发射筒热力耦合场下力学性能研究

发射筒是潜载导弹发射装置的重要组成部分,需要有足够的强度和刚度满足不同发射条件。本文结合实验数据,建立仿真模型,通过静力分析得到压力和结构载荷作用下的变形和应力分布;通过温度场分析得出筒上温度分布及温度载荷作用下应力应变情况;通过热力耦合场分析得到发射筒整体变形与应力分布。结果表明:在气压和结构载荷作用下发射筒最大变形1.5 mm,筒底应力125 MPa;温度场下温度自筒底段至筒体段阶梯分布,热应力作用下最大变形3.5 mm,最大应力317 MPa;热力耦合场下发射筒最大变形4.23 mm,最大应力384 MPa。3种工况下分析结果显示温度载荷是影响发射筒应力应变的主要因素,设计时在筒底圆弧面中心处需要加强。     

风切变对风电机组塔筒定制化载荷特性影响

塔筒定制化过程中,塔底合弯矩极限载荷和塔底俯仰弯矩疲劳等效载荷是塔筒定制化设计的主要载荷。影响塔筒定制化设计主要载荷的因素有很多,本研究分析风切变幂指数对风电机组塔筒定制化载荷特性的影响,并以当前主流机型6.XMW风电机组,运用当前主流仿真软件GH Bladed软件,对于相同外部条件不同风切变幂指数下的风电机组塔筒定制化载荷仿真计算,计算分析出不同风切变幂指数对于风电机组塔筒定制化塔底合弯矩极限载荷和塔底俯仰弯矩疲劳等效载荷的特性影响规律并运用至风电机组塔筒定制化中去。     

锚绞机绞缆筒的载荷计算和结构分析

介绍了应用ANSYS软件,对绞缆筒进行线性静力结构分析的方法和结果。从分析绞缆筒所承受的载荷特点入手,提出了缆绳对于筒壁的正压力与摩擦力的计算公式和用表函数对非线性载荷进行加载的方法。     

圆筒型FPSO阻尼板结构强度计算方法研究

阻尼板作为增加圆筒型FPSO附连水质量和黏性阻尼的关键装置,可有效降低垂荡和横摇运动.阻尼板通常为与柱型筒体相连的悬臂梁式箱型结构,阻尼板及其与筒体连接区域处的结构设计及强度校核是圆筒型FPSO结构设计的关键.以阻尼板处最大压力及最大阻尼力作为目标设计载荷,采用子模型法校核其结构强度,以总强度分析得到的变形作为子模型边界条件,采用Morison法模拟黏性阻尼载荷,对阻尼板结构强度进行校核分析,为阻尼板的结构设计提供依据和指导.     

海上风电机组门洞焊缝应力计算及测试验证

风电机组的塔筒门框焊缝应力状态复杂,且在机组全寿命周期服役过程中承受超高周的动态载荷,其疲劳可靠性是塔筒设计工程师需重点关注的设计项点之一。由于塔筒面内弯矩载荷Mx、My塔筒疲劳设计的主导载荷,在进行塔筒门框焊缝疲劳设计时仅考虑面内弯矩载荷即可,门框焊缝的疲劳强度计算精度取决于焊缝处评估应力的计算精度,门框焊缝疲劳强度的评估应力通常采用国际焊接学会（IIW）推荐的热点应力法计算得到。文章首先针对某大兆瓦海上风电机组得塔筒门框焊缝区域进行有限元仿真计算,得到在塔筒面内弯矩Mx、My的单位载荷作用下选定的多处门框焊缝应力插值点的应力结果。然后基于测试得到的塔底截面弯矩时间历程,线性推导得到各焊缝应力插值点处的应力时间历程。最后将推导得到的应力时间历程与测试得到的应力时间历程进行对比,以此验证门框焊缝应力计算模型的正当性。对比结果表明,文章采用的门框焊缝应力计算模型是满足工程设计需求的。     

FPSO火炬塔设计与制作要领

介绍火炬塔架设计原理,就火炬塔选型、腹杆和横隔设置、平台设置、排气筒安装问题分别提出解决方案,用Ansys软件建模对结构进行应力分析,以验证结构强度满足功能要求,对降低其疲劳强度的TKY节点提出解决办法。     

篱笆式卷筒结构的动态特性研究

为了提高篱笆式卷筒结构设计的安全性和可靠性,分析了多层钢丝绳缠绕作用下卷筒体承受径向外压力、横向力和棘爪力的受力情况,利用有限元技术计算了卷筒在筒体、端板作用力下的屈曲特征,将卷筒体视为变质量系统得到了不同缠绕情况下的结构模态,最后分析了不同工作压力载荷状态下整体结构的频率响应特性。研究工作为卷筒体结构的优化设计提供了分析手段和参考依据。     

