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Thin-Walled Structures 2025年 215卷

作者： Song, Zhao Jun Yang, Xin Xu, Ren Jie Liu, Qing Chao Duan, Hao Li, Xiao Bin Hubei Defense Science and Technology Key Laboratory of Ship Explosion Damage and Protection Wuhan China Ministry of Education Wuhan China School of Naval Architecture Ocean and Energy Power Engineering Wuhan University of Technology Wuhan China Marine Design and Research Institute of China Shanghai China

Ultimate strength of stiffened panels in ship structures is a fundamental component to resist the vertical hull girder bending moment combined by still water and wave loads. Stiffened panels in deck and bow/stern structures have oblique angle between attached plate and stiffener due to the beam camber and oblique/curved hull plate. Several predominate parameters were investigated in the ultimate strength prediction of stiffened panels by finite element method, such as stiffener type including flange direction in angle bar and included angle. Periodic and symmetric boundary conditions were applied on the 1/2 + 1 + 1/2 bays/spans stiffened panels to simulate adjacent structural constraints effects. It is found that current existing empirical formulae derived from stiffened panels with right angle under longitudinal compression may lead to large errors of ultimate strength under oblique angle conditions, especially for small included angle between attached plate and stiffener. Based on the existing expressions of assessing ultimate strength, the improved empirical formulae with additional reduction expression are proposed for stiffened panels with oblique angle, which could consider the comprehensive influences of included angle, column slenderness and plate slenderness for different stiffener types. © 2025 Elsevier Ltd

关键词： Structural panels

Evaluation of CO2 and NOx Emissions from Container Trucks Using a Portable Emissions Measurement System

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SSRN 2023年

作者： Zhao, Hongmei He, Hongdi Lu, Danni Fang, Xiaorui Zhou, Dai Peng, Zhongren Center for Intelligent Transportation Systems and Unmanned Aerial Systems Applications State Key Laboratory of Ocean Engineering School of Naval Architecture Ocean and Civil Engineering Shanghai Jiao Tong University Shanghai200240 China School of Naval Architecture Ocean and Civil Engineering Shanghai Jiao Tong University Shanghai200240 China Key Laboratory of Hydrodynamics of Ministry of Education Shanghai Jiao Tong University Shanghai200240 China International Center for Adaptation Planning and Design College of Design Construction and Planning University of Florida PO Box 115706 GainesvilleFL32611-5706 United States

Vehicle emission has been regarded to the major source of air pollution in urban area. Especially, the emissions originating from container diesel trucks (CDTs) constitute a significant portion of road transportation emissions in port city. However, the instantaneous measurement of CDTs emission in real road situation remains limited. In this study, we employed a portable emission measurement system (PEMS) to measure the real-world emissions of CDTs that meet the China IV and China V standards on highway and port roads. The impacts of vehicle speed, acceleration, and vehicle specific power (VSP) on CO2 and NOx emission rates are analyzed. Furthermore, a random forest model is employed to explore the interplay of driving, engine, and external factors on vehicle emission rates, as well as to predict these rates. Finally, the emission factors under diverse driving conditions are examined. The results indicate that elevated CO2 and NOx emission rates are primarily observed during instances of low and medium-speed acceleration on highway. On port road, the distribution of high CO2 and NOx emission rates are relatively scattered. The relationship between the emission rates of CO2 and NOx and VSP follows a third-order polynomial function. Engine power, engine speed, and VSP exhibit a strong correlation with CO2 and NOx emission rates. Remarkably, the CO2 and NOx emission factors on highway for China V CDT have decreased by 58.04% and 55.13%, respectively, compared to China IV CDT. © 2023, The Authors. All rights reserved.

