scholarly journals On the Application of Laser Vibrometry to Perform Structural Health Monitoring in Non-Stationary Conditions of a Hydropower Dam

Sensors ◽  
2019 ◽  
Vol 19 (17) ◽  
pp. 3811 ◽  
Author(s):  
Mateja Klun ◽  
Dejan Zupan ◽  
Jože Lopatič ◽  
Andrej Kryžanowski
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Rapid Development ◽  
Laser Doppler Vibrometer ◽  
Vibration Monitoring ◽  
Hydropower Plant ◽  
Structural Vibration ◽  
Measurement Technology ◽  
Structural Health ◽  
Stationary Conditions

This paper presents the first application of the Laser Doppler Vibrometer (LDV) in non-stationary conditions within a hydropower plant powerhouse. The aim of this research is to develop a methodology to include non-contact vibration monitoring as part of structural health monitoring of concrete dams. We have performed in-situ structural vibration measurements on the run-of-the-river Brežice dam in Slovenia during the start-up tests and regular operation. In recent decades, the rapid development of laser measurement technology has provided powerful methods for a variety of measuring tasks. Despite these recent developments, the use of lasers for measuring has been limited to sites provided with stationary conditions. This paper explains the elimination of pseudo-vibration and measurement noise inherent in the non-stationary conditions of the site. Upon removal of the noise, fatigue of the different structural elements of the powerhouse could be identified if significant changes over time are observed in the eigenfrequencies. The use of laser technology is to complement the regular monitoring activities on large dams, since observation and analysis of integrity parameters provide indispensable information for decision making and maintaining good structural health of ageing dams.

scholarly journals Structural Vibration Monitoring Using Cumulative Spectral Analysis

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Satoru Goto ◽  
Yoshinori Takahashi ◽  
Mikio Tohyama
Keyword(s):  
Spectral Analysis ◽  
Structural Health Monitoring ◽  
Impulse Response ◽  
Health Monitoring ◽  
Structural Condition ◽  
Vibration Monitoring ◽  
Structural Vibration ◽  
Scale Model ◽  
Structural Health ◽  
Resonance Decay

This paper describes a resonance decay estimation for structural health monitoring in the presence of nonstationary vibrations. In structural health monitoring, the structure's frequency response and resonant decay characteristics are very important for understanding how the structure changes. Cumulative spectral analysis (CSA) estimates the frequency decay by using the impulse response. However, measuring the impulse response of buildings is impractical due to the need to shake the building itself. In a previous study, we reported on system damping monitoring using cumulative harmonic analysis (CHA), which is based on CSA. The current study describes scale model experiments on estimating the hidden resonance decay under non-stationary noise conditions by using CSA for structural condition monitoring.

scholarly journals A Review of Recent Distributed Optical Fiber Sensors Applications for Civil Engineering Structural Health Monitoring

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1818
Author(s):  
Mattia Francesco Bado ◽  
Joan R. Casas
Keyword(s):  
Structural Health Monitoring ◽  
Optical Fiber ◽  
Health Monitoring ◽  
Optical Fiber Sensors ◽  
Vibration Monitoring ◽  
Fiber Sensors ◽  
Structural Health ◽  
Comprehensive Collection ◽  
Monitoring Tools ◽  
Distributed Optical Fiber

The present work is a comprehensive collection of recently published research articles on Structural Health Monitoring (SHM) campaigns performed by means of Distributed Optical Fiber Sensors (DOFS). The latter are cutting-edge strain, temperature and vibration monitoring tools with a large potential pool, namely their minimal intrusiveness, accuracy, ease of deployment and more. Its most state-of-the-art feature, though, is the ability to perform measurements with very small spatial resolutions (as small as 0.63 mm). This review article intends to introduce, inform and advise the readers on various DOFS deployment methodologies for the assessment of the residual ability of a structure to continue serving its intended purpose. By collecting in a single place these recent efforts, advancements and findings, the authors intend to contribute to the goal of collective growth towards an efficient SHM. The current work is structured in a manner that allows for the single consultation of any specific DOFS application field, i.e., laboratory experimentation, the built environment (bridges, buildings, roads, etc.), geotechnical constructions, tunnels, pipelines and wind turbines. Beforehand, a brief section was constructed around the recent progress on the study of the strain transfer mechanisms occurring in the multi-layered sensing system inherent to any DOFS deployment (different kinds of fiber claddings, coatings and bonding adhesives). Finally, a section is also dedicated to ideas and concepts for those novel DOFS applications which may very well represent the future of SHM.

scholarly journals Advances in the Structural Health Monitoring of Bridges Using Piezoelectric Transducers