某型导弹发射装置筒盖系统降载技术研究

通过分析筒盖系统模态和筒口压力场规律,得出筒盖系统最大载荷是由耦合共振引起的结论。根据该结论,提出了在筒盖锁定器与其连接支撑之间增加阻尼器的降载方案。经理论分析,该方案可大大降低筒盖系统在筒口压力场作用下的最大载荷。     

浮式起重机篱笆式卷筒的结构强度及稳定性分析

为了提高浮式起重机篱笆式卷筒结构设计的安全性和可靠性,分析了包括筒体压力、端板压力和棘爪力在内的多层钢丝绳缠绕作用下卷筒体的受力情况,利用有限元技术计算了筒体-端板的结构强度和变形。同时给出了目前常用的稳定性计算方法,根据有限元法得到了卷筒在承受径向外压力、横向力作用下的整体稳定性,并对各种计算方法进行了比较。研究工作为结构优化设计提供了分析手段和参考依据。     

锥面边界球冠有机玻璃观察窗应力及试验

依据有机玻璃窗设计手册对锥面边界球冠有机玻璃观察窗进行初步设计。结合该类型有机玻璃观察窗的几何形式和受力情况给出其结构应力理论计算公式,并据此进行观察窗的优化设计。对设计的观察窗建造实尺度样机进行压力筒测试,监控实时应变和极限载荷,对结构应力和极限载荷理论计算值进行验证。     

基于疲劳强度谱分析的火炬塔支撑结构设计

火炬塔是FPSO上主要装置之一,火炬塔支撑结构的疲劳强度是结构设计重点关注的对象。在介绍疲劳谱分析方法及BV-Homer软件的基础上,总结整理出基于该软件的疲劳谱分析的基本流程,利用BV-Homer软件对火炬塔支撑结构原设计方案的疲劳损伤进行了分析校核,根据计算结果对支撑结构设计方案进行了修改。研究表明：原设计方案的疲劳强度不满足规范要求,修改方案的疲劳寿命大幅提高,满足规范要求;火炬塔支撑外侧主管及外侧热点的疲劳损伤较大,设计时需要重点关注;增加肘板、热点区域结构板厚是提高疲劳强度的有效方式;基于谱疲劳分析的结构疲劳强度分析方法可应用于其他类似结构。     

大型集装箱船舷侧外飘砰击特性研究

基于概率随机理论研究大型集装箱船舷侧外飘砰击特性,预报不同海况和航速情况下船舶非线性运动响应时历,采用Chuang理论计算船艏舷侧区域的外飘砰击压力,对随机海浪下集装箱船外飘砰击概率、砰击压力极值沿船长和高度方向空间分布规律进行分析,在直接预报的基础上给出载荷的确定方法。     

超大型集装箱船艏艉砰击强度直接计算方法

超大型集装箱船的船艏显著外飘、船艉宽平外悬,使其在恶劣海况下航行时容易发生严重的砰击。为确保船体艏艉部结构在砰击中不发生损坏,需要研究作用到艏艉外板上的砰击压力,并以此为设计载荷来校核外板和相连结构的强度。目前对集装箱船砰击局部强度的校核要求仍以经验公式为主,但是为提高对超大尺度船舶强度校核的可靠性,近年来推出了砰击的直接分析方法。本文初步分析了砰击直接分析方法的基本原理,并运用该方法对20,000 TEU集装箱船的艏、艉部砰击压力以及最小板厚要求进行了研讨,其结果可为超大型集装箱船的结构设计提供重要的参考。     

大型集装箱船迎浪航行的外飘砰击压力研究

该文采用直接计算法研究一艘大型集装箱船迎浪航行时的外飘砰击压力特点。先基于三维势流理论Rankine面元法,应用DNV船级社的商业软件Wasim计算出该船在压载时不同海况下以不同航速航行时在非规则波中时域内的非线性运动响应时历,再根据Wagner型冲击理论计算得到该集装箱船艏外飘区域的外飘砰击压力。最后,依据概率随机理论,得到不同工况下的外飘砰击概率以及外飘砰击压力极值,并分析概率和极值特点。     

