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Repair tolerance assessment for aircraft composite structures using Bayesian updating

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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

A hybrid deep neural network based on multi-time window convolutional bidirectional LSTM for civil aircraft APU hazard identification

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Chinese Journal of Aeronautics 2022年第4期35卷 344-361页

作者： Di ZHOU Xiao ZHUANG Hongfu ZUO civil a viation key laboratory of aircraft health monitoring and intelligent maintenance College of Civil AviationNanjing University of Aeronautics and AstronauticsNanjing 210016China Department of Mechanical and Industrial Engineering University of TorontoToronto M5S 3G8Canada College of Science Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Safety is one of the important topics in the field of civil aviation. Auxiliary Power Unit(APU) is one of important components in aircraft, which provides electrical power and compressed air for aircraft. The hazards in APU are prone to cause economic losses and even casualties. So,actively identifying the hazards in APU before an accident occurs is necessary. In this paper, a Hybrid Deep Neural Network(HDNN) based on multi-time window convolutional neural network-Bidirectional Long Short-Term Memory(CNN-Bi LSTM) neural network is proposed for active hazard identification of APU in civil aircraft. In order to identify the risks caused by different types of failures, the proposed HDNN simultaneously integrates three CNN-Bi LSTM basic models with different time window sizes in parallel by using a fully connected neural network. The CNN-Bi LSTM basic model can automatically extract features representing the system state from the input data and learn the time information of irregular trends in the time series data. Nine benchmark models are compared with the proposed HDNN. The comparison results show that the proposed HDNN has the highest identification accuracy. The HDNN has the most stable identification performance for data with imbalanced samples.

关键词： civil aviation Convolutional neural networks Deep neural networks Hazard identification Long short-term memory

Comparative analysis of thermodynamic and mechanical responses between underground hydrogen storage and compressed air energy storage in lined rock caverns

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International Journal of Mining Science and Technology 2024年第4期34卷 531-543页

作者： Bowen Hu Liyuan Yu Xianzhen Mi Fei Xu Shuchen Li Wei Li Chao Wei Tao Zhang State key laboratory of intelligent Construction and healthy Operation and maintenance of Deep Underground Engineering China University of Mining and TechnologyXuzhou 221116China key laboratory of Large Structure health monitoring and Control Shijiazhuang Tiedao UniversityShijiazhuang 050043China School of Mechanics and civil Engineering China University of Mining and TechnologyXuzhou 221116China

Underground hydrogen storage(UHS)and compressed air energy storage(CAES)are two viable largescale energy storage technologies for mitigating the intermittency of wind and solar ***,it is meaningful to compare the properties of hydrogen and air with typical thermodynamic storage *** study employs a multi-physical coupling model to compare the operations of CAES and UHS,integrating gas thermodynamics within caverns,thermal conduction,and mechanical deformation around rock *** thermodynamic responses are validated using additional simulations and the field test *** and pressure variations of air and hydrogen within rock caverns exhibit similarities under both adiabatic and diabatic simulation *** reaches higher temperature and pressure following gas charging stage compared to air,and the ideal gas assumption may lead to overestimation of gas temperature and *** steel lining of CAES,the sealing layer(fibre-reinforced plastic FRP)in UHS is prone to deformation but can effectively mitigates stress in the sealing *** CAES,the first principal stress on the surface of the sealing layer and concrete lining is tensile stress,whereas UHS exhibits compressive stress in the same *** present research can provide references for the selection of energy storage methods.

关键词： Underground hydrogen storage Compressed air energy storage Mechanical response Thermodynamic response Lined rock caverns

Distributed fiber optic sensing system for vibration monitoring of 3D printed bridges

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Optoelectronics Letters 2025年第1期21卷 28-34页

作者： ZHAO Shuai ZHOU Ran LUO Mingming LIU Jianfei LIU Xiongfei ZHOU Tao School of Electronic Information Engineering Hebei University of Technology Tianjin key laboratory of Electronic Materials and Devices School of civil Engineering and Transportation Hebei University of Technology Tianjin Jinhang Institute of Technical Physics

The fiber optic sensing technology provides data support in structural health monitoring of the macro facilities, including design, construction, and maintenance of bridges, tunnels, ports and other infrastructures. In this paper, a distributed vibration sensing system is proved to be responsive to a single touch over a 1.8-m-long equivalent fiber segment, covering a vibration frequency from 5 Hz to 25 kHz. The sensing fiber was arranged as an S type layout on the bridge to recognize the standing state, windblown disturbance, and walking vibration. Moreover, the knocking and climbing events are recognized fiber laying spinning lines and hanging on the fences, respectively. The demonstration shows an accurate positioning and sensitive vibration monitoring applied on the automated three-dimensional(3D) printed bridge, which is applicable to all kinds of 3D printed facilities as intelligent sensory neuro-networks.

