scholarly journals Damage Detection of Concrete Gravity Dams using Hilbert-Huang Method

2018 ◽  
Vol 8 (2) ◽  
pp. 7-16 ◽  
Author(s):  
Sajad Esmaielzadeh ◽  
Hassan Ahmadi ◽  
Seyed Abbas Hosseini
Keyword(s):  
Damage Detection ◽  
Structural Damage ◽  
Frequency Error ◽  
Gravity Dams ◽  
Concrete Gravity Dams ◽  
Common Signal ◽  
Processing Techniques ◽  
Damage In Concrete ◽  
Signal Processing Techniques ◽  
Measured Response

Abstract Damage detection in concrete gravity dams using Hilbert-Huang Method, as one of the most common signal processing techniques, is studied in this research. After considering a typical geometry for dams, damage is modelled by a reduction in the modulus of elasticity in the dam’s body (in three levels of damage) and in different areas of the structure. The dam is excited by a horizontal earthquake and the primary natural frequencies of the dam are calculated by applying Hilbert-Huang Method to the measured response, which is the acceleration of five points in the system. Based on the changes in the frequencies of the damaged and undamaged structure, a parameter, called relative frequency error, has been introduced. The results show that the proposed criterion used in this study can not only properly identify the location of damage but also predict the severity of the structural damage in concrete gravity dams accurately.

A field guide to equalisation and dynamics processing on rock and electronica records

Popular Music ◽  
2010 ◽  
Vol 29 (2) ◽  
pp. 283-297 ◽  
Author(s):  
Jay Hodgson
Keyword(s):  
Signal Processing ◽  
Frequency Response ◽  
Knowledge Base ◽  
Audio Signals ◽  
Core Component ◽  
Field Guide ◽  
Audio Engineering ◽  
Common Signal ◽  
Processing Techniques ◽  
Signal Processing Techniques

AbstractThis paper examines two of the most common signal processing techniques, namely, equalisation and dynamics processing. As with all signal processing techniques, equalisation and dynamics processing modify audio signals in particular ways to suit the evolving requirements of a mix. Rock and electronica records currently feature the most extroverted uses for these techniques and, thus, the clearest examples for a field guide like this. It is for this reason, and this reason alone, that I focus on records from these two genres. I begin this field guide by suggesting a definition for ‘signal processing’ which is sufficiently broad to account for every technique that recordists currently use. I then relate that definition to the concept of ‘frequency response’. In my opinion, this concept is crucial to any understanding of signal processing – a core component of the knowledge base for audio engineering, which is the discipline under which signal processing is typically subsumed; the concept of ‘frequency response’ guides many of the decisions about signal processing that recordists make, especially those concerning equalisation. Finally, I explain how equalisation and dynamics processing work, and I offer a field guide to their most common applications on hit rock and electronica records today.

scholarly journals A Universal Fast Algorithm for Sensitivity-Based Structural Damage Detection

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Q. W. Yang ◽  
J. K. Liu ◽  
C.H. Li ◽  
C.F. Liang
Keyword(s):  
Damage Detection ◽  
Fast Algorithm ◽  
Structural Damage ◽  
Research Area ◽  
Detection Methods ◽  
Structural Damage Detection ◽  
Response Data ◽  
Flexibility Matrix ◽  
New Research ◽  
Measured Response

Structural damage detection using measured response data has emerged as a new research area in civil, mechanical, and aerospace engineering communities in recent years. In this paper, a universal fast algorithm is presented for sensitivity-based structural damage detection, which can quickly improve the calculation accuracy of the existing sensitivity-based technique without any high-order sensitivity analysis or multi-iterations. The key formula of the universal fast algorithm is derived from the stiffness and flexibility matrix spectral decomposition theory. With the introduction of the key formula, the proposed method is able to quickly achieve more accurate results than that obtained by the original sensitivity-based methods, regardless of whether the damage is small or large. Three examples are used to demonstrate the feasibility and superiority of the proposed method. It has been shown that the universal fast algorithm is simple to implement and quickly gains higher accuracy over the existing sensitivity-based damage detection methods.

scholarly journals A SURVEY OF MATLAB EFFICIENCY IN DAMAGE DETECTION OF CONCRETE GRAVITY IN CONCRETE GRAVITY DAMS

2019 ◽  
Vol 20 (1) ◽  
pp. 29-48
Author(s):  
Sajad Esmaielzadeh ◽  
Hassan Ahmadi ◽  
Seyed Abbas Hosseini
Keyword(s):  
Structural Damage ◽  
Sudden Change ◽  
Point Of View ◽  
Dam Failure ◽  
Discrete Wavelet ◽  
Concrete Gravity Dam ◽  
Gravity Dams ◽  
Concrete Gravity Dams ◽  
Before And After ◽  
The Difference

