散货船舱口盖剩余强度

通过对散货船舱口盖极限强度的理论分析，采用了正交各向异性板及刚塑性模型进行了理论上的推导，并对7万t散货船的1号舱的舱口盖(两块对称滚动式)，进行了ILL66及IACS URS21(1998年版与上述ILL66的88议定书中载荷的量级相当)的外载荷的比较及线性和非线性的有限元分析。本文所采用的有限元的线性及弹塑性计算对实际的舱口盖进行评估的结果证明，IACS URS21(ILL66的88议定书)的标准比ILL66的标准有所提高。采用非线性有限元法是在初始设计阶段使用的可行方法。这些结果可供规范研制工作参考。

Residual Strength of Hatch Cover of Bulk Carriers

The casualty of Derbyshire results in the approval of regulation 16 about loading on hatch covers in ILL66 Protocol 88 by IMO MSC76 in December 2002. The paper presents theoretical ultimate strength analysis for the hatch covers of bulk carriers, in which the orthogonal stiffened plate model and the plastic hinge line model are used. In the method, the hatch cover is a structure consisting of plates stiffened by both preliminary structures including girders and transverse web elements and secondary structures including longitudinals and stiffeners, etc., but it may be regarded as such a structure made of a member of equivalent orthogonal plates so that the orghogonal plate theory and the plastic hinge line theory can be adopted smoothly herein. Meanwhile, linear FEM and non FEM calculation are performed to carry out a calibration study compared with the above mentioned theoretical analysis results. The results show that IACS URS21 (1998 version) adopted a higher standard than those of ILL66. Therefore the method consisting of the bound theory and FEM correction and non linear FEM are very suitable to be used analyze the ultimate strength of hatch covers in the initial design stage.