【作者】 王海涛；

【导师】 杨平；

【作者基本信息】 武汉理工大学 ， 工程力学， 2004， 硕士

【摘要】 近年来，基于结构极限强度的极限状态设计法在结构工程领域得到了迅猛发展，在船舶工程中，用基于极限承载能力的设计方法来取代传统的基于线弹性理论的设计方法也成为一种趋势。研究表明，在计算船体总纵强度时，必须考虑构件的屈曲、屈服等各种可能的破坏模式，要考虑受压构件屈曲后及崩溃后非线性性能影响。船体总纵极限弯矩的计算，由于要计及材料的和几何的非线性因素而变得十分复杂，必须用增量的方法逐步计算，获得完整的弯矩—曲率曲线后，才能得到总纵极限弯矩值。目前已有的各种简化方法，其基本原理都是相同的，主要区别在于所用的单元性能曲线有所不同，以及对初始变形、残余应力和侧向载荷等影响因素的处理方法也各不相同。 本文方法的基本原理是将船体截面离散成不同的加筋板单元，根据实际受力情况，将单元分成受拉取和受压区。受拉区单元由理想弹塑性理论得到其应力应变关系曲线；受压区单元可以分成一般单元和硬角单元。当船体梁在中拱或中垂状态下时，假定一个初始曲率，累积各个单元对瞬时中和轴的弯矩，然后判断弯矩是否达到极限，如未达到，则增加曲率，重复上述过程，直至弯矩为极值。 由于加筋板侧倾屈曲是一种非常危险的破坏形式，本文采用不同方法分析了加筋板侧倾屈曲，并作出了比较；基于上述方法运用计算机程序计算出了箱型梁和几种实船的极限承载能力以及各种加筋板单元的极限强度，并和著名学者的结果进行了比较，结果令人满意；分析了某实船的考虑腐蚀影响的可靠性指标；最后，为了验证理论的精确度，作者参与了钢箱型梁的极限强度试验，通过比较试验数据与理论数据，结果基本一致。更多还原

【Abstract】 Recently, the method which bases on structure ultimate strength developed very rapidly in the domain of structure engineering. It has been a trend that the design method which bases on structure ultimate strength replaces the traditional method which bases on the theory of elasticity. The study indicates we must take into account several possible destructive modes such as buckle and yield et al and consider the non-linear effect of post-buckling and post- collapse of components.Then, a step-by-step increase of vertical bending curvature is applied to the hull girder assuming that the plane cross section remains plane. At each incremental step, the stress of the cross section is evaluated using the average stress-strain curves of the elements as well as the incremental bending moment due to the curvature increment.This method was first used by Smith. Firstly, it needs to separate the girder hull into many elements-compressive one and tension one. Secondly, when the ship is in hogging or sagging, you should assume one curvature value so you can get the moment value of every element. And then you may add up all the moment of every element. Thirdly, you mast judge whether the moment is the ultimate moment. If not, increase the curvature, and redo the above steps until get the ultimate strength.In the thesis the author analyzes the tripping of stiffened panels by three different methods. Based on the above method, the author calculates the ultimate longitudinal strength of a boxlike girder, several ships and many stiffed panels by program. And then checks with some famous experts’ results. The result is approving. Also the author analyses the reliability of ship considering corrosion. At last an experiment is done to verify the theory.更多还原