Nondestructive Damage Detection Research Articles

Flat nose low velocity drop-weight impact response of carbon fibre composites using non-destructive damage detection techniques

AbstractThis work is mainly concerned with the nondestructive post-impact damage evaluation of carbon fibre reinforced laminated composite panels subject to low velocity drop-weight impact by flat and round nose impactors. Quasi-isotropic laminates consisting of eight-, sixteen-, and twenty-four plies were impacted by flat and round nose impactors at different velocity levels. Load-time history data were recorded and plotted to correlate loaddrop as damage level to the impactor nose profiles. Test produced data, non-destructive damage detection techniques: visual, ultrasonic, and eddy- current, and computer simulations were utilised to identify and quantify status of the impact induced damage. To evaluate damage in relatively thick laminates (consisting of 24-Ply), the damage ratios and deflection quantities were correlated to the corresponding impactor nose profiles. Damage induced by the flat nose impactor to thick laminates was compared against the data produced by the round nose impactor. Results show that relatively thin laminates were largely affected by the impactor nose. Reasonable difference was observed in damage caused by flat and round impactor nose profiles to thick laminates impacted at relatively higher velocity impacts. Resultswere compared and validated against simulation produced data.

OS11-3 Non-destructive Detection of CMAS Damage on Thermal Barrier Coatings using AC Impedance Technique(Characterization and Inspection of Coatings,OS11 Reliability of heat resisting alloys and coatings,STRENGTH OF MATERIALS)

OS11-3 Non-destructive Detection of CMAS Damage on Thermal Barrier Coatings using AC Impedance Technique(Characterization and Inspection of Coatings,OS11 Reliability of heat resisting alloys and coatings,STRENGTH OF MATERIALS)

A new standing‐wave testing system for bridge structure nondestructive damage detection using electromagnetic wave

Several data analysis algorithms exist for detecting damages in bridges; however, such algorithms only approximately locate the damaged areas. To increase the accuracy and sensitivity, a new nondestructive, standing‐wave, bridge‐testing system as well as algorithm is proposed. The proposed system sends 3.8–5.8 GHz modulated sweeping waves to an object, the input and reflected waves form a standing wave, which is used to check and evaluate the state of the object under examination. In comparison with other systems, the proposed system is compact and less expensive, and offers higher sensitivity, higher resolution, and higher accuracy. Simulations and experiments verified its effectiveness. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Damage Signature of Fatigued Fabric Reinforced Plastics in the Pulsed Ultrasonic Polar Scan

This study investigates the use of both the amplitude and time-of-flight based pulsed ultrasonic polar scan (P-UPS) for the nondestructive detection and evaluation of fatigue damage in fabric reinforced composites. Several thermoplastic carbon fabric reinforced PPS specimens (CETEX), loaded under various fatigue conditions, have been scanned at multiple material spots according to the P-UPS technique in order to extract material degradation in a quantitative way. The P-UPS results indicate that shear dominated fatigued carbon/PPS goes with a reduction of shear properties combined with large fiber distortions. The P-UPS results of the tension-tension fatigued carbon/PPS samples on the other hand reveal a directional degradation of the stiffness properties, reaching a maximum reduction of −12.8 % along the loading direction. The P-UPS extracted damage characteristics are fully supported by simulations, conventional destructive tests as well as visual inspection. The results demonstrate the excellent capability of the P-UPS method for nondestructively assessing and quantifying both shear-dominated and tension-tension fatigue damage in fabric reinforced plastics.

Détection de fissures dans les poutres d'acier : une nouvelle approche par balayage de mesures de vibrations

In the last few years, the techniques of detection and identification of damage in structures benefited from important research efforts. Several methods of non-destructive damage detection, such as techniques based on modal analysis, were developed in addition to the traditional methods. The difficulties encountered by these techniques are their low performance, considering the industrial requirements to detect cracks as early as possible.In this work, a retrospective of the principal modal parameters is done, in order to discuss their sensibility for identifying precociously a transverse crack in a steel beam (shaft, tube, bars, etc.), and if possible to find more sensitive properties or techniques. Our preliminary experimental results, as predicted by a bibliographical study, showed that the parameters used have a low sensitivity due to their dependence on measurement errors and to the low variation of the total stiffness rate. In fact, although testing has covered a broad range of modes, results remained always below our hopes to detect early cracks. However, it turned out, according to the theory, that local flexibility is significantly affected in the case of small cracks. Investigating other parameters that have good local characteristics seems to be the best way to improve the sensitivity of techniques allowing one to detect cracks at an early stage. Parameters such as local stiffness were used. A comparison of results concerning the sensitivity of various properties as well as of the introduced parameters is presented and discussed in this article.

