气垫船铝合金整体壁板应用初探

气垫船的高速性特点决定了全船重量控制的重要性。在影响结构重量的主要因素中,材料的选择尤为重要,为此大、中型气垫船船体材料都采用铝合金。而传统铝合金焊接结构在实际应用中存在着焊接变形较大且难以控制,焊缝和焊接热影响区力学性能下降等不足。文章首先基于气垫船船体线型简单、平直的特点提出了铝合金整体壁板的概念,并由此引出悬架式骨架系统;其次分析了铝合金整体壁板的优点;此外,文中还在国外应用背景基础上总结了整体壁板应用注意事项;最后提出了应用及优化上亟待解决的问题,为后续研究及推广应用提供参考。     

Drift-wood collision load on bow structure of high-speed vessels

Impact load estimation of drift-wood hitting against the bow structure of high-speed vessels has been investigated. It may be difficult for the craft operator to detect in advance a drift-wood floating just below the ocean surface and to avoid the collision with it. It is particularly difficult for operators of the high-speed vessels in night cruising mode. The probability of the accident may be higher than that of the collision with rocks or other ships because of the difficulties of early detection of the floating object. Impact loads are estimated for drift-wood of different sizes and craft speed considering whipping motion and local crushing of the wood at the hitting region. A simplified formula for the load estimation is proposed based on the modal approach and the energy balance. Predicted impact loads can be applied to the initial design of the bow structure and collision bulkhead of the craft to secure the structural safety against a possible accident.     

Numerical weight function method for the structural analysis of ships: a speedy direct calculation with condensed structural information

The weight function method was originally derived for crack problems to calculate stress intensity factors for arbitrary loading conditions. In this article, a numerical weight function method has been extended to formulate the structural response analyses of two-dimensional elasticity, plate-bending, and three-dimensional plate-structures by using the finite-element method. The solution procedure is based on the well-known Maxwell–Betti reciprocal theorem, which is applied to the original and properly defined auxiliary problems. The present numerical weight function may be considered as a finite-element version of a Green’s function in an integral equation solution scheme. Although ship structures are certainly analysed by the finite-element method in a practical design procedure, the weight function approach has not yet been realized. The method is very useful for the analysis of structures subjected to a vast range of loading conditions, because structural responses can simply be calculated by the inner product of the universal weight function and load vectors. The validity and convergence characteristics of the present method are investigated by two-dimensional elastic and plate-bending problems, respectively. Finally, the method is applied to the calculation of the response amplitude operator of a stress component at a critical structural detail of a double-hull tanker, and the speed and efficiency of the method are quantitatively discussed based on the practical results.     

Optimisation of laser-welded sandwich panels with multiple design constraints

This paper investigates the possibilities for structural optimisation of laser-welded sandwich panels with an adhesively bonded core and uni-directional vertical webs. Closed form expressions for the equivalent stiffness and elastic buckling strength of laser-welded sandwich panels are discussed and numerically evaluated to demonstrate the effect of parameter variations on stress and deflection. Due to the number of design variables and constraints a structural optimisation method based on the method of moving asymptotes (MMA) is implemented and used to minimise the structural weight per square meter of panel for a typical accommodation deck configuration. It is concluded that, within the span of production parameters and rule requirements, substantial improvements can be made with or without an adhesively bonded core. Without core material and without any changes to the surrounding structure the structural weight for standard production panels can be reduced considerably, by reducing the face plate thickness and by using thinner and fewer webs. Additional weight can be saved by removing all but a few webs and injecting low-cost polyurethane foam into the cavities, giving added thermal–acoustic insulation, or by incorporating a more structural core with greater thickness and higher density, by which the free span of the sandwich panel can be increased.     

