Design Solutions for Jack up Platform Retrofitting

The paper is focused on the structural problems related to the retrofitting of a ship structure into a maritime self-elevating platform. The study is referred on the design of the global and local strengthening of the platform and legs structures. The joint structure built as the connection between the platform hull and the tubular legs, is designed so that to be acted by the special actuators. The total force provided by the actuators during the lifting operations is necessary to balance the total weight of the platform hull and operating equipment. The work described in the paper shows a methodology for FEM global and local strength calculation of platform structure and legs structure using site-specific parameters recommended by DNV rules, such as water depth, wave and wind loads. Also, the global static and dynamic behavior analysis of the jack up unit is presented. From the case study results it may conclude that the proposed methodology offers economic advantages to the field in which they are employed. In the paper, the platform structural capacity, incorporating yielding and buckling, is the limiting condition for the scenario under investigation.

基于JACK虚拟仿真的学龄前脑瘫儿童助行器人机优化设计

目的减少学龄前脑瘫儿童助行器的安全隐患,解决患儿在训练过程中的肢体二次损伤问题,提升助行器人机舒适性,对学龄前脑瘫儿童助行器进行优化设计。方法通过JACK虚拟仿真软件的RULA工具,分析得到学龄前脑瘫儿童在使用助行器过程中存在的不合理姿势,并对其进行人机工学与受力分析,提出改进方法并进行设计优化,最后导入JACK虚拟仿真软件进行风险与舒适性验证。结果优化后的学龄前脑瘫儿童助行器的使用受伤风险从4级降低到1级,患儿躯干弯曲力矩、L4/L5脊柱压缩力、剪切力的姿势载荷指数分别降低53%、47%、81%,上身各关节处于舒适角度。结论经过JACK仿真分析及人机优化后的助行器,有效降低了学龄前脑瘫儿童在康复训练中的二次损伤风险,减轻了患儿步行训练中的身体负担,提升了助行器使用的舒适性。

Study on General Performance of Jack-up Under Elevated Condition

Method of checking for jack-up elevated performance including leg structure strength, fixation system or jacking system beating capacity, pre-load requirements, spud can beating capacity and overturning stability is suggested in this paper. As an example, a jack-up with truss legs is analyzed by finite element analysis method. This paper may be helpful to the rig owners, operators and designers.

Soil-Structure Interaction Analysis of Jack-up Platforms Subjected to Monochrome and Irregular Waves

As jack-up platforms have recently been used in deeper and harsher waters, there has been an increasing demand to understand their behaviour more accurately to develop more sophisticated analysis techniques. One of the areas of significant development has been the modelling of spudean performance, where the load-displacement behaviour of the foundation is required to be included in any numerical model of the structure. In this study, beam on nonlinear winkler foundation （BNWF） modeling--which is based on using nonlinear springs and dampers instead of a continuum soil media--is employed for this purpose. A regular monochrome design wave and an irregular wave representing a design sea state are applied to the platform as lateral loading. By using the BNWF model and assuming a granular soil under spudcans, properties such as soil nonlinear behaviour near the structure, contact phenomena at the interface of soil and spudcan （such as uplifting and rocking）, and geometrical nonlinear behaviour of the structure are studied. Results of this study show that inelastic behaviour of the soil causes an increase in the lateral displacement at the hull elevation and permanent unequal settlement in soil below the spudcans, which are increased by decreasing the friction angle of the sandy soil. In fact, spudeans and the underlying soil cause a relative fixity at the platform support, which changes the dynamic response of the structure compared with the case where the structure is assumed to have a fixed support or pinned support. For simulating this behaviour without explicit modelling of soil-structure interaction （SSI）, moment- rotation curves at the end of platform legs, which are dependent on foundation dimensions and soil characteristics, are obtained. These curves can be used in a simplified model of the platform for considering the relative fixity at the soil- foundation interface.

