摘要船体梁的极限强度问题是船舶设计中的重要问题，船体结构的总纵极限强度关 系着船舶整体的安全性，这历来受到船舶结构设计者的高度重视。传统上，对于船 体梁总纵极限强度的计算，基本上采用的是经典的弹性理论。但是结构的破坏总是 非线性的，包括几何非线性和材料非线性，有可能这两种破坏形式还一起发生。加 筋板单元在达到该材料的屈服应力之前可能会发生多种方式的屈曲，这会给船舶结 构设计工作者计算船体极限承载能力带来较大的困难。79829

因为考虑到材料的和几何的非线性因素，要计算船体梁的总纵极限强度变得非 常复杂。当前，想要计算船体梁的总纵极限弯矩，基本上有三种，即逐步破坏法、 理想结构单元法和非线性有限元法。在本次毕业设计中，笔者将基于 IACS 规范， 采用非线性有限元法，对油船的总纵极限强度进行分析。主要内容如下：

1、对油船船体梁的极限强度简单的介绍了其定义，为了确保后面章节所研究内 容的准确性，笔者选取矩形板和圆柱形壳，利用文献中提供的理论方法计算出来的 结果与有限元结果作对比，这样便能证明程序计算的准确性和可靠性；

2、笔者选择了两种最接近于油船实船的经典箱型梁—Reckling No。23 和 Nishihara 模型，利用有限元程序计算出来的结果和试验值、文献值进行比较，还有 讨论是否有倒角对于最后结果的影响，以及分析不同位置加筋板的应力、位移关 系；

3、利用有限元程序 ANSYS，对一艘双壳油船（Double hull VLCC）的分段结 构计算了它的极限弯矩，并将结果和文献值作比较，讨论结构中同一垂直线上的五 个箱型梁上的 T 型板的应力、位移关系。

毕业论文关键词：船体梁，ANSYS，极限强度，油船

Abstract The ultimate strength of hull girder is an important problem in ship design。 The ultimate strength of ship hull structure is related to the safety of the ship。 This has always been highly valued by the designers of the ship structure。 Traditionally, we basically adopt the classic linear elastic theory to calculate the ultimate longitudinal strength of hull girder。 But the destruction of the structure is always nonlinear, including geometric nonlinearity and material nonlinearity, it is possible that these two forms of destruction happen together。 There may be many kinds of buckling of stiffened plate in a variety of ways before the yield stress of the material can be achieved, which will bring great difficulty to the calculation of ultimate load bearing capacity of ship structural design workers。

Considering the material and geometric nonlinear factors, it is very complicated to calculate the ultimate longitudinal ultimate strength of ship hull girder。 At present, there are three main methods to calculate the ultimate bending moment of ship hull girder, which are the progressive failure method, the ideal structural unit method and the nonlinear finite element method。 In this present graduation design, the nonlinear finite element method has been used for the oil tanker longitudinal ultimate strength analysis based on IACS rules。

The main research works are as follow:

1。The definition of the tanker hull girder ultimate strength was introduced firstly。 In order to ensure the accuracy of the later chapters of the research content, the author selected rectangular plate and cylindrical shell, calculated by the use of literature and to provide the theory and method of results and finite element results for comparison so that they can prove the accuracy and reliability of calculation program;

2。Two tanker ships in the classic box type beam Reckling No。23 and Nishihara model were chosed and results, test values and literature values using finite element program calculated are compared, and discuss whether the effect of chamfer on the final results, and analysis of reinforcement plate in different position of force and displacement relationship;