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Multistate Degradation Model for prognostics of Solder Joints Under Vibration Conditions

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Chinese Journal of Electronics 2016年第4期25卷 779-785页

作者： TANG Wei JING Bo HUANG Yifeng SHENG Zengjin JIAO Xiaoxuan Aeronautics and Astronautics Engineering College Air Force Engineering University

This paper develops a multistate degradation structure of the solder joints which can be used under various vibration conditions based on nonhomogeneous continuous-time hidden semi-Markov process.The parameters of the structure were estimated to illustrate the stochastic relationship between the degradation process and the monitoring indicator by using unsupervised learning methods.Random vibration tests on solder joints with different levels of power spectral density and fixed forms were conducted with a real time monitoring electrical resistance to examine the suitability of the model.It was experimentally verified that the multistate degradation structure matches the experimental process reasonably and accurately.Based on this multistate degradation model,the online prognostics of solder joint were analyzed and the results indicated that faults or failures can be detected timely,leading to appreciate maintenance actions scheduled to avoid catastrophic failures of electronics.

关键词： Multistate degradation prognostics Solder joint Vibration loading

A model-based prognostics method for fatigue crack growth in fuselage panels

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Chinese Journal of Aeronautics 2019年第2期32卷 396-408页

作者： Yiwei WANG Christian GOGU Nicolas BINAUD Christian BES Jian FU School of Mechanical Engineering and Automation Beihang University Institut Clément Ader (UMR CNRS 5312) INSA/UPS/ISAE/Mines Albi Université de Toulouse

This paper proposes a model-based prognostics method that couples the Extended Kalman Filter(EKF) and a new developed linearization method. The proposed prognostics method is developed in the context of fatigue crack propagation in fuselage panels where the model parameters are unknown and the crack propagation is affected by different types of uncertainties. The coupled method is composed of two steps. The first step employs EKF to estimate the unknown model parameters and the current damage state. In the second step, the proposed efficient linearization method is applied to compute analytically the statistical distribution of the damage evolution path in some future time. A numerical case study is implemented to evaluate the performance of the proposed method. The results show that the coupled EKF-linearization method provides satisfactory results: the EKF algorithm well identifies the model parameters, and the linearization method gives comparable prediction results to Monte Carlo(MC) method while leading to very significant computational cost saving. The proposed prognostics method for fatigue crack growth can be used for developing predictive maintenance strategy for an aircraft fleet, in which case, the computational cost saving is significantly meaningful.

关键词： Aircraft fuselage panels Extended Kalman filter Fatigue crack propagation Linearization method Model-based prognostics

The Use of High-Performance Fatigue Mechanics and the Extended Kalman/Particle Filters,for Diagnostics and prognostics of Aircraft Structures

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Computer Modeling in Engineering & Sciences 2015年第5期105卷 1-24页

作者： Hai-Kun Wang Robert Haynes Hong-Zhong Huang Leiting Dong Satya N.Atluri School of Mechanical Electronicand Industrial EngineeringUniversity of Electronic Science and Technology of China Center for Aerospace Research&Education University of CaliforniaIrvine Vehicle Technology Directorate US Army Research Laboratory Department of Hohai University China

In this paper,we propose an approach for diagnostics and prognostics of damaged aircraft structures,by combing high-performance fatigue mechanics with filtering theories.Fast&accurate deterministic analyses of fatigue crack propagations are carried out,by using the Finite Element Alternating Method(FEAM)for computing SIFs,and by using the newly developed Moving Least Squares(MLS)law for computing fatigue crack growth rates.Such algorithms for simulating fatigue crack propagations are embedded in the computer program Safe-Flaw,which is called upon as a subroutine within the probabilistic framework of filter theories.Both the extended Kalman as well as particle filters are applied in this study,to obtain the statistically optimal and semi-optimal estimates of crack lengths,from a series of noisy measurements of crack-lengths over time.For the specific problem,a simple modification to the particle filter,which can drastically reduce the computational burden,is also proposed.Based on the results of such diagnostic analyses,the prognostics of aerospace structures are thereafter achieved,to estimate the probabilistic distribution of the remaining useful life.By using a simple example of a single-crack near a fastener hole,we demonstrate the concept and effectiveness of the proposed framework.This paper thus forms the scientific foundation for the recently proposed concepts of VRAMS(Virtual Risk-Informed Agile Maneuver Sustainment)and Digital Twins of aerospace vehicles.