关键词： Spinning (fibers)

Comprehensive Assessment of Pilot Mental Workload in Various Levels

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Journal of Harbin Institute of Technology(New Series) 2018年第2期25卷 59-72页

作者： Kun Yang Cuanyan Feng Jie Bai key laboratory of civil aircraft Airworthiness and maintenance Civil Aviation University of ChinaTianjin 300300China School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China

Physiological measures indexed by fixation frequency and total fixation time,task performance based on n-back accuracy,subjective assessment based on NASA Task Load Index(NASA-TLX) were used to measure the Mental Workload(MW) in different levels which were induced by vision-related flight task combined with auditory cognitive load. 16 healthy novice pilots were recruited to complete a monitoring task based on Head-Up Display(HUD) and an auditory n-back task which was used to manipulate the Mental Workload Level(MWL) in flight simulation environment. In our experiment,fixation frequency,average saccade time,blink rate and average pupil diameter were sensitive to MW. What's more,a comprehensive assessment method of pilot mental workload based on various measures was advocated. At last,a Fisher projection function based on the Fisher discrimination method and a three-level discriminate model established by the Bayes discrimination method were built up,the original validation and cross-validation methods of both models were 97. 92% and 95. 83% respectively,which could discriminate various Mental Workload Levels(MWLs) ideally.

关键词： mental workload fixation frequency bayes discrimination method

Short-term tunnel-settlement prediction based on Bayesian wavelet:a probability analysis method

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2023年第11期24卷 960-977页

作者： Yang DING Xiaowei YE Zhi DING Gang WEI Yunliang CUI Zhen HAN Tao JIN key laboratory of Safe Construction and intelligent maintenance for Urban Shield Tunnels of Zhejiang Province Hangzhou City UniversityHangzhou 310015China Zhejiang Engineering Research Center of intelligent Urban Infrastructure Hangzhou City UniversityHangzhou 310015China Department of civil Engineering Hangzhou City UniversityHangzhou 310015China Department of civil Engineering Zhejiang UniversityHangzhou 310058China Nanjing Metro Operation Co. Ltd.Nanjing 210012China

As urbanization accelerates,the metro has become an important means of *** the safety problems caused by metro construction,ground settlement needs to be monitored and predicted regularly,especially when a new metro line crosses an existing *** this paper,we propose a settlement-probability prediction model with a Bayesian emulator(BE)based on the Gaussian prior(GP),that is,a *** addition,considering the distortion characteristics of monitoring data,the data is denoised using wavelet decomposition(WD),so the final prediction model is *** particular,the effects of different prediction ratios and moving windows on prediction performance are explored,and the optimal number of moving windows is *** addition,the predicted value for GPBE based on the original data is compared with the predicted value for WD-GPBE based on the denoised *** year of settlement-monitoring data collected by a structural health monitoring(SHM)system installed on the Nanjing Metro is used to demonstrate the effectiveness of WDGPBE and GPBE for predicting settlement.

关键词： Metro construction Settlement probability prediction Structural health monitoring(SHM) Wavelet denoising Gaussian prior(GP) Bayesian emulator(BE)

Study on creep deformation and energy development of underground surrounding rock under four‐dimensional support

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Deep Underground Science and Engineering 2024年第1期3卷 25-38页

作者： Zhanguo Ma Junyu Sun Peng Gong Pengfei Yan Nan Cui Ruichong Zhang School of Mechanics and civil Engineering China University of Mining and TechnologyXuzhouChina State key laboratory of intelligent Construction and healthy Operation and maintenance of Deep Underground Engineering China University of Mining and TechnologyXuzhouChina Department of Mining Engineering Colorado School of MinesGoldenUSA

There is an urgent need to develop optimal solutions for deformation control of deep high‐stress roadways,one of the critical problems in underground *** previously proposed four‐dimensional support(hereinafter 4D support),as a new support technology,can set the roadway surrounding rock under three‐dimensional pressure in the new balanced structure,and prevent instability of surrounding rock in underground ***,the influence of roadway depth and creep deformation on the surrounding rock supported by 4D support is still *** study investigated the influence of roadway depth and creep deformation time on the instability of surrounding rock by analyzing the energy *** elastic strain energy was analyzed using the program redeveloped in *** numerical simulation results indicate that the combined support mode of 4D roof supports and conventional side supports is highly applicable to the stability control of surrounding rock with a roadway depth exceeding 520 *** the increase of roadway depth,4D support can effectively restrain the area and depth of plastic deformation in the surrounding ***,4D support limits the accumulation range and rate of elastic strain energy as the creep deformation time increases.4D support can effectively reduce the plastic deformation of roadway surrounding rock and maintain the stability for a long deformation period of 6 *** confirmed by in situ monitoring results,4D support is more effective for the long‐term stability control of surrounding rock than conventional support.

