Search results

1 – 10 of 46
Article
Publication date: 17 June 2020

Seyed Foad Mousavi, Seyed Hassan Hashemabadi and Jalil Jamali

The purpose of this study is to numerically simulate the Lamb wave propagation through a clamp-on ultrasonic gas flowmeter (UGF) in contact mode, using a new semi…

120

Abstract

Purpose

The purpose of this study is to numerically simulate the Lamb wave propagation through a clamp-on ultrasonic gas flowmeter (UGF) in contact mode, using a new semi three-dimensional approach. Moreover, experimental and analytical modeling results for transit time difference method have been used to confirm the simulation results at different gas flow velocities from 0.3 to 2.4 m/s.

Design/methodology/approach

The new semi three-dimensional approach involves the simulation of the flow field of the gas in a three-dimensional model and subsequently the simulation of wave generation, propagation and reception in a two-dimensional (2D) model. Moreover, the analytical model assumes that the wave transitions occur in a 2D mode.

Findings

The new approach is a semi three-dimensional approach used in this work, has better accuracy than a complete 2D simulation while maintaining the computing time and costs approximately constant. It is faster and less expensive than a complete 3D simulation and more accurate than a complete 2D simulation. It was concluded that the new approach could be extended to simulate all types of ultrasonic gas and non-gas flowmeters, even under harsh conditions.

Originality/value

In this work, a new approach for the numerical simulation of all types of ultrasonic flowmeters is introduced. It was used for simulation of a Lamb wave ultrasonic flow meter in contact mode.

Article
Publication date: 7 September 2010

Gao Guili, Li Dayong, Shi Dequan and Dong Jingwei

The purpose of this paper is to demonstrate by experiments that non‐linear Lamb wave modulation spectrum (NLWMS) will be a good indicator of fatigue cracks in a metallic plate.

Abstract

Purpose

The purpose of this paper is to demonstrate by experiments that non‐linear Lamb wave modulation spectrum (NLWMS) will be a good indicator of fatigue cracks in a metallic plate.

Design/methodology/approach

A system composed of piezoelectric transducers, arbitrary waveform generator, power amplifier, laser vibrometer, digital oscilloscope and computer has been constructed, and using this system, three samples made of 7075‐T6 aluminium alloy plates are studied, respectively. One is with a fatigue crack, one is with a through hole and the other is intact.

Findings

The experimental results show that there are no significant harmonics and sidebands in the intact sample, and there are no modulation frequencies in the drilled‐hole sample. On the contrary, in the cracked sample, there is an abundance of the harmonics and sidebands. Therefore, these new modulation frequency components can be used to indicate the presence of the fatigue crack.

Practical implications

This paper will provide a method for detecting fatigue crack in metallic plates, especially aluminium alloy plates for aerospace applications.

Originality/value

Under the excitation of two different frequency Lamb waves, experiments on 7075‐T6 alloy plates show that new rising modulation frequency components can be used to indicate the presence of the crack. So, the fatigue crack in metallic plates can be detected by NLWMS.

Details

Aircraft Engineering and Aerospace Technology, vol. 82 no. 5
Type: Research Article
ISSN: 0002-2667

Keywords

Article
Publication date: 14 January 2014

Javad Abbaszadeh, Herlina Binti Abdul Rahim, Ruzairi Bin Abdul Rahim and Sahar Sarafi

Since the importance role of ultrasonic tomography (UT) in industry, especially in oil industry, to produce noninvasive and nondestructive plane images, research on UT system with…

Abstract

Purpose

Since the importance role of ultrasonic tomography (UT) in industry, especially in oil industry, to produce noninvasive and nondestructive plane images, research on UT system with a metal pipe conveyor is investigated. The produced cross-sectional images are used for detecting the concentration of solid and liquid mixture inside the pipe, noninvasively. In practice, due to application of metal pipes as the conveyor of oil mixture so the capability of manufacturing an UT system with a metal pipe is investigated in this paper. The paper aims to discuss these issues.

Design/methodology/approach

Finite element software (COMSOL Multiphysics 3.5) for visualizing the structure of pipe with mounted sensors on the periphery of the pipe is used. The manner of ultrasonic wave propagation on different layers on various frequencies and finding the time of flight for transmission mode signal and lamb mode signal are achieved by the means of done simulations. Finding the proper ultrasonic sensor base on its efficiency is the main step of designing an UT system. This is done by estimating the resonance frequency of sensor due to the manner of ultrasonic wave propagation in different frequencies shown in simulation results.

