Damage Detection in Composite Structures via Scanning Laser Doppler Vibrometry Using Linear and Nonlinear Ultrasonic Wave Features

2020 ◽  
Author(s):  
Mingjing Cen ◽  
Yanfeng Shen
Keyword(s):  
Damage Detection ◽  
Composite Structures ◽  
Structural Damage ◽  
Numerical Study ◽  
Fiber Composite ◽  
Tone Burst ◽  
Nonlinear Ultrasonic ◽  
Nonlinear Features ◽  
Linear And Nonlinear ◽  
Delamination Area

Abstract This study presents the modeling and experimental investigation of damage detection and evaluation methods based on the linear and nonlinear features of ultrasonic guided waves while they interact with possible structural damage sites. Such wave damage interaction features are visualized via the full field imaging capability of SLDV. First, numerical modeling is conducted to develop an in-depth understanding of the mechanism behind the wave damage interactions. A coupled-filed transient dynamic finite element model is constructed with a simulated delamination area. The modeling of Contact Acoustic Nonlinearity (CAN) is realized by defining the contact surfaces at the delamination area. The linear ultrasonic features such as the trapped modes as well as the nonlinear features such as the mixed frequency response are illustrated using the numerical simulation. Based on the numerical study, experimental investigations are further conducted. Experiments are performed to explore linear ultrasonic technique for damage quantification. For the linear case, the detection utilizes a short tone burst in both spatial and temporal domain, generated by a Piezoelectric Wafer Active Sensor (PWAS); the trapped wave energy and a directional vector field technique are adopted to visualize an impact damage in a carbon fiber composite plate. The nonlinear detection methodology combines a continuous resonant low frequency harmonic pumping wave with a high frequency tone burst probing wave, simultaneously generated by two PWAS transducers on both sides of the specimen to take advantage of the mixed nonlinear interactions between the vibroacoustic waves and the structural damage. This study shows that both linear and nonlinear ultrasonic techniques possess great application potential for the damage detection and quantification in composite structures. The paper finishes with summary, concluding remarks, and suggestions for future work.

scholarly journals Numerical Simulation on Micro-damage Detection In CFRP Composites Based on Nonlinear Ultrasonic Guided Waves

2021 ◽  
Keyword(s):  
Damage Detection ◽  
Composite Structures ◽  
Guided Waves ◽  
Second Harmonic ◽  
Wave Mode ◽  
Guided Wave ◽  
Reinforced Plastics ◽  
Matrix Cracks ◽  
Nonlinear Ultrasonic ◽  
Contact Acoustic Nonlinearity

Abstract. Micro-damages such as pores, closed delamination/debonding and fiber/matrix cracks in carbon fiber reinforced plastics (CFRP) are vital factors towards the performance of composite structures, which could collapse if defects are not detected in advance. Nonlinear ultrasonic technologies, especially ones involving guided waves, have drawn increasing attention for their better sensitivity to early damages than linear acoustic ones. The combination of nonlinear acoustics and guided waves technique can promisingly provide considerable accuracy and efficiency for damage assessment and materials characterization. Herein, numerical simulations in terms of finite element method are conducted to investigate the feasibility of micro-damage detection in multi-layered CFRP plates using the second harmonic generation (SHG) of asymmetric Lamb guided wave mode. Contact acoustic nonlinearity (CAN) is introduced into the constitutive model of micro-damages in composites, which leads to the distinct SHG compared with material nonlinearity. The results suggest that the generated second order harmonics due to CAN could be received and adopted for early damage evaluation without matching the phase of the primary waves.

