Damage Detection in Composites Using Vibration Signatures and Mode Shapes

2008 ◽  
Author(s):  
K. Oruganti ◽  
M. Mehdizadeh ◽  
S. John ◽  
I. Herszberg
Keyword(s):  
Damage Detection ◽  
Epoxy Composite ◽  
Composite Beams ◽  
Matrix Cracking ◽  
Mode Shapes ◽  
Laser Vibrometer ◽  
Modern Times ◽  
Marine Industry ◽  
Service Operation ◽  
Vibration Signatures

Composite materials are supplanting conventional metals in aerospace, automotive, civil and marine industries in modern times. However, despite these advantageous properties, they are prone to delamination or matrix cracking. Thus, necessitating the early detection of the crack or flaw before it initiates into a serious defect. An offline approach was commonly used where in the parts examined away from service/operation. This not only consumed a lot of time but risked damage to the part during operation and handling. A detailed understanding of the various proven methods and techniques and their applicability in the analysis of vibration signatures obtained from damaged structures under dynamic conditions is essential to develop a reliable Structural Health Monitoring System (SHMS). This paper includes Vibration based damage detection testing on Carbon/Epoxy composite beams. Such composites are commonly used in the aerospace and marine industry. This material type is gaining acceptance not only in the aerospace industry but also in the automotive and construction industries. The paper reports the processing of the vibration signatures from healthy and damaged composite beams upon excitation and analysis of the mode shapes acquired. The study comprises of testing carbon/epoxy composite beams with various embedded delaminations with a mechanical actuator and a scanning laser vibrometer (SLV) as a sensor for recording the frequency response and analysing the acquired signatures based on Displacement and Curvature Mode Shapes.

scholarly journals Damage Detection in Plates with the Use of Laser-Measured Mode Shapes

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Ziemowit Dworakowski ◽  
Kajetan Dziedziech ◽  
Pawel Zdziebko ◽  
Krzysztof Mendrok
Keyword(s):  
Damage Detection ◽  
Laboratory Experiment ◽  
Fault Location ◽  
Element Model ◽  
Metal Plate ◽  
Aluminum Plate ◽  
Mode Shapes ◽  
Laser Vibrometer ◽  
Spatial Filters ◽  
Damage Scenarios

This paper presents the use of laser vibrometer measurements to detect and locate damage in a metal plate. An algorithm based on local spatial filters was selected, and for the purpose of comparison, the fault location was also determined based on the wavelet analysis of mode shapes. The research was carried out first on the created finite element model of aluminum plate, where two kinds of damage of increasing size and temperature change were simulated. After obtaining positive results, a laboratory experiment was carried out, which consisted of measuring the vibration of the aluminum plate with the laser vibrometer in undamaged condition, at increased temperatures, and with various damage scenarios. The conclusions of the laboratory experiment confirm the damage detection capabilities of the methods but question their damage localization potential.

Experimental Damage Identification of Carbon/Epoxy Composite Beams Using Curvature Mode Shapes

2004 ◽  
Vol 3 (4) ◽  
pp. 333-353 ◽  
Author(s):  
Cole S. Hamey ◽  
Wahyu Lestari ◽  
Pizhong Qiao ◽  
Gangbing Song
Keyword(s):  
Damage Identification ◽  
Epoxy Composite ◽  
Composite Beams ◽  
Mode Shapes

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

2013 ◽  
Vol 569-570 ◽  
pp. 1273-1280 ◽  
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.

scholarly journals Experimental Detection and Measurement of Crack-Type Damage Features in Composite Thin-Wall Beams Using Modal Analysis

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 8102
Author(s):  
Josué Pacheco-Chérrez ◽  
Diego Cárdenas ◽  
Oliver Probst
Keyword(s):  
Damage Detection ◽  
Modal Analysis ◽  
Simultaneous Detection ◽  
Sensor Arrays ◽  
Composite Beams ◽  
Mode Shapes ◽  
Thin Wall ◽  
Proof Of Concept ◽  
Experimental Proof ◽  
Crack Type

An experimental proof-of-concept for damage detection in composite beams using modal analysis has been conducted. The purpose was to demonstrate that damage features can be detected, located, and measured on the surface of a relatively complex thin-wall beam made from composite material. (1) Background: previous work has been limited to the study of simple geometries and materials. (2) Methods: damage detection in the work is based on the accurate measurement of mode shapes and an appropriate design of the detection mesh. Both a method requiring information about the healthy structure and a baseline-free method have been implemented. (3) Results: short crack-type damage features, both longitudinal and transverse, were detected reliably, and the true length of the crack can be estimated from the damage signal. Simultaneous detection of two cracks on the same sample is also possible. (4) This work demonstrates the feasibility of automated damage detection in composite beams using sensor arrays.

