TLD的减振原理及其在JZ20－2MUQ平台减冰振中的应用研究

ＴＬＤ在基底运动下内部液体对基底结构的作用可由分析液体运动或直接通过试验测定得到，将所得的ＴＬＤ对基底结构作用与基底运动的关系直接应用到结构动力平衡方程中，求得结构系统在安装ＴＬＤ后在外力作用下的响应。根据这一思路，建立了ＴＬＤ减振作用的分析步骤和表达式。运用该方法对ＪＺ２０－２ＭＵＱ平台利用ＴＬＤ减冰振进行了试验和分析研究。首先测定在ＪＺ２Ｏ－２ＭＵＱ平台减冰振中采用的原型ＴＬＤ的基底剪力关于基底位移的传递函数和阻尼系数，将测量值代入在安装ＴＬＤ后的结构响应关于外力传递函数表达式中求得其值，由安装ＴＬＤ所带来的结构响应传递函数值变化推算减振效果。此外，通过ＪＺ２Ｏ－２ＭＵＱ平台利用ＴＬＤ减振的室内模拟和现场试验验证该方法预报结果是可靠的。     

固定式海洋平台利用TLD的减震研究

本文研究固定式海洋平台利用调谐液体阻尼器（ＴｕｎｅｄＬｉｑｕｉｄＤａｍｐｅｒ，简称ＴＬＤ）减小地震反应的方法。首先探讨了调谐频率比、激磁频率比对减震效果的影响，在此基础上建立了ＴＬＤ——平台系统的力学模型和运动方程，通过数值计算验证了该方法的有效性     

冰激结构振动的非线性分析

冰对结构的作用表现为冰的变形和破碎两个阶段,具有间隙非线性特性.考虑到这个特性,我们利用非线性分析方法建立了非线性的冰-结构相互作用的动力学模型,从理论上阐明,冰激柔性结构的振动是一种多频干扰、自激和强迫的耦合振动系统,并研究了试验中观察到的锁频现象的机理.本文得到的冰力计算公式可用于海洋工程结构的设计计算.     

桶型基础结构与土壤相互作用的有限元—无限元—接触元耦合线性分析

桶型基础是一种新型的海洋基础结构型式，在负压作用下的下沉过程中，桶型基础结构与地基产生了相互作用，考虑结构与土壤的相互作用的强度分析为桶型基础的设计提供依据，本文将有限元－无限地－接触元相耦合的线性数值分析方法引入桶型基础的结构与土壤之间的相互作用的强度分析，采用接触单元考虑结构与土壤之间的错动滑移及拉裂，采用无限元更有效地反映地基无限域的远场效应，还推导出三节点，七节点，八节点三种新形式的单向无限地坐标映射函数，应用该方法的计算结果与模型试验结果比较，取得较好的效果。     

极端荷载作用下海洋导管架平台体系可靠度分析

采用非线性倒塌分析方法，考虑桩－土－结构的非线性相互作用，研究了导管架平台在极端荷载作用下承载能力的计算模型，分析了平台结构体系在极端荷载作用下的全倒塌全过程，在此基础上，结合蒙特卡洛法，提出了海洋导管架平台结构的体系可靠度计算方法。最后对工程实例－涠11－4C海洋平台的结构进行了体系可靠性分析，并对比分析了不同的荷载效应计算公式对计算经的影响，研究表明计算经满足工程设计要求，便于工程应用。     

大洋钻探与中国边缘海沉积地质学

边缘海沉积地质学研究在大洋钻探计划中占据着重要地位，也是我国的优势所在，应该成为我国ＯＤＰ近期工作的主要内容。本文讨论了与ＯＤＰ有关的几个中国边缘海沉积地质学问题：古黑潮的演变与陆海相互作用，长江、黄河入海时间及其对海洋沉积作用的影响，冲绳海槽的沉积相和沉积体系，古季风与海平面变化，这些问题的深入研究与解决将会为实现ＯＤＰ的学术目标，为全球变化研究做出重要贡献。     

重力式单腿平台结构相互作用体系平、扭动力响应分析

本文主要对钢筋混凝土重力式单腿海洋平台结构相互作用体系在地震激励下进行了响应分析。按波动理论,建立土—结构—流体相互作用体系的非线性运动方程组。它包含了两类相互作用问题:土—结构相互作用;流体—结构相互作用。分析了在不同方向地震SH波输入下非对称结构及流体作用等影响对体系的地震响应,最后结合一个简单的例子给出了数值计算结果。     

海洋桩基平台地震随机响应分析

本文应用地震随机响应分析理论,研究了海洋桩基平台地震随机响应分析方法。该分析方法将强地面运动视为三向平稳白噪声随机过程,同时考虑了桩土相互作用和水与结构的耦联作用。应用该方法对一典型平台进行了计算,并与现行的响应谱法进行了比较,从而验证了本文所述方法的适用性。     