 Detection of damage in concrete gravity dams (CGDs) is one of the challenges that need to be overcome since dam failure may lead to irreversible consequences. This research aims to detect structural damage within CGDs by wavelet analysis. From a structural point of view, stiffness is an important factor in the dynamic behaviour of concrete gravity dam systems. Any sudden change in the stiffness leads to alteration in the dynamic response of the structures. The proposed analysis of such a condition will help to investigate the responses before and after the occurrence of any structural damage. The main contributions of this paper are to detect the existence of any damage in the dam structure and determine the damage location along the height of the dam. In order to achieve these purposes, three finite element models of the Pine Flat, Bluestone, and Folsom dams are chosen as case studies. These dams have been modelled for both intact and damaged states, and their geometrical, physical, and mechanical characteristics are defined by SAP2000 software. A series of modal analyses was performed to determine the frequencies and shapes of the structural motions. After reduction of the elasticity modulus by 20% and 50%, the Discrete Wavelet Transform (DWT) was applied to the difference between the intact and damaged observations. Then, the DWT outputs were analysed to get information about the existence of damage as well as its location in the dam structure. Overall, from the obtained results, the main finding of this study states that the location and severity of the structural damages have been efficiently detected according to the significant amplitude variations in DWT diagrams. ABSTRAK: Pengesanan kerosakan pada empangan graviti konkrit (CGDs) adalah salah satu cabaran yang perlu diatasi disebabkan kegagalan empangan yang boleh membawa kepada akibat buruk. Kajian ini bertujuan bagi mengesan kerosakan struktur dalam CGDs menggunakan analisis wavelet. Dari sudut pandang struktur, struktur yang kukuh adalah faktor penting dalam sifat dinamik sistem empangan graviti konkrit. Sebarang perubahan secara tiba-tiba pada struktur bangunan membawa kepada perubahan tindak balas dinamik struktur. Analisis yang dicadangkan terhadap keadaan ini membantu dalam memberi tindak balas sebelum dan selepas jika berlaku sebarang kerosakan struktur. Sumbangan utama kajian ini adalah bagi mengesan jika terdapat sebarang kerosakan pada struktur dalam empangan dan menentukan lokasi kerosakan sepanjang ketinggian empangan. Bagi mencapai matlamat ini, tiga model unsur terhingga daripada empangan Pine Flat, Bluestone dan Folsom telah dipilih sebagai kes kajian. Kesemua empangan ini dimodelkan bagi kedua-dua keadaan iaitu ketika baik dan rosak. Ciri geometri, fizikal dan ciri-ciri mekanikal juga telah ditakrif menggunakan perisian SAP2000. Satu siri model analisis telah dijalankan bagi menentukan frekuensi dan bentuk gerakan struktur. Selepas pengurangan modulus keanjalan sebanyak 20% dan 50%, Transformasi Wavelet Diskret (DWT) telah digunakan bagi mengesan perbezaan antara keadaan baik dan rosak. Kemudian, hasil dari DWT ini dianalisis bagi mendapatkan maklumat mengenai kewujudan kerosakan pada empangan dan juga lokasi kerosakan dalam struktur empangan. Secara keseluruhan, hasil kajian berjaya menentukan lokasi dan tahap kerosakan struktur dengan cekap mengikut variasi amplitud ketara dalam rajah DWT.

scholarly journals A Robust Estimate Method for Damage Detection of Concrete Structures Using Contaminated Data

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
X. Peng ◽  
F. J. Qin ◽  
Q. W. Yang ◽  
H. Chen
Keyword(s):  
Damage Detection ◽  
Structural Damage ◽  
Concrete Structures ◽  
Element Model ◽  
Coefficient Matrix ◽  
Reinforced Concrete Beam ◽  
Computational Accuracy ◽  
Robust Estimate ◽  
Estimate Method ◽  
Measured Response