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4312 ◽  
Author(s):  
Yunzhu Chen ◽  
Xingwei Xue
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Piezoelectric Materials ◽  
Low Cost ◽  
Rapid Development ◽  
Concrete Strength ◽  
Steel Corrosion ◽  
Fast Response ◽  
Future Application ◽  
Structural Health

With the rapid development of the world’s transportation infrastructure, many long-span bridges were constructed in recent years, especially in China. However, these bridges are easily subjected to various damages due to dynamic loads (such as wind-, earthquake-, and vehicle-induced vibration) or environmental factors (such as corrosion). Therefore, structural health monitoring (SHM) is vital to guarantee the safety of bridges in their service lives. With its wide frequency response range, fast response, simple preparation process, ease of processing, low cost, and other advantages, the piezoelectric transducer is commonly employed for the SHM of bridges. This paper summarizes the application of piezoelectric materials for the SHM of bridges, including the monitoring of the concrete strength, bolt looseness, steel corrosion, and grouting density. For each problem, the application of piezoelectric materials in different research methods is described. The related data processing methods for four types of bridge detection are briefly summarized, and the principles of each method in practical application are listed. Finally, issues to be studied when using piezoelectric materials for monitoring are discussed, and future application prospects and development directions are presented.

scholarly journals Comparative Study of Fiber Bragg Gratings and Fiber Polarimetric Sensors for Structural Health Monitoring of Carbon Composites

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Massimo Olivero ◽  
Guido Perrone ◽  
Alberto Vallan ◽  
Daniele Tosi
Keyword(s):  
Structural Health Monitoring ◽  
Comparative Study ◽  
Health Monitoring ◽  
Smart Materials ◽  
Vibration Monitoring ◽  
Carbon Fiber Composites ◽  
Test Plate ◽  
Structural Health ◽  
Dynamic Excitation ◽  
Cheap Alternative

A comparative study is presented between Bragg grating (FBG) and polarimetric sensors (PS), two of the most promising fiber optic sensing techniques for the structural health monitoring of smart materials based on carbon fiber composites. The paper describes the realization of a test plate equipped with both types of sensors and reports the characterization under static and dynamic conditions, highlighting pros and cons of both technologies. The FBG setup achieves 1.15 ± 0.0016 pm/kg static load response and reproduces dynamic excitation with 0.1% frequency uncertainty; the PS system exhibits a sensitivity of 1.74 ± 0.001 mV/kg and reproduces dynamic excitation with 0.5% frequency uncertainty. It is shown that the PS technology is a good and cheap alternative to FBG for vibration-monitoring of small structures at high frequency.

Structural Health Monitoring of Rotating Machines in Manufacturing Processes by Vibration Methods

2014 ◽  
Vol 1036 ◽  
pp. 642-647 ◽  
Author(s):  
Rafał Burdzik ◽  
Łukasz Konieczny ◽  
Piotr Folęga
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Vibration Signal ◽  
Technical Condition ◽  
Operating Conditions ◽  
Vibration Monitoring ◽  
Manufacturing Processes ◽  
Diagnostic Systems ◽  
Structural Health ◽  
Run Up

The paper presents results of the active diagnostics experiments on influence of fatigue metal damage of the inner race of bearing and unbalance of rotating masses on vibration generated by the machine. Analysis of vibration related phenomena is a solution commonly applied in Structural Health Monitoring (SHM) systems. The application of vibroacoustics methods for technical condition monitoring has been developed in the past years in many systems of manufacturing processes. Vibroacoustic methods, based on the analysis of vibration or acoustic signals perceived as residual processes of non-invasive nature, is becoming more and more important in this respect. The scope of its application as well as the applicability of methods in numerous diagnostic systems also results from the capabilities of advanced methods of signal analysis and identification of numerous characteristics of technical condition. One of the most common operation damages are caused by rolling bearings wear. The scope of research contains tests on bearing damage and the unbalance of disc. The wear processes and unbalance are closely related to the vibration levels (arising from the mass loss of plastic deformation, and the fatigue damage). The research was conducted on special research test bench for vibration monitoring for rotating machinery. Structural health monitoring of machinery has to be conducted in different states and working conditions of the manufacturing system. Thus for simulating of different operating conditions the experiments have been conducted during run up of the machine which consist the transient states of working and during work on constant rotational speed of the power generate engine. For the identification of the symptoms of the machinery and equipments health monitoring the vibration signal have been analysed in time domain and frequency transformation as well. The performed signals are not stationary. Thus it is better to observe the signal simultaneously in time and frequency domains. For this purpose the spectrograms were determined. Spectrograms computes the short-time Fourier transform of a signal by default divided into segments. During the transformation the Hamming window and noverlap were used. For the comparison of the vibration of good and damage bearings signals registered for different frequencies have been presented in form of spectrograms and RMS distributions.

