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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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Multiple model PHD filter for tracking sharply maneuvering targets using recursive RANSAC based adaptive birth estimation

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Journal of Systems Engineering and Electronics 2024年第3期35卷 780-792页

作者： DING Changwen ZHOU Di ZOU Xinguang DU Runle LIU Jiaqi School of astronautics Harbin Institute of TechnologyHarbin 150001China School of Electronics and Information Engineering Harbin Institute of TechnologyHarbin 150001China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing 100076China

An algorithm to track multiple sharply maneuvering targets without prior knowledge about new target birth is proposed. These targets are capable of achieving sharp maneuvers within a short period of time, such as drones and agile *** probability hypothesis density (PHD) filter, which propagates only the first-order statistical moment of the full target posterior, has been shown to be a computationally efficient solution to multitarget tracking problems. However, the standard PHD filter operates on the single dynamic model and requires prior information about target birth distribution, which leads to many limitations in terms of practical applications. In this paper,we introduce a nonzero mean, white noise turn rate dynamic model and generalize jump Markov systems to multitarget case to accommodate sharply maneuvering dynamics. Moreover, to adaptively estimate newborn targets’information, a measurement-driven method based on the recursive random sampling consensus (RANSAC) algorithm is proposed. Simulation results demonstrate that the proposed method achieves significant improvement in tracking multiple sharply maneuvering targets with adaptive birth estimation.

关键词： multitarget tracking probability hypothesis density(PHD)filter sharply maneuvering targets multiple model adaptive birth intensity estimation

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A Multi-strategy Improved Snake Optimizer Assisted with Population Crowding Analysis for Engineering Design Problems

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Journal of Bionic Engineering 2024年第3期21卷 1567-1591页

作者： Lei Peng Zhuoming Yuan Guangming Dai Maocai Wang Jian Li Zhiming Song Xiaoyu Chen School of Computer Science China University of GeosciencesWuhan430074China Hubei Key Laboratory of Intelligent Geo-Information Processing China University of GeosciencesWuhan430074China China astronautics Standards institute Beijing100071China

Snake Optimizer(SO)is a novel Meta-heuristic Algorithm(MA)inspired by the mating behaviour of snakes,which has achieved success in global numerical optimization problems and practical engineering ***,it also has certain drawbacks for the exploration stage and the egg hatch process,resulting in slow convergence speed and inferior solution *** address the above issues,a novel multi-strategy improved SO(MISO)with the assistance of population crowding analysis is proposed in this *** the algorithm,a novel multi-strategy operator is designed for the exploration stage,which not only focuses on using the information of better performing individuals to improve the quality of solution,but also focuses on maintaining population *** boost the efficiency of the egg hatch process,the multi-strategy egg hatch process is proposed to regenerate individuals according to the results of the population crowding *** addition,a local search method is employed to further enhance the convergence speed and the local search *** is first compared with three sets of algorithms in the CEC2020 benchmark functions,including SO with its two recently discussed variants,ten advanced MAs,and six powerful CEC competition *** performance of MISO is then verified on five practical engineering design *** experimental results show that MISO provides a promising performance for the above optimization cases in terms of convergence speed and solution quality.

关键词： Snake optimizer Multi-strategy Population crowding analysis Engineering design problem

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Controllable self-transport of bouncing droplets on ultraslippery surfaces with wedge-shaped grooves

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Droplet 2024年第2期3卷 138-145页

作者： Chuchen Yue Qingwen Dai Xiaolong Yang Carsten Gachot Wei Huang Xiaolei Wang College of Mechanical and Electrical Engineering Nanjing University of Aeronautics&AstronauticsNanjingChina institute of Engineering Design and Product Development Tribology Research GroupTU WienViennaAustria

Preventing the accretion of droplets on surfaces is vital and slippery liquid-infused porous surfaces(SLIPS)have promising application prospects,such as surface self-cleaning and droplet *** this work,controllable self-transport of bouncing droplets on ultraslippery surfaces with wedge-shaped grooves is *** impact behaviors of droplets on SLIPS under various impact velocities and diameters are explored,which can be classified as hover,total bounce,partial bounce,Worthington jet,and *** with wedge-shaped grooves were designed to transport accreted *** energy and transport model is established to explain the impact and self-transport mechanism,where the Laplace pressure and moving resistance between droplets play a key ***,SLIPS with branched wedge-shaped grooves were designed for droplet self-transport and demonstrated *** work provides a general reference for spontaneous motion control of sessile droplets,droplets with initial impacting velocity,or even liquid films.