Detection and Monitoring Technologies of Bridge Cable Force and Disease

Investigation is carried out aiming at analysis of bridge cable detection and monitoring. Detection and monitoring technology characteristics are summarized, while technology advantages and disadvantages analyzed. Dynamic detection technology of cable force is used most often. Effects of various factors of this technology are analyzed. Cable structure internal and external injury detection technologies are analyzed. Nondestructive testing technology specific comparison is carried out, the advantages and disadvantages of each technology and application. Nondestructive damage detection technique prospect is presented.

Damage Identification in Beams Using Experimental Data

There are several techniques for non-destructive damage detection in structures. However, they are costly and require a very precise analysis of the extent of the structure. Numerical methods can help in nondestructive testing of structures, showing the possible location of the damage and thereby decreasing the area of analysis and constituting less expensive non-destructive tests. Outstanding among the numerical methods most used to detect damage are the finite element method and the boundary element method. This paper presents the application of wavelet transform for damage detection to the static response of a beam (profile I) simply supported with a point load. Damage simulation was achieved using saw cuts in the top and bottom flanges of the beam.

Experimental Free Vibration Analysis of Clinched Beams

Clinching is a high-speed mechanical fastening technique which is suitable for point joining coated and pre-painted sheet materials. In this study, an experimental measurement technique was provided for the prediction of the free vibration behavior of single-lap cantilevered clinched beams. The dynamic test software and the data acquisition hardware were used in the experimental measurement of the dynamic response of the single-lap cantilevered clinched beams. The frequency response functions of the clinched beams of different clinching number were measured and compared. The main goal of the paper is to provide a basis for further research on vibration based non-destructive damage detection in clinched beams.

Structural Damage Detection by Using Finite Element Method as Function of Length

The work concerned exactly a structural damage. In this paper also involves the effect of length on the damping of the composite. The calculation of laminate damping is performed by use of a strain energy method. The modal analysis of the structure for different loading rates is based on the analytical method used to solve the equation of free vibrations. The difference between strain energies for both cases (damaged and undamaged) are calculated by the finite element method. The structural damping of the different beams is evaluated from these energies. The results deduced from the damping by finite element analysis for the first three modes that the evaluation of laminate damping takes account the variation of the structural damping η with lengths. This study shows clearly the decrease of one of dynamic characteristics especially the frequency when the loading rate increases for all lengths studied; this should have high utility as a decisive test for non-destructive damage detection.

Free Vibration Measurements of Single-Lap Cantilevered SPR Beams

Self-pierce riveting (SPR) is a new high-speed mechanical fastening technique which is suitable for point joining dissimilar materials, as well as coated and pre-painted materials. In this study, an experimental measurement technique was provided for the prediction of the free vibration behavior of single-lap cantilevered SPR beams. The dynamic test software and the data acquisition hardware were used in the experimental measurement of the dynamic response of the single-lap cantilevered SPR Beams. The frequency response functions of the SPR beams of different rivet number were measured and compared. The main goal of the paper is to provide a basis for further research on vibration based non-destructive damage detection in single-lap cantilevered SPR beams.

Intelligent damage identification method for large structures based on strain modal parameters

Early damage detection not only improves the safety and reliability of structures but also reduces maintenance cost. However, damage detection is difficult to implement in large structures under ambient excitation because of the limitation of sensors, the uncertainty of ambient excitation, and the global properties of modal frequencies and displacement modes. This paper proposes a new damage detection method that employs the real encoding multi-swarm particle swarm optimization algorithm and fitness functions evolved from strain modes to find the optimal match between measured and simulated modal parameters and to determine the actual condition of structures. The proposed method requires low-frequency modes and incomplete modes and does not require mass normalization of parameters, thus making the method suitable for nondestructive dynamic damage detection of large structures under ambient excitation. Taking a concrete guide wall structure as an example, this paper studied the global searching performance and the sensitivity of the proposed method. The efficiency of the proposed method was analyzed by using different noise levels and sensor numbers. Results show that the proposed method is effective and can be applied in many types of large structures.

