Ultrasonic Characterization of Anisotropic Materials

The transference of torsional surface waves in an infinite anisotropic cylinder has been investigated. The equation of motion has been expressed in the cylindrical coordinate system, and by the means of the separation of variables, the displacement has been derived in terms of the Bessel function of the first kind and second kind. With the use of suitable boundary conditions, the dispersion equation has been deduced in a closed-form. Particular cases have been derived for monoclinic, orthotropic, transversely isotropic(precisely transtropic), and isotropic medium. In order to exhibit the present findings, graphs have been plotted for phase velocity against wave number to study the impact of elastic coefficients and the ratio of radii of the cylinder. In the end, phase velocity for different media has been compared. The study can be useful to construct torsional wave sensors in predicting the extent of damage during an earthquake by means of artificial explosions.

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“…Thus a = 0 and b = 1. Table 1 contains stiffness matrices for several materials derived from [16][17][18][19][20].…”

Section: Particular Casesmentioning

confidence: 99%

Dynamic response of torsional waves in an anisotropic infinite cylinder with finite thickness

Kumawat

Vishwakarma²

2022

Phys. Scr.

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“…where Re denotes the real part. The importance of using R and G lies in the fact that maximum of G curves occurs at resonant frequencies, whereas the maximum of R curves occurs at antiresonant frequencies [2,31]. Moreover, G is proportional to the electric power consumed by the sample, thus it is a representative magnitude that takes into account the energy losses.…”

Section: Calculation Of Electrical Characteristicsmentioning

confidence: 99%

Determination of full piezoelectric complex parameters using gradient-based optimization algorithm

Kiyono

Pérez

Silva

2016

Smart Mater. Struct.

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At present, numerical techniques allow the precise simulation of mechanical structures, but the results are limited by the knowledge of the material properties. In the case of piezoelectric ceramics, the full model determination in the linear range involves five elastic, three piezoelectric, and two dielectric complex parameters. A successful solution to obtaining piezoceramic properties consists of comparing the experimental measurement of the impedance curve and the results of a numerical model by using the finite element method (FEM). In the present work, a new systematic optimization method is proposed to adjust the full piezoelectric complex parameters in the FEM model. Once implemented, the method only requires the experimental data (impedance modulus and phase data acquired by an impedometer), material density, geometry, and initial values for the properties. This method combines a FEM routine implemented using an 8-noded axisymmetric element with a gradient-based optimization routine based on the method of moving asymptotes (MMA). The main objective of the optimization procedure is minimizing the quadratic difference between the experimental and numerical electrical conductance and resistance curves (to consider resonance and antiresonance frequencies). To assure the convergence of the optimization procedure, this work proposes restarting the optimization loop whenever the procedure ends in an undesired or an unfeasible solution. Two experimental examples using PZ27 and APC850 samples are presented to test the precision of the method and to check the dependency of the frequency range used, respectively.

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“…Three parameters-density, Poisson's ratio and modulus of elasticity-were needed to define the isotropic materials. However, for the transversely isotropic material, in addition to the density, five parameters were still needed to be defined in the stress-strain matrix [40]. The matrix equation of stress and strain was as follows: Three parameters-density, Poisson's ratio and modulus of elasticity-were needed to define the isotropic materials.…”

mentioning

confidence: 99%

“…The matrix equation of stress and strain was as follows: Three parameters-density, Poisson's ratio and modulus of elasticity-were needed to define the isotropic materials. However, for the transversely isotropic material, in addition to the density, Energies 2020, 13, 2046 9 of 16 five parameters were still needed to be defined in the stress-strain matrix [40]. The matrix equation of stress and strain was as follows:…”

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confidence: 99%

Experimental and Simulation Modal Analysis of a Prismatic Battery Module

Xia

Liu

et al. 2020

Energies

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The battery pack is the core component of a new energy vehicle (NEV), and reducing the impact of vibration induced resonance from the ground is a prerequisite for the safety of an NEV. For a high-performance battery pack design, a clear understanding of the structural dynamics of the key part of battery pack, such as the battery module, is of great significance. Additionally, a proper computational model for simulations of battery module also plays a key role in correctly predicting the dynamic response of battery packs. In this paper, an experimental modal analysis (EMA) was performed on a typical commercial battery module, composed of twelve 37Ah lithium nickel manganese cobalt oxide (NMC) prismatic cells, to obtain modal parameters such as mode shapes and natural frequencies. Additionally, three modeling methods for a prismatic battery module were established for the simulation modal analysis. The method of simplifying the prismatic cell to homogenous isotropic material had a better performance than the detailed modeling method, in predicting the modal parameters. Simultaneously, a novel method that can quickly obtain the equivalent parameters of the cell was proposed. The experimental results indicated that the fundamental frequency of battery module was higher than the excitation frequency range (0–150 Hz) from the ground. The mode shapes of the simulation results were in good agreement with the experimental results, and the average error of the natural frequency was below 10%, which verified the validity of the numerical model.

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Ultrasonic Characterization of Anisotropic Materials

Cited by 5 publications

References 15 publications

Dynamic response of torsional waves in an anisotropic infinite cylinder with finite thickness

Dynamic response of torsional waves in an anisotropic infinite cylinder with finite thickness

Determination of full piezoelectric complex parameters using gradient-based optimization algorithm

Experimental and Simulation Modal Analysis of a Prismatic Battery Module

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