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Repair tolerance assessment for aircraft composite structures using Bayesian updating

Chinese Journal of Aeronautics 2024年第6期37卷 360-391页

作者： Xin LI Hongfu zuo Bin YANG school of Automotive and Rail Transit Nanjing Institute of TechnologyNanjing 211167China Civil Aviation Key Laboratory of Aircraft Health Monitoring and Intelligent Maintenance College of Civil AviationNanjing University of Aeronautics and AstronauticsNanjing 211106China

Detection and repair of composite damage is crucial to ensure the safety and reliability of aircraft structures.A novel approach to quantitatively evaluate the repair tolerance of composite structures in civil aircraft based on Bayesian updating is *** method incorporates historical damage inspection data to determine the prior distribution of damage size,which is then updated with newly collected damage size data using Bayesian *** Carlo simulation is employed to investigate the probability of failure and estimate maintenance costs,considering various factors such as the frequency and timing of damage events,damage detection,structural strength,gust loads,and maintenance expenses throughout the lifecycle of composite *** and economic factors are considered to establish a lower threshold for repairs and an upper threshold for maintenance based on the occurrence of accidental impact *** of the effectiveness and feasibility of a quantitative assessment method for repair tolerance is conducted using damage statistics data from civil aircraft routes utilizing the structural skin panels of composite outer *** results demonstrate that the method proposed in conjunction with extensive simulations and full utilization of field damage inspection data can effectively simulate unexpected impact damage situations that may occur during civil aircraft service and evaluate the reliability and economic feasibility of the repair of *** research findings hold significant theoretical and practical value for the preparation of documents for continued airworthiness of composite structures,including structural repair manuals and maintenance programs.

关键词： Composite structures Repair tolerance Maintenance Bayesian updating Probability of failure

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Motion-pressure coupled control and simulation of long-endurance capability for multicapsule stratospheric airships

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Chinese Journal of Aeronautics 2024年第6期37卷 137-150页

作者： Zhiguang sHI Wei HUO Zongyu zuo school of Automation science and Electrical Engineering Beihang UniversityBeijing 100191China Beijing Near space Airship Technology Development Co. LtdBeijing 100070China

The current study focuses on the motion-pressure coupled control for a multicapsule stratospheric airship and transforms the path-tracking and heading-hold control of airships into guidance tracking with a time-varying weighted sum of longitudinal and lateral velocities by the definition of compound ***,an improved nonlinear predictive control method is provided to reduce the control energy consumption by the rolling optimization of controller parameters based on finite time intervals,ensuring infinite-time path-tracking ***,combined with the proposed cyclic regulation process of safe pressure between internal and external capsules,this study can fully reflect the force-thermal coupled rule of airships under the actions of atmospheric environment and maneuvering force,while evaluating the long-endurance capability of airships under the conditions of safe superheating and *** effectiveness of the motionpressure coupled controller was verified through numerical simulations,which can overcome the influence of environmental wind and achieve a tracking effect for the desired cruise path and compound *** airspeed provided during the cyclic circadian time caused the maximum superheating of the helium controlled within 30*** helium in the internal and external capsules achieved circadian *** equivalent micropore diameter of the capsule of 5 mm can achieve 55 days of long-endurance *** controller satisfies the requirements of cruise-flight application modes for multicapsule stratospheric airships with important engineering value.

关键词： Compound speed Nonlinear predictive control Cyclic pressure regulation Long-endurance capability stratospheric airship

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A new elastoplastic model for bolt-grouted fractured rock

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International Journal of Mining science and Technology 2024年第7期34卷 995-1016页

作者： Haoyi Li shuangying zuo Peiyuan Lin state Key Laboratory for Tunnel Engineering Sun Yat-Sen UniversityGuangzhou 510275China southern Marine science and Engineering Guangdong Laboratory Zhuhai 519082China school of Civil Engineering Sun Yat-Sen UniversityGuangzhou 510275China College of Resources and Environmental Engineering Guizhou UniversityGuiyang 550025China

Complexities in mechanical behaviours of rock masses mainly stem from inherent discontinuities,which calls for advanced bolt-grouting techniques for stability *** the mechanical properties of bolt-grouted fractured rock mass(BGFR)and developing accurate prediction methods are crucial to optimize the BGFR support *** paper establishes a new elastoplastic(E-P)model based on the orthotropic and the Mohr-Coulomb(M-C)plastic-yielding *** elastic parameters of the model were derived through a meso-mechanical analysis of composite materials mechanics(CMM).Laboratory BGFR specimens were prepared and uniaxial compression test and variable-angle shear test considering different bolt arrangements were carried out to obtain the mechanical parameters of the *** showed that the anisotropy of BGFR mainly depends on the relative volume content of each component material in a certain ***,the mechanical parameters deduced from the theory of composite materials which consider the short fibre effect are shown to be in good agreement with those determined by laboratory experiments,and the variation rules maintained good ***,a case study of a real tunnel project is provided to highlight the effectiveness,validity and robustness of the developed E-P model in prediction of stresses and deformations.