Nondestructive damage detection in Euler-Bernoulli beams using nodal curvatures-Part I: Theory and numerical verification

SUMMARY This paper deals with the problem of nondestructively detecting, locating, and quantifying damage in beam-type structures. To achieve this objective, structural responses collected prior and subsequent to damage are related to the changes in physical properties of the structure. The proposed methodology is based on the moment–curvature relations of the Euler–Bernoulli beam theory and the assumption that internal stress resultants are invariant before and after damage. Damage is expressed in terms of local decreases in the flexural stiffness of structural members. These decreases are shown to cause singularities in the curvature profile of the beam. Utilizing fundamental equations of solid mechanics, we relate discontinuities in the flexural stiffness distribution to the pre-damage and post-damage nodal curvatures. The resulting system of linear equations can be solved to obtain specific element damage indices. The performance of the proposed methodology is evaluated using numerically generated experiments. It is shown that the location, the extent, and the severity of damage in beams may be successfully identified with the proposed technique provided that the structure conforms to the deformations dictated by the Euler–Bernoulli beam theory. The practicality of the methodology under field conditions is demonstrated in the accompanying paper Nondestructive damage detection in Euler-Bernoulli beams using nodal curvatures-Part II: Field measurements. Copyright © 2013 John Wiley & Sons, Ltd.

Non-destructive parametric system identification and damage detection in truss structures by static tests

This article presents theoretical background, computational implementation and numerical applications of a study devoted to the non-destructive parametric identification of truss structures by means of static load tests. The proposed methodology determines the (residual) stiffness of the bars. Therefore, it detects the elements with global or localised damages and assesses the extent of damage in terms of stiffness loss. A novelty introduced by the proposed technique is the ability to take into account plane and three-dimensional structures, both statically determinate and indeterminate. Moreover, when only a partial set of measurements is available, the procedure uses genetic algorithms to overcome the lack of information. Five numerical applications are collected to prove the capabilities of the proposed methodology and to exemplify the procedure.

Nondestructive damage detection in Euler-Bernoulli beams using nodal curvatures-Part II: Field measurements

The objective of this paper is to evaluate, using field measurements, the performance of the nondestructive evaluation methodology presented in the accompanying paper ‘Nondestructive damage detection in Euler–Bernoulli beams using nodal curvatures – Part I: Theory and numerical verification’. Experimental modal data collected from the Interstate 40 bridge are utilized to accomplish the stated objective. Prior to the replacement of the bridge in 1993, researchers from New Mexico State University and Los Alamos National Laboratory introduced incremental levels of damage on the structure and performed experimental modal analyses at each damage stage. The results of the experiments were utilized to evaluate the performance of five previously published nondestructive damage identification methods. Utilizing the measured modal parameters from the Interstate 40 bridge study, structural damage is localized and quantified with the nondestructive evaluation methodology presented in the accompanying paper. The results of this study indicate that the proposed methodology performed equally as well as the damage index method for damage localization and additionally provided realistic estimates of damage severity. Copyright © 2013 John Wiley & Sons, Ltd.

Analysis of the Electromagnetic Signature of Reinforced Concrete Structures for Nondestructive Evaluation of Corrosion Damage

This paper presents a nondestructive corrosion damage detection method for reinforced concrete structures based on the analysis of the electromagnetic signature of the steel rebar corrosion. The signature of the corrosion on the scattered field upon microwave illumination is first numerically analyzed. First-order quality factor parameters, the energy and the mean propagation delay, are proposed to quantify the corrosion amount in the structure. To validate the model, low-profile ultra-wide-band antennas (3-12 GHz) are fabricated and measured. Measurements on 12 reinforced concrete samples with induced corrosion are performed, using three different antenna setups. The experiments demonstrate a good correlation between an increase in the corrosion amount with a decrease in the energy and an increase in the time delay of the propagated signal.