关键词： Carbon dioxide

Dynamic Modeling and Comparative Analysis of Heat Exchangers in Supercritical Co2 Power Cycles

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SSRN 2024年

作者： Qin, Tianyang Sun, Yuwei Wei, Wei Lin, Jie Yan, Xinping State Key Laboratory of Maritime Technology and Safety Wuhan University of Technology Hubei Province Wuhan430063 China Reliability Engineering Institute National Engineering Research Center for Water Transport Safety Wuhan University of Technology Hubei Province Wuhan430063 China School of Transportation and Logistics Engineering Wuhan University of Technology Hubei Province Wuhan430063 China School of Naval Architecture Ocean and Energy Power Engineering Wuhan University of Technology Hubei Province Wuhan430063 China

Heat exchangers are critical components of supercritical CO2 power cycles. Developing dynamic computational programs for the thermal-hydraulic characteristics of heat exchangers using mechanistic equations is essential for analyzing the dynamic behavior of supercritical CO2 power cycles under varying boundary conditions such as load, cold and hot-side heat sources. In this study, we present a dynamic model of printed circuit heat exchangers for supercritical CO2 power cycle coolers, employing the finite volume method and Modelica language. We use 100 control volumes, achieving a balance between simulation accuracy and computational time, and validating the independence of the number of control volumes on the dynamic process calculations of the model. Simulation results were validated against Fluent models, affirming the efficacy of our approach in dynamic analysis. Subsequently, we compared the effects of different application forms of governing equations on the dynamic calculation process. We found that variations in the application of the energy conservation equation have negligible effects on results, offering flexibility in selection. Simplified momentum conservation equations are recommended to enhance computational speed, with minimal discrepancy in pressure calculation. Moreover, incorporating heat transfer equations that account for non-uniform wall temperature distributions is essential for ensuring simulation accuracy. © 2024, The Authors. All rights reserved.

关键词： Heat exchangers

Hydrodynamic Energy Collection Using A Cylinder With Different Cross Sections Based on Macro-Fibre Composite

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SSRN 2023年

作者： Shen, Yu Wang, Jiasong Zheng, Hanxu Sun, Yuankun School of Naval Architecture Ocean and Civil Engineering Shanghai Jiao Tong University Shanghai200240 China MOE Key Laboratory of Hydrodynamics Shanghai Jiao Tong University Shanghai200240 China SJTU-Sanya Yazhou Bay Institute of Deepsea Science and Technology Sanya572024 China

With the rapid development of micro and small electronic devices, energy utilization from the surrounding environment has been paid significant attention. This study aims to enhance the performance of energy harvesting devices in low-speed water flow utilizing Macro-Fibre Composite (MFC) attached to a cantilever beam with a cylinder attached at the free end with three different cross-sections, namely circular, square, and triangular. Experiments were conducted in a low-speed circulating water flume at Reynolds numbers ranging within 770-8800. Three oscillation modes based on different cross-sections can be observed: (1) vortex-induced vibration (VIV) for circular cylinder water energy harvester (CWEH);(2) Combined VIV-galloping for triangular cylinder water energy harvester (TWEH);(3) Separated weak vortex-induced vibration (WVIV)-galloping for square cylinder water energy harvester (SWEH). The characteristics of MFC water energy harvester are revealed through the vibration mechanism analysis. The effects of flow velocity, resistance, and cross-section on energy harvester were studied, and the flow field was analyzed. The energy harvesting results indicate that the TWEH exhibits the highest voltage, power, power density, and efficiency, among the three devices, the maximum voltage, power, power density, and efficiency achieved are 28.9 V, 241.1 µW, 512.6 µW/cm3, and 0.23%, respectively. Despite the TWEH exhibiting a maximum efficiency that is 0.68 times that of the CWEH, it is noteworthy that the TWEH presents a superior performance in terms of maximum voltage, power, and power density by factors of 2.77, 7.37, and 7.38, respectively, compared to the CWEH. Hence, the research suggests that the TWEH is the most suitable device for energy collection under low-speed water flow conditions. © 2023, The Authors. All rights reserved.

关键词： Circular cylinders

Based on the ship power spectrum method preparation of seaplane water load spectrum

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Based on the ship power spectrum method preparation of seapl...

