【作者】 孙承猛；

【导师】 纪卓尚；

【作者基本信息】 大连理工大学 ， 船舶与海洋结构物设计制造， 2009， 博士

【摘要】 下水驳船是一种高效的船舶产品及大型海洋结构物的下水和运载工具,在造船业兴旺的今天,可大大减轻船厂对干船坞和船台的使用需求。随着造船模式的发展和建造船舶吨位的增加,下水产品重量也在不断增加。在使用下水驳船作为产品下水工具时,如何保证整个作业过程平稳、安全和快速地完成,是一个非常值得研究的问题。本文针对下水驳船使用过程中各调载水舱调载方案的实时确定,上驳产品对驳船施加载荷的计算方法以及待调载水舱阀门的打开时刻确定等几个方面作了深入的研究。下水驳船在整个作业过程中,需要始终保持特定的、适宜的浮态,而驳船浮态的调整是通过调节各压载水舱的水量来实现的。何时进行调载,需要调节哪些压载水舱以及调节多少水量,这都是影响整个下水过程的关键因素。通常采用传统的人工手动方式进行调节,但其主要依靠操作人员经验,而且操作繁琐,效率低下。本文首先依照力学平衡原理,分析了驳船的受力特点,建立了力学平衡方程组模型。针对该模型,以总调水量最小为原则,采用牛顿迭代方法求解,并引入了差商代替导数的思想求解雅可比迭代矩阵;针对水舱按行列布置的较有规律的驳船,研究了四种特殊的有针对性的模型求解方法,并通过算例分析比较了这四种方法的特点,给出了方法选择的依据和准则。接着,结合上驳时间要求尽量短的特点,以力学平衡方程和调水舱水量的限制为约束,调水量绝对值之和为目标函数,建立了驳船实时配载优化模型。针对优化模型的非线性规划特点,对模型进行了归一化处理,分别采用了惩罚函数法和乘子法进行求解。通过工程实例计算分析,证明了所建模型和对应解法的正确性和适用性,同时也比较得出了两种模型及求解方法的优缺点。对于舱室布置对称性明显的驳船,适于采用力学平衡方程组模型求解,其计算速度快,结果稳定。而对于舱室布置任意性较强的驳船,则宜于采用优化模型求解,尽管计算速度稍慢,但其适应性较强,配载结果也较为合理。在下水驳船移运产品的上驳过程中,需要实时确定上驳产品对驳船所施加的压力载荷,从而为配载模型的计算提供必要和准确合理的已知数据。而该部分载荷的计算方法与产品上驳的方式密切相关。本文主要分析了滑道和气囊两种移运方式下的该载荷计算方法。对于滑道移运方式,分别采用了对已上驳部分产品重量载荷直接积分方法、弹性基础梁法和弹性支座的有限元法进行了计算分析。实例计算结果表明,对于支承滑道覆盖整个产品上驳长度的情形,可采用产品重量载荷直接积分方法进行计算,该计算方法具有简单和快速的优点,同时也不会与实际重量产生较大的误差;而对于产品相对于其支承滑道存在较大悬臂端的情形,则宜采用弹性基础梁法进行计算,其公式虽然复杂,但计算结果精度较高,且与实际情形较为接近;有限元法则适用于各种情形,并且计算结果具有很高的精度,但这往往又涉及到其他有限元软件的参与,不能满足上驳过程的实时计算要求。对于气囊移运方式,驳船承受产品的压力载荷既与驳船上支承产品的各气囊实时压力有关,又与驳船上支承产品的气囊根数及其位置密切相关。首先,本文依照力平衡原理,通过适当的假设,给出了支承产品气囊压力的实时计算方法。接着,依照运动学原理,分析了气囊和产品的相对运动关系,给出了不同的产品上驳长度时驳船上支承产品的气囊根数和其对应位置坐标的计算公式。最后,通过相应气囊的合力计算和坐标转换,得到了驳船所承受的气囊压力载荷计算公式。通过实例计算分析表明,在气囊移运方式下,驳船所承受产品的载荷具有离散性、突变性和周期性的特点,一般不宜采用滑道移运的方式进行近似计算。当配载方案确定后,如何控制阀门开关时刻来保证整个调水过程中驳船处于最佳的浮态,对于产品上驳作业过程具有重要的意义。通常,阀门开关操作存在两种不同的作业方式。在两种作业方式下,阀门开关时刻都会影响调水过程中驳船的浮态。而阀门开关时刻的确定主要与产品的上驳速度、调水舱室的阀门流量和潮位变化密切相关。通过分析调水过程特点,本文选取适当的驳船浮态表征函数作为目标函数,阀门调水时间范围作为约束条件,建立了作业过程中调水舱室阀门开关时刻的优化模型,分别研究了惩罚函数法、网格法和模拟退火法在模型求解中的应用。通过实例计算分析表明,所建的优化模型是正确和有效的,采用的解法均可使驳船在调水过程中保持较好的浮态。但采用网格法的计算量随调水舱室数量或调载时间等分份数的增加而急剧增长,导致求解时间不可接受;惩罚函数法虽求解时间较短,但调水过程中驳船浮态相对差些;而采用模拟退火法所得到的驳船浮态最好,只是计算时间稍长。因此,对于计算时间要求较短而浮态限制较松的情形可采用惩罚函数法;反之,则宜于采用模拟退火法或网格法。更多还原

