Hydroelastic responses and interactions of floating fuel storage modules placed side-by-side with floating breakwaters

This paper is concerned with the hydroelastic responses and hydrodynamic interactions of two large floating fuel storage modules placed side-by-side with the presence of floating breakwaters. These modules and breakwaters form the floating fuel storage facility (FFSF). The floating storage modules and breakwaters are modeled as plates and the linear wave theory is used to model the water waves in the numerical model. The numerical model is verified with existing numerical results and validated with experimental test. Numerical simulations are performed to determine the hydroelastic behavior and hydrodynamic interactions of floating storage modules placed adjacent to each other and enclosed by floating breakwaters under various incident wave angles. The effects of breakwaters, drafts, channel spacing formed by the two adjacent modules and water depth on the hydroelastic responses of the modules are investigated. The wave induced responses of multiple floating storage modules enclosed by floating breakwaters are also examined.     

Store-and-forward based methods for the signal control problem in large-scale congested urban road networks

The problem of designing network-wide traffic signal control strategies for large-scale congested urban road networks is considered. One known and two novel methodologies, all based on the store-and-forward modeling paradigm, are presented and compared. The known methodology is a linear multivariable feedback regulator derived through the formulation of a linear-quadratic optimal control problem. An alternative, novel methodology consists of an open-loop constrained quadratic optimal control problem, whose numerical solution is achieved via quadratic programming. Yet a different formulation leads to an open-loop constrained nonlinear optimal control problem, whose numerical solution is achieved by use of a feasible-direction algorithm. A preliminary simulation-based investigation of the signal control problem for a large-scale urban road network using these methodologies demonstrates the comparative efficiency and real-time feasibility of the developed signal control methods.     

Active regulation of battery charge-sustaining in ECMS: Application in energy management for engine waste heat recovery system

Equivalent consumption minimization strategy (ECMS) is a widely used energy management method in the battery equipped bio-sources energy system, in which an equivalence factor is adopted to weigh the two kinds of energy, usually fuel and electricity. The regulation of the equivalence factor will affect not only the fuel consumption but also the battery's state of charge (SOC) sustainability, which results great influence upon the energy management of the system. In this paper, a new perspective of treating the relationship between the equivalence factor and instantaneous fuel consumption as well as instantaneous electricity consumption as a first-order dynamic system is proposed, thus the relationship between the equivalence factor and SOC is deduced as a second-order dynamic system. Based on the perspective, a linear second-order Active Disturbance Rejection Control (ADRC) is employed to regulate the equivalence factor, which can estimate and compensate, in real-time, disturbances in the system from input-output information only. An engine waste heat recovery energy network constructed by <engine> - <power turbine> - <Organic Rankine Cycle System> - <electric cooling system> - <battery> - <Integrated starter and Generator> is selected as the research object, simulation verifications upon 11 different driving cycles based on the simulation platform established by GT-SUITE software are conducted to test the fuel-saving capability and SOC self-sustainability by the proposed approach with a same set of tuning parameters. Simulation results indicate that both the fuel-saving capability and the SOC self-sustainability can be ensured by the active control of equivalent factor with a same set of tuning parameters upon all the 11 driving cycles, demonstrating a great adaptability of the control parameters.     

Time domain modeling and simulation of warship flooding process based on counter-flooding activities北大核心CSCD

[目的]实战损伤条件下,舰艇进水是舱室进水漫延与舰员抗沉行为相对抗的过程。现有的不沉性理论无法客观、全面评估抗沉干预对战损舰艇进水过程的影响,缺少从全时域的角度对战损舰艇进水过程开展预测的手段。[方法]首先,分析抗沉干预下舰艇破损进水的耦合关系,构建进水过程时域模型,进而给出数值求解算法;其次,结合案例分析抗沉干预要素对不沉性的影响,并开发可视化、交互式的仿真系统。[结果]通过仿真系统实现了进水过程与多种抗沉干预方式的综合评估,是对现有不沉性理论的有效补充。[结论]该成果不仅可帮助设计人员掌握抗沉设计方案对干预进水过程的有效性,指导舰艇抗沉能力的设计;还可应用于抗沉指挥决策的态势预报,具有较高的军事应用价值。     

基于非线性渗流模型的管道型岩溶隧道突水机理研究北大核心CSCD

管道型岩溶突水是一个复杂的多场耦合的非线性渗流问题,致灾具有突发性。为揭示管道型岩溶突水灾害的发生机理,文章基于多物理场耦合作用机理,开展了不同溶腔水压、岩溶管道内不同填充介质、不同岩溶管道宽度及岩溶管道长度条件下的多场耦合分析。得到以下结论:(1)管道型岩溶破坏模式下发生的突水灾害,根据填充介质透水性能的异同而表现不同;(2)流体从富水溶腔中流出时流速较小,流经岩溶管道后流速逐渐增加,进入隧道后达到最大值;(3)影响突水过程的因素主要有:富水溶腔水压、岩溶管道或断层裂隙带内填充介质的种类、岩溶管道的宽度、隧道与水源的距离,其中,岩溶管道宽度及岩溶管道内填充介质类型对突水影响大于其他因素。     

Parameter optimization and parametric deviation influence for shock resistance of double-stage vibration isolation system with limiters北大核心CSCD