International Joint Conference on Civil and Marine engineering (JCCME 2023)

作者： T. Yu Q. Hu M. Sun J. Sun School of Naval Architecture and Ocean Engineering Huazhong University of Science and Technology (HUST) Wuhan Hubei People's Republic of China Key Laboratory of High- Speed Hydrodynamic Aviation Science and Technology China Special Vehicle Research Institute Jingmen Hubei People's Republic of China

ISBN: (数字)9781837240241

Seaplanes bear complex hydrodynamic loads during takeoff and landing in different waters. It is of great guiding significance for the design and manufacture of seaplanes to master the variation of water load in different mission scenarios and to use appropriate methods to compile water load spectrum. In view of the lack of measured data of similar seaplane when compiling water load spectrum for seaplanes, the method of calculating water load spectrum based on power spectrum is studied: According to the meaningful wave height and overload increment of the model pool test, the corresponding amplitude operator of the real machine is calculated, and the wave spectrum of the target water area is input. The overload incremental power spectrum of the real seaplane is obtained through spectral analysis. Then the power spectrum method is used to calculate the overpass times of each overload increment, and the gravity overload spectrum of seaplane in different task situations is obtained, which reflects the change of water load during the seaplane mission. And the STAR-CCM+ software was used to calculate and analyze the load and motion response of the seaplane during landing and gliding at a certain speed and attitude angle, in order to verify the reliability of the research method.

关键词：

Analyzing Ship Emissions Under Complex Operating Conditions: Insights from Onboard Measurement Data

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SSRN 2024年

作者： Fan, Ailong Yan, Junhui Xiong, Yuqi Yang, Liu Zhang, Mingyang State Key Laboratory of Maritime Technology and Safety Wuhan University of Technology Wuhan China School of Transportation and Logistics Engineering Wuhan University of Technology Wuhan China School of Naval Architecture Ocean and Energy Power Engineering Wuhan University of Technology Wuhan China Hubei East Lake Laboratory Wuhan China School of Engineering Department of Mechanical Engineering Aalto University Espoo20110 Finland

The proportion of older ships in the Yangtze River exceeds 70%, leading to substantial emissions due to frequent low-load sailing. This research employing a shaft power meter and a PEMS system assessed the power, load, and emissions of these ships under typical operating conditions, varying cruising revolutions, and lock transit scenarios. This research reveals that low-load sailing accounts for 65-68% of the total voyage duration, with emissions during cruising and manoeuvring making up over 70%. NOX and SO2 emission factors significantly vary with cruising revolutions. When the main engine operates at less than 25% load, NOx emissions comprise 30% of the voyage’s total. Emissions during departure and docking are notably concentrated in the 10-15% and 5-10% ranges, respectively. It is recommended that the standard engine test cycle include low-load condition points. This research is pivotal for comprehending and controlling the emission levels of older ships in the Yangtze River. © 2024, The Authors. All rights reserved.

关键词： Nitrogen oxides

Energy-efficient tracking control of x rudder auv with rudder dynamics compensation 31st

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Energy-efficient tracking control of x rudder auv with rudde...

31st International ocean and Polar engineering Conference, ISOPE 2021

作者： Xia, Yingkai Xu, Kan Xu, Guohua Zeng, Xin Wang, Yicai Qi, Xianghong College of Engineering Huazhong Agricultural University Wuhan Hubei China Key Laboratory of Agricultural Equipment in Mid-Lower Yangtze River Ministry of Agriculture and Rural Affairs Wuhan Hubei China Wuhan Second Ship Design and Research Institute Wuhan Hubei China School of Naval Architecture and Ocean Engineering Huazhong University of Science and Technology Wuhan Hubei China

ISBN: (纸本)9781880653821

In this paper, an energy-efficient tracking control method is proposed for a X rudder AUV. First, the mathematical model and trajectory tracking problem are presented. Then, an energy-efficient tracking controller is designed based on time-varying LOS guidance and feedback dynamics control law. Besides, in order to achieve energy-efficient X rudder allocation, a multi-objective optimization method is proposed. Moreover, the rudder error dynamics is considered and compensated by rudder error disturbance observer. Finally, comparative numerical simulations are carried out to demonstrate the robustness and effectiveness of the proposed approach. © 2021 by the International Society of Offshore and Polar Engineers (ISOPE).

关键词： Error compensation

Study on compiling water load spectrum for take off and landing of amphibious aircraft based on task analysis method

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Study on compiling water load spectrum for take off and land...

