摘要
把船体甲板或船底板结构视为是一系列加筋板单元的组合 ,然后利用复合材料梁柱理论计算船体加筋板单元构件的极限承载能力 ,最后用 Smith法计算复合材料船体的极限承载能力。由于复合材料船体纵向极限强度的极限状态方程不能简单地用船体各参数显式表达 ,故将近年发展起来的响应面法与 JC法相结合 ,对复合材料船体纵向极限强度进行了可靠性分析。
A simply and effective analytical tool for longitudinal ultimate strength calculation and reliability analysis of composite ship hull girder is presented in this paper. At present, most of temporary large size ships are the longitudinally framed structure. Deck and ship bottom structures are assemblies of a series of stiffened panels. With regard to general ship structure, the most common failure mode is that the grillage, which is between stiffened panels, is damaged then the overall failure of stiffened panels occurs. Every stiffened panel of the ship hull girder works almost independently. Therefore, we only study stiffened panels separately, which is the theoretic basis of Smith method. So in this paper, on the basis of column theory, ultimate strength formula of composite stiffened panel having initial imperfection is obtained firstly. Then, Smith method is applied to calculate the longitudinal ultimate strength of composite ship bull girder. Because the limited state function of the longitudinal ultimate strength of composite ship hull girder cannot be expressed simply, the response surface method and JC method are combined to reliability analysis for composite ship hull girder. Sensitivity analysis is an important part of structural reliability assessments. One benefit of sensitivity studies is the identification of the model parameters that have the most effect on the estimated reliability or safety index. The other benefit is being able to identify those parameters that can be taken as fixed values and need not be considered as random variables in reliability models. As a result, the sensitivity of each variable that has effect on the reliability is discussed. From the results of the sensitivity analysis to a high speed composite ship, we can draw the conclusion: longitudinal ultimate moment capacity of composite ship, the discounting factor of panel and Yong's modulus of the materials has a great effect on the safety index. The model error in predicting ultimate moment of the ship hull girder, the model errors in predicting of the general longitudinal bending, the discounting factor of panel and Young's modulus of the materials must be dealt with as stochastic variables. The compressive strength of materials, the initial geometric imperfections of stiffened panel and general longitudinal bending after introducing the model errors in predicting of general longitudinal bending could be regarded as fixed variables.
出处
《中国造船》
EI
CSCD
北大核心
2002年第2期29-35,共7页
Shipbuilding of China