［Objectives］For marine nuclear power plants, the relative displacement of the pump supported by a vibration isolation system should be strictly restricted. In order to improve the shock resistance of a vibration isolation system with displacement limiters, the parameter optimization and parametric deviation influence are studied. ［Methods］The theoretical model of a double-stage vibration isolation system with typical limiter parameters is established, the analysis of the shock response characteristics of the system is carried out using the direct integration method, the optimal limiter parameters are obtained using a genetic algorithm, and the influence of parameter deviation on the shock resistance of the system is studied. ［Results］Limiter parameters significantly affect the shock response characteristics of the vibration isolation system. The optimal limiter parameters improve the shock resistance of the system, but parameter deviation has a great influence on shock resistance. Based on the influence of parameter deviation, a deviation control strategy is proposed in which the elastic parameter should have a positive deviation and the gap parameter a negative deviation. The simulation results show that the proposed strategy can effectively alleviate the shock resistance degradation caused by deviation.［Conclusions］The results of this study can be used to guide the design, manufacturing and variation control of limiters for vibration isolation systems. © 2022 Journal of Clinical Hepatology. All rights reserved.     

具有无序排列管片环结构的地铁盾构隧道数字模型智能重建北大核心CSCD

运营地铁隧道的管理、健康监测及维护正逐渐趋向于数字化、智能化;但常因地铁盾构隧道管理和检测单位缺少隧道数字模型,限制了地铁隧道智能维护和管理系统的应用和发展。文章针对地铁盾构隧道中无序排列的管片环结构,提出了一种基于深度学习和机器视觉的地铁盾构隧道数字模型智能重建方法,利用检测车获取的隧道衬砌内表面高清图片,对管片特征物(螺栓孔)进行智能识别与自动分类,再根据螺栓孔群的分布特点自动推断隧道管片环的排版规律,从而结合隧道实际线路实现隧道数字模型快速重建。某地铁隧道的实例应用结果表明,该方法适用于管片无规律性错缝拼装的情况,能以100%的准确率实现地铁盾构隧道数字模型的智能重建。     

黏性场地列车荷载影响下衬砌半渗透边界盾构隧道诱发地表固结沉降解

列车荷载作用下衬砌长期渗漏会显著影响软土盾构隧道周围土体的固结沉降，对邻近环境和地铁的安全运营造成不良影响。针对盾构隧道周围土体固结沉降的既有理论研究一般多考虑衬砌不透水条件，较少考虑衬砌渗漏水及列车荷载耦合作用对于地层固结沉降的影响。引入隧道衬砌半渗透边界和列车三角形循环时效荷载，基于Terzaghi-Rendulic固结理论，采用Boltzmann三元件模型模拟土体流变效应，推导了列车荷载作用下黏弹性地层盾构隧道渗漏水诱发的土体超孔隙水压力消散和地表固结沉降的复变函数解析表达式，并与6个工程实测数据进行对比，验证了所给出解析解的正确性与适用性。此外，通过参数分析讨论了衬砌-土体渗透比和列车荷载参数对土体固结沉降的影响。结果表明：衬砌-土体渗透比是影响盾构扰动地层固结快慢的主要影响因素，衬砌-土体渗透比越大，固结完成时间越早；列车荷载作用下，早期固结沉降速率相较于不考虑列车荷载时会有较明显的增加，但在列车荷载当量增加后，固结沉降速率的增长有所放缓，且其增量与衬砌-土体渗透比密切相关，衬砌-土体渗透比越大，沉降增加量则越大；隧道衬砌可以视为扰动地层的排水边界，其加速了土体固结沉降，而列车荷载与衬砌半渗透性耦合，进一步改变了土体固结沉降形态。     

Fuzzy sliding mode control method for vertical motion of autonomous underwater gliders北大核心CSCD

［Objective］This paper proposes a fuzzy sliding mode controller based on T-S fuzzy logic for the vertical plane motion control of an autonomous underwater glider (AUG) with limited actuator capability. ［Methods］In the fuzzy sliding mode controller, the fuzzy switching rate is used to replace the switching rate in the fixed time controller to effectively suppress buffeting. The fuzzy switching rate is obtained by fitting the switching rate of the fixed time controller with T-S fuzzy rules. Based on the limited capabilities of AUG actuators, a saturation auxiliary system is designed to improve the actuator saturation effect. Finally, the performance of the system is verified by Lyapunov stability analysis and numerical simulation. ［Results］The results show that the AUG under the fuzzy sliding mode controller and the saturation auxiliary system can converge in finite time. The effectiveness of the fuzzy sliding mode controller and the saturation auxiliary system are verified by numerical simulation. ［Conclusions］By making comparisons with the fixed-time controller, it is verified that the two controllers have similar control performance, and the buffeting of the fuzzy sliding mode controller is lesser. © 2022 Journal of Clinical Hepatology. All rights reserved.     

基于遗传算法的盾构隧道管片接头刚度反演研究北大核心CSCD

梁-弹簧模型在管片衬砌结构计算中应用较广泛,目前接头刚度取值方法主要有模型试验法及经验取值法,模型试验法耗时长、成本高昂,而依据经验取值难免存在一定主观性。鉴于此,利用C++编程语言,基于遗传算法开发了盾构隧道管片结构位移反分析程序,首先通过弹性模量值反演算例,得出反演值与理论值误差为1.4%,验证了算法和程序的可行性。利用程序将反演接头刚度值与实际设计案例管片接头刚度值进行对比,反演计算结果表明:正弯矩下管片环向接头转动刚度值反演误差为2.6%,负弯矩下管片环向接头转动刚度值反演误差为4.3%。