关键词： Bolt-grouted fractured rock mass Elastoplastic model Composite materials mechanics Laboratory experiment

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A Novel Prescribed-Performance Path-Following Problem for Non-Holonomic Vehicles

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IEEE/CAA Journal of Automatica sinica 2024年第6期11卷 1476-1484页

作者： Zirui Chen Jingchuan Tang Zongyu zuo seventh Research Division Beihang University(BUAA)Beijing 100191China IEEE

The issue of achieving prescribed-performance path following in robotics is addressed in this paper,where the aim is to ensure that a desired path within a specified region is accu-rately converged to by the controlled *** this context,a novel form of the prescribed performance guiding vector field is introduced,accompanied by a prescribed-time sliding mode con-trol ***,the interdependence among the pre-scribed parameters is *** validate the effectiveness of the proposed method,numerical simulations are presented to demonstrate the efficacy of the approach.

关键词： Guiding vector field non-holonomic vehicle path following prescribed performance sliding mode control

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single and combined effects of secondary polyethylene microplastic on the growth of Pak choi and the soil microbiome composition

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Frontiers of Environmental science & Engineering 2024年第5期18卷 1-12页

作者： Jiamin Hu Zhenwen Xie Jiane zuo state Key Joint Laboratory of Environmental simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing100084China Tsinghua shenzhen International Graduate school Tsinghua UniversityShenzhen518055China

It has been confirmed that microplastics(MPs)are present in the *** study simulated secondary PE-MPs via aging and mechanical processes to evaluate their effects on Pak choi(Brassica rapa L.)over 21 *** common pollutants,dichlorodiphenyltrichloroethane(DDT)and naphthalene,were used in the combined toxicity *** results indicated that the growth of Pak choi was significantly inhibited after exposure to secondary PE-MPs,and the combined effects were antagonistic,owing to the adsorption capacity of secondary PE-MPs to DDT and *** stress in Pak choi can be markedly affected,leading to oxidative damage to plant *** moisture content,soil bulk density,soil density,cation exchange capacity(CEC),and FDA hydrolase in the planted soils increased in the treated groups,and the TOC content changed *** also found that the microbial composition of the soil in the DDT and naphthalene groups showed more significant alterations than that in the other *** diversity analysis showed that species diversity increased in the combined groups but indicated a clear downward trend in the single MPs *** study suggests that secondary PE-MPs harm the growth of Pak choi and can change soil properties,revealing the harm to the ecosystem of MPs in the soil.

关键词： secondary PE-MPs Combined effects Oxidative stress soil properties Bacterial community

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Optimization Method for Electrical Water Heaters Considering shifting Potentials of Electricity Consumption and Water-use Activities

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Journal of Modern Power systems and Clean Energy 2024年第4期12卷 1250-1259页

作者： Yuqing Bao Zhonghui zuo Xuehua Wu school of Electrical and Automation Engineering Nanjing Normal UniversityNanjing 210046China school of Electrical Engineering Nanjing Vocational University of Industry TechnologyNanjing 210023China

Electrical water heaters(EWHs)are important can-didates to provide demand-response *** traditional op-timization method for EWHs focuses on the optimization of the electricity consumption,without considering the shifting poten-tial of the water-use *** paper proposes an optimiza-tion method for EWHs considering the shifting potentials of both the electricity consumption and water-use ***-sidering that the water-use activities could be monolithically shifted,the shifting model of the water-use activities was *** addition to the thermodynamic model of the EWH,the optimal scheduling model of the EWH was developed and solved using mixed-integer linear *** studies were performed on a single EWH and aggregate EWHs,demon-strating that the proposed method can shift the water-use activi-ties and therefore increase the load-shifting potential of the EWHs.

关键词： Electrical water heater(EWH) demand response load-shifting water-use activity

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Three-dimensional limit variation analysis on the ultimate pullout capacity of the anchor cables based on the Hoek-Brown failure criterion

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Journal of Mountain science 2024年第3期21卷 1036-1047页

作者： zuo shi ZHAO Lianheng HU shihong College of Civil Engineering Changsha UniversityChangsha 410022China Hunan Provincial Key Laboratory for Disaster Prevention and Mitigation of Rail Transit Engineering structure Key Laboratory of Heavy-Haul Railway Engineering StructureMinistry of EducationCentral South UniversityChangsha 410075China College of Civil Engineering Central South UniversityChangsha 410075China

Only simplified two-dimensional model and a single failure mode are adopted to calculate the ultimate pullout capacity(UPC)of anchor cables in most previous *** study focuses on a more comprehensive combination failure mode that consists of bond failure of an anchorage body and failure of an anchored rock *** three-dimensional ultimate pullout capacity of the anchor cables is calculated based on the Hoek-Brown failure criterion and variation analysis *** numerical solution for the curvilinear function in fracture plane is obtained based on the finite difference theory,which more accurately reflects the failure state of the anchor cable,as opposed to that being assumed in *** results reveal that relying solely on a single failure mode for UPC calculations has limitations,as changes in parameter values not only directly impact the UPC value but also can alter the failure model and thus the calculation method.