Damage detection of concrete structures based on finite element model and measured response parameters has been an important research topic in recent years. It is well known that test data of mechanical behavior of concrete show great scatterness. As a result, the measured response parameters of concrete structures sometimes have gross errors. The gross error is a physical quantity that is much larger than data noise, which may lead to serious distortion of calculation results. To this end, a new robust estimate method termed as the augmented inverse estimate is proposed in this work for damage detection of concrete structures to resist gross errors in data. It has the advantages of very simple programming, convenient utilization, high computational accuracy, and broad prospect of application. Central to the augmented inverse estimate are the augmentation of coefficient matrix and the multiple computations based on feedback evaluation. A reinforced concrete beam structure is used as an example to verify the proposed method. It was found that the proposed method can successfully identify the location and extent of structural damage even if the used data have gross errors.

scholarly journals Structural Damage Location by Low-Cost Piezoelectric Transducer and Advanced Signal Processing Techniques

Proceedings ◽  
2018 ◽  
Vol 4 (1) ◽  
pp. 2 ◽  
Author(s):  
Bruno A. Castro ◽  
Fabricio G. Baptista ◽  
José A. C. Ulson ◽  
Alceu F. Alves ◽  
Guilherme A. M. Clerice ◽  
...  
Keyword(s):  
Signal Processing ◽  
Piezoelectric Transducer ◽  
Acoustic Waves ◽  
Structural Damage ◽  
Damage Identification ◽  
Low Cost ◽  
Time Of Arrival ◽  
Damage Location ◽  
Processing Techniques ◽  
Signal Processing Techniques

The development of new low-cost transducers and systems has been extensively aimed at in both industry and academia to promote a correct failure diagnosis in aerospace, naval, and civil structures. In this context, structural health monitoring (SHM) engineering is focused on promoting human safety and a reduction in the maintenance costs of these components. Traditionally, SHM aims to detect structural damages at the initial stage, before it reaches a critical level of severity. Numerous approaches for damage identification and location have been proposed in the literature. One of the most common damage location techniques is based on acoustic waves triangulation, which stands out as an effective approach. This method uses a piezoelectric transducer as a sensor to capture acoustic waves emitted by cracks or other damage. Basically, the damage location is defined by calculating the difference in the time of arrival (TOA) of the signals. Although it may be simple, the detection of TOA requires complex statistical and signal processing techniques. Based on this issue, this work proposes the evaluation of a low-cost piezoelectric transducer to determine damage location in metallic structures by comparing two methodologies of TOA identification, the Hinkley criterion and the statistical Akaike criterion. The tests were conducted on an aluminum beam in which two piezoelectric transducers were attached at each end. The damage was simulated by pencil lead break (PLB) test applied at four different points of the specimen and the acoustic signals emitted by the damage were acquired and processed by Hinkley and Akaike criteria. The results indicate that, although both signal processing methodologies were able to determine the damage location, Akaike presented higher precision when compared to Hinkley approach. Moreover, the experimental results indicated that the low-cost piezoelectric sensors have a great potential to be applied in the location of structural failures.

Advanced Signal Processing Techniques for Multi-Damage Detection With an Improved Embedded Ultrasonic Structural Radar Algorithm and Piezoelectric Wafer Active Sensors

2004 ◽  
Author(s):  
Lingyu Yu ◽  
Victor Giurgiutiu
Keyword(s):  
Signal Processing ◽  
Damage Detection ◽  
Large Area ◽  
Active Sensors ◽  
Piezoelectric Wafer Active Sensors ◽  
Active Sensor ◽  
Piezoelectric Wafer ◽  
Processing Techniques ◽  
User Friendly ◽  
Signal Processing Techniques

The embedded ultrasonic structural radar (EUSR) algorithm was developed by using piezoelectric wafer active sensor (PWAS) array to detect defects within a large area of a thin-plate specimen. EUSR was verified to be effective for detecting a single crack either at a broadside or at an offside position. However, the damage location was not very precise. This algorithm is improved by using advanced signal processing techniques. The improvement includes: 1) EUSR is able to provide better image of the specimen under monitoring; 2) it is able to detect multiple defects such as several cracks; 3) it is also able to identify different damage types. This paper starts with an introduction of embedded ultrasonic structural radar algorithm. Then the application of using Hilbert transform for extracting the envelopes of the wave packages is discussed. This can eliminate or reduce the effect of side robes so that EUSR produces better images. The improvement of EUSR detectability is concluded through the comparison to the previous results, followed by the experiments to verify the multi-damage detection of EUSR. Finally, we present the results of how EUSR can distinguish different types of damage. This system is implemented by developing a graphical user-friendly interface program in LabView. We conclude with a description of our vision for an even more powerful EUSR for structural health monitoring and embedded nondestructive evaluation.

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