Design of A Bionic Spudcan and Analysis of Penetration and Extraction Performances for Jack-up Platform

The mechanisms of soil structure interaction have drawn much attention in the past years in the installation and operation of jack-up platform. A bionic spudcan produced by biomimetic of egg and snail shell is proposed, and the performance of the penetration and extraction are analyzed by numerical method. The geometric contour of egg and snail shell is measured, and its mathematical model is established respectively. According to the structure of existing spudcan of jack-up platform, three kinds of typical biomimetic spudcan are designed. Furthermore, numerical analysis models of biomimetic spudcan are established respectively to study the soil structure interaction mechanism in the process of penetration and extraction, and contrastive analysis of resistance characteristics are carried out. To conclude, the results show that the biomimetic spudcan facilitates the platform installation, and it is also beneficial to the improvement of the bearing capacity of spudcan.

The Calculating Model of Structural Analysis for Jack-Up Rig Legs

The selection or establishment of structural calculating model is a matter of primary importance in structural analysis. By analysing the irrationality of the calculating models used by some research organizations at home and abroad in structural analyses for truss jack-up rig legs, this paper introduces a new calculation model which is more reasonable. This model can simulate better the load situation of a rig reflecting more precisely the effects of the leg loads caused by the spring support of gearboxes of the jacking system and the secondary bending moment raised by hull displacement under extreme conditions. The rig conversion was completed in 1989. In July 1991 the rig safely stood the frontal hitting of Typhoon with the wind speed of 52 m / s, which shows that the checking on the structure is correct.

Prediction Methods of Spudcan Penetration for Jack-up Units

Jack-up units are extensively playing a successful role in drilling engineering around the world, and their safety and efficiency take more and more attraction in both research and engineering practice. An accurate prediction of the spudcan penetration depth is quite instrumental in deciding on whether a jack-up unit is feasible to operate at the site. The prediction of a too large penetration depth may lead to the hesitation or even rejection of a site due to potential difficulties in the subsequent extraction process; the same is true of a too small depth prediction due to the problem of possible instability during operation. However, a deviation between predictive results and final field data usually exists, especially when a strong-over-soft soil is included in the strata. The ultimate decision sometimes to a great extent depends on the practical experience, not the predictive results given by the guideline. It is somewhat risky, but no choice. Therefore, a feasible predictive method for the spudcan penetration depth, especially in strata with strong-over-soft soil profile, is urgently needed by the jack-up industry. In view of this, a comprehensive investigation on methods of predicting spudcan penetration is executed. For types of different soil profiles, predictive methods for spudcan penetration depth are proposed, and the corresponding experiment is also conducted to validate these methods. In addition, to further verify the feasibility of the proposed methods, a practical engineering case encountered in the South China Sea is also presented, and the corresponding numerical and experimental results are also presented and discussed.

基于Jack的挖掘装载机驾驶室人机工程分析与改进设计

为提高挖掘装载机驾驶室的舒适性,采用人体模型建模分析法确定H点位置,并建立挖掘装载机驾驶室人机仿真系统。以人机分析软件Jack为工具,从驾驶员可视性、可达性及舒适性3方面进行挖掘装载机多作业姿势的人机合理性分析,根据仿真结果对中控台界面及控制部件布局进行改进设计,改进方案的分析校核结果表明:驾驶员可视域得到提升,常用控制部件位于驾驶员舒适可达范围内,改进后驾驶员的多个作业姿势舒适性得到提升。通过人机仿真软件对驾驶员多作业姿势进行人机合理性分析,较准确地发现了挖掘装载机驾驶室存在的设计缺陷,为具有复杂人机系统的工程装备驾驶室布局设计研究提供一定参考。

