领域备受关注,其结构设计及强度分析是产业化应用的瓶颈。为探讨内压工况下输氢复合柔性管的结构响应,考虑不同层材料的各向同性及各向异性,基于三维各向异性弹性力学,建立了纤维增强输氢复合管道在内压作用下的力学理论模型,并采用数学方法求解管道位移微分方程,进而获得了N层缠绕增强层输氢复合管道在内压作用下的应力应变解析解,计算结果与内压作用下13层输氢复合柔性管的数值计算结果相符。管道的环向应力最大值出现在防渗透层,输氢软管的增强层承担约70%的载荷作用,径向应力绝对值大小随距离管道截面中心点的距离增大而减小。提出的力学行为分析模型及求解方法为设计输氢复合柔性管提供了重要的理论支撑。     

2004年4月1日磁通量传输事件特性的研究——通量管内电流密度、粒子运动与管轴方向的对比分析

本文利用Cluster四颗卫星上磁通门磁力计(FGM)的同时观测,采用旋度器方法(Curlometer),计算和分析了2004年4月1日12:24到12:54UT期间Cluster卫星观测的多个磁通量传输事件(FTEs)的特性。结果表明:磁通量管内电流密度较大,可达到约10-7A/m2。应用最小方向微分法(MDD),发现这些FTE事件具有准二维结构,即为圆柱形结构,其通量管轴线方向与管内电流方向及粒子运动方向基本平行。