关键词： Diagnostics and prognostics fatigue mechanics extended Kalmanfilter particle filter

Special Issue on Machine Fault Diagnostics and prognostics

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Chinese Journal of Mechanical Engineering 2017年第6期30卷 1283-1284页

作者： Zhigang Tian Wilson Wang University of Alberta Edmonton Canada Lakehead University Thunder Bay Canada

Machine components and systems, such as gears, bearings, pipes, cutting tools and turbines, may experience various types of faults, such as breakage, crack, pitting, wear, corrosion. If not being properly monitored and treated, such faults can propagate and lead to machinery perfor- mance degradation, malfunction, or even severe compo- nent/system failure. It is significant to reliably detect machinery defects, evaluate their severity, predict the fault propagation trends, and schedule optimized maintenance and inspection activities to prevent unexpected failures. Advances in these areas will support ensuring equipment and production reliability, safety, quality and productivity.

关键词： Special Issue Machine Fault Diagnostics prognostics

Current role of surgery for tuberous sclerosis complex-associated epilepsy

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Pediatric Investigation 2022年第1期6卷 16-22页

作者： Nicola Specchio Giusy Carfi Pavia Luca de Palma Alessandro De Benedictis Chiara Pepi Marta Conti Carlo Efisio Marras Federico Vigevano Paolo Curatolo Rare and Complex Epilepsy Unit Department of NeurosciencesBambino GesùChildren’s HospitalIRCCSRomeItaly Neurosurgery Unit Department of NeurosciencesBambino GesùChildren’s HospitalIRCCSRomeItaly Department of Neurosciences Bambino GesùChildren’s HospitalIRCCSRomeItaly Child Neurology and Psychiatry Unit Systems Medicine DepartmentTor Vergata UniversityRomeItaly

Tuberous sclerosis complex(TSC)is a rare multisystem,autosomal dominant neurocutaneous syndrome in which epilepsy is the most common of several neurological and psychiatric manifestations.Around two thirds of patients develop drug-resistant epilepsy for whom surgical resection of epileptogenic foci is indicated when seizures remain inadequately controlled following trial of two antiseizure medications.The challenge with presurgical and surgical approaches with patients with TSC is overcoming the complexity from the number of tubers and the multiplex epileptogenic network forming the epileptogenic zone.Data suggest that seizure freedom is achieved by 55%-60%of patients,but predictive factors for success have remained elusive,which makes for unconfident selection of surgical candidates.This article presents three different cases as illustrations of the potential challenges faced when assessing the suitability of TSC patients for epilepsy surgery.

关键词： Epilepsy Everolimus Imaging prognostics Surgery Tuberous sclerosis complex(TSC)

Functions of three ubiquitin-conjugating enzyme 2 genes in hepatocellular carcinoma diagnosis and prognosis

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World Journal of Hepatology 2022年第5期14卷 956-971页

作者： Chun-Ye Zhang Ming Yang Department of Veterinary Pathobiology University of MissouriColumbiaMO 65211United States Department of Surgery University of MissouriColumbiaMO 65211United States

