粘性对方尾船波浪力的影响分析

航行船舶绕射问题的准确求解是预报船舶波浪中运动的基础.文章分别采用基于三维移动脉动源的边界元法和基于RANS方程的CFD方法求解了规则波中航行的方尾船模型的波浪力,并通过与试验结果比较验证了方法的可靠性.CFD计算时通过从波浪力中分离出粘性力,研究了粘性对方尾船波浪力的影响.结果表明,基于RANS方程的波浪力计算结果与试验结果和势流理论结果吻合良好,在长波中与试验值更接近.粘性对船模斜浪航行时的横摇力矩有较大影响.     

行人激励载荷下大跨径异形天桥抗震支座设计研究

为了解决抗震支座弯矩受到行人不确定激励载荷影响，出现参量获取不全面的现象，导致支座抗震效果不佳这一问题，进行了行人激励载荷下大跨径异形天桥抗震支座设计研究。首先，考虑到行人对桥梁激励的不确定性，设置了多种载荷激励类型，并提出利用区间过程法来描述桥上行人的不确定激励，使用自相关系数函数分析在行人激励载荷作用下的桥梁非随机振动情况；其次，利用有限元软件中的单元构造了抗震支座模型，并对桥梁位移、桥墩弯矩、桩基弯矩进行数值模拟；最后，将支座参量数值模拟结果代入有限元模型中，设计出一种双曲面球抗震支座结构。结果表明，设计的支座在慢跑、快跑情况下纵向弯矩与实际数据之间的最大误差分别为25 k N·m、250 k N·m，横向弯矩与实际数据一致，说明根据数值模拟结果设计的支座能够起到良好减震效果。     

Uncertainty analysis of propulsion shafting vibration北大核心CSCD

［Objective］In view of the insufficient safety and reliability of the traditional deterministic vibration analysis of ship propulsion shafting system, the vibration response analysis of the shafting system under uncertain excitation conditions is carried out. ［Methods］Using non-random vibration analysis based on non-probabilistic convex model process, the uncertain excitation and vibration response are described in the form of the upper and lower bounds of the interval to reduce dependence on a large amount of excitation sample data. Compared with the calculation results in the relevant literature, the validity of the program for solving the response bound of the two-degrees-of-freedom (2-DOFs) system is verified, and the uncertain vibration problem of the shafting system is then explored on this basis. ［Results］The results show that when the shafting system is excited by [−30 N, 30 N] propeller laterally, a displacement response of the magnitude of about 10−6 m is generated at the bearing. It is also indicate that the shafting system is excited in a certain interval, so a certain interval response must be produced. ［Conclusions］Applying the non-probabilistic convex model process and non-random vibration analysis to the field of the uncertain vibration analysis of ship propulsion shafting system, the vibration displacement response bound of the shafting under uncertain excitation conditions can be obtained with fewer excitation samples, thereby providing useful references for improving the robustness of the dynamic response prediction of ship propulsion shafting systems. © 2023 Chinese Journal of Ship Research. All rights reserved.