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

2015 ◽  
Vol 220-221 ◽  
pp. 264-270 ◽  
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.

Detection of Embedded Damage Growth by Analysing Its Structural Dynamic Response

2009 ◽  
Author(s):  
Mohammad Mehdizadeh ◽  
Krishna Oruganti ◽  
John Sabu ◽  
Michael Bannister ◽  
Israel Herszberg
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Dynamic Response ◽  
Crack Growth ◽  
Epoxy Composite ◽  
Composite Beams ◽  
Mode Shapes ◽  
Structural Dynamic ◽  
Damage Site ◽  
Damage Types

The primary focus of this paper is to report on the technique developed to extend a simulated damage site (such as a delamination) without inducing other extraneous damage modes. This was done in order to assess the suitability of curvature mode shape analyses in detecting damage types which are similar in type but different in severity or size. This paper highlights the use of vibration based testing on Carbon/Epoxy composite beams for damage detection. Such composites are commonly used in the aerospace and marine industry. The study comprises of testing carbon/epoxy composite beams with various embedded delaminations with a mechanical actuator and a Scanning Laser Vibrometer (SLV) as a sensor for recording the frequency response and the subsequent analyses of the acquired dynamic response based on Displacement and Curvature Mode Shapes. The paper also discusses the Finite Element Method (FEM)-based Analysis to validate the experimental results. In order to assess the effect of an increasing damage zone on a particular damage configuration, it was necessary to extend the damage without inflicting other damage types in the process. This paper reports on an innovative way of extending an existing delamination by a fatigue crack-growth technique. The ASTM E399-90 standard was used for the experiment and a carefully designed fatigue crack growth routine was implemented to advance the delamination in a controlled manner.

scholarly journals Identification of Damage in a Beam Structure by Using Mode Shape Curvature Squares

2010 ◽  
Vol 17 (4-5) ◽  
pp. 601-610 ◽  
Author(s):  
S. Rucevskis ◽  
M. Wesolowski
Keyword(s):  
Damage Detection ◽  
Mode Shape ◽  
Dynamic Structure ◽  
Mode Shapes ◽  
Difference Approximation ◽  
Laser Vibrometer ◽  
Beam Structure ◽  
Central Difference ◽  
Modal Data ◽  
Healthy State

During the last decades a great variety of methods have been proposed for damage detection by using the dynamic structure characteristics, however, most of them require modal data of the structure for the healthy state as a reference. In this paper the applicability of the mode shape curvature squares determined from only the damaged state of the structure for damage detection in a beam structure is studied. To establish the method, two aluminium beams containing different-size mill-cut damage at different locations are tested by using the experimentally measured modal data. The experimental modal frequencies and the corresponding mode shapes are obtained by using a scanning laser vibrometer with a PZT actuator. From the mode shapes, mode shape curvatures are obtained by using a central difference approximation. With the example of the beams with free-free and clamped boundary conditions, it is shown that the mode shape curvature squares can be used to detect damage in the structures. Further, the extent of a mill-cut damage is identified via modal frequencies by using a mixed numerical-experimental technique. The method is based on the minimization of the discrepancy between the numerically calculated and experimentally measured frequencies.

scholarly journals VIBRATION-BASED DAMAGE DETECTION IN A BEAM STRUCTURE WITH MULTIPLE DAMAGE LOCATIONS

Aviation ◽  
2009 ◽  
Vol 13 (3) ◽  
pp. 61-71 ◽  
Author(s):  
Sandris Ručevskis ◽  
Miroslaw Wesolowski ◽  
Andris Chate
Keyword(s):  
Damage Detection ◽  
Mode Shape ◽  
Failure Modes ◽  
Mode Shapes ◽  
Difference Approximation ◽  
Laser Vibrometer ◽  
Shape Information ◽  
Modal Data ◽  
Damage Indices ◽  
Damage Extent

