Detection of delamination in composite beams using frequency deviations due to concentrated mass loading

Yang, Chen; Oyadiji, S. Olutunde

doi:10.1016/j.compstruct.2015.12.002

Cited by 14 publications

(10 citation statements)

References 20 publications

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“…Moreover, it seems that the test frequency has remarkable effect on E″ , G″ and tanδ, which means test frequency has great influence on energy dissipation of composite materials. Some researchers have reported that delamination induced modal frequency shifting and modal damping increasing due to modal stiffness reduction [12,16,31].…”

Section: Discussionmentioning

confidence: 99%

“…Zhang et al [14,15] investigated the size and location parameters of delamination in carbon fiber-reinforced plastic (CFRP) and glass fiber-reinforced plastic (GFRP) plates based on the changes in natural frequencies and these parameters were predicted using a Surrogate Assisted Optimization method. Yang and Oyadiji [16] found the behavior of the modal frequency deviation depends on the axial location as well as the interlayer position of the delamination.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Dynamic Mechanical Analysis on Delaminated Flax Fiber Reinforced Composites

et al. 2019

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It is well-known that the presence of the delamination in a plant fiber-reinforced composite is difficult to detect. However, the delamination introduces a local flexibility, which changes the dynamic characteristics of the composite structure. This paper presents a new methodology for composite laminate delamination detection, which is based on dynamic mechanical analysis. A noticeable delamination-induced storage modulus reduction and loss factor enhancement have been observed when the delaminated laminate was subjected to a forced oscillation compared to the intact composite laminate. For delamination area of 12.8% of the whole area of the composite laminate, loss factor of approximately 12% increase was observed. For near-to-surface delamination position, loss factor of approximately an 18% increment was observed. The results indicate that the delamination can be reliably detected with this method, and delamination position shows greater influence on the loss factor than that of the delamination size. Further investigations on different frequencies and amplitudes configurations show that the variation of loss factor is more apparently with low frequency as well as the low amplitude.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dynamic Mechanical Analysis on Delaminated Flax Fiber Reinforced Composites

et al. 2019

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“…The developed method was able to detect damages from the early stage of micro-cracks up to delamination in composite structures. Yang et al [24] proposed that the variations of modal frequency under mass loading could be used to quantify the effects of delamination in laminated composites. Mei et al [25] studied high-frequency local vibration for detecting and quantifying the size, shape, and depth of delamination in composite plates.…”

Section: Introductionmentioning

confidence: 99%

A Deep Learning Framework for Vibration-Based Assessment of Delamination in Smart Composite Laminates

Khan

Shin

Lim

et al. 2020

Sensors

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Delamination is one of the detrimental defects in laminated composite materials that often arose due to manufacturing defects or in-service loadings (e.g., low/high velocity impacts). Most of the contemporary research efforts are dedicated to high-frequency guided wave and mode shape-based methods for the assessment (i.e., detection, quantification, localization) of delamination. This paper presents a deep learning framework for structural vibration-based assessment of delamination in smart composite laminates. A number of small-sized (4.5% of total area) inner and edge delaminations are simulated using an electromechanically coupled model of the piezo-bonded laminated composite. Healthy and delaminated structures are stimulated with random loads and the corresponding transient responses are transformed into spectrograms using optimal values of window size, overlapping rate, window type, and fast Fourier transform (FFT) resolution. A convolutional neural network (CNN) is designed to automatically extract discriminative features from the vibration-based spectrograms and use those to distinguish the intact and delaminated cases of the smart composite laminate. The proposed architecture of the convolutional neural network showed a training accuracy of 99.9%, validation accuracy of 97.1%, and test accuracy of 94.5% on an unseen data set. The testing confusion chart of the pre-trained convolutional neural network revealed interesting results regarding the severity and detectability for the in-plane and through the thickness scenarios of delamination.

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“…For instance, Luo and Hanagud (2000) presented a model using four Timoshenko beams connected at delamination edges with nonlinear interaction. Yang and Oyadiji (2016) investigated the detection of delamination in composite beams using frequency deviations due to a concentrated mass loading. Jafari-Talookolaei et al (2015) investigated the dynamic analysis of generally laminated composite beam with a delamination based on a higher order shear deformable theory.…”

Section: Introductionmentioning

confidence: 99%

Analysis of delamination of unimorph cantilever piezoelectric energy harvesters

Zeng

Zhang

Wang

et al. 2018

Journal of Intelligent Material Systems and Structures

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Unimorph piezoelectric energy harvesters are typically a unimorph cantilever beam located on a vibrating host structure. Delamination is one of the major failure modes of such unimorph cantilevers and therefore is studied in this article. The delaminated cantilever unimorph is modeled with one through-width crack using four Euler beams connected at delamination edges. The governing equations, the corresponding boundary conditions, and the kinematic continuity conditions are derived based on the Hamiltonian principle. The solutions of the voltage and power output for the present model are derived. The influence of the position and the length of the delamination, frequency of input base excitation, and load resistance on the voltage and power output are discussed in detail. The results show that delamination in the unimorph of the energy harvester will impressively decrease the voltage and power outputs. Influences of the delamination located at the free end of the cantilever are more obvious. For a given active length of the delaminated cantilever energy harvester, it is useful to increase the overall length of the cantilever to obtain a higher voltage and power outputs.

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Detection of delamination in composite beams using frequency deviations due to concentrated mass loading

Cited by 14 publications

References 20 publications

Dynamic Mechanical Analysis on Delaminated Flax Fiber Reinforced Composites

Dynamic Mechanical Analysis on Delaminated Flax Fiber Reinforced Composites

A Deep Learning Framework for Vibration-Based Assessment of Delamination in Smart Composite Laminates

Analysis of delamination of unimorph cantilever piezoelectric energy harvesters

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