关键词： coal mines elastic strain energy four‐dimensional support large roadway depth long‐term stability control plastic deformation surrounding rock

Shear failure behaviors and degradation mechanical model of rockmass under true triaxial multi-level loading and unloading shear tests

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International Journal of Mining Science and Technology 2024年第10期34卷 1385-1408页

作者： Zhi Zheng Ronghua Li Pengzhi Pan Jinghua Qid Guoshao Su Hong Zheng State key laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures Key Laboratory of Disaster Prevention and Structural Safety of Ministry of EducationCollege of Civil Engineering and ArchitectureGuangxi UniversityNanning 530004China State key laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China China Energy Engineering Group Guangxi Electric Power Design Institute Co.Ltd. Nanning 530007China State key laboratory of intelligent Construction and healthy Operation and maintenance of Deep Underground Engineering China University of Mining and TechnologyXuzhou 221116China

The redistribution of three-dimensional(3D)geostress during underground tunnel excavation can easily induce to shear failure along rockmass structural plane,potentially resulting in engineering ***,the current understanding of rockmass shear behavior is mainly based on shear tests under2D stress without lateral stress,the shear fracture under 3D stress is unclear,and the relevant 3D shear fracture theory research is ***,this study conducted true triaxial cyclic loading and unloading shear tests on intact and bedded limestone under different normal stress σ_(n) and lateral stressσ_(p)to investigate the shear strength,deformation,and failure *** results indicate that under differentσ_(n)and σ_(p),the stress–strain hysteresis loop area gradually increases from nearly zero in the pre-peak stage,becomes most significant in the post-peak stage,and then becomes very small in the residual stage as the number of shear test cycles *** shear peak strength and failure surface roughness almost linearly increase with the increase inσ_(n),while they first increase and then gradually decrease asσ_(p)increases,with the maximum increases of 12.9%for strength and 15.1%for *** shear residual strength almost linearly increases withσ_(n),but shows no significant change withσ_(p).Based on the acoustic emission characteristic parameters during the test process,the shear fracture process and microscopic failure mechanism were *** the shear stressτincreases,the acoustic emission activity,main frequency,and amplitude gradually increase,showing a significant rise during the cycle near the peak strength,while remaining almost unchanged in the residual *** true triaxial shear fracture process presents tensile-shear mixture failure characteristics dominated by microscopic tensile *** on the test results,a 3D shear strength criterion considering the lateral stress effect was proposed,and the determination met

关键词： True triaxial shear test Lateral stress effect Acoustic emission monitoring Shear parameters evolution Shear degradation mechanical model

monitoring and detection of steel bridge diseases:A review

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第2期11卷 188-208页

作者： Chuang Cui Qinghua Zhang Dengke Zhang Wulve Lao Lemou Wu Zhenxiong Jiang National key laboratory of Bridge intelligent and Green Construction Southwest Jiaotong UniversityChengdu 610031China School of civil Engineering Southwest Jiaotong UniversityChengdu 610031China Jiangsu Provincial Transportation Engineering Construction Bureau Nanjing 210004China

Fatigue,corrosion,and bolt loosening are the main causes of structural performance degradation and collapse in steel *** monitoring of steel bridge diseases is a basic premise for ensuring high-quality operation and maintenance of steel *** this regard,a summary and analysis were conducted on the classification of steel bridge diseases,monitoring and detection methods,application statuses,and major *** main causes,research status,and development trends of steel bridge diseases are *** results showed that,for fatigue crack problems,fatigue crack initiation has a small scale,high difficulty in monitoring and detection,few methods,and low *** the cracks grow,the difficulty of monitoring and detection decreases,the number of methods increases,and the accuracy *** crack monitoring and detection are affected by the environmental and vehicular *** corrosion features are evident in steel bridges,and corrosion identification methods and technologies are rapidly *** and detecting corrosion in concealed areas is difficult and requires further improvements in monitoring and detection technologies and their *** and detection methods and supporting equipment for bolt loosening in steel bridges are rapidly *** development of intelligent monitoring and detection technologies and supporting equipment is an important research topic that urgently needs to be addressed for the full-lifecycle operation and maintenance of steel bridges and the sustainable development of bridge *** new intelligent sensing components based on high-performance materials and sensing element design theory to improve the monitoring and detection perception ability is an important development direction for steel bridge monitoring and *** on intelligent monitoring and detection technologies,standardized indicators,and related topics based on intelligent oper

关键词： Steel bridge Diseases Fatigue crack Corrosion Bolt loosening monitoring and detection