基于确定性规则波法的CALM系统锚链疲劳强度分析

CALM型单点系泊系统作为原油装卸终端通常通过悬链式锚链固定在特定海域,锚链在风、浪、流等载荷作用下很容易产生疲劳破坏,合理确定锚链的疲劳寿命至关重要。以某30×10^4 t的CALM系统为例,首先基于Longuet-Higgins分布对其所在海域的波浪散布图进行离散,得到了规则波散布图,最后采用确定性规则波法对锚链疲劳损伤进行了评估。通过实例分析,给出了基于Longuet-Higgins分布的波浪散布图离散为规则波的一般方法,提供了采用确定性规则波法进行锚链疲劳损伤的分析流程。该方法具有计算速度快、占用资源少的优点,可为系泊锚链的疲劳评估提供参考。

3种非线性波浪载荷计算方法介绍及其实船应用比较

介绍3种预报非线性波浪载荷的时域方法,分别是规则波法、等效韦布尔法和极大波法。以第二代40万吨超大型矿砂船为例,分别使用此3种方法对中垂和中拱波浪弯矩做了预报,得到3种方法下的不同波浪弯矩值,并比较3种方法的优缺点。此3种方法,在实际工程中都可被船级社接受使用,但从目标船的计算结果看,最终的弯矩值有10%左右的差距。所以非线性波浪弯矩的计算结果,会根据计算方法的不同而有所不同,实际工程项目中可以根据需要合理选择计算方法。

A nonlinear hydroelastic method considering wave memory effect for ship load responses in irregular waves

Since the amplitude and frequency of irregular waves change with time,great difficulties are brought for solving ship load responses in random waves.To take the effect of various frequencies of irregular waves into consideration in load responses of hull,the wave memory effect is necessary.A semi-analytical method is introduced for the time-domain retardation functions,and then a nonlinear hydroelastic method considering memory effect for ships in irregular waves is proposed.Segmented self-propelling model experiments of a container ship were carried out in a towing tank,a ship motion measuring device for self-propelling model test was designed.Whipping responses of the ship in regular and irregular waves are analyzed.Finally,the calculation results are compared with those measured by segmented model experiments,and the result indicates that the memory effect has little effect on load responses of ship in regular waves,but pronounced effect on results in irregular waves.Moreover,the presented method is reasonable for the prediction of ship load responses in irregular waves.

A method of rule-base optimization based on evaluation

For improving the translation quality of transfer-based MT system,a new metric for rule evaluation was proposed and applied to rule-base optimization.At the same time,a frequency filter was used to delete redundance before new acquired rules were added into rule-base.The new optimization method was applied to a general MT system.Experimental results show that the frequency filter is helpful to provide the knowledge expansion space of MT system for new acquired rules.The translation assessment score of open test corpus (including 2500 Chinese sentences) obtained is increased by 3.58% under 5-gram Nist metric,which is two times of that obtained by previous methods.

Legal Frame for Criminal Proceedings Against Juveniles in the Federation of Bosnia and Herzegovina

The paper analyzes applicability of legal frame of international standards on the protection of juvenile rights which are expressed through the concept of protection of ＂the best interests of a child and juvenile＂, in view of the question whether the Federation of Bill performs appropriate activities and to which extent, and are there controversy points that need to be resolved separately. It points out the unknowns which the practices of the courts in the Federation of Bill have not yet completely resolved, and are related to the applicability of the new rules adopted by the Law on Protection and Treatment of Children and Juveniles in Criminal Proceedings of the Federation of Bill. Also, it presents a set of legal rules that regulate criminal proceedings against juveniles within the Federation of Bill, with a special emphasis on the basic characteristics of this process. Finally, possible solutions to the mentioned ambiguities and dilemmas are proposed in accordance with the principle of legal certainty as essential to addressees of the relevant legal norms

Full time-domain nonlinear coupled dynamic analysis of a truss spar and its mooring/riser system in irregular wave

A new full time-domain nonlinear coupled method has been established and then applied to predict the responses of a Truss Spar in irregular wave. For the coupled analysis, a second-order time-domain approach is developed to calculate the wave forces, and a finite element model based on rod theory is established in three dimensions in a global coordinate system. In nu- merical implementation, the higher-order boundary element method （HOBEM） is employed to solve the velocity potential, and the 4th-order Adams-Bashforth-Moultn scheme is used to update the second-order wave surface. In deriving convergent solu- tions, the hull displacements and mooring tensions are kept consistent at the fairlead and the motion equations of platform and mooring-lines/risers are solved simultaneously using Newmark-fl integration scheme including Newton-Raphson iteration. Both the coupled quasi-static analysis and the coupled dynamic analysis are performed. The numerical simulation results are also compared with the model test results, and they coincide very well as a whole. The slow-drift responses can be clearly ob- served in the time histories of displacements and mooring tensions. Some important characteristics of the coupled responses are concluded.