快艇轴系设计的几个问题

在分析比较英国劳氏船级社(LR)规范和美国船艇协会(ABYC)有关技术标准的基础上,阐述快艇轴系设计中快艇螺旋桨轴及螺旋桨直径、快艇螺旋桨轴轴承间距、快艇螺旋桨轴的轴系材料、尾管密封装置等要点的具体操作,供设计人员快速理解掌握。     

计算圆舭快艇阻力的一种简便方法

根据排水量长度系数C和排水量纵向分布是影响圆舭快艇静水阻力主要参数的观点,本文对文献国舭快艇阻力试验的系列图谱进行了重新计算和整理后,得出了一组剩余阻力系数C_k=/(C,F_n)曲线图。用此曲线可简单、迅速而比较正确地计算高速国舭快艇的静水阻力,供设计图舭快艇的初始阶段作估算用。 为了使这类艇的阻力性能比较良好,文中还扼要地介绍了一些船型和附体设计的特点供参考。     

120客位高速客船结构设计研究

本文介绍了一型海上高速客船的结构设计研究。提出了立体刚架加薄板双向密加筋结构型式，进行了强度、振动等特性计算，有效地控制了船体结构重量。     

地效翼船主翼结构优化设计

本文利用ANSYS软件,建立了地效翼船主翼结构工程实用的优化模型,根据主翼结构的制造工艺和设计载荷工况确定了关键构件截面的优化设计变量和应力约束条件,以主翼结构最小重量为目标函数进行优化设计,取得了明显的减重效果.在对优化结果可靠性评估的基础上,提出了应力折减系数以修改关键构件的应力约束条件,进行主翼结构的二次优化,提高了优化设计的可靠度.     

四边形蜂窝夹层板的优化设计分析

夹层板结构是近代发展起来的一种比较先进的结构形式,具有比强度高、比刚度大等特点。以某舰船中部双层船底一个纵桁和肋板间距的船底板架单元为基础,在保证夹层板总质量、主尺寸与原板架相同的前提下,建立一系列夹层质量不同的四边形蜂窝夹层板模型。利用仿真算法,从结构损伤、能量吸收的角度分析其抗爆与抗冲击性能。对四边形蜂窝夹层板进行优化分析,得到一种优化模型。     

Test of extensively damaged hybrid ship hull

A hybrid ship hull model made with a steel truss and composite sandwich panels was tested and analyzed with the goal of gaining insight into how well this structural concept holds up after major damage. One of the ideas of the concept was to mount the sandwich panels to the steel truss such that they can be blown out in a controlled fashion to ventilate a large internal blast. The hull should be designed to have sufficient strength for the ship to reach a port safely even after such extensive damage. A 6-m model of such a hybrid ship hull, consisting of a stainless steel truss and 60 composite sandwich panels, was manufactured and mechanically tested. A number of panels were then removed one by one and the hull was retested to the design load after each panel had been removed. The removed panels simulated major damage. After nine panels had been removed, from all the different areas of the hull, it could still carry the design load, although with considerable nonreversible deformations of the hull girder. The hull was eventually loaded to final failure, which occurred at 25% above the design load.     

Least-weight topology and size optimization of high speed vehicle-passenger catamaran structure by genetic algorithm

Selection of the “best” or “optimum” engineering design has always been a major concern of designers. Reduction of hull weight is the most important aim in the structural design of many ship types. But the ability of designers to produce optimal designs of ship structures is severely limited by the calculation techniques available for this task. Complete definition of the optimal structural design requires formulation of size–topology–shape–material optimization task unifying optimization problems from four areas and effective solution of the problem. So far a significant progress towards solution of this problem has not been achieved. In other hand in recent years attempts have been made to apply genetic algorithm (GA) optimization techniques to design of ship structures. An objective of the paper was to create a computer code and investigate a possibility of simultaneous optimization of both topology and scantlings of structural elements of large spatial sections of ships using GA. In the paper GA is applied to solve the problem of weight minimization of a high speed vehicle-passenger catamaran structure with several design variables as dimensions of the plate thickness, longitudinal stiffeners and transverse frames and spacing between longitudinals and transversal members. Results of numerical experiments obtained using the code are presented. They show that GA can be an efficient optimization tool for simultaneous design of topology and sizing high speed craft structures.     

