自升式平台动态响应特性及其控制研究

发布时间：2019-02-20 21:26

【摘要】：随着人类开发海洋资源步伐的不断加快,自升式平台成为了海上油气资源勘探、开采的重要技术装备。然而,恶劣的海洋环境载荷会使自升式平台产生过大的船体位移及速度,从而发生屈服及断裂失效,且长期的船体振动使得平台极易发生疲劳失效现象;因此,自升式平台的动态响应特性将关系到整个平台的工作安全性能。本文首先研究了Super M2自升式平台桩腿及升降锁紧系统的力学性能,并基于Abaqus/Aqua模块分析了自升式平台的动态响应特性及TMD装置对平台动态响应的控制特性。其主要研究内容及结论如下:1)基于弹塑性理论分析研究了各特征作用角度下桩腿的力学性能,即桩腿位移与侧向力的变化关系曲线,基于弯曲变形积分求解法提出了一种桩腿等效建模方法,并通过模态分析对桩腿详细模型、等效模型及广义模型的固有频率及振型进行了对比分析,其中,桩腿广义模型与详细模型前两阶固有频率的误差率为84.65%,而桩腿等效模型的前两阶固有频率误差率仅为2.92%-15.86%。2)通过建立自升式平台升降锁紧系统的详细数值模型,仿真分析了各特征作用角度下升降锁紧系统的力学性能,获得了上/下导向与桩腿及锁紧系统横向、垂向、扭转、弯转的连接刚度曲线;其中,上/下导向与桩腿及锁紧系统的垂向和扭转刚度值为常量,而锁紧系统的横向及弯转刚度呈现各向异性和非线性特性。3)根据以上研究结果及相关规范要求建立了自升式平台动态响应分析模型,通过模态分析得到了作业工况及暴风自存工况下自升式平台的固有频率及振型,其中,作业工况下自升式平台的前三阶固有频率分别为0.0503494Hz、0.051409Hz和0.0597066Hz,而暴风自存工况下的前三阶固有频率分别为0.0533153Hz、0.0544372Hz和0.0632236Hz,且均分别与两种工况下的波浪频率极为接近。4)运用斯托克斯波理论研究了各特征角度海洋环境载荷作用下自升式平台的动态响应特性,基于Sadek提出的TMD装置最优参数计算方法,研究了TMD装置对自升式平台动态响应的控制特性,并以此为基础,分别论述了TMD装置与自升式平台的质量比、刚度比及阻尼比对平台运动参量的控制特性。研究结果表明,作业工况及暴风自存工况下自升式平台的最大位移及速度均出现于特征角度为90°时,且TMD装置对自升式平台的运动参量具有显著的控制效果,其中,90°暴风载荷作用下,自升式平台X、Y方向的位移及速度振幅分别减小了59.4%、68.16%、35.01%和48.72%。
[Abstract]:With the rapid development of marine resources, the jack-up platform has become an important technology and equipment for offshore oil and gas exploration and exploitation. However, the severe marine environment load will cause excessive ship displacement and velocity, which will lead to yield and fracture failure, and the long-term ship vibration will make the platform prone to fatigue failure. Therefore, the dynamic response of the jack-up platform will affect the safety performance of the whole platform. In this paper, the mechanical properties of Super M2 jack-up platform pile leg and lifting and locking system are studied, and the dynamic response characteristics of the platform and the control characteristics of the TMD device to the platform dynamic response are analyzed based on the Abaqus/Aqua module. The main research contents and conclusions are as follows: 1) based on the elastoplastic theory, the mechanical properties of the pile leg under various characteristic action angles are analyzed and studied, that is, the relationship curve between displacement and lateral force of the pile leg. Based on the integral method of bending deformation, an equivalent modeling method for pile leg is proposed. The natural frequencies and modes of the detailed model, equivalent model and generalized model of pile leg are compared and analyzed by modal analysis. The error rate of the first two natural frequencies of the generalized pile-leg model and the detailed model is 84.65. The error rate of the first two natural frequencies of the equivalent model of pile and leg is only 2.92-15.86.2) by establishing a detailed numerical model of the lifting and locking system of the self-elevating platform, The mechanical properties of the lifting and locking system under different characteristic action angles are simulated and analyzed. The connection stiffness curves of the upper / lower steering and pile-leg and the locking system are obtained, including transverse, vertical, torsional and flexural stiffness curves. Among them, the vertical and torsional stiffness of the upper / lower guidance and the pile leg and the locking system are constant, The lateral and bending stiffness of the locking system is anisotropic and nonlinear. 3) according to the above research results and related specifications, the dynamic response analysis model of the self-lifting platform is established. Through modal analysis, the natural frequencies and modes of the jack-up platform are obtained under the operating condition and the storm self-storage condition. The first three natural frequencies of the platform are 0.050 3494 Hz and 0.0597066 Hz, respectively, under the operating conditions, and the first three natural frequencies of the platform are 0.050 3494 Hz and 0.0597066 Hz, respectively, in which the first three natural frequencies are 0.050 3494 Hz and 0.0597066 Hz, respectively. The first three natural frequencies of the storm are 0.0533153Hz, 0.0544372Hz and 0.0632236Hz, respectively. And the wave frequencies are very close to those under two operating conditions. 4) the dynamic response characteristics of the jack-up platform under the action of marine environmental loads at different characteristic angles are studied by using Stokes wave theory. Based on the optimal parameter calculation method of TMD device proposed by Sadek, the control characteristics of TMD device to the dynamic response of jack-up platform are studied. On the basis of this, the mass ratio of TMD device and jack-up platform is discussed respectively. Stiffness ratio and damping ratio control characteristics of platform motion parameters. The results show that the maximum displacement and velocity of the platform appear when the characteristic angle is 90 掳, and the TMD device has a remarkable control effect on the motion parameters of the platform. Under the action of 90 掳storm load, the displacement and velocity amplitude in the direction of XY of the jack-up platform are reduced by 59.48.16% and 48.72%, respectively.
【学位授予单位】：江苏科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE951

【参考文献】