Evaluation of expected maximum values of forces acting on containers and lashing rods on a container ship

The appearance of a number of large container ships in the 8000 TEU range raises the importance of a plan for container lashing arrangements on deck in relation to the design of the ship. Therefore, it is expected that a new method for evaluating the lashing arrangements on deck will be introduced which is applicable regardless of the ship's size and the lashing pattern, instead of using the standards of several different societies, as happens at present. To evaluate the lashing arrangements on deck, the expected maximum values of the forces acting on the containers and lashing rods should be evaluated. This paper presents a new method of evaluating the container lashing arrangements on a container ship using an "acceleration ellipsoid." The applicability of the acceleration ellipsoid to an evaluation of the expected maximum values of the forces was examined by comparing the expected maximum values of the forces calculated by the long-term distribution calculation known as the "Fukuda method," to those calculated using the acceleration ellipsoid. By comparing these results, it was confirmed that the expected maximum values of the forces calculated using the acceleration ellipsoid were not less than those calculated through by the long-term distribution calculation. It is concluded that the acceleration ellipsoid can be used to evaluate the expected maximum values of the forces acting on containers and lashing rods. Received: December 14, 2000 / Accepted: March 22, 2001     

大型集装箱船绑扎桥结构优化设计

为有效降低大型集装箱船的空船重量,针对绑扎桥结构轻量化设计进行研究。以某14500TEU集装箱船为研究对象,根据船级社规范要求针对结构设计方案进行有限元计算分析,依次从剪力墙布置、立柱设置和局部尺寸优化等三个层次对原始方案进行优化设计。研究结果表明,优化方案在满足船级社规范要求、保证堆重指标的同时有效降低了绑扎桥的结构重量。本文的设计思路和优化方法可以为今后大型集装箱船绑扎桥的结构设计提供一定参考。     

Experimental and numerical investigation of lashing bridge and container stack dynamics using a scaled model test

Previously reported container losses were generally attributed to extremely violent motions of containerships due to adverse weather conditions. However, most existing specifications or standards adopted for containers and lashing equipment meet the requirement of static conditions. Hence, further researches on safer container shipping under heavy sea states are required. Consequently, an experimental study method is proposed to measure the dynamic response of 1/10 scaled lashing bridge and container stack. The scaled model of the lashing bridge is constructed based on the similarity theory. Based on two dimensionless numbers, Froude's number and Cauchy's number, eleven container scaled models are employed. A series of experiments with controlled parameters are performed using a three-degrees shaking table (roll, pitch, heave) to present sufficient data to verify the effectiveness of the numerical model. The results of experiments, numerical simulations and calculations of the VERISTAR procedure (developed according to the BV rule) are compared. This study aimed to explore the mechanical behavior of the lashing bridge and container stack under predetermined driving excitations (roll and pitch) which simulated heavy sea states. According to the results, the model can predict conditions similar to real situations of the lashing bridge and container stacks while storages on the weather deck.     

超大型集装箱船的设计优化

本文以大连船舶重工集团有限公司自主研发设计的一系列集装箱船为基础,分析了超大型集装箱船的总体性能和结构特性及航线和货物特点,阐述了与总体性能、分舱、结构设计、集装箱布置和营运安全管理等有关的设计改进建议和优化措施,期望通过设计改进得到性能全面优化的超大型集装箱船。     

基于CATIA V6的绑扎桥三维设计方法

在集装箱船逐步大型化的大趋势下,对绑扎桥的设计要求逐渐凸显。本文基于CATIA V6软件平台,提出了一套绑扎桥三维设计方法。综合考虑了绑扎桥的实际设计需求以及三维模型化的技术难点,通过利用参数化定义,EKL二次开发手段,以及CATIA V6中片体模型转实体模型,片体模型转FEM模型等强大的原生功能有效地解决了快速建模、CAD/CAE一体化、BOM数据与出图信息集成等一系列难题,充分利用了三维技术减少设计流程中的信息孤岛现象,基于高度集成的参数化模型来提高设计响应速度与准确性。最后通过实践案例予以验证并分析了该方法的工程实用价值。     

超大型集装箱船甲板最大堆重研究

德国劳氏船级社规范(GL-2013)对集装箱船尤其是超大型集装箱船的横向加速度系数计算进行了调整,大幅度提高了甲板上集装箱堆重。文章根据绑扎计算结果,将规范变化前后的横向加速度系数和最大堆重进行对比,以及对2层箱高绑扎桥和3层箱高绑扎桥的最大堆重进行对比。结果显示,随着规范的更新及绑扎点高度提高,集装箱甲板最大堆重显著增加,堆重分布更加优化合理,为今后超大型集装箱船甲板面堆重设计参数的合理选取提供了一定的参考。