筏式波浪能发电装置浮体水动力相互作用与能量俘获研究

基于三维势流理论,建立筏式波浪发电装置多浮体水动力模型。利用AQWA水动力软件研究多浮体水动力相互作用对发电装置浮体单元水动力系数的影响;将能量转换系统等效成刚度-阻尼模型后,对其进行不规则波时域模拟,对比分析方向谱和频率谱波浪模型对波浪发电装置能量吸收的影响。结果表明:浮体之间的水动力相互作用对浮体单元纵荡方向上的附加质量与辐射阻尼系数有明显的影响,对垂荡和纵摇方向上的水动力系数影响较小;不同的波浪模型下,能量俘获功率有着较大的差别,特别是在迎浪状态下。     

流体——重力式锥状单腿平台结构——土相互作用体系的地震动力响应

本文用配点法对流体——重力式锥状单腿平台结构——土相互作用体系在地震作用下的动力响应问题进行了研究。采用频域分析法，将锥柱体Ｎ等分，利用运动方程和边界条件联立解方程组，继而求出平台结构顶端弹性位移和腿柱所受的动水压力、基础平移和基础转角的频响函数。分析不同锥角下体系的动力响应的影响，并分析研究了刚性地基和考虑土——结构相互作用时结构体系的动力响应情况，得到一些很有益的结果。     

Lateral Vibration Behavior Analysis and TLD Vibration Absorption Design of the Soft Yoke Single-Point Mooring System

Mooring system is the key equipment of FPSO safe operation. The soft yoke mooring system is regarded as one of the best shallow water mooring strategies and widely applied to the oil exploitation in the Bohai Bay in China and the Gulf of Mexico. Based on the analysis of numerous monitoring data obtained by the prototype monitoring system of one FPSO in the Bohai Bay, the on-site lateral vibration behaviors found on the site of the soft yoke subject to wave load were analyzed. ADAMS simulation and model experiment were utilized to analyze the soft yoke lateral vibration and it was determined that lateral vibration was resonance behaviors caused by wave excitation. On the basis of the soft yoke longitudinal restoring force being guaranteed, a TLD-based vibration damper system was constructed and the vibration reduction experiments with multi-tank space and multi-load conditions were developed. The experimental results demonstrated that the proposed TLD vibration reduction system can effectively reduce lateral vibration of soft yoke structures.     

Suppression of Wave-Excited Vibration of Offshore Platform by Use of Tuned Liquid Dampers

This paper describes experimenlal and theoretical investigations of Tuned Liquid Damper (TLD) characteristics tor suppressing the wave-excited structural vibration. The structural model lor the experiments is scaled according to a full size offshore platform by matching their dynamic properties. Rectangular TLDs of different sizes with partially filled liquid are examined. By observing the performance and behavior of TLDs through laboratory experiments, the study investigates the influence of a number of parameters, including container size, container shape, frequency ratio, and incident wave characteristics. In an analytical study, a mathematical model that describes the nonlinear behavior of liquid in TLD and the interaction of TLD and structure is prerequisite. The validity of the model is evaluated and simulating results can reasonably match the corresponding experimental results.     

Study on the dynamic characteristic of a U-type tuned liquid damper

By means of Lagrange's equation, the “coupled” equations of motion for a horizontal plate carrying a U-type tuned liquid damper (TLD) are derived. The “uncoupled” equations of motion for the liquid (in the TLD) and the structural system are then obtained by decoupling the “coupled” ones. Unlike the existing literature to indirectly determine the natural frequencies of a damped vibrating system by using the resonant method, the “complex” eigenvalues of the coupled damped system are obtained directly from the associated eigenvalue equations. Besides, the pressure intensities in the two air chambers and the sizes of the two vertical tanks together with the horizontal conduit are arbitrary in the formulation of this paper. The influence of some key parameters of the TLD on the dynamic responses of the structural system is studied.     

A simplified 3-D human body–seat interaction model and its applications to the vibration isolation design of high-speed marine craft

High-speed boats experience a harsh vibration environment and human response to this environment is of increasing interest to naval architects who wish to mitigate the effects of vibration and shocks. Based on published experiment data, a three-dimensional human body model with one degree-of-freedom in each direction is established. This model is combined with a simple seat model to construct a simplified 3-D human body–seat interaction model for naval architects to investigate the integrated interaction system when subjected to ship motions. The governing equations describing the dynamics of the human body–seat interactions are formulated and their theoretical solutions are derived. This model, in association with the experimental data recorded on board a high-speed marine craft, is used to study seat isolation system designs. The spring coefficient of the seat isolation system is chosen to avoid any resonance of the human–seat interaction system excited by sea waves. The damping coefficient of the seat isolation system is determined to attenuate motions at the most common excitation frequencies. The designed system is further checked by considering its response to an individual slam impact where the designed system is compared with typical existing seats to illustrate the potential advantages of the proposed approach. In addition the designed seat is compared with existing seats excited by actual boat loads. The study provides a simplified, effective approach for high-speed craft seat design in reducing the shock and vibration level experienced by the crew.     

