A novel damage index for damage detection and localization of plate-type structures using twist derivatives of laser-measured mode shapes

The deflection of the beam estimated from modal flexibility matrix (MFM) indirectly is used in structural damage detection due to the fact that deflection is less sensitive to experimental noise than the element in MFM. However, the requirement for mass-normalized mode shapes (MMSs) with a high spatial resolution and the difficulty in damage quantification restricts the practicability of MFM-based deflection damage detection. A damage detection method using the deflections estimated from MFM is proposed for beam structures. The MMSs of beams are identified by using a parked vehicle. The MFM is then formulated to estimate the positive-bending-inspection-load (PBIL) caused deflection. The change of deflection curvature (CDC) is defined as a damage index to localize damage. The relationship between the damage severity and the deflection curvatures is further investigated and a damage quantification approach is proposed accordingly. Numerical and experimental examples indicated that the presented approach can detect damages with adequate accuracy at the cost of limited number of sensors. No finite element model (FEM) is required during the whole detection process.

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Vibration-Based Damage Detection Techniques for Health Monitoring of Construction of a Multi-Storey Building

Materials Science Forum ◽

10.4028/www.scientific.net/msf.931.178 ◽

2018 ◽

Vol 931 ◽

pp. 178-183 ◽

Cited By ~ 2

Author(s):

Yuriy Y. Shatilov ◽

Alexander A. Lyapin

Keyword(s):

Damage Detection ◽

Damage Index ◽

The State ◽

Diagnostic Methods ◽

Detection Methods ◽

Mode Shapes ◽

Dynamic Parameters ◽

Labor Costs ◽

Detection Techniques ◽

Storey Building

Conducting surveys of multi-storey buildings is a laborious task, because large volumes of visual and instrumental research should be carried out. Reduction of labor costs with an increase in the reliability of information about the state of damage and technical condition is an actual scientific and practical task. One of the ways to solve it is to use non-destructive vibration diagnostic methods. The purpose of carrying out diagnostics with the use of vibration based damage detection methods is to search for damages in structural elements that can cause the deviation of the dynamic parameters of a structure from calculated ones. Determination of the dynamic parameters of the structure, in particular natural frequencies and mode shapes of mechanical systems, is one of the most important tasks that allows obtaining integral information about the state of a structure. This article presents the results of calculations for the localization of slabs defects in a multi-storey building with a transverse crack, span L = 4.5 (m), height H = 0.2 (m), with prestressed reinforcement d = 0.05 (m). Vibration based Damage Index method was used to localize the defect. During the study, reliable localization values of the defect area of the slab were obtained, this indicates that the vibration method for determining the damage index with a sufficient degree of accuracy allowed predicting the site of damage to the structure.

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Damage Detection of Surface Crack in Composite Quasi-Isotropic Laminate Using Modal Analysis and Strain Energy Method

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.306-308.757 ◽

2006 ◽

Vol 306-308 ◽

pp. 757-762 ◽

Cited By ~ 4

Author(s):

Hui Wen Hu ◽

Bor Tsuen Wang ◽

Cheng Hsin Lee

Keyword(s):

Damage Detection ◽

Modal Analysis ◽

Surface Crack ◽

Strain Energy ◽

Differential Quadrature Method ◽

Damage Index ◽

Mode Shapes ◽

Cutting Machine ◽

Before And After ◽

Energy Formula

This paper presents a damage detection of surface crack in composite laminate. Carbon/epoxy composite AS4/PEEK was used to fabricate a quasi-isotropic laminate [0/90/±45]2s. Surface crack was created by using laser cutting machine. Modal analysis was performed to obtain the mode shapes of the laminate before and after damage. The mode shapes were then adopted to compute the strain energy, which was used to define a damage index. Consequently, the damage index successfully predicted the location of surface crack in the laminate. Differential quadrature method (DQM) was introduced to calculate the partial differential terms in strain energy formula.

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Damage Detection in Laminated Composite Plates and Shells Using Second Derivatives of Mode Shape Data Through Dynamic Analysis of These Structures

Volume 4B: Dynamics, Vibration, and Control ◽

10.1115/imece2015-51600 ◽

2015 ◽

Author(s):

Mahendran Govindasamy ◽

Chandrasekaran Kesavan ◽

Malhotra Santkumar

Keyword(s):

