Reconstruction of the nine stiffness coefficients of composites using a laser generation based imaging method

Zhao, Jianfu; Qiu, Jinhao; Ji, Hongli

doi:10.1016/j.compscitech.2016.02.001

Cited by 28 publications

(20 citation statements)

References 24 publications

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“…25 A relatively low-dimensional inverse problem is to estimate the material properties using ultrasonic measurements. 26,27 Ultrasonic guided wave suits the task, because its dispersion relation is uniquely determined by the material properties. 28 In these problems, material properties are assumed to be constant across the onedimensional (1D) spatial measurement of guided waves.…”

Section: Introductionmentioning

confidence: 99%

“…For instance, Young's modulus, Poisson's ratio, and the plate thickness were inverted for an adhesive layer in Koreck et al 26 This type of inversion is performed through best estimating these parameters to fit the dispersion relationship and created using experimental measurements. 27 Higher dimensions of inverse problems are commonly formulated for damage imaging, in which each pixel is, at least, one parameter to be inverted for. For example, TFM can be modified to an inverse method with much better performance through inverting damage simply as binary values at a variety of locations.…”

Section: Introductionmentioning

confidence: 99%

“…For instance, Young’s modulus, Poisson’s ratio, and the plate thickness were inverted for an adhesive layer in Koreck et al 26 This type of inversion is performed through best estimating these parameters to fit the dispersion relationship and created using experimental measurements. 27…”

Section: Introductionmentioning

confidence: 99%

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Guided wave tomography based on least-squares reverse-time migration

Rocha

Sava

2019

Structural Health Monitoring

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A key to successful damage diagnostics and quantification is damage imaging through ultrasonic guided wave tomography. We propose the implementation of least-squares reverse-time migration in a circular array for damage imaging in an aluminum plate. The theory of least-squares reverse-time migration is formulated for guided wave applications along with the summary of an efficient optimization algorithm: the conjugate gradient method. Numerical simulation and laboratory experiments are used to evaluate its performance with a circular array setup. In order to improve the data processing efficiency, the concept of using a limited number of actuators but a relatively large number of sensors is tested. Studies are conducted on three numerical cases, including a rectangular-shaped damage site, a complex-shaped damage site, and six other damage sites varying in size. As an inversion-based method, least-squares reverse-time migration shows significantly improved shape reconstruction with the amplitude quantification capability, compared to conventional reverse-time migration. Our experimental data are generated by piezoelectric wafers as actuators, measured by a scanning laser Doppler vibrometer to form a circular array on an aluminum plate, with a rectangular notch located in the inner region of the array. The damage images using experimental data show consistency in both the simulations using Born scattering and in altered material properties in the damaged region. According to the comparison, least-squares reverse-time migration for guided wave tomography is a promising technology to provide high-resolution large area damage imaging for plate-like structures.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Guided wave tomography based on least-squares reverse-time migration

Rocha

Sava

2019

Structural Health Monitoring

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“…For example, Marzani et al used semianalytical finite element (SAFE) method to model the dispersion curves of guided waves in an anisotropic composite plate, and combined the experimentally obtained dispersion curves from time-frequency analysis to identify the elastic parameters [30]. Zhao et al used a laser-ultrasonic system to measure the phase velocity of ultrasonic guided waves in composites, and then employed genetic algorithm combined with the measured phase velocity to invert the elastic modulus [31]. Tao et al selected phase velocity of the S0 mode Lamb wave in the low frequency region to characterize the fatigue damage in a composite laminate under cyclic loads in different fatigue stages.…”

Section: Introductionmentioning

confidence: 99%

Guided Wave-Based Monitoring of Evolution of Fatigue Damage in Glass Fiber/Epoxy Composites

Yan

Tang

2019

Applied Sciences

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This paper presents an experimental study on detecting and monitoring of evolution of fatigue damage in composites under cyclic loads by using guided waves. Composite specimens fabricated by glass fiber/epoxy laminates and surface mounted with piezoelectric wafers are fatigued under tension–tension loads. A laser extensometer is used to obtain the degradation of longitudinal stiffness of the specimens under fatigue states to reflect the accumulation of internal fatigue damage. Meanwhile, at different fatigue cycles, one wafer acts as actuator to excite diagnostic guided waves, and the other acts as sensor to receive corresponding response waves. These guided wave signals are then processed by wavelet packet transform to extract characteristic features of energies in multiple frequency bands. A statistical multivariate outlier analysis is then performed to determine the existence of fatigue damage and to characterize their evolution using Mahalanobis squared distance. Experimental results have demonstrated the potential applicability and effectiveness of guided waves for continuous monitoring of fatigue damage in composite structures.

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“…Therefore, this relationship can be used to pass from a set of measured velocities to an estimation of the mechanical parameters, a procedure known as inverse problem (Bucur and Archer 1984;Castagnede and Sachse 1989;Bucur 2006;Dahmen et al 2010;Longo et al 2012;Gonçalves et al 2014;Alves et al 2015;Tallavo et al 2017). For instance, ultrasonic goniometry relies on the principle of inverse problem to determine the elastic constants of the stiffness matrix for the characterization of different composite materials (Siva et al 2005;Zhao et al 2016), including wood (Preziosa 1982;Bachtiar et al 2017). The mentioned procedure works by using small samples with cubic, prismatic, polyhedral geometry, or multifaceted discs, to determine the nine elastic constants of wood, by assuming the homogeneity of the specimens, and thus that the mechanical properties are constants within the specimens.…”

Section: Introductionmentioning

confidence: 99%

Effects of Convection and Microwave Drying Schemes on the Characteristics and Sound Absorption of Acoustic Oil Palm Boards

Dangvilailux

Charoensuk

2017

BioResources

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To perform a non-destructive evaluation of wood, the Christoffel equation is frequently used to describe the relationship between the ultrasonic wave velocity and the mechanical parameters. In the context of acoustical tomography imaging of standing trees, the key contribution of this numerical study is to determine the influence of mechanical parameters of the wood radial-tangential plane on the wave velocity computation using the Christoffel equation. Mechanical parameters from six species were selected. A sensitivity analysis was carried out by increasing and decreasing every parameter by a given percentage, and then by computing the variation of velocity for a set of wave direction of propagations. The evolution of the wave velocity, according to the direction of propagation, depended on the considered species; there was a difference between the softwoods and the hardwoods. The sensitivity analysis showed a bigger influence of the Young's moduli, followed by the Poisson's ratio, and finally by the shear modulus. However, these last two parameters cannot be neglected when using the Christoffel equation to solve the inverse problem of standing tree tomography. A proposed solution involves determining the propagation paths using the Young's moduli as variables and then inversing the set of equations in accordance with the overall parameters.

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Reconstruction of the nine stiffness coefficients of composites using a laser generation based imaging method

Cited by 28 publications

References 24 publications

Guided wave tomography based on least-squares reverse-time migration

Guided wave tomography based on least-squares reverse-time migration

Guided Wave-Based Monitoring of Evolution of Fatigue Damage in Glass Fiber/Epoxy Composites

Effects of Convection and Microwave Drying Schemes on the Characteristics and Sound Absorption of Acoustic Oil Palm Boards

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