Delamination detection in laminated composite beams using the empirical mode decomposition energy damage index

Fiber reinforced plastic composite (FRPC) beams have been widely used as effective stand-alone structural elements and/or reinforcing agents in various engineering applications. Such lightweight, stiff and strong structural elements may suffer, however, from inter-ply defects (referred to as delaminations), arising from various causes and factors. A delamination in such structural components could propagate into severely large damage zone, thus compromising the structural integrity. Therefore, detection of delamination at an early stage is of paramount importance.The application of a relatively new empirical-mode-decomposition-based, non-destructive damage detection methodology for detecting delamination damage in composite beams is introduced. The method uses the vibration signature of the structure, captured through piezoelectric sensors. The integrity of the methodology is established through both experimental and computational investigations. The method was successful in distinguishing lengthwise and through-the-thickness locations of delamination, as well as the growth in delamination size.

Polyvinylidene fluoride film sensors in collocated feedback structural control: application for suppressing impact-induced disturbances

Polyvinylidene fluoride (PVDF) films are light, flexible, and have high piezoelectricity. Because of these advantages, they have been widely used as sensors in applications such as underwater investigation, nondestructive damage detection, robotics, and active vibration suppression. PVDF sensors are especially preferred over conventional strain gauges in active vibration control because the PVDF sensors are easy to cut into different sizes or shapes as piezoelectric actuators and they can then be placed as collocated pairs. In this work, to focus on demonstrating the dynamic sensing performance of the PVDF film sensor, we revisit the active vibration control problem of a cantilever beam using a collocated lead zirconate titanate (PZT) actuator/PVDF film sensor pair. Before applying active vibration control, the measurement characteristics of the PVDF film sensor are studied by simultaneous comparison with a strain gauge. The loading effect of the piezoelectric actuator on the cantilever beam is also investigated in this paper. Finally, four simple, robust active vibration controllers are employed with the collocated PZT/PVDF pair to suppress vibration of the cantilever beam subjected to impact loadings. The four controllers are the velocity feedback controller, the integral resonant controller (IRC), the resonant controller, and the positive position feedback (PPF) controller. Suppression of impact disturbances is especially suitable for the purpose of demonstrating the dynamic sensing performance of the PVDF sensor. The experimental results also provide suggestions for choosing between the previously mentioned controllers, which have been proven to be effective in suppressing impact-induced vibrations.

A dynamic nondestructive damage detection methodology for orthotropic plate structures

This paper presents a methodology to detect and locate damages and faults in orthotropic plate structures. A specific damage index based on dynamic mode shapes of the damaged and undamaged structures has been introduced. The governing differential equation on transverse deformation, the transverse shear force equations and the invariant expression for the sum of transverse loading of an orthotropic plate are employed to obtain the aforementioned damage indices. The validity of the proposed methodology for isotropic and orthotropic damage states is demonstrated using a numerical example. It is shown that the algorithm is able to detect damages for both isotropic and orthotropic damage states acceptably.

Structural Damage Detection Depending on Curvature Matrix of Change in Flexibility

Flexibility is more sensitive to structural damage than frequency or mode. Curvature matrix of change in flexibility is presented as a new index of nondestructive damage detection, which is derived from change in structural flexibilities calculated from before damaging and after damaging by means of difference calculation twice, firstly to columns, and then to rows. Therefore a new indicator called as δ Flexibility Curvature Matrix Diagonal (δFCMD) is constructed from the principal diagonal elements based on curvature matrix of change in flexibility. The numerical simulation examples indicate that the damage location and severity in structures, with single damage, multiple ones, slight ones and ones at the supports, can be detected efficiently for a cantilever beam, a fixed supported beam, a simply supported beams and so on by the indicator of δFCMD depending on only a few of lower order modes.

Damage Detection for Simply Supported Beams Using Mid-Span Displacement Indicator

This paper investigates the detection of damage for simply supported beams to ensure their safety. Based on the analysis of possible kinds of damage may occur, this paper presents a new approach which relies on the fact that any change in local stiffness caused by damage can be reflected by the change of mid-span displacement between the intact and damaged beams. Direct relationship between the change in local stiffness and the measured mid-span displacement values is developed. This approach can identify the geometric locations of damage and then inspection means are used as a complement to find the real damage phenomena within the obtained small region. A numerical example is given to illustrate the feasibility and the effectiveness of the approach. The novel content offered by authors provides a simple, convenient, cost-effective, and nondestructive damage detection approach for simply supported beams.