玻璃钢高速船动力装置设计

针对玻璃钢高速客船的特点,就如何选取主推进柴油机,如何解决机座的强度问题,以及对减小柴油机振动、隔离噪声、防止尾倾过大、控制机舱部位重量等问题进行探讨。通过对名牌柴油机选型、机舱结构优化、环境温度的控制并采取减振措施等,经航行试验实测,动力装置的设计取得较满意的效果。     

船用电机冷却器的防腐设计

船用电机冷却器在使用中会出现严重的腐蚀现象，本文着重探讨了冷却器在海水中腐蚀的原因，并从原材料选择、工艺方法以及表面处理三个方面对电机冷却器进行防腐设计，对充电发电机冷却器的研制有指导作用。     

基于水动力分析的高速滑行艇阻力估算

针对滑行艇高速航行的运动特性进行其动态阻力的估算研究。首先通过分析滑行艇在高速航行时艇体受到的各种水动力,建立其六自由度操纵性数学模型,并利用四阶龙格一库塔法解算滑行艇的运动姿态。然后计算滑行艇高速航行时的动态阻力,所得结果与船模试验数据吻合较好,并对各种滑行阶段的运动特性进行分析,结果表明基于水动力分析的阻力估算方法具有较强的工程实用性。     

空爆载荷作用下波形夹层板抗爆结构优化设计

为了提高空爆载荷作用下夹层板的抗爆能力,提升其在舰船和海工装备上的应用程度,本文提出了一种针对波形夹层板结构的优化方法,该方法以结构质量和在爆炸载荷作用下的结构应力、变形以及吸能作为评估标准,利用正交试验筛选出样本点,通过BP神经网络生成夹层板结构参数与评估标准间的响应面模型,用遗传算法对响应面模型进行多目标优化分析,得出全局最优解,形成一套夹层板的优化设计方案,这为夹层板抗爆结构优化设计提供了一种新的设计思路和优化方法。     

美国气垫登陆艇装甲防护技术发展及其对总体性能的影响

美国气垫登陆艇(LCAC)的艇体浮箱及上层建筑均为焊接铝结构,板厚较薄,防弹能力较差,LCAC对驾驶舱等重要部位采用额外装甲进行防护。随着轻质装甲材料的发展,其单位面积质量大为减轻,LCAC将装甲防护范围进一步扩大,以增强中弹后的返航能力。文章系统介绍LCAC装甲防护技术的发展,并就装甲防护对总体性能的影响进行分析,也可为国内气垫船的技术发展提供借鉴。     

高速铝合金船的材料选择及结构设计

本文着重从耐腐蚀角度讨论铝合金材料的选择，介绍带筋板的效益及结构类型，分析带筋板结构的优异性能及结构设计。     

基于喷射成形7055铝合金的舰载机机轮设计与分析

介绍了舰载飞机对机轮轮毂的特殊需求,采用高强度、高韧性、耐腐蚀的喷射成形7055铝合金材料,开展机轮轮毂结构设计,采用Abaqus软件建立轮毂的有限元模型。通过分析轮毂受载工况下的应力,并结合试验结果,验证了喷射成形7055铝合金材料的应用能够显著减轻机轮轮毂的重量。     

22000吨级超宽浅吃水双桨油船结构设计关键技术

22000吨级超宽浅吃水双桨油船是目前世界上最大的加油船。文章简要介绍了该船的船型特点,阐述了该船结构设计的关键技术。针对该船超常规尺度的特点,采用波浪载荷预报及有限元直接计算方法计算其结构尺寸,并与常规尺度船舶进行比较发现二者结构尺寸差别较大。创新采用的只设顶墩不设底墩槽形舱壁设计满足结构强度、舱容和工艺要求,并实现舱壁轻量化设计。创新采用的"肋板/纵桁+半高桁材+局部支撑"半开放式槽形舱壁支撑设计,既方便了施工,又减轻了结构重量。采用多项轻量化设计技术,减轻了结构重量,降低了建造成本,提高了营运经济性。该船的超常规尺度结构设计对类似船型的结构设计具有一定的借鉴意义。     

基于神经网络与遗传算法的潜艇舱壁结构优化

建立了某潜艇端部耐压平面舱壁结构优化设计的数学模型,以舱壁上加强桁(筋)结构的剖面尺寸为设计变量,结构强度、稳定性、工艺性要求为约束条件,以加强桁(筋)结构总体积为目标函数,用人工神经网络方法代替结构的有限元分析,结合遗传算法完成了舱壁的结构优化设计。在为网络生成学习样本时,自行设计了正交表,解决了因为设计变量多,无法选取合适正交表而随机取样的问题。数值仿真结果表明,优化设计方案质量较原始初步设计方案减少了18.3%。