Reflection and mode-conversion of ultrasonic leaky Lamb waves at inaccessible discontinuities in layered structures

2023

Applied Sciences

This work deals with the evaluation of adhesive single-lap joints using ultrasound guided waves; in particular, it is intended to characterize the signal propagation when defects are present in the adhesive joint by simulation and experimental approaches. The propagation of guided waves in the joint is developed from matrix formulations. The behavior of the guided wave modes that exist in the bonded region is characterized. It is found that its amplitudes can be estimated from the properties of the incoming wave that propagates in the non-bonded region. It is verified that the excitation of these modes is related to the degree to which the shapes of both modes match each other. A 3D simulation of two aluminum-bonded plates using 500 kHz ultrasonic transducers in a pitch-and-catch configuration was implemented using the Matlab k-Wave toolbox. Scattering effects, due to some defects located in the bond line of the joints, were simulated. The experimental setup with some artificial defects produced in the aluminum joints was used in order to compare it with the simulation. Qualitative agreement was observed between the two approaches. The observed deviation can be due to the different characteristics of the experimental and simulated defects.

Section: Introductionmentioning

confidence: 99%

Adhesive Single-Lap Joint Evaluation Using Ultrasound Guided Waves

2023

Applied Sciences

“…Fewer spatial and temporal grid points are needed for accurate simulations [18]. Recently many authors have used the k-Wave toolbox in NDT applications related to attenuation in ultrasonic computed tomography [20], guided waves in layered structures [21,22], time domain power law attenuation in breast and liver tissues [23], one-sided ultrasonic nondestructive evaluation [24], high intensity focused ultrasound [25], nonlinear ultrasound propagation in absorbing media [26], ultrasonic transducers field modelling [27], 3-D ultrasound imaging [28], and A-scan ultrasound simulation in ophthalmology [29].…”

Section: Introductionmentioning

confidence: 99%

Computational Simulation of Microflaw Detection in Carbon-Fiber-Reinforced Polymers

Petrella

2022

Electronics

The evaluation of microflaws in carbon-fiber-reinforced composite laminate (CFRP) via ultrasound requires the knowledge of some important factors in addition to its structural composition. Since the laminates are heterogeneous, the high-frequency requirements to acquire high-resolution signals have limitations due to the great scattering that prevents good signal-to-noise ratios. Additionally, the ultrasonic probe’s spatial and lateral resolution characteristics are important parameters for determining the detectability level of microflaws. Modelling appears as a good approach to evaluating the abovementioned factors and the probability of detection of defects in the micron range because it makes it possible to reduce the time and cost associated with developments based on experimental tests. Concerning the subject of this work, simulation is the best way to evaluate the detectability level of the proposed defects since experimental samples are not available. In this work, the simulation was implemented using the Matlab k-Wave toolbox. A 2D matrix for mimicking a CFRP was constructed with 1 μm of resolution. Four different defect types in the micron range were created in the matrix. The simulated and experimental results presented good agreement. It was concluded that the highest frequency probe that could be used to detect the simulated defects without ambiguity was 25 MHz.

“…Fewer spatial and temporal grid points are needed for accurate simulations [51]. Recently many authors have used the k-Wave toolbox in applications related to attenuation in ultrasonic computed tomography [53], guided waves in layered structures [54] and [55] time domain, power law attenuation in breast and liver tissues [56], one-sided ultrasonic nondestructive evaluation [57], high intensity focused ultrasound [58], nonlinear ultrasound propagation in absorbing media [59], ultrasonic transducers field modelling [60], and 3-D ultrasound imaging [61].…”

Section: Introductionmentioning

confidence: 99%

Ultrasonic Scattering Attenuation in Nodular Cast Iron: Experimental and Simulation Studies

2021

SV-JME

This work evaluates the ultrasonic scattering attenuation of structures with complex scatterer distributions via experimental and simulation studies. The proposed approach uses experimental attenuation knowledge to infer the scatterer size and its concentration in the studied structures, which are important for the effective construction of simulated models. The MATLAB k-Wave toolbox has been used to implement the simulator. Several cast-iron samples have been used to demonstrate the importance of simulation in the characterization of such structures. First, the scattering attenuation was evaluated using the Truell and Papadakis models, and then the results were compared with experimental ones. Emphasis was given to the Papadakis approach because it takes into account the scatterer size distribution. It is demonstrated that both analytical models provide results that are far from the experimental ones. The developed simulator for the studied samples led to a predictive model, in which the attenuation was proportional to the fifth power of the scatterer size, and the corresponding formulation is close to the one proposed by the analytical models.