Findings

Due to simulation results, lamb wave is a permanent propagation mode of ultrasonic wave which makes interference in measuring process of straight path signal and it is impossible to remove. Relief of the mentioned problem finding an optimum frequency to decrease the affection of lamb wave in detecting point. Optimum frequency of ultrasonic wave to satisfy the objective is 45 kHz which is measured by considering of mathematic of ultrasonic wave propagation in different layers. The reaching time of straight path signal and lamb wave signal in opposite sensor as the receiver are 5.5 and 4.6 μs, respectively.

Originality/value

This investigation is the first step to perform the UT in a noninvasive method to produce the cross-sectional images of metal pipe. Due to the wide application of metal pipes as the conveyor of the liquids/gases, metal pipe for the UT application is studied in this research.

Details

Sensor Review, vol. 34 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 12 April 2018

Ambuj Sharma, Sandeep Kumar and Amit Tyagi

The real challenges in online crack detection testing based on guided waves are random noise as well as narrow-band coherent noise; and to achieve efficient structural health…

Abstract

Purpose

The real challenges in online crack detection testing based on guided waves are random noise as well as narrow-band coherent noise; and to achieve efficient structural health assessment methodology, magnificent extraction of noise and analysis of the signals are essential. The purpose of this paper is to provide optimal noise filtering technique for Lamb waves in the diagnosis of structural singularities.

Design/methodology/approach

Filtration of time-frequency information of guided elastic waves through the noisy signal is investigated in the present analysis using matched filtering technique which “sniffs” the signal buried in noise and most favorable mother wavelet based denoising methods. The optimal wavelet function is selected using Shannon’s entropy criterion and verified by the analysis of root mean square error of the filtered signal.

Findings

Wavelet matched filter method, a newly developed filtering technique in this work and which is a combination of the wavelet transform and matched filtering method, significantly improves the accuracy of the filtered signal and identifies relatively small damage, especially in enormously noisy data. A comparative study is also performed using the statistical tool to know acceptability and practicability of filtered signals for guided wave application.

Practical implications

The proposed filtering techniques can be utilized in online monitoring of civil and mechanical structures. The algorithm of the method is easy to implement and found to be successful in accurately detecting damage.

Originality/value

Although many techniques have been developed over the past several years to suppress random noise in Lamb wave signal but filtration of interferences of wave modes and boundary reflection is not in a much matured stage and thus needs further investigation. The present study contains detailed information about various noise filtering methods, newly developed filtration technique and their efficacy in handling the above mentioned issues.

Details

Multidiscipline Modeling in Materials and Structures, vol. 14 no. 4
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 9 April 2018

Ambuj Sharma, Sandeep Kumar and Amit Tyagi

The presence of random noise as well as narrow band coherent noise makes the structural health monitoring a really challenging issue and to achieve efficient structural health…

Abstract

Purpose

The presence of random noise as well as narrow band coherent noise makes the structural health monitoring a really challenging issue and to achieve efficient structural health assessment methodology, very good extraction of noise and analysis of the signals are essential. The purpose of this paper is to provide optimal noise filtering technique for Lamb waves in the diagnosis of structural singularities.

Design/methodology/approach

Filtration of time-frequency information of multimode Lamb waves through the noisy signal is investigated in the present analysis using matched filtering technique and wavelet denoising methods. Using Shannon’s entropy criterion, the optimal wavelet function is selected and verification is made via the analysis of root mean square error of filtered signal.

Findings

The authors propose wavelet matched filter method, a combination of the wavelet transform and matched filtering method, which can significantly improve the accuracy of the filtered signal and identify relatively small damage, especially in enormously noisy data. Correlation coefficient and root mean square error are additionally computed for performance evaluation of the filters.

Originality/value

The present study provides detailed information about various noise filtering methods and a first attempt to apply the combination of the different techniques in signal processing for the structural health monitoring application. A comparative study is performed using the statistical tool to know whether filtered signals obtained through three different methods are acceptable and practicable for guided wave application or not.

Details

International Journal of Structural Integrity, vol. 9 no. 2
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 28 June 2019

Tomasz Wandowski, Pawel Malinowski and Wieslaw Ostachowicz

The purpose of this paper is to present the results of experimental analysis of the elastic-guided wave mode conversion phenomenon in glass fiber-reinforced polymers. The results…

Abstract

Purpose

The purpose of this paper is to present the results of experimental analysis of the elastic-guided wave mode conversion phenomenon in glass fiber-reinforced polymers. The results of this research presented in this paper are strictly focused on S0/A0’ mode conversion phenomenon caused by discontinuities in the form of circular Teflon inserts (artificial delaminations) and impact damage. Results of this research could be useful in problems of damage detection and localization.