Application of Phased Array Antenna Technique in Structural Damage Detection

2011 ◽  
Vol 368-373 ◽  
pp. 1667-1671
Author(s):  
Yu Zhang ◽  
Long Yu ◽  
Yun Ju Yan ◽  
Yu Guo
Keyword(s):  
Wave Propagation ◽  
Damage Detection ◽  
Structural Damage ◽  
Phased Array ◽  
Tone Burst ◽  
Array Antenna ◽  
Detection Accuracy ◽  
Structural Damage Detection ◽  
Phased Array Antenna ◽  
Energy Leakage

Over decades phased array antenna technique attracts much more attention in Lamb wave based structural damage detection. Lamb wave generated by the piezoelectric wafers omnidirectionally could be steered at a specific direction during its propagation. Thus, the wave beam steering and focusing has been established, the location of structural damage is done with pulse-echo method by wave propagation. However, the detection accuracy will decrease as side bands energy leakage during wave propagation, so, signals to be generated have to be modified by window tone burst in order to concentrate energy in main bands and minimize the effect of dispersion side bands. In this paper, signals modified by Hanning-windowed tone burst was used to decrease the effect of side bands energy leakage, the results improved the detection accuracy better than signals without window tone burst and show good agreement with theoretical results. Meanwhile, A numerical simulation of aluminium plate demonstrates that phased array antenna technique is feasible in structural damage detection.

Delamination Detection in Composite Plates Using Linear and Nonlinear Ultrasonic Guided Waves

2019 ◽  
Author(s):  
Yanfeng Shen ◽  
Mingjing Cen
Keyword(s):  
Wave Propagation ◽  
Guided Waves ◽  
Fiber Composite ◽  
Composite Plates ◽  
Ultrasonic Guided Waves ◽  
Carbon Fiber Composite ◽  
Laser Doppler Vibrometry ◽  
Delamination Detection ◽  
Nonlinear Ultrasonic ◽  
Linear And Nonlinear

Abstract This paper presents a delamination detection strategy for composite plates using linear and nonlinear ultrasonic guided waves via the wave field imaging and signal processing based on Scanning Laser Doppler Vibrometry (SLDV). The anisotropic elastodynamics in composite plates is first studied. Two numerical methods are deployed to analyze the wave mechanics within the composite plates. The Semi-analytical Finite Element (SAFE) method is utilized to obtain the dispersion curves and mode shapes for a carbon fiber composite plate by bonding two quasi-isotropic carbon fiber composite panels together. The Local Interaction Simulation Approach has been employed to investigate the wave propagation and interaction with the delamination. Contact Acoustic Nonlinearity (CAN) between the delamination interfaces during wave damage interaction is presented as a potential mechanism for delamination detection. After developing an in-depth understanding of the wave propagation and wave damage interaction mechanism, active sensing experiments are conducted using the Piezoelectric Wafer Active Sensors (PWAS) and the Scanning Laser Doppler Vibrometry (SLDV). Two delamination imaging methodologies are presented. The first one utilizes the total wave energy to detect the delamination, taking advantage of the trapped modes within the delaminated area. The second one adopts the nonlinear second harmonic imaging algorithm, highlighting the nonlinear interaction traces at the delamination region. The damage detection images are finally compared and fused to provide detailed diagnostic information of the delamination. The damage imaging technique presented in this paper possesses great potential in material evaluation and characterization applications. This paper finishes with summary, concluding remarks, and suggestions for future work.

scholarly journals Structural Damage Diagnosis-Oriented Impulse Response Function Estimation under Seismic Excitations

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5413
Author(s):  
Jian-Fu Lin ◽  
Junfang Wang ◽  
Li-Xin Wang ◽  
Siu-seong Law
Keyword(s):  
Damage Detection ◽  
Impulse Response ◽  
Response Function ◽  
Structural Damage ◽  
Numerical Study ◽  
Damage Index ◽  
Impulse Response Function ◽  
Function Estimation ◽  
Seismic Excitations ◽  
Transformation Matrices

Impulse response function (IRF) is an ideal structural damage index for the identification of structural damage associated with changes in modal properties. However, IRFs from multiple excitations applied at different degrees-of-freedoms jointly contribute to the dynamic response, and their estimation is often underdetermined. Although some efforts have been devoted to the estimation of IRF for a structure under single excitation, the case under multiple excitations has not been fully investigated yet. The estimation of IRF under multiple excitations is generally an ill-conditioned inverse problem such that an incorrect or non-feasible solution is common, preventing its application to damage detection. This work explores this problem by introducing dimensionality reduction transformation matrices relating two sets of IRFs of a structure with discussions on the performance of the non-unique transformation matrices. Then, the extraction of IRF via wavelet-based and Tikhonov regularization-based methods are compared. Finally, a numerical study with a truss structure is conducted to validate the estimation of the IRFs and to demonstrate their applicability for damage detection under seismic excitations. Both the damage locations and severity are accurately identified, indicating the proposed methodology can enable the IRFs estimation under multiple excitations for successful damage detection.

