基于piece-wise方法的横风横浪中破损船舶瘫船稳性及其倾覆机理研究

Dead ship condition is the most dangerous mode among the intact ships, but its affect on the damaged ships and the capsizing mechanism under the severe sea states are still unknown to all. All previous maritime accidents show that the contemporary damaged stability criterion, which is based on static stability, is not suitable to evaluate the ship’s safety. The research proposes the piece-wise method to study the stability under dead ship condition and capsizing probability in beam wind and waves, based on the combination of damage stability in static and intact stability in wave, which introduces the piece-wise method to the solution of the capsizing probability model, to realize the model solution's fast convergency. The research couples the strategy of numerical calculation, theory analysis and model test, which starts with the time domain analysis of flooding process, according to the basis of the single-freedom roll movement function and taking the effect of fluid viscosity into consideration, to analyze the rolling of damaged ship under dead ship condition, the investigation establishes the capsizing probability model in beam wind and waves, to analyze the stability under dead ship condition and capsizing mechanism of damaged ship in beam wind and waves. The related theory methods are verified and improved relying on the container ship model and relative test equipments of corporative unit, which is helpful to disclose the capsizing mechanism of damaged ship in wave, also makes useful attempt to the subsequent establishment of the new damaged stability criterion.

瘫船是完整船舶失效模式中最危险的，但瘫船对破损船舶的影响程度及恶劣海况下船舶的倾覆机理无从知晓。历次海难事故证实现行的基于静稳性的破舱稳性衡准已经不适用于衡量船舶的安全性。本项目提出基于piece-wise方法来研究横风横浪中破损船舶的瘫船稳性及其倾覆机理，在静水破舱稳性和波浪完整稳性研究结合的基础上，将piece-wise方法引入到破损船舶倾覆概率模型的求解中，解决模型求解收敛速度慢的问题。项目采用数值计算、理论分析和模型试验结合的策略，从破损船舶进水过程的时域分析入手，依据单自由度横摇运动方程，考虑流体粘性的影响，分析破损船舶瘫船时的横摇运动，建立适用于横风横浪条件下破损船舶的倾覆概率模型，研究横风横浪中破损船舶的瘫船稳性及倾覆机理。最终依托合作单位的集装箱船模及相关试验设备，进行有关理论方法的验证和完善，为波浪中破损船舶的倾覆机理研究和后续破舱稳性衡准的制定做出有益的尝试。

为了研究横风横浪中破损船舶的瘫船稳性及其倾覆机理，基于准静态方法建立了破损船舶进水过程的时域模型，开发了具有自主知识产权的破损船舶进水过程的时域计算程序，实现了破舱稳性和时域进水过程的有效结合；基于单自由度横摇运动方程分析了破损船舶瘫船时的横摇运动，研究了破损船舶非线性横摇方程的数值计算方法及其解析解，得到横风横浪中破损船舶的瘫船稳性；研究了不同破舱类型的复原力矩计算方法，对横风横浪中破损船舶时域内的倾覆概率进行了分析；总结了不同船舶类型、载况、有效波倾系数、GM等条件下完整船舶的倾覆概率，分析了完整船舶倾覆概率的影响规律和倾覆特性，研究了横风横浪中完整船舶的倾覆因素。在此基础上，研究了基于进水过程的抗沉辅助决策系统，为下一步基于稳性的船舶安全评估系统研究奠定基础。本项目的研究成果可为波浪中破损船舶的倾覆机理研究和新的破舱稳性衡准的制定做出有益的尝试。