Design/methodology/approach

In the research, guided waves are excited using a piezoelectric transducer and sensed in a non-contact manner using a scanning laser Doppler vibrometer. Full wavefield measurements are analyzed. Analysis of the influence of investigated discontinuities on S0/A0’ mode conversion is based on the elastic wave mode filtration in frequency-wavenumber domain. Mode filtration process allows us to remove the effects of the propagation of unwanted type of mode in forward or backward direction. Effects of S0/A0’ mode conversion are characterized by a mode conversion indicator (MCI) based on the amplitude of new mode A0’ and the amplitude of incident S0 mode.

Findings

It was noticed that the magnitude of MCI depends on the depth at which the Teflon inserts were located for all analyzed excitation frequencies and diameters of inserts (10 and 20 mm). The magnitude of MCI also increases with increasing impact energies. The S0/A0’ mode conversion phenomenon could be utilized for the detection of surface and internal located discontinuities.

Originality/value

This paper presents the original results of this research related to the influence of discontinuity location with respect to the sample thickness and severity of discontinuity on S0/A0’ mode conversion.

Details

International Journal of Structural Integrity, vol. 10 no. 3
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 12 July 2013

Sascha Duczek and Ulrich Gabbert

Piezoelectric actuators and sensors are an invaluable part of lightweight designs for several reasons. They can either be used in noise cancellation devices as thin‐walled…

Abstract

Purpose

Piezoelectric actuators and sensors are an invaluable part of lightweight designs for several reasons. They can either be used in noise cancellation devices as thin‐walled structures are prone to acoustic emissions, or in shape control approaches to suppress unwanted vibrations. Also in Lamb wave based health monitoring systems piezoelectric patches are applied to excite and to receive ultrasonic waves. The purpose of this paper is to develop a higher order finite element with piezoelectric capabilities in order to simulate smart structures efficiently.

Design/methodology/approach

In the paper the development of a new fully three‐dimensional piezoelectric hexahedral finite element based on the p‐version of the finite element method (FEM) is presented. Hierarchic Legendre polynomials in combination with an anisotropic ansatz space are utilized to derive an electro‐mechanically coupled element. This results in a reduced numerical effort. The suitability of the proposed element is demonstrated using various static and dynamic test examples.

Findings

In the current contribution it is shown that higher order coupled‐field finite elements hold several advantages for smart structure applications. All numerical examples have been found to agree well with previously published results. Furthermore, it is demonstrated that accurate results can be obtained with far fewer degrees of freedom compared to conventional low order finite element approaches. Thus, the proposed finite element can lead to a significant reduction in the overall numerical costs.

Originality/value

To the best of the author's knowledge, no piezoelectric finite element based on the hierarchical‐finite‐element‐method has yet been published in the literature. Thus, the proposed finite element is a step towards a holistic numerical treatment of structural health monitoring (SHM) related problems using p‐version finite elements.

Details

Engineering Computations, vol. 30 no. 5
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 7 December 2015

Artur Szewieczek, Christian Willberg, Daniel Schmidt and Michael Sinapius

A design of sensor networks for structural health monitoring (SHM) with guided waves poses a hard challenge. Therefore different approaches are possible. A known one is the usage…

Abstract

Purpose

A design of sensor networks for structural health monitoring (SHM) with guided waves poses a hard challenge. Therefore different approaches are possible. A known one is the usage of probability of detection (POD) criteria. Here, areas of potential impact sensitivity are calculated for every sensor which leads to a POD. The number of sensors is increased until a demanded POD is reached. However, these calculations are usually based on finite element methods and underlie different assumptions and approximations which can cause different inaccuracies. These limitations are avoided by using an experimental data basis for virtual sensors in this paper. The paper aims to discuss these issues.

Design/methodology/approach

An air-coupled ultrasound scanning technique is used for guided wave investigations. Recorded displacements of a structure surface are used as stimulation of virtual sensors which can be designed by software and positioned within available data field. For the calculation of sensor signals an isogeometric finite element model is used. The virtually bonded layer of the virtual piezoceramic sensor interpolates with non-uniform rational B-Splines (NURBS) the measured nodal data for each time step. This interpolation corresponds to a displacement boundary condition and is used to calculate the electrical potential at the free surface of the sensor.