BACKGROUND Liver cancer ranks the third cause of cancer-related death worldwide.The most common type of liver cancer is hepatocellular carcinoma(HCC).The survival time for HCC patients is very limited by years due to the lack of efficient treatment,failure of early diagnosis,and poor prognosis.Ubiquitination plays an essential role in the biochemical processes of a variety of cellular functions.AIM To investigate three ubiquitination-associated genes in HCC.METHODS Herein,the expression levels of ubiquitin-conjugating enzymes 2(UBE2)including UBE2C,UBE2T,and UBE2S in tumor samples of HCC patients and nontumor controls at the Cancer Genome Atlas(TCGA)database,was comprehensively analyzed.The relationship of UBE2 gene expression level with cancer stage,prognostic outcome,and TP53 mutant status was studied.RESULTS Our results showed that UBE2C,UBE2T,and UBE2S genes were overexpressed in HCC samples compared to non-tumor tissues.Dependent on the cancer progression stage,three UBE2 genes showed higher expression in tumor tissues at all four stages compared to non-tumor control samples.Furthermore,a significantly higher expression of these genes was found in stage 2 and stage 3 cancers compared to stage 1 cancer.Additionally,overexpression of those genes was negatively associated with prognostic outcome and overall survival time.Patients with TP53 mutation showed a higher expression level of three UBE2 genes,indicating an association between UBE2 expression with p53 function.CONCLUSION In summary,this study shed light on the potential roles of UBE2C,UBE2T,UBE2S on diagnostic and prognostic biomarkers for HCC.Moreover,based on our findings,it is appealing to further explore the correlation of those genes with TP53 mutation in HCC and the related mechanisms.

关键词： Hepatocellular carcinoma Ubiquitin-conjugating enzyme 2 UBE2C UBE2T UBE2S TP53 mutant Biomarker Diagnostic prognostics

Reliability estimation and remaining useful lifetime prediction for bearing based on proportional hazard model

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Journal of Central South University 2015年第12期22卷 4625-4633页

作者：王鹭张利王学芝 School of Information Liaoning University

As the central component of rotating machine,the performance reliability assessment and remaining useful lifetime prediction of bearing are of crucial importance in condition-based maintenance to reduce the maintenance cost and improve the reliability.A prognostic algorithm to assess the reliability and forecast the remaining useful lifetime(RUL) of bearings was proposed,consisting of three phases.Online vibration and temperature signals of bearings in normal state were measured during the manufacturing process and the most useful time-dependent features of vibration signals were extracted based on correlation analysis(feature selection step).Time series analysis based on neural network,as an identification model,was used to predict the features of bearing vibration signals at any horizons(feature prediction step).Furthermore,according to the features,degradation factor was defined.The proportional hazard model was generated to estimate the survival function and forecast the RUL of the bearing(RUL prediction step).The positive results show that the plausibility and effectiveness of the proposed approach can facilitate bearing reliability estimation and RUL prediction.

关键词： prognostics reliability estimation remaining useful life proportional hazard model

A data-driven health indicator extraction method for aircraft air conditioning system health monitoring

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Chinese Journal of Aeronautics 2019年第2期32卷 409-416页

作者： Jianzhong SUN Chaoyi LI Cui LIU Ziwei GONG Ronghui WANG Department of Civil Aviation Nanjing University of Aeronautics and Astronautics Maintenance Engineering Department Xiamen Airlines

prognostics and Health Management(PHM) has become a very important tool in modern commercial aircraft. Considering limited built-in sensing devices on the legacy aircraft model,one of the challenges for airborne system health monitoring is to find an appropriate health indicator that is highly related to the actual degradation state of the system. This paper proposed a novel health indicator extraction method based on the available sensor parameters for the health monitoring of Air Conditioning System(ACS) of a legacy commercial aircraft model. Firstly, a specific Airplane Condition Monitoring System(ACMS) report for ACS health monitoring is defined. Then a non-parametric modeling technique is adopted to calculate the health indicator based on the raw ACMS report data. The proposed method is validated on a single-aisle commercial aircraft widely used for short and medium-haul routes, using more than 6000 ACMS reports collected from a fleet of aircraft during one year. The case study result shows that the proposed health indicator can effectively characterize the degradation state of the ACS, which can provide valuable information for proactive maintenance plan in advance.

关键词： Air conditioning system Aircraft health monitoring Airplane condition monitoring system Health indicator prognostics and health management

prognostics for lithium-ion battery operating under different depth of discharge using hybrid method

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Prognostics for lithium-ion battery operating under differen...