Heave compensation system of lifting pipeline for deep-sea mining based on combined action of vibration absorber and accumulator

ABSTRACT

A heave compensation system combined with a vibration absorber and accumulator is proposed, with regard to the requirement for poly-metallic nodule mining systems at an ocean depth of 6,000?m in China. The principle of the compensation system was analyzed, its main parameters were designed, and its mathematical model was established. The system performance was simulated and analyzed in MATLAB, and the frequency domain characteristics and compensation rate of the system with different volume accumulators, and with or without vibration absorbers, were compared. A simulation test of the compensation system was conducted. The proposed compensation system had a better compensation effect for a random wave interference under level-6 sea conditions, and the compensation rate being more than 72% with optimal system parameters.     

基于ABAQUS的轨道振动特性有限元仿真分析

以某水池轨道系统为研究对象,考虑支座对轨道固有频率的影响,采用三维变形体单元、三维变形壳单元、三维变形梁单元分别建立轨道有限元模型。基于特征值法,计算轨道系统一阶固有频率,对比评估轨道的振动特性,找出规律,指出不同方法的特点及工程中针对不同方法的取舍,总结可指导设计性的结论。旨在为以后设计中有关轨道振动特性计算及相似平台设计提供参考指导。     

Mooring system of ocean turbulence observation based on submerged buoy

A comparison experiment has been taken in the Kiaochow Bay between a newly designed mooring turbulence observation instrument (MTOI) and microstructure profiler MSS60 made by Sea & Sun. The whole observing system is based on a submerged buoy, in which the turbulence observation instrument is embedded, with a streamline-shape floating body, which is made of buoyancy material of glass microsphere. For the movement of seawater and the cable shaking strongly anytime influence the behaviors of the floating body, the accelerate sensors are used for the vibration measurement in the instrument together with the shear probe sensor. Both the vibration data and the shear data are acquired by the instrument at the same time. During data processing, the vibration signals can be removed and leave the shear data which we really need. In order to prove the reliability of the new turbulence instrument MTOI, a comparison experiment was designed. The measuring conditions are the same both in time and space. By this way, the two groups of data are comparable. In this paper, the conclusion gives a good similarity of 0.93 for the two groups of shear data in dissipation rate. The processing of the data acquired by MTOI is based on the cross-spectrum analysis, and the dissipation rate of it matches the Nasmyth spectrum well.     

Improved description of global mixed-layer depth using Argo profiling floats

A global data set describing the gridded mixed-layer depth (MLD) in 10-day intervals was produced using high-quality Argo float data from 2001 to 2009. The characteristics and advantages provided by the new MLD data set are described here, including a comparison based on two different thresholds and using data sets of different vertical and temporal resolution. The MLD in the data set was estimated on the basis of a shallower depth of the iso-thermal layer (TLD) or iso-pycnal layer (PLD), calculated using the finite difference method. The MLD data are incorporated into 2° × 2° grid in the global ocean, including marginal seas. Also, two threshold values were used to examine differences in the MLD and its seasonal temporal variability. The characteristics and advantages of using the Argo 10-day intervals to determine the MLD were then confirmed by comparing those data with the station buoy daily means and the Argo monthly means. With respect to vertical and temporal resolutions, the Argo 10-day data has two distinct advantages: (1) improved representation of the MLD vertical change due to high vertical resolution, especially during periods of large MLD variability and (2) more detailed representation of the temporal change in MLD than achieved with the Argo monthly mean data, especially from winter to spring in mid and high latitudes. These advantages were maintained in the case of a larger threshold despite the fact that the MLD is rather deep and the detailed variation in its distribution differs depending on the season and location. This study also investigated the relative influence of TLD and PLD to the MLD calculation for each grid. Generally, the MLD is primarily determined based on the PLD at low and mid latitudes (TLD > PLD), whereas the TLD is more important at high latitudes, especially in winter (TLD < PLD). In the case of a larger threshold, the area of the larger PLD influence spreads polewards because of the greater effect of salinity in winter. Although there are some differences in the effect of temperature and salinity in estimations of the MLD, both are indispensable factors for the MLD estimations even at different thresholds.     

基于实测的导管架海洋平台振动对人员安全评价

目前我国的海洋工程结构中,导管架式海洋平台占有很大比重,动荷载作用下导管架式海洋平台的振动问题日益突出。随着石油开发向深海进军,平台结构柔性更大,振动问题更为显著,可能对结构、设备及人员造成一定的安全隐患。基于现场监测获得的导管架平台振动响应,结合相关规范给出振动对人体的影响,提出人员感受评价流程。最后,以渤海、南海海域的导管架平台为例,基于现场监测,分析了结构的振动特性及作业人员在相应振动环境下的感受。此方法对导管架平台上部作业人员的工作与安全保障提供了科学依据。