基于Jack的老年电动代步车人机工程设计与优化

目的满足行动不便的老年用户群体复杂的出行需求,提高电动代步车类工具使用过程中的舒适度。方法在传统老年电动代步车的基础上附加辅助站立结构,创新设计出一款坐、立两用的新型电动代步车,并借助Jack仿真软件,对老年用户坐姿驾驶和辅助站立支撑状态下的舒适度、可达域、可视域,以及上车过程中L4/L5下背部的受力情况进行分析,以验证关键人机交互结构、尺寸设计的合理性及舒适性。结论通过验证和调整,对电动代步车的初期设计方案进行改进,优化后的方案为老年电动代步工具的设计提供了参考,可以为满足老年用户复杂的出行需求、提高电动代步车类工具使用过程中的舒适度和安全性提供帮助。

Jack-up日费对钻修井机具比选的敏感性分析

低油价下大量自升式钻井平台(Jack-up)资源处于闲置状态,在油服公司为降低损失,允许Jack-up日费有较大谈判空间的情况下,对于推荐采用固定式钻修井机具开发的油气田,有必要反算出与推荐方案投资相平衡的Jack-up日费,从而与油服公司谈判,以不高于平衡日费的条件租赁Jack-up,达到降低开发成本的目的。通过研究Jack-up日费对油气田开发各组成费用的影响,得出了油气田开发投资随日费变化的计算方法,对海上油气田开发的钻修井机具选择具有重要的指导意义。

Discussion on Key Points of Wind Load of Jack-up Unit

The anti-overturning ability and structure safety of jack-up unit in in-place condition are often affected by environment loads, especially wind load. According to the MODU rule, the projected area method is used for calculating the wind load. However, the calculated results are conservative and not good for structure optimization design. In this paper, a 400 ft jack-up is studied as an example. Based on the wind tunnel test and numerical simulation method, some key points of wind load calculation, such as shielding effect, lift effect and shape coefficient of component, are discussed. The study shows that the points mentioned above, which are ignored in the MODU rule calculation, result in the conservative result.

Numerical simulation of frost jacking response of a single pile considering hydro-thermo-mechanical coupling

Permafrost is widely distributed in China and around the world.In permafrost regions,soil frost heave and thawing are severe and frequent,and can destabilize pile foundations.To this end,a finite element model of a single pile in frozen soil is established to investigate the frost heave and frost jacking response to ensure its safety in the Qinghai-Tibet Plateau.Firstly,a hydro-thermal coupling model of a single pile in frozen soil is established based on coupling parameters and initial and boundary conditions.Then the temperature and moisture distributions are analyzed through the established coupling model.A hydro-thermo-mechanical coupling model is developed by importing the ice content and temperature results.Simulation results indicate that the amount of frost heave is greater at locations closer to the ground surface,and the displacement is smaller for frozen soil that is closer to the side of the pile.The results on frost jacking behavior of piles from this study can serve as a reference for the design,construction and maintenance of foundations.

Uplift Resistance Calculation and Sensitive Analysis of Jack-up Wind Installation Vessels

The uplift resistance calculation is an important basis for the construction decisions of the jack-up wind installation vessel and the design of the jacking system,and determines the operation risk and reliability in the installation process of the wind turbine. The influence factors of the pile shoe's penetration depth and uplift resistance are analyzed,and the calculation model and flow of the uplift resistance are given. Based on a construction example,the influence rules are analyzed for the change of the pile shoe's structural parameters on the penetration depth and uplift resistance.The analysis results show that the penetration depth is more sensitive to the width of the pile shoe,and the height has greater influence on the uplift resistance than the length and width of the spud. With the increase of the height,the uplift resistance may increase rapidly.Although the decreases of the length,width and height of the pile shoe may reduce the uplift resistance,the penetration depth may increase in the meantime. This will increase the pulling pile time and reduce the construction efficiency. So the parameters of the pile shoe should be optimized according to the adaptable geology condition so as to obtain the optimal uplift resistance and working efficiency.