Damage Detection ◽

Mode Shape ◽

Laminated Composite ◽

Vibration Characteristics ◽

Mode Shapes ◽

Experimental Investigations ◽

Structural Elements ◽

Plate And Shell ◽

Second Derivatives ◽

Derivatives Of

The main objective of this study is to evaluate the dynamics-based techniques for damage detection in laminated composite cantilevered rectangular plates and cylindrical shells with damages in the form of surface macro-level cracks using finite element analysis (FEA). However, the quantitative change in global vibration characteristics is not sufficiently sensitive to local structural damages especially to small size damages. Hence certain parameters called damage indicators based on mode shape curvature, which are the second derivatives of the vibration characteristics (mode shapes), are used in this study to detect the location and size of even small damages accurately in laminated composite structures. The commercial FEA package ANSYS is used for the theoretical modal analysis to generate the natural frequencies and normalized mode shapes of the intact and damaged structures. Experimental investigations are carried out on the laminated plate and shell structural elements to provide a validation of the analysis. Experimental investigations are carried out on the laminated composite (E-glass unidirectional fibers reinforced epoxy resin) cantilevered plate and shell structural elements to provide a validation of the analysis. The effectiveness of these methods is clearly demonstrated by the results obtained.

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Detection and Localisation of Structural Damage Based on the Polynomial Annihilation Edge Detection: An Experimental Verification

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.569-570.1273 ◽

2013 ◽

Vol 569-570 ◽

pp. 1273-1280 ◽

Cited By ~ 4

Author(s):

Cecilia Surace ◽

Massimiliano Mattone ◽

Marco Gherlone

Keyword(s):

Edge Detection ◽

Damage Detection ◽

Structural Damage ◽

High Spatial Resolution ◽

Mode Shapes ◽

Laser Vibrometer ◽

Numerical Assessment ◽

Polynomial Annihilation ◽

Vibration Tests ◽

Derivatives Of

The present paper describes an experimental validation of a new structural damage detection method based on the Polynomial Annihilation Edge Detection (PAED) technique. It is well known that concentrated damage such as a crack, causes a discontinuity in the rotations and consequently in the first derivatives of the mode shapes. On this basis, the PAED, a numerical method for detecting discontinuities in smooth piecewise functions and their derivatives, can be applied to the problem of damage detection and localisation in beam-like structures for which only post-damage mode shapes are available. As described in this paper, in order to verify this approach experimentally (a numerical assessment having already been documented in previous papers), vibration tests on a cantilever steel beam with a saw-cut have been performed and the Operational Deflection Shapes (ODS) determined. As the approach requires a reasonably high spatial resolution of the ODS, a scanning laser vibrometer, capable of acquiring data rapidly at a very large number of observation points, was used.

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A Novel Damage Detection Algorithm using Time-Series Analysis-Based Blind Source Separation

Shock and Vibration ◽

10.1155/2013/237805 ◽

2013 ◽

Vol 20 (3) ◽

pp. 423-438 ◽

Cited By ~ 24

Author(s):

A. Sadhu ◽

B. Hazra

Keyword(s):

Time Series ◽

Time Series Analysis ◽

Damage Detection ◽

Blind Source Separation ◽

Source Separation ◽

Damage Index ◽

Detection Algorithm ◽

Mode Shapes ◽

Series Analysis ◽

Modal Response

In this paper, a novel damage detection algorithm is developed based on blind source separation in conjunction with time-series analysis. Blind source separation (BSS), is a powerful signal processing tool that is used to identify the modal responses and mode shapes of a vibrating structure using only the knowledge of responses. In the proposed method, BSS is first employed to estimate the modal response using the vibration measurements. Time-series analysis is then performed to characterize the mono-component modal responses and successively the resulting time-series models are utilized for one-step ahead prediction of the modal response. With the occurrence of newer measurements containing the signature of damaged system, a variance-based damage index is used to identify the damage instant. Once the damage instant is identified, the damaged and undamaged modal parameters of the system are estimated in an adaptive fashion. The proposed method solves classical damage detection issues including the identification of damage instant, location as well as the severity of damage. The proposed damage detection algorithm is verified using extensive numerical simulations followed by the full scale study of UCLA Factor building using the measured responses under Parkfield earthquake.

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Numerical and Experimental Study on the Application of Mode Shape Curvature for Damage Detection in Plate-Like Structures

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.220-221.264 ◽

2015 ◽

Vol 220-221 ◽

pp. 264-270 ◽

Cited By ~ 2

Author(s):

Sandris Rucevskis ◽

Pavel Akishin ◽

Andris Chate

Keyword(s):

Experimental Study ◽

Damage Detection ◽

Mode Shape ◽

Research Effort ◽

Random Noise ◽

Damage Index ◽

Simulated Data ◽

Detection Algorithm ◽

Mode Shapes ◽

Laser Vibrometer

The paper describes on-going research effort at detecting and localizing damage in plate-like structures using mode shape curvature based damage detection algorithm. The proposed damage index uses data on exclusively mode shape curvature from the damaged structure. This method was originally developed for beam-like structures. The article generalizes the method of plate-like structures characterized by two-dimensional mode shape curvature. To examine limitations of the method, several sets of simulated data are applied and the obtained results of the numerical detection of damage are validated by comparing them with the findings of the case of the experimental test. The simulated test cases include the damage of various levels of severity. In order to ascertain the sensitivity of the proposed method for noisy experimental data, numerical mode shapes are corrupted with different levels of random noise. Modal frequencies and corresponding mode shapes of an aluminium plate containing mill-cut damage are obtained via finite element models for numerical simulations and by using a scanning laser vibrometer (SLV) for the experimental study.