During the last two decades structural damage identification using dynamic parameters of the structure has become an important research area for civil, mechanical, and aerospace engineering communities. The basic idea of the vibration‐based damage detection methods is that a damage as a combination of different failure modes in the form of loss of local stiffness in the structure alters its dynamic characteristics, i.e., the modal frequencies, mode shapes, and modal damping values. A great variety of methods have been proposed for damage detection by using dynamic structure parameters; however, most of them require modal data of the healthy state of structure as a reference. In this paper a vibration‐based damage detection method, which uses the mode shape information determined from only the damaged state of the structure is proposed. To establish the method, two aluminium beams containing different sizes of mill‐cut damage at a single location as well as two aluminium beams containing different sizes of mill‐cut damage at multiple locations are examined. The experimental modal frequencies and the corresponding mode shapes for the first 15 flexural modes are obtained by using a scanning laser vibrometer with a PZT actuator. From the mode shapes, mode shape curvatures are obtained by using a central difference approximation. In order to exclude the influence of measurement noise on the modal data and misleading damage indices, it is proposed to use the sum of mode shape curvature squares for each mode. With the example of the beams with free‐free and clamped boundary conditions, it is shown that the mode shape curvature squares can be used to detect damage in the structures. The extent of mill‐cut damage is identified via the modal frequencies by using mixed numerical‐experimental technique. The method is based on the minimization of the discrepancy between the numerically calculated and the experimentally measured frequencies. The numerical frequencies are calculated by employing a finite‐element model for beam with introduced damage. Further, by using the response surface approach, a relationship (second‐order polynomial function) between the modal frequencies and the damage extent is constructed. The damage extent is obtained by solving the minimization problem. Santrauka Tyrimo metu buvo ieškomos sijines konstrukcijos pažeidimo frezuojant vietos, apimtis ir pažeidimo dydis pagal atlikto vibraciju eksperimento dinamines charakteristikas. Pažeidimo padetis ir apimtis buvo nustatomi pagal išlinkio formos virpesiu kvadrato dydi. Pažeidimo dydis buvo nustatomas skaitiniu‐eksperimentiniu metodu, taikant modalinius dažnius. Šio metodo efektyvumas ir patikimumas parodytas tiriant dvi aliuminio sijas, kurios buvo pažeistos frezos vienoje vietoje ir kurios buvo pažeistos skirtingose vietose.

scholarly journals Modal Kinetic Energy Change Ratio-based Damage Assessment of Laminated Composite Beams using Noisy and Incomplete Measurements

2019 ◽  
Vol 3 (3) ◽  
pp. 452 ◽  
Author(s):  
Du Dinh-Cong ◽  
Linh Vo-Van ◽  
Dung Nguyen-Quoc ◽  
Trung Nguyen-Thoi
Keyword(s):  
Kinetic Energy ◽  
Damage Detection ◽  
Composite Beam ◽  
Structural Damage ◽  
Laminated Composite ◽  
Composite Beams ◽  
Mode Shapes ◽  
Damage Scenarios ◽  
Creative Commons ◽  
Laminated Composite Beams

Modal kinetic energy (MKE) feature has been mostly employed for optimal sensor layout strategies; nevertheless, little attention is paid to use the feature to the field of structural damage detection. The article presents the extensive applicability of MKE change ratio (MKECR), a good damage sensitive parameter, to damage localization and quantification of laminated composite beams. The formulation of the parameter is based on the closed-form of element MKE sensitivity. The performance of the offered damage detection method is numerically verified by a clamped-clamped composite beam and a two-span continuous composite beam with different hypothetical damage scenarios. The influence of incomplete mode shapes, various noise levels as well as damage magnitudes on damage prediction results are also investigated. The obtained results from these numerical examples indicate that the offered method reliably localize the actually damaged elements and approximately estimate their severities, even under incomplete measurements at a high noise level.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited. 

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