Findings

Experimental data based on air-coupled ultrasound scanning technique can be used for elimination of disadvantages in numerical simulations by developing sensor networks for SHM. In combination with a transfer matrix method (TM) a three-dimensional displacement of specimen surface for complex composites can be calculated. To obtain the sensor signal a surface-bonded sensor is modeled by an isogeometric finite element approach. A good accordance is found between calculated virtual sensor signal and its experimental verification.

Research limitations/implications

Some deviations between calculated signal and its experimental verification are mainly justified by different spectral transfer functions between wave field scanning technique and signal recording of applied sensors. Furthermore, sensor influence on wave propagation is neglected in the presented method.

Originality/value

In this paper, the principle of virtual sensors is applied on anisotropic multilayered lamina by using isogeometric finite elements for piezoelectric sensors. This enables any sensor dimension, layout and position on complex composites. Furthermore a bonding layer between specimen and sensor is considered. The method allows a detailed analysis of sensor behavior on a specimen surface and the design and optimization of entire sensor networks for SHM.

Details

International Journal of Structural Integrity, vol. 6 no. 6
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 29 November 2022

Claudia Barile, Caterina Casavola, Giovanni Pappalettera and Vimalathithan Paramsamy Kannan

The acousto-ultrasonic approach is used for propagating stress waves through different configurations of CORTEN steel specimens. The propagated waves are recorded and analysed by…

Abstract

Purpose

The acousto-ultrasonic approach is used for propagating stress waves through different configurations of CORTEN steel specimens. The propagated waves are recorded and analysed by piezoelectric sensors. The purpose of the study is to study the characteristics of the CORTEN steel by analysing the propagated waves.

Design/methodology/approach

To investigate the attenuation in acoustic wave propagation due to the corrosion formation in CORTEN steel specimens and to train a neural network model to classify the attenuated acoustic waves automatically.

Findings

Due to the corrosion formation in CORTEN steel specimens, attenuation is observed in amplitude, energy, counts and duration of the propagated waves. When the waves are analysed in their time-frequency characteristics, attenuation is observed in their frequency and spectral energy.

Originality/value

The corrosion formation in CORTEN steel can automatically be analysed by using the acousto-ultrasonic approach and the trained deep learning neural network.

Details

International Journal of Structural Integrity, vol. 14 no. 1
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 7 February 2020

Namita Nanda

The purpose of the study is to present a frequency domain spectral finite element model (SFEM) based on fast Fourier transform (FFT) for wave propagation analysis of smart…

Abstract

Purpose

The purpose of the study is to present a frequency domain spectral finite element model (SFEM) based on fast Fourier transform (FFT) for wave propagation analysis of smart laminated composite beams with embedded delamination. For generating and sensing high-frequency elastic waves in composite beams, piezoelectric materials such as lead zirconate titanate (PZT) are used because they can act as both actuators and sensors. The present model is used to investigate the effects of parametric variation of delamination configuration on the propagation of fundamental anti-symmetric wave mode in piezoelectric composite beams.

Design/methodology/approach

The spectral element is derived from the exact solution of the governing equation of motion in frequency domain, obtained through fast Fourier transformation of the time domain equation. The beam is divided into two sublaminates (delamination region) and two base laminates (integral regions). The delamination region is modeled by assuming constant and continuous cross-sectional rotation at the interfaces between the base laminate and sublaminates. The governing differential equation of motion for delaminated composite beam with piezoelectric lamina is obtained using Hamilton’s principle by introducing an electrical potential function.

Findings

A detailed study of the wave response at the sensor shows that the A0 mode can be used for delamination detection in a wide region and is more suitable for detecting small delamination. It is observed that the amplitude and time of arrival of the reflected A0 wave from a delamination are strongly dependent on the size, position of the delamination and the stacking sequence. The degraded material properties because of the loss of stiffness and density in damaged area differently alter the S0 and A0 wave response and the group speed. The present method provides a potential technique for researchers to accurately model delaminations in piezoelectric composite beam structures. The delamination position can be identified if the time of flight of a reflected wave from delamination and the wave propagation speed of A0 (or S0) mode is known.

Originality/value

Spectral finite element modeling of delaminated composite beams with piezoelectric layers has not been reported in the literature yet. The spectral element developed is validated by comparing the present results with those available in the literature. The spectral element developed is then used to investigate the wave propagation characteristics and interaction with delamination in the piezoelectric composite beam.

Details

Aircraft Engineering and Aerospace Technology, vol. 92 no. 3
Type: Research Article
ISSN: 1748-8842

Keywords

Access

Year

All dates (46)

Content type

1 – 10 of 46