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Output-Only Damage Detection in Plate-Like Structures Based on Proportional Strain Flexibility Matrix

Sensors ◽

10.3390/s20236862 ◽

2020 ◽

Vol 20 (23) ◽

pp. 6862

Author(s):

Kang Yun ◽

Mingyao Liu ◽

Jiangtao Lv ◽

Jingliang Wang ◽

Zhao Li ◽

...

Keyword(s):

Damage Detection ◽

Damage Index ◽

Identification Accuracy ◽

Mode Shapes ◽

Engineering Structures ◽

Strain Mode ◽

Flexibility Matrix ◽

Construction Procedure ◽

Output Only ◽

Strain Mode Shapes

For engineering structures, strain flexibility-based approaches have been widely used for structural health monitoring purposes with prominent advantages. However, the applicability and robustness of the method need to be further improved. In this paper, a novel damage index based on differences in uniform load strain field (ULSF) is developed for plate-like structures. When estimating ULSF, the strain flexibility matrix (SFM) based on mass-normalized strain mode shapes (SMSs) is needed. However, the mass-normalized strain mode shapes (SMSs) are complicated and difficult to obtain when the input, i.e., the excitation, is unknown. To address this issue, the proportional strain flexibility matrix (PSFM) and its simplified construction procedure are proposed and integrated into the frames of ULSF, which can be easily obtained when the input is unknown. The identification accuracy of the method under the damage with different locations and degrees is validated by the numerical examples and experimental examples. Both the numerical and experimental results demonstrate that the proposed method provides a reliable tool for output-only damage detection of plate-like structures without estimating the mass-normalized strain mode shapes (SMSs).

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Optimal Sensor Positioning for Damage Detection in Composite Sensorised Panels

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.713.191 ◽

2016 ◽

Vol 713 ◽

pp. 191-194 ◽

Cited By ~ 1

Author(s):

Laure Sainfort ◽

Zahra Sharif Khodaei ◽

M.H. Ferri Aliabadi

Keyword(s):

Damage Detection ◽

Ray Tracing ◽

Lamb Waves ◽

Damage Index ◽

Optimization Methods ◽

Composite Panel ◽

Index Method ◽

Average Probability ◽

Detection And Localization ◽

Optimal Configurations

In this work the optimal configuration of transducers for damage detection and localization has been investigated. A particular interest is given to three optimization methods: mini-max, average Probability of Non Detection (POND) and ray tracing approach, coupled with genetic algorithm. After optimal configurations have been computed for each technique, they are experimentally tested and compared on a composite panel with one or two damages by generating and receiving Lamb waves signals. Damage detection is carried out with the Probability Based Damage Index Method (PBDIM). It was found that, in most cases, the ray tracing method and the average POND technique give better results, with a good detection of damages in comparison to the minimax POND technique, even if the latter seems numerically better.

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Assessment of Internal Damage in Sandwich Structures by Post-Processing of Mode Shapes Using Curvelet Transform

Materials ◽

10.3390/ma14164517 ◽

2021 ◽

Vol 14 (16) ◽

pp. 4517

Author(s):

Andrzej Katunin ◽

Sandris Ručevskis

Keyword(s):

Hybrid Algorithm ◽

Structural Damage ◽

Sandwich Structures ◽

Boundary Effect ◽

Damage Index ◽

Curvelet Transform ◽

Mode Shapes ◽

Internal Damage ◽

Novel Approach ◽

Detection And Localization

Identification and quantification of structural damage is one of the crucial aspects of proper maintenance of mechanical and civil structures, which is directly related to their integrity and safety. The paper presents a novel approach for detecting various types of damage in sandwich structures by processing the mode shapes using a hybrid algorithm based on the curvelet transform and the standardized damage index concept. The proposed approach uses the properties of directional selectivity, absence of the boundary effect, typical of such a class of transforms, and excellent filtration capabilities of the curvelet transform as well as the classification hypothesis in the standardized damage index, which allows the exclusion of irrelevant information and emphasizes proper damage location and shape. The proposed hybrid algorithm allowed to successfully identify a subsurface core damage in sandwich structures, such as local lack of a core or its debonding from facings. The performed quantification study aimed to evaluate the correctness of identified damage shape confirmed the validity and accuracy of the proposed algorithm not only for the damage detection and localization but also for the estimation of the size of structural damage.

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