scholarly journals A Brief Review on Structural Health Monitoring Sensor Technology in Civil and Aviation Technology Applications

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Ahmad Hamdan Ariffin ◽  
◽  
Zaleha Mohamad ◽  
Shahruddin Mahzan ◽  
◽  
...  
Keyword(s):  
Structural Health Monitoring ◽  
Cost Analysis ◽  
Health Monitoring ◽  
Structural Changes ◽  
Rapid Development ◽  
Structural Monitoring ◽  
Sensor Technology ◽  
Structural Health ◽  
Technology Applications ◽  
Aviation Technology

The Structural Health Monitoring (SHM) system is a method for evaluating and monitoring the integrity of the structure. It has been widely used in various engineering sectors, such as in aerospace, civil and energy sectors due to its ability to react to structural changes on an online basis or in real-time monitoring. The SHM system was able to evolve and work in a variety of structures or components due to the rapid development of sensor technology. It is believed that SHM will become an important tool in various industries for structural monitoring in future years. The paper presents a summary of the latest SHM technology in civil and aviation technology applications as well as the challenges in cost analysis and certification issues for the implementation of SHM.

scholarly journals Modelling tower fatigue loads of a wind turbine using data mining techniques on SCADA data

2020 ◽  
Author(s):  
Artur Movsessian ◽  
Marcel Schedat ◽  
Torsten Faber
Keyword(s):  
Feature Selection ◽  
Structural Health Monitoring ◽  
Wind Turbine ◽  
Health Monitoring ◽  
Rapid Development ◽  
Component Analysis ◽  
Structural Health ◽  
Partial Load ◽  
Measuring Period ◽  
Feature Selection Techniques

Abstract. The rapid development of the wind industry in recent decades and the establishment of this technology as a mature and cost-competitive alternative have stressed the need for sophisticated maintenance and monitoring methods. Structural health monitoring has risen as a diagnosis strategy to detect damage or failures in wind turbine structures with the help of measuring sensors. The amount of data recorded by the structural health monitoring system can potentially be used to obtain knowledge about the condition and remaining lifetime of wind turbines. Machine learning techniques provide the opportunity to extract this information, thereby improving the reliability and cost-effectiveness of the wind industry as well. This paper demonstrates modeling damage equivalent loads of the fore-aft bending moments of a wind turbine tower with the advantage of using the neighborhood component analysis as a feature selection technique in comparison to common dimension reduction/feature selection techniques such as correlation analysis, stepwise regression or principal component analysis. For this study a one-year measuring period of data was gathered, pre-processed, and filtered by different operational modes, namely stand still, full load, and partial load. Finally, a sensitivity analysis was performed in the partial load model to determine the required length of the data collection campaign that guarantees the most precise results. The results indicate that applying neighborhood component analysis yields more conservative models regarding the number of features and equally accurate outcomes than traditional feature selection techniques.

scholarly journals Multiphysics Finite Element Analysis of In-Pile Sensors for Advanced Nuclear Reactors

2020 ◽  
Author(s):  
Takoda Linn Bingham
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Structural Health Monitoring ◽  
Acoustic Wave ◽  
Health Monitoring ◽  
Nuclear Reactors ◽  
Laser Doppler Vibrometer ◽  
Acoustic Sensors ◽  
Element Analysis ◽  
Structural Health

Nuclear reactors have large needs for in-pile sensors that are durable in high temperature, radioactive, and corrosive environments. With the use of multiphysics finite element analysis (FEA) researchers can speed up sensor prototyping. FEA also allows for a better fundamental understanding of sensors and enables sensor optimization. This research focuses on three types of in-pile sensors developed at Idaho National Laboratory: acoustic sensors, linear variable differential transformers (LVDT), and capacitance based strain gauges (CSG). Two acoustic sensors, magnetostrictive waveguides and piezoelectric surface acoustic wave (SAW) sensors were first modeled. These models showed the acoustic wave patterns and estimated the speed of sound. The modeling results were compared to results from laser Doppler vibrometer testing. The model was implemented to enhance the performance of the sensor designs. This research then modeled a LVDT sensor used to measure fuel rod deformation and structural health monitoring. A parametric FEA study was completed for the purpose of sensor miniaturization. The FEA model was also used to investigate the potential of adding a fiber optic cable through the LVDT core. This research eventually modeled CSGs used in nondestructive structural health monitoring. Multiphysics models were used to investigate the discrepancies in experiments and previous analytical models.

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