Structural health monitoring of rotating blades on helicopters

The paper discusses the structural health monitoring of rotating blades on helicopters (RBH) based on the application of Modal Analysis. The study discussed in this paper includes the experimental validation of state-of-the-art techniques for the on-line measurement of dynamic signals of helicopter rotating units, optimization of the sensor type for rotating unit measurement, analysis of the practical applicability of modal analysis techniques for condition-based monitoring of rotating structures and estimation of the efficiency of the experimental system for the identification of practical damages of blades. The research was conducted using helicopter blade models operating within an experimental test bench. The capabilities of diagnostic technique application to main rotor gears and bearings are also presented. Conclusions are made about the successful analysis of the operational modal analysis technique applicability for the structural health monitoring of a rotating blade, and its effectiveness for damage identification. Two strategies of the RBH repair – with a continuously condition-based monitoring with the proposed technology and one without such monitoring, were discussed. The Markov chain reliability models for each strategy were analyzed and the reliability improvement factor for the proposed monitoring technology in comparison with a traditional one was evaluated. It is shown that the reliability improvement factor is more effective for the proposed method as compared to the traditional one

Effectiveness of application of modal analysis for the monitoring of stressed or operated structures

This paper presents a brief summary of the research results of the application of experimental and operational modal analysis (EMA and OMA) effectiveness for the assessment of the change in the condition of operating structures by modifying their dynamic characteristics. Special focus is given to the topicality of the operational modal analysis for the definition of the dynamic features of the structures (frequencies, modes and deformation) under near-natural conditions. The research was conducted using two operating laboratory models, when the first one imitated a part of a fuel/gas pipeline and the second – a helicopter blade. The results of finite-element model simulation, identification of natural mode and the influence of the two types of virtual defects on the changes in the dynamic properties are provided. The work describes the results of experimental research of the dynamic behaviour of the pipe model, using the methods of OMA and comparing them with the modelling results. The research results demonstrate how the modification of the condition of the large-scaled models impacts pipe and blade models when the defects of local and global nature are introduced

An Integrated Micro- and Macroarchitectural Analysis of the Drosophila Brain by Computer-Assisted Serial Section Electron Microscopy

A new software package allows for dense electron microscopy reconstructions of neuronal networks in the fruit fly brain, and reveals specific differences in microcircuits between insects and vertebrates

Experimental Technology of Operational Pipeline Condition Monitoring

This work presents a summary of the research study of operational modal analysis (OMA) application for condition monitoring of operating pipelines. Special focus is on the topicality of OMA for definition of the dynamic features of the pipeline (frequencies and mode shapes) in operation. The research was conducted using two operating laboratory models imitated a part of the operating pipeline. The results of finite-element modeling, identification of pipe natural modes and its modification under the influence of virtual failure are discussed. The work considers the results of experimental research of dynamic behavior of the operating pipe models using one of OMA techniques and comparing dynamic properties with the modeled data. The study results demonstrate sensitivity of modal shape parameters to modification of operating pipeline technical state. It is resumed about ability of operating pipeline condition monitoring by measuring dynamic deformations of the operating pipe and OMA techniques application for dynamic properties extraction

Condition Monitoring Of Operating Pipelines With Operational Modal Analysis Application

In the petroleum, natural gas and petrochemical industries, great attention is being paid to safety, reliability and maintainability of equipment. There are a number of technologies to monitor, control, and maintain gas, oil, water, and sewer pipelines. The paper focuses on operational modal analysis (OMA) application for condition monitoring of operating pipelines. Special focus is on the topicality of OMA for definition of the dynamic features of the pipeline (frequencies and mode shapes) in operation. The research was conducted using two operating laboratory models imitated a part of the operating pipeline. The results of finite-element modeling, identification of pipe natural modes and its modification under the influence of virtual failure are discussed. The work considers the results of experimental research of dynamic behavior of the operating pipe models using one of OMA techniques and comparing dynamic properties with the modeled data. The study results demonstrate sensitivity of modal shape parameters to modification of operating pipeline technical state. Two strategies of pipeline repair – with continuously condition-based monitoring with proposed technology and without such monitoring, was discussed. Markov chain reliability models for each strategy were analyzed and reliability improvement factor for proposed technology of monitoring in compare with traditional one was evaluated. It is resumed about ability of operating pipeline condition monitoring by measuring dynamic deformations of the operating pipe and OMA techniques application for dynamic properties extraction

Effectiveness of Application of Modal Analysis for the Monitoring of Stressed or Operated Structures

This paper presents a brief summary of the research results of the application of experimental and operational modal analysis (EMA and OMA) effectiveness for the assessment of the change in the condition of operating structures by modifying their dynamic characteristics. Special focus is given to the topicality of the operational modal analysis for the definition of the dynamic features of the structures (frequencies, modes and deformation) under near-natural conditions. The research was conducted using two operating laboratory models, when the first one imitated a part of a fuel/gas pipeline and the second – a helicopter blade. The results of finite-element model simulation, identification of natural mode and the influence of the two types of virtual defects on the changes in the dynamic properties are provided. The work describes the results of experimental research of the dynamic behaviour of the pipe model, using the methods of OMA and comparing them with the modelling results. The research results demonstrate how the modification of the condition of the large-scaled models impacts pipe and blade models when the defects of local and global nature are introduced

Health Monitoring of Serial Structures Applying Piezoelectric Film Sensors and Modal Passport

Health monitoring of critical structures, that form parts of serial operating objects, is a pressing task. The Operational Modal Analysis (OMA) techniques could be the optimal solution. An inexpensive measurement system, such as the OMA, uses a lot of sensors for structural response assessment. The health monitoring of serial structures has to also consider possible deviations between samples. A solution providing the OMA application includes the compact measurement system based on piezoelectric film sensors and modal passport (MP) techniques. For validation of the proposed approach, a series of five similar composite cylinders, with a network of piezoelectric film sensors, was used. Applying modal tests on the specimens, and using OMA with MP methods, the set of typical modal parameters was determined and analyzed. The results of the study confirmed the feasibility of the sensor network and its applicability for structural health monitoring of serial samples using OMA methods. The proven effectiveness of OMA/MP techniques, combined with a sensor network, provides a prototype of intelligent sensor technology, which can be used for health monitoring of structures, including those that are part of an operating facility