International Joint Conference on Civil and Marine engineering (JCCME 2023)

作者： M. Sun Q. Hu T. Yu J. Sun School of Naval Architecture and Ocean Engineering Huazhong University of Science and Technology (HUST) Wuhan 430074 Hubei People's Republic of China Key Laboratory of High-Speed Hydrodynamic Aviation Science and Technology China Special Vehicle Research Institute Jingmen 448035 Hubei People's Republic of China

ISBN: (数字)9781837240241

The amphibious aircraft generally uses the form of hull water dynamic layout, carrying the forest fire fighting, sea rescue and other special operation tasks, and needs to frequently take off and land on the water surface. However, it bears complex water dynamic loads in the process of takeoff and landing, and the existence of these loads will cause the dynamic response of the aircraft structure. The compilation of load spectrum plays a very important role in designing the structural fatigue, damage tolerance and service life of designing amphibious aircraft. In this paper, the water load spectrum is defined as the center of gravity overload spectrum of the amphibious aircraft taking off and landing on the water surface, mainly studies the use characteristics of the amphibious aircraft for takeoff and landing on the surface of the water plane, according to the typical mission profile of the amphibious aircraft. The task analysis method, which is the basic method of spectrum compilation, is used to establish the compilation method of water surface precipitation load spectrum of amphibious aircraft, and the implementation steps of this method are described.

关键词：

Effects of geometrical and physical factors on light particles dispersion by agitation characteristic curve

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Chinese Journal of Chemical engineering 2019年第10期27卷 2313-2324页

作者： Meng Li Yangbo Tan Yufeng Liu Jianglong Sun De Xie Zeng Liu School of Naval Architecture and Ocean Engineering Huazhong University of Science and TechnologyWuhan 430074China Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration(CISSE) Shanghai 200240China Hubei Key Laboratory of Naval Architecture and Ocean Engineering Hydrodynamics(HUST) Wuhan 430074China

In this study,the effects of geometrical and physical factors on light particles dispersion in stirred tank were investigated by agitation characteristic *** experiments and CFD simulations with discrete phase model(DPM)and volume of fluid model(VOF)were conducted in this *** factors,which include four geometrical factors(submergence,impeller-to-tank ratio,number of impeller blades and baffling mode)and a physical factor(liquid viscosity)were *** each factor,the power consumption curve and agitation characteristic curve were drawn to compare the power consumption and mixing results in the stirred *** of the agitation characteristic curves were compared with the previous published literatures and *** is found that the agitation characteristic curves reflect the tendency of power consumption and particles distribution well in stirred *** good agreement indicates the applicability of the agitation characteristic curves for the study of light particles distribution in stirred tank.

关键词： Agitation characteristic curve Geometrical and physical factors Light particles Solid–liquid mixing Stirred tank

Fiv and Energy Harvesting Using Bluff Body Piezoelectric Water Energy Harvester with Different Cross-Sections

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SSRN 2023年

作者： Shen, Yu Wang, Jiasong Alam, Md. Mahbub School of Naval Architecture Ocean and Civil Engineering Shanghai Jiao Tong University Shanghai200240 China MOE Key Laboratory of Hydrodynamics Shanghai Jiao Tong University Shanghai200240 China SJTU-Sanya Yazhou Bay Institute of Deepsea Science and Technology Sanya572024 China Shenzhen518055 China

Research utilizing piezoelectric fiber composites to power network nodes or micro-sensors by capturing energy from the surrounding environment is becoming a hot spot, and the structural design to efficiently improve the performance of energy harvesting is very important. We examined the performance of a vertical cantilever beam piezoelectric water energy harvester (PWEH) with three different cross-sections including circular, square, and equilateral triangle, each with a mass ratio of 4.8. The focus is given on the effects of the bluff body cross-section, load resistance, and flow velocity on the flow-induced vibration (FIV) and energy response of the vertical cantilever beam of PWEH. The equilateral triangular cylinder water energy harvester (TWEH) demonstrates excellent performance. It has a maximum amplitude of 3.8D, 3.4 times that of CWEH. The peak pendulum angle of TWCH is 13.9◦, 3.2 times that of CWEH. It has a voltage of 0.057 V at the resistance of ∞, which is 3.4 times that of CEWH. Besides, TWCH has an output power of 0.38 nW at a resistance of 106 Ω, which is 9.5 times that of CWEH. This study suggests that the best energy efficiency of TWEH is achieved by coupling vortex-induced vibration (VIV) and galloping excitation. © 2023, The Authors. All rights reserved.

关键词： Flow velocity