关键词： wedge shaped droplets

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Hybrid hydrovoltaic electricity generation driven by water evaporation

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Nano Research Energy 2024年第2期3卷 47-55页

作者： Xuemei Li Gu Feng Yiding Chen Jidong Li Jun Yin Wei Deng Wanlin Guo State Key Laboratory of Mechanics and Control of Mechanical Structures Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of EducationInstitute for Frontier ScienceNanjing University of Aeronautics and AstronauticsNanjing 210016China College of Material Science and Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China College of Aerospace Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Water evaporation is a ubiquitous natural process exploiting thermal energy from ambient *** technologies emerged in recent years offer one prospective route to generate electricity from water evaporation,which has long been ***,we developed a hybrid hydrovoltaic generator driven by natural water evaporation,integrating an“evaporation motor”with an evaporation-electricity device and a droplet-electricity device.A rotary motion of the“evaporation motor”relies on phase change of ethanol driven by water-evaporation induced temperature *** motion enables the evaporation-electricity device to work under a beneficial water-film operation mode to produce output of~4 V and~0.2μA,as well as propels the droplet-electricity device to convert mechanical energy into pulsed output of~100 V and~0.2 *** different types of hydrovoltaic devices require distinctive stimuli,it was challenging to make them work simultaneously,especially under one single driving *** here for the first time empower two types of hydrovoltaic devices solely by omnipresent water ***,this work presents a new pathway to exploiting water evaporation-associated ambient thermal energy and provides insights on developing hybrid hydrovoltaic generators.

关键词： hybrid hydrovoltaic generator ambient thermal energy evaporation motor water evaporation

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Analysis and optimization of stamping and forming process of bearing outer ring

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Theoretical & Applied Mechanics Letters 2024年第3期14卷 227-237页

作者： Shichao Zhu Yulu Ding Bing Long Hun Guo Linhan Ouyang Wengang Chen Zhengyi Jiang College of Aeronautics and Mechanical Engineering Changzhou Institute of TechnologyChangzhou 213002China College of Economics and Management Nanjing University of Aeronautics and AstronauticsNanjing 211106China eering University of WollongongWollongong NSW 2522Australia

To address the common issues of wrinkling,tearing,and uneven wall thickness in the actual sheet metal stamp-ing process of the outer ring of needle roller bearings,this study analyzes critical technical indicators such asforming limits,thickness distribution,and principal strains in the forming process in ***-dimensionalmodels of the concave and convex dies were *** effects of different process parameters,includingstamping speed,edge pressure,sheet metal thickness,and friction coefficient,on the quality of the forming partswere investigated by varying these ***,the orthogonal experimental method was used todetermine an optimal experimental group from multiple sets of *** was found that under the processparameters of a stamping speed of 3000 mm/s,edge pressure of 2000 N,sheet metal thickness of 0.9 mm,andfriction coefficient of 0.125,the forming quality of the outer ring of the bearing is ideal.

关键词： Plate stamping Bearing outer ring Mold design Optimization

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Power Allocation for SE Maximization in Uplink Massive MIMO System Under Minimum Rate Constraint

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China Communications 2024年第3期21卷 104-117页

作者： Wang Hui Yu Xiangbin Liu Fuyuan Bai Jiawei College of Electronic and Information Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106China Key Laboratory of Wireless Sensor Network and Communication Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200050China

In this paper,we optimize the spectrum efficiency(SE)of uplink massive multiple-input multiple-output(MIMO)system with imperfect channel state information(CSI)over Rayleigh fading *** SE optimization problem is formulated under the constraints of maximum power and minimum rate of each ***,we develop a near-optimal power allocation(PA)scheme by using the successive convex approximation(SCA)method,Lagrange multiplier method,and block coordinate descent(BCD)method,and it can obtain almost the same SE as the benchmark scheme with lower *** this scheme needs three-layer iteration,a suboptimal PA scheme is developed to further reduce the complexity,where the characteristic of massive MIMO(i.e.,numerous receive antennas)is utilized for convex reformulation,and the rate constraint is converted to linear *** suboptimal scheme only needs single-layer iteration,thus has lower complexity than the near-optimal ***,we joint design the pilot power and data power to further improve the performance,and propose an two-stage algorithm to obtain joint *** results verify the effectiveness of the proposed schemes,and superior SE performance is achieved.

关键词： imperfect CSI massive MIMO minimum rate constraint power allocation spectral efficiency

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Towards Sustainable Grinding of Difficult-to-Cut Alloys-A Holistic Review and Trends

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 1-28页

作者： Ning Qian Jiajia Chen Aqib Mashood Khan Biao Zhao Yurong Chen Wenfeng Ding Yucan Fu Jiuhua Xu Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016China College of Mechanical and Electronic Engineering Nanjing Forestry UniversityNanjing 210037China JITRI institute of Precision Manufacturing Nanjing 211805China