基于JACK的不同身高笔记本电脑使用者的脊椎受力状态研究

目的在探讨笔记本电脑放置位置对使用者胸椎、腰椎受力和头部屈曲的影响。方法通过Jack软件构建了P 1、P 5、P 50、P 95和P 99的数字人仿真办公模型,分析了屏幕在不同垂直距离和水平距离下人体spinetT1/T2、spineL4/L5受到的力矩和Head Flexion的角度,使用SPSS对获得的数据进行相关性分析。结果在坐姿使用笔记本电脑时,用户的身高越高,其胸椎和腰椎所承受的力矩也越大。笔记本电脑屏幕的高度对使用者的影响显著高于水平距离的影响。结论通过调整笔记本电脑的放置位置,特别是屏幕的高度,可以有效降低不同身高群体颈部和腰部的疲劳和疼痛症状,减少对身体的损伤。

基于人因学及Jack仿真的消防操作台设计

从人因学的角度出发,根据消防救援任务对车载单人消防机器人操作控制平台进行设计,并依托计算机辅助布局方法和双手作业分析,借助yaahp软件等进行操控器位置协助和布局,针对设计后的人机界面进行了Jack仿真分析,通过人因学多项反应时间实验及按键双手协调实验对设计效果进行分析评价,以减少长期作业带来的疲劳,有效提高作业人员操作的精准性。

Starting up Africa The Jack Ma Foundation launches a fund dedicated to young Africans wanting to create their own startups

On his second trip to Africa in August last year, Jack Ma said it is the entrepreneurs who will propel the African economy. The dynamic executive chairman of Alibaba Group, the Chinese e-conimerce giant, made the comment while speaking at a special event in Johannesburg, South Africa. He was there to announce a new $10-million prize to support African entrepreneurs.

基于JACK软件的人工检验台人因工效评价

为了提升成品检验台作业人员工作的舒适性,以J公司光伏新能源生产线的成品检验台为研究对象,基于工效学理论,运用Jack软件,构建数字人模型,对成品检验操作台进行建模仿真。对于数字人的工作环境进行了舒适度和疲劳度的检验,发现了其中存在的问题,同时提出了相应的改善措施。数据显示,通过调整工作台布局等方式,数字人的工作舒适度得到显著提升。

基于JACK平台的作战仿真研究

针对目前作战仿真Agent无法适应复杂战场环境、动态规划能力不足的问题,找到了一个基于BDI行为模型的多Agent智能开发平台JACK。基于此平台,开发了装甲步兵班阵地进攻作战仿真系统;依托JACK Team平台,设计了作战仿真Agent能力组件的结构、功能类和行为算法,构建了单兵行为模型和班组行为模型;通过表现模块,实现了JACK Team和Unity3D仿真环境数据交互。同过系统仿真数据统计,验证了JACK平台BDI模型的有效性和与开放环境的良好交互性。

基于Jack仿真的助浴产品作业过程人机优化设计

为解决助浴师在长期上门助浴作业时可能导致的肌肉骨骼疾病问题,本文对助浴产品作业过程进行人机分析和设计优化。首先基于HTA法对助浴行为进行分层归纳,再利用Jack软件模拟助浴环境,对助浴任务进行分析,最后基于分析结果进行人机优化设计实践。本文提出可供参考的助浴床尺寸设计标准,为助浴床增加辅助翻身结构。有助于减少助浴师的疾病风险及提高工作效率,为助浴产品行业提供人机设计标准,促进行业的发展和创新。

Application Strategies of Pipe Jacking Technology in Municipal Rainwater Pipeline Engineering

Traditional construction techniques have a significant impact on the environment and are associated with long construction durations in the construction of municipal rainwater pipelines.Pipe jacking technology,a new type of pipeline construction method,enables non-excavation construction and can address the shortcomings of traditional pipeline construction.This article analyzes the concept and application advantages of pipe jacking technology.Combining engineering examples,it explores the application strategies of pipe jacking technology in the construction process of municipal rainwater pipelines for reference.