Evaluation of Material Nonlinearities Using Rectangular Pulse Trains for Excitation

Chaziachmetovas, Andrius; Svilainis, Linas; Kybartas, Darius; Aleksandrovas, Arturas; Liaukonis, Dobilas

doi:10.1016/j.phpro.2015.08.026

Cited by 3 publications

(4 citation statements)

References 6 publications

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“…On the contrary, rectangular signals are generated by simple switches, without the need for conversion, so binary excitation is more attractive and is widely used because: (i) it is simpler and the cost of the equipment is lower [42], [43], (ii) has higher efficiency, resulting in less temperature and longer battery life [44] and (iii) the size and weight of the equipment are lower, allowing portable equipment to be designed. Unfortunately, binary signals have certain disadvantages in the same direction as those we saw related to the type of excitation, that is, the irregularity of the spectrum, since chirp (unipolar or bipolar) signals add curly to the spectrum [45], and the lack of dynamic margin, as additional lateral lobes appear in the correlation [29].…”

Section: Introductionmentioning

confidence: 91%

On the Optimization of Spread Spectrum Chirps Into Arbitrary Position and Width Pulse Signals. Application to Ultrasonic Sensors and Systems

et al. 2022

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This work presents in detail a new method for the optimization of rectangular spread spectrum excitation signals for its use in simple and low-cost ultrasonic pulsers, but that could be extended to other applications based on spread spectrum signals. Starting from rectangular linear frequency modulated (RLFM) chirps, it uses the transfer function of the transmitted signal and received echoes from reference specimens to iterate through a recursive algorithm to obtain arbitrary position and width pulse (APWP) signals with the desired bandwidth, maximizing the energy and the flatness of the spectrum, and enhancing the resolution and dynamic range of conventional chirp excitation signals. This optimization procedure can be repeated for any transducer and material, so that it achieves the best performance in each experimental environment. Such characteristics are ideal for Time-of-Flight estimation, imaging, and applications in which spectral regularity is needed, such as the Split Spectrum Processing (SSP) algorithm, which is used as example to test the performance of the proposed excitation signals. It also allows to specify and change the bandwidth reducing the need to change the transducers. The method is tested with different transducers (2 and 5 MHz focused transducers) and complex composite materials (aluminum-carbon aviation composite and high porosity GFRP composite) in immersion setup for imaging applications using SSP algorithm.INDEX TERMS Ultrasound, Spread Spectrum, chirp, arbitrary position and width pulses, Split Spectrum Processing, non destructive testing.

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Section: Introductionmentioning

confidence: 91%

On the Optimization of Spread Spectrum Chirps Into Arbitrary Position and Width Pulse Signals. Application to Ultrasonic Sensors and Systems

et al. 2022

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“…5a) usually is done using correlation peak location or minima of the remainder after subtraction in order to exploit SNR in a best way [20]. Signal amplitude is a byproduct of such estimation which can be simplified to sine-wave correlation if single frequency component is investigated [21]. Proper selection of the interpolation technique and sampling parameters allows getting the ToF estimation resolution far beyond the clock period [22].…”

Section: Signal Processing Techniquesmentioning

confidence: 99%

“…9b) or nonlinearity (Fig. 9c) can also be applied if accurate amplitude estimation is available [21].…”

Section: Solid State Phenomena Vol 251mentioning

confidence: 99%

Review of Ultrasonic Signal Acquisition and Processing Techniques for Mechatronics and Material Engineering

Svilainis

2016

SSP

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Review of ultrasound applications in mechanical and material engineering is presented. Application examples in material thickness, profile measurement are given. Applications for load, stress, stiffness, porosity, density, viscosity, bond strength, hardening depth evaluation are discussed. Composite or polymer curing states can be monitored. Ultrasonic signal propagation velocity, attenuation or nonlinearity can be used for aforementioned parameters extraction. Signal acquisition setup configurations along with signal processing techniques are discussed. Ultrasound can be used for structure integrity testing or monitoring. Imaging of the inner material structure or properties distribution requires special reconstruction techniques. Presence of the structural noise is masking the defects. Image reconstruction and structural noise reduction techniques are outlined.

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“…The nonlinear effects in the propagation of sound waves have been discussed by many researchers. [4][5][6][7][8][9][10] When two finite-amplitude primary waves propagate together in fluids, the sum and difference frequency waves as well as higher harmonics are produced as secondary waves, owing to the nonlinear interaction between the primary waves. From the absorptive properties of the medium, which prefer higher frequencies to lower ones, there remains only the difference frequency wave in the far-field.…”

Section: Introductionmentioning

confidence: 99%

Design of Ultrasonic Transducer for Secondary Wave Generations with High Directivity

Kim¹,

Kim²,

Ri³

2019

The International Journal of Acoustics and Vibration

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In this paper, we described a method of designing ultrasonic transducer which simultaneously radiates two finite-amplitude ultrasonic waves to produce the secondary waves with high directivity. For nonlinear effects, it is necessary that the frequencies of two primary waves are coincident with natural frequencies of the ultrasonic transducer. The main problem here is to predict the resonance frequencies of the first mode as well as higher modes. While the first resonance frequency of the transducer can be estimated easily, it is not trivial to do higher ones. When the length of transducer is much greater than its diameter, this problem is reduced to one-dimensional and higher mode frequencies are nothing but multiples of the first mode frequency. However, such a case is seldom encountered. Using the transfer matrix method, we obtained the resonance frequencies of the transducer analytically and compared these with numerical results from the simulation. The theoretical and simulation results are in good agreement with the difference of 3--6 kHz.

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Evaluation of Material Nonlinearities Using Rectangular Pulse Trains for Excitation

Cited by 3 publications

References 6 publications

On the Optimization of Spread Spectrum Chirps Into Arbitrary Position and Width Pulse Signals. Application to Ultrasonic Sensors and Systems

On the Optimization of Spread Spectrum Chirps Into Arbitrary Position and Width Pulse Signals. Application to Ultrasonic Sensors and Systems

Review of Ultrasonic Signal Acquisition and Processing Techniques for Mechatronics and Material Engineering

Design of Ultrasonic Transducer for Secondary Wave Generations with High Directivity

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