Grinding,a critical precision machining process for difficult-to-cut alloys,has undergone continual technological advancements to improve machining ***,the sustainability of this process is gaining heightened attention due to significant challenges associated with the substantial specific grinding energy and the extensive heat generated when working with difficult-to-cut alloys,renowned for their exceptional physical and mechanical *** response to these challenges,the widespread application of massive coolant in manufacturing industries to dissipate grinding heat has led to complex post-cleaning and disposal ***,in turn,has resulted in issues such as large energy consumption,a considerable carbon footprint,and concerns related to worker health and safety,which have become the main factors that restrict the development of grinding *** paper provides a holistic review of sustainability in grinding difficult-to-cut alloys,encompassing current trends and future *** examination extends to developing grinding technologies explicitly tailored for these alloys,comprehensively evaluating their sustainability ***,the exploration delves into innovative sustainable technologies,such as heat pipe/oscillating heat pipe grinding wheels,minimum quantity lubrication,cryogenic cooling,and *** groundbreaking technologies aim to reduce dependence on hazardous coolants,minimizing energy and resource consumption and carbon emissions associated with coolant-related or subsequent disposal *** essence of these technologies lies in their potential to revolutionize traditional grinding practices,presenting environmentally friendly ***,future development trends and research directions are put forward to pursue the current limitation of sustainable grinding for difficult-to-cut *** paper can guide future research and development efforts toward more environmentally friendly

关键词： Grinding Sustainability Cooling Energy consumption Carbon footprint Difficult-to-cut alloys

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Event-Triggered Bipartite Consensus Tracking and Vibration Control of Flexible Timoshenko Manipulators Under Time-Varying Actuator Faults

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1190-1201页

作者： Xiangqian Yao Hao Sun Zhijia Zhao Yu Liu School of Automation Science and Engineering South China University of TechnologyGuangzhou 510640China Yongjiang Laboratory Ningbo 315202 School of astronautics Harbin Institute of TechnologyHarbin 150001China School of Mechanical and Electrical Engineering Guangzhou UniversityGuangzhou 510006China

For bipartite angle consensus tracking and vibration suppression of multiple Timoshenko manipulator systems with time-varying actuator faults,parameter and modeling uncertainties,and unknown disturbances,a novel distributed boundary event-triggered control strategy is proposed in this *** contrast to the earlier findings,time-varying consensus tracking and actuator defects are taken into account *** addition,the constructed event-triggered control mechanism can achieve a more flexible design because it is not required to satisfy the input-to-state *** achieve the control objectives,some new integral control variables are given by using back-stepping technique and boundary ***,adaptive neural networks are applied to estimate system *** the proposed event-triggered scheme,control inputs can reduce unnecessary ***,tracking errors and vibration states of the closed-looped network can be exponentially convergent into some small fields,and Zeno behaviors can be *** last,some simulation examples are given to state the effectiveness of the control algorithms.

关键词： Vibration satisfy bipartite

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Influence of Vanes and Blades on Ingress in Axial Rim Seal for Turbine Stages

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Journal of Thermal Science 2024年第3期33卷 833-846页

作者： REN Ran DU Qiang LIU Guang ZENG Yanlian XIE Lei institute of Engineering Thermophysics Chinese Academy of SciencesBeijing100190China National Key Laboratory of Science and Technology on Advanced Light-duty Gas-turbine Beijing100190China School of Aeronautics and astronautics University of Chinese Academy of SciencesBeijing100190China

Hot gas ingestion refers to the phenomenon of mainstream hot gas flowing into the space cavity of a turbine *** studies have found that mainstream annulus pressure distribution plays an important role in hot gas ingestion,but due to its complexity,the mechanism of the interaction between mainstream flow and hot gas ingestion remains *** paper adopts the URANS method,and three sealing flow rates are considered,named C_(w)=0,C_(w)=500,and C_(w)=*** time-averaged annulus pressure distribution shows that an increase in the sealing flow decreases the pressure value,and the effects of the sealing flow on the pressure distribution of the leading edge of the blade are much more influential than that of the trailing edge of the *** unsteady pressure time-space distribution in the annulus indicates that a time-space tilted distribution of pressure at the rim exits when the sealing flow *** phenomenon is mainly due to the strong feedback mechanism of the sealing flow to the annulus pressure field.A comparison of the pressure and mean radial velocity distribution of the mainstream shows that the ingestion mainly occurs on the blade side,where the pressure is lower than on the vane *** flow characteristics at the wheel rim are analyzed with a sealing flow rate C_(w)=5000,and under these conditions,both pressure-induced ingestion and ingestion caused by a passage vortex can be *** three-dimensional and inertial effects of the mainstream at the wheel rim lead to the generation of separation vortices on the blade side,and the presence of separation vortices leads to ingestion along the blade *** the same time,pressure on the blade side will cause the fluid to have a radial inward flow tendency,which will promote the formation of separation vortices,leading to more serious ingestion in the high-pressure region on the blade *** blade pressure field can be more significant than the vane trailing pressure field in the rim sea

关键词： separation vortex unsteady rim seal the effect of blade on ingestion

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