Efficient calculation of slamming pressures on ships in irregular seas

An efficient method for calculation of the slamming pressures on ship hulls in irregular waves is presented and validated for a 290-m cruise ship. Nonlinear strip theory was used to calculate the ship–wave relative motions. The relative vertical and roll velocities for a slamming event were input to the slamming calculation program, which used a two-dimensional boundary element method (BEM) based on the generalized 2D Wagner formulation presented by Zhao et al. To improve the calculation efficiency, the method was divided into two separate steps. In the first step, the velocity potentials were calculated for unit relative velocities between the section and the water. In the next step, these precalculated velocity potentials were used together with the real relative velocities experienced in a seaway to calculate the slamming pressure and total slamming force on the section. This saved considerable computer time for slamming calculations in irregular waves, without significant loss of accuracy. The calculated slamming pressures on the bow flare of the cruise ship agreed quite well with the measured values, at least for time windows in which the calculated and experimental ship motions agreed well. A simplified method for calculation of the instantaneous peak pressure on each ship section in irregular waves is also presented. The method was used to identify slamming events to be analyzed with the more refined 2D BEM method, but comparisons with measured values indicate that the method may also be used for a quick quantitative assessment of the maximum slamming pressures.     

水力式升船机塔楼结构分析

塔楼结构是升船机的主体建筑物,针对景洪水电站水力式升船机塔楼的受力特点,采用数值计算方法及模型试验方法对水力式升船机塔楼结构进行深入研究。结果表明:数值计算结果和模型试验结果基本一致。通过施工完建后的相关监测结果对该设计进行论证,可为同类水力式升船机的塔楼设计提供借鉴。     

浅水塔架式单点系泊系统低频响应实验研究

浅水中,单点系泊系统可能存在显著的低频运动,低频大幅运动响应会给系泊系统设计带来严重影响,是系泊系统设计的控制因素之一,在水动力性能预报时必须仔细予以考虑。针对HYSY113FPSO单点系泊系统在浅水风浪流条件下的运动性能进行了物理模型试验研究和数值对比,定量分析了低频运动的运动量和产生的原因,所得结论可供今后浅水水域塔架式单点系泊系统设计参考。     

Numerical and experimental analysis of bow flare slamming on a Ro–Ro vessel in regular oblique waves

A method for the prediction of slamming loads on ship hulls is presented and validated for a 20-knot, 120-m car carrier. A nonlinear strip theory is used to calculate the relative motions of ship and wave. The relative vertical and roll velocities for a slamming event are given as input to the slamming calculation program, which is based on a generalized two-dimensional Wagner formulation and solved by the boundary element method. The method is fast and robust. Model tests of a car carrier have been carried out in regular head, bow, and bow quartering waves of various heights. Slamming on two panels in the upper part of the bow flare has been studied. It has been found that the water pile-up around the bow due to the forward speed of the vessel significantly increases the slamming pressures. A simplified way of including this effect is presented. When the calculated slamming pressures are corrected for 3D effects, they compare well with the measured data. Since the effect of the wave elevation due to the forward speed and the effect of three-dimensional flow act in opposite directions, excluding both of them produced results that also agreed quite well with the experiments, especially for the most severe slamming events.     

On the vibrational characteristics of a two-tier scaled container stack

It is estimated that around 10,000 containers are lost during maritime transportation every year, representing an economic loss to the liner industry. Regulations and norms used to calculate values to secure them to the ship’s deck account for static loads only, neglecting more realistic conditions. This paper describes an approach to simulate a two-tier scaled model of a 20-ft ISO freight container and its linking connectors, denominated twist locks, subject to a dynamical load induced by its base. To analyze this problem two methods were employed: a shaking table test and finite-element analysis. Results of this study indicate that the numerical model built to simulate two-tier container stack dynamics is a promising tool for further studies. Moreover, the model is able to predict conditions close to real situations faced by container stacks while stored on deck.     

Integrated design optimization of spar floating wind turbines

A linearized aero-hydro-servo-elastic floating wind turbine model is presented and used to perform integrated design optimization of the platform, tower, mooring system, and blade-pitch controller for a 10 MW spar floating wind turbine. Optimal design solutions are found using gradient-based optimization with analytic derivatives, considering both fatigue and extreme response constraints, where the objective function is a weighted combination of system cost and power quality. Optimization results show that local minima exist both in the soft-stiff and stiff-stiff range for the first tower bending mode and that a stiff-stiff tower design is needed to reach a solution that satisfies the fatigue constraints. The optimized platform has a relatively small diameter in the wave zone to limit the wave loads on the structure and an hourglass shape far below the waterline. The shape increases the restoring moment and natural frequency in pitch, which leads to improved behaviour in the low-frequency range. The importance of integrated optimization is shown in the solutions for the tower and blade-pitch control system, which are clearly affected by the simultaneous design of the platform. State-of-the-art nonlinear time-domain analyses show that the linearized model is conservative in general, but reasonably accurate in capturing trends, suggesting that the presented methodology is suitable for preliminary integrated design calculations.