Fully decoupling geometry from discretization in the Bloch–Floquet finite element analysis of phononic crystals

Boom, Sanne J. van den; Keulen, Fred van; Aragón, Alejandro M.

doi:10.1016/j.cma.2021.113848

Cited by 11 publications

(6 citation statements)

References 52 publications

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“…Band-structure analysis, a typical eigenvalue problem in wave engineering, examines the inherent wave-propagating characteristics of a system [52,53]. Applying an input voltage to a piezoelectric defect falls in the same vein as applying an external load to a structure.…”

Section: Prediction Of a Phononic Bandgap Defect-band Frequencies And...mentioning

confidence: 99%

Double piezoelectric defects in phononic crystals for ultrasonic transducers

Jo¹,

Lee²,

Yoon³

et al. 2023

J. Phys. D: Appl. Phys.

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Significant prior research has explored elastic wave-energy localization via a defect mode of a phononic crystal (PnC). The integration of defect-introduced PnCs and piezoelectric materials has paved the path for the development of new conceptual products for applications in energy harvesters, wave filters, and ultrasonic sensors. Recently, an attempt has been made to deviate from this paradigm and design an ultrasonic transducer that generates elastic waves. Unfortunately, the previous works have been limited to a single-defect situation. Therefore, as an advanced approach, this work aims to expand the PnC design space into double defects, which will make the ultrasonic transducer useful at several frequencies. As a first step, this study targets longitudinal wave generation. To predict the wave-generation performance, a previous analytical model that was built for energy-harvesting purposes under a single-defect situation is modified to be suitable for the present wave-generation purpose under a double-defect situation. Moreover, two parametric studies are executed to analyze how the output responses change based on changes to the input voltage setting and the spacing between the double defects. We hope that these ultrasonic transducers can be potentially applicable for nondestructive testing in structural health monitoring and ultrasonic imaging in medical science.

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Section: Prediction Of a Phononic Bandgap Defect-band Frequencies And...mentioning

confidence: 99%

Double piezoelectric defects in phononic crystals for ultrasonic transducers

Jo¹,

Lee²,

Yoon³

et al. 2023

J. Phys. D: Appl. Phys.

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“…45 FEM is a four-step process: (i) discretization of the solution area into the finite number of subregions or elements, (ii) derivation of the controlling equation corresponding to each subregion, (iii) gathering of all the elements in the solution region, and (iv) finding out the solution of the obtained system of equations. 46 The main challenge in FEM is the requirement of matching mesh, which means that finite element edges should match with material interfaces and sides of the periodic unit cell (PUC). Even with known geometries, producing matching meshes is computationally costly and inaccurate.…”

Section: Introductionmentioning

confidence: 99%

“…47 In addition, a significant amount of time and computer memory is needed for 3D finite element analysis. 46 We have taken care of both of these aspects by selecting appropriate boundary conditions and mesh size, which are discussed subsequently.…”

Section: Introductionmentioning

confidence: 99%

Systematic Investigation of the Optical Characteristics of GaAs Solar Cells with Antireflection Coatings and Metallic Nanoparticles Using Finite Element Analysis

Singh,

Samajdar,

Dutta

2024

ACS Appl. Electron. Mater.