关键词： Anchor cable Ultimate pullout capacity(UPC) Failure model Variation analysis Hoek-Brown failure criterion

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Navigating the safe operation of high-voltage cathodes:Challenges and strategies

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Nano Research 2024年第10期17卷 8694-8705页

作者： Yue sun Changjian zuo Yi-Chun Lu Electrochemical Energy and Interfaces Laboratory Department of Mechanical and Automation EngineeringThe Chinese University of Hong KongHong Kong 999077China

Lithium-ion batteries play a crucial role in storing energy for renewable sources and electric vehicles,yet face challenges related to insufficient energy *** the working-voltage of cathodes is promising to boost the energy density of batteries by increasing both the output voltage and capacity of cathode,which however could compromise life cycle and *** review provides a comprehensive summary of essential factors governing pathways of cathode-induced thermal runaway,including electrolyte decomposition,phase transitions,and crosstalk-induced *** and electrolyte modifications aimed at mitigating parasitic reactions and preventing crosstalk were also *** review concludes with insights into the future application of these strategies,providing a comprehensive perspective on the realization of high-energy and safe batteries.

关键词： battery safety high-voltage cathode lithium-ion battery thermal runaway

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An Improved UNet Lightweight Network for semantic segmentation of Weed Images in Corn Fields

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Computers, Materials & Continua 2024年第6期79卷 4413-4431页

作者： Yu zuo Wenwen Li school of Information and Control Engineering Jilin Institute of Chemical TechnologyJilin132022China school of Mechanical and Control Engineering Baicheng Normal UniversityBaicheng137000China

In cornfields,factors such as the similarity between corn seedlings and weeds and the blurring of plant edge details pose challenges to corn and weed *** addition,remote areas such as farmland are usually constrained by limited computational resources and limited collected ***,it becomes necessary to lighten the model to better adapt to complex cornfield scene,and make full use of the limited data *** this paper,we propose an improved image segmentation algorithm based on ***,the inverted residual structure is introduced into the contraction path to reduce the number of parameters in the training process and improve the feature extraction ability;secondly,the pyramid pooling module is introduced to enhance the network’s ability of acquiring contextual information as well as the ability of dealing with the small target loss problem;and lastly,Finally,to further enhance the segmentation capability of the model,the squeeze and excitation mechanism is introduced in the expansion *** used images of corn seedlings collected in the field and publicly available corn weed datasets to evaluate the improved *** improved model has a total parameter of 3.79 M and miou can achieve 87.9%.The fps on a single 3050 ti video card is about *** experimental results show that the network proposed in this paper can quickly segment corn weeds in a cornfield scenario with good segmentation accuracy.

关键词： semantic segmentation deep learning UNet pyramid pooling module

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Multi-circular formation control with reinforced transient profiles for nonholonomic vehicles:A path-following framework

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Defence Technology（防务技术） 2024年第1期31卷 278-287页

作者： Jintao Zhang Xingling shao Wendong Zhang Zongyu zuo school of Instrument and Electronics North University of ChinaTaiyuan 030051China state Key Laboratory of Dynamic Measurement Technology North University of ChinaTaiyuan 030051China seventh Research Division School of Automation Science and Electrical EngineeringBeihang UniversityBeijing 100191China

This article investigates a multi-circular path-following formation control with reinforced transient profiles for nonholonomic vehicles connected by a digraph.A multi-circular formation controller endowed with the feature of spatial-temporal decoupling is devised for a group of vehicles guided by a virtual leader evolving along an implicit path,which allows for a circumnavigation on multiple circles with an anticipant angular *** addition,notice that it typically imposes a stringent time constraint on time-sensitive enclosing scenarios,hence an improved prescribed performance control(IPPC)using novel tighter behavior boundaries is presented to enhance transient capabilities with an ensured appointed-time convergence free from any *** significant merits are that coordinated circumnavigation along different circles can be realized via executing geometric and dynamic assignments independently with modified transient ***,all variables existing in the entire system are analyzed to be *** and experimental results are provided to validate the utility of suggested solution.

关键词： Multi-circular formation Reinforced transient profiles Nonholonomic vehicles Path following

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