【Abstract】 The launch barge is a highly-efficient tool to launch and carry ship products and it can reduce the demand to the dry dock and building berth of a shipyard greatly for today’s prosperous shipbuilding industry. The weight of the launched products increases a lot with the development of shipbuilding mode and increasing of the ship tonnage. To ensure the whole launching process completed stably, safely and quickly is worthy of investigation for the launch barge. In this paper, the determination of real-time stowage planning, the calculating method about the loads of ship products and the choice about valve open time of ballast tanks are studied deeply in the launching process respectively.Special and proper floating conditions of the barge need to be remained in the whole launching process all the while. And the floatation is adjusted by changing the water volume of each ballast tank. When, where and how much water needs to be adjusted are the key factors influencing the whole launching process. Usually this process is completed manually which is of low efficiency and complex operation. In this paper, firstly by analyzing mechenics characteristics of the barge, a static equilibrium equations model is established. And it is solved by Newton iteration method on the least adjusted water criteria in which the idea that derivative is replaced with difference quotient is involved in calculating each item of Jacobi matrix. For those barges which subvision has obvious orderly ranks, four special solving methods are studied to the model, and through an example’s analysis, these four methods’ characteristics are shown and concluded. Then the real-time stowage optimization model is established combined with the characteristic of load-out time as short as possible. It is constraint of static equilibrium equations and the upper and lower limits of the water quantity, and its objective function is determined as the absolute value of the adjusting water. Penalty function method and multiplier method are adopted as to the nonlinear characteristic of the optimization model and normalization processing is applied meantime. The results of the practical examples prove the correctness and applicability of the two models and corresponding solving method. And at the same time the advantages and disadvantages between them are pointed out. That is, the former model is suitable to the case that the barge subvision is symmetrically, and it is of fast calculation speed and stable results, while the latter model is better to the barge subvision with strong arbitrariness. Although the calculation speed is slower slightly, the optimization model has good adaptability and more reasonable load-out results.The pressure exerted onto the barge by the transferring object needs to be determined real-timely in the load-out process in order to provide necessary data for calculation of the stowage model, and its calculation is closely related to the transferring mode. This paper mainly discussed the calculation method under two modes transferring by slideway and gasbags. As to the slideway mode, directional integral method to weight load of the project on the barge, elastic foundation beam method and finite element method with elastic support are analyzed respectively. The examples show that directional integral method is adapted to the case that the support slideway covers the whole object transferring length because of its simplicity, speedness and result close to the practice, and elastic foundation beam method having advantage of high precision should be adopted if there is a large cantilever end between the object and supporting slideway although its formula are very complex. The finite element method is suitable for all cases and of high precision, but it doesn’t satisfy the demand of real-time calculation because of participation of other software. To the gasbag mode, the pressure is related to both real-time pressure of each gasbag and number and position of those gasbags on the barge supporting the object closely. Firstly, the real-time calculation of each gasbag pressure is derived according to static equilibrium principle with some proper assumptions. Secondly, the relative movement relation between the gasbag and object is analyzed in terms of kinematics principle, and the calculation formulas of gasbags number and corresponding coordinate are given for different transferring length. Finally, the calculation formula of pressure onto the barge from the gasbags can be obtained through the resultant force calculation and coordinate transformation of corresponding gasbags. The example results demonstrate that the loads onto the barge from the object have three characteristics of discreteness, mutagenicity and periodicity under the gasbag transferring mode. So the slideway mode method shouldn’t be used to calculate approximately in this case.How to control the valve open time is of significance to ensure the barge being desirable floatation in the load-out process after the stowage planning determined. Usually, there are two different working modes in the operation of the valves, and the barge floatation in the process will be influenced by the valve open time for both modes. The determination of valve open time is closely related to the object movement velocity, the flux of the ballast tank and the variation in tidal level. Analyzing the characteristics of the water adjusting process, a proper function for characterizing the barge floatation is chosen as objective function, the range of adjusting time is regarded as constraint condition, thus an optimization model on valve open time for ballast tanks of the launch barge can be built, and penalty function method, grid method and simulated annealing method are adopted to solve this model. The example results demonstrate that the optimization model is effective and all the methods are well to maintain good barge floatation in the adjusting process. But the calculated amount of grid method will increase rapidly with the increasing of the number of ballast tanks adjusted or the number of adjusting time’s division, and it maybe lead to an unacceptable solution time. Although penalty function method has advantage of short solution time, the barge floatation is not good enough relatively during the adjusting process. While the barge floatation will be the best if simulated annealing method is adopted and just the computing time is slightly longer. So it can draw the conclusion that penalty function method can be used under the case of computing time demanded shortly and floatation limited loosely, and vice versa, grid method or simulated annealing should be adopted.更多还原