Structural Damage Identification Based on Information Fusion Techniques

2010 ◽  
Author(s):  
Hui Li ◽  
Yuequan Bao
Keyword(s):  
Damage Detection ◽  
Information Fusion ◽  
Structural Damage ◽  
Damage Identification ◽  
Yellow River ◽  
Numerical Study ◽  
Detection Methods ◽  
Data Sets ◽  
Structural Damage Detection ◽  
Selective Fusion

With the aim to decrease the uncertainties of structural damage detection, two fusion models are presented in this paper. The first one is a weighted and selective fusion method for combing the multi-damage detection methods based on the integration of artificial neural network, Shannon entropy and Dempster-Shafer (D-S) theory. The second one is a D-S based approach for combing the damage detection results from multi-sensors data sets. Numerical study on the Binzhou Yellow River Highway Bridge and an experimental of a 20-bay rigid truss structure were carried out to validate the uncertainties decreasing ability of the proposed methods for structural damage detection. The results show that both of the methods proposed are useful to decrease the uncertainties of damage detection results.

A Damage Detection Method: CMSE Combined with Niche GA

2007 ◽  
Vol 334-335 ◽  
pp. 929-932 ◽  
Author(s):  
Xu Ge ◽  
Yun Ju Yan ◽  
Huan Guo Chen
Keyword(s):  
Composite Material ◽  
Damage Detection ◽  
Composite Structures ◽  
Structural Damage ◽  
Strain Energy ◽  
Detection Method ◽  
Detection Methods ◽  
Damage Localization ◽  
Complex Structures ◽  
Modal Strain Energy

The paper presents an effective damage detection method of complex composite structures. It can be carried out through the experimental modal analysis of the damaged structure. The method using the improved Cross Modal Strain Energy (CMSE) technique and Niche GA has many advantages compared with other damage detection methods. The CMSE method can use any modes of the structure and the modes don’t need to be normalized or consistent in scale. The Niche GA improves the efficiency of the calculation and enhances the capacity of identifying structural damage localization. The model is the composite material airfoil case. The numerical results show that the method proposed in this paper is successful for damage detection of complex structures.

Optimization of Element Parameters for a New OPFC Ultrasonic Phased Array Transducer

2014 ◽  
Vol 609-610 ◽  
pp. 1293-1298
Author(s):  
Zi Ping Wang ◽  
Ying Luo
Keyword(s):  
Damage Detection ◽  
Structural Damage ◽  
Phased Array ◽  
Low Voltage ◽  
Fiber Composite ◽  
Array Element ◽  
Structural Damage Detection ◽  
Array Transducer ◽  
Verification Methods ◽  
Ultrasonic Phased Array

An orthotropic piezoelectric fiber composite (OPFC) element and related OPFC ultrasonic phased array transducer which applied in damage detection of metal structures are investigated by theoretical analysis, numerical simulation and experimental verification methods. Based on electromechanical coupling, the influence of the material characteristics and geometry parameters on actuation performance is studied for the thickness expansion type OPFC elements. In view of lack in the mechanic-electronic parameter design of the existing single PZT element for modern ultrasonic phased array transducer, the related OPFC ultrasonic phased array transducer which used in metal structural damage detection is designed, which have the merits such as low voltage and limit the effects on grating lobe. The focusing acoustic field distribution is analyzed by finite element method together with directivity analysis in metals. The optimal array parameters such as phased array element interval, array element width and number of element are obtained by studying the total displacement changes as various parameters changes at focus point. The preparation of OPFC actuator used in metal structural damage detection is studied. The performance of interdigital OPFC element is also obtained by testing and comparing with the traditional PZT element. The experimental results displayed good agreement with the theoretical predictions.

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