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For energy-efficient thin-film solar cells, photovoltaic researchers are investigating alternative strategies like metallic nanostructures supporting plasmon resonance and ultrathin coatings of antireflective materials to minimize optical absorption loss. To reduce the reflection losses from the surface of the solar cells (SCs), optimizing the dimensions of the metallic nanostructures and antireflection coating (ARC) is essential. A systematic step-by-step approach is used to gain scientific insights into improving the planar GaAs SC performance. In this article, device performance optimization of a solar cell was studied with five distinct architectures, namely, planar GaAs, GaAs with metal nanoparticle (MNP) on top, GaAs coated with ARC, GaAs with MNP over ARC, and GaAs with MNP embedded in ARC using the finite element method. To analyze the effect of ARC thickness and MNP size on optical characteristics, the optical short-circuit current density (J opt) is computed using absorptance data as the performance parameter. We used various metals on the GaAs/Al architecture to choose MNP materials, and titanium (Ti) nanoparticles were chosen because they have the maximum Jopt. For ARC, we have chosen three oxides, Ta2O5, MoO3, and ZnO, and two polymeric materials, P3HT and PEDOT:PSS. We have compared the optical performance of the different optimized architectures using J opt, absorption spectra, electric field, and photogeneration rate. This exhaustive analysis shows that Ti MNPs with a diameter of 180 nm and P3HT ARC with an 80 nm thickness, placed over GaAs planar structure, deliver maximum J opt values of 29.87 and 27.67 mA/cm2, respectively. Further, to understand the dual impact of plasmons and ARC, we simultaneously varied the MNP size and the ARC thickness and found that GaAs planar structure coated with 10 nm thick MoO3 and Ti plasmon with diameter of 160 nm has the best J opt of 29.66 mA/cm2. Secondly, we embedded Ti plasmons of 60, 120, and 180 nm diameters into the ARC film and found that MNPs enhance photocurrent. It is observed that Ti MNPs with an optimized diameter of 180 nm embedded in a 40 nm thick MoO3 ARC and placed directly over the GaAs structure deliver the highest J opt of 30.45 mA/cm2. This comprehensive analysis can help researchers to improve the GaAs SC efficiency using the combined effect of geometrically optimized ARCs and MNPs.

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“…9 Since the coupling conditions at the interface of the matrix and the scatterers are ignored when using the finite difference time domain method, poor results will be obtained. 10,11 Some methods, such as the multiple scattering theory method, 12 the Dirichlet-to-Neumann map method, 13,14 the finite element method 15 and the meshless methods, 16,17 consider both coupling conditions at the interface and transverse waves in solid parts. However, both the multiple scattering theory method and the Dirichlet-to-Neumann map method are only suitable for special scatterer shapes such as circle and sphere.…”

Section: Introductionmentioning

confidence: 99%

Band structures analysis of fluid–solid phononic crystals using wavelet‐based boundary element method and frequency‐independent fundamental solutions

Wei

Xiang

Zhu

et al. 2023

Numerical Meth Engineering

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A novel method of combination of wavelet‐based boundary element method (WBEM) with frequency‐independent fundamental solutions is proposed to determine the band structures of fluid–solid phononic crystals (PCs) with square and triangular lattices. Integral equations established are based on the frequency‐independent fundamental solutions, which can avoid nonlinear eigenvalue problems and reduce computing time. Domain integral terms arising from the use of frequency‐independent fundamental solutions are handled with the radial integration method (RIM) and dual reciprocity method (DRM), respectively. The results show the lower precision in high frequency domain of using RIM to handle domain integral terms than that of using DRM, which can be solved by increasing Gauss point. The B‐spline wavelet on the interval and wavelet coefficients are applied to approximate the physical boundary conditions. It is proved that coupling conditions between matrix and scatterers and Bloch theorem are also applicable to wavelet coefficients. Some small matrix entries generated by wavelet vanishing moment characteristics are truncated by the provided matrix compression technique, and the influence of compressed matrices on the results is studied. Furthermore, the final Eigen equations constructed are modified to avoid numerical instability. Some examples are provided to demonstrate the accuracy and efficiency of the proposed method.

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Fully decoupling geometry from discretization in the Bloch–Floquet finite element analysis of phononic crystals

Cited by 11 publications

References 52 publications

Double piezoelectric defects in phononic crystals for ultrasonic transducers

Double piezoelectric defects in phononic crystals for ultrasonic transducers

Systematic Investigation of the Optical Characteristics of GaAs Solar Cells with Antireflection Coatings and Metallic Nanoparticles Using Finite Element Analysis

Band structures analysis of fluid–solid phononic crystals using wavelet‐based boundary element method and frequency‐independent fundamental solutions

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