Band structures of elastic SH waves in nanoscale multi-layered functionally graded phononic crystals with/without nonlocal interface imperfections by using a local RBF collocation method

The excellent applications and researches of so-called photonic crystals raise the exciting researches of phononic crystals. By the analogy between photon and phonon, repetitive composite structures that are made up of different elastic materials can also prevent elastic waves of some certain frequencies from passing by, i.e., the frequency band gap features also exist in acoustic waves. In this paper, we present the results of the tunable band gaps of acoustic waves in two-dimensional phononic crystals with reticular band structures using the finite element method. Band gaps variations of the bulk modes due to different thickness and angles of reticular band structures are calculated and discussed. The results show that the total elastic band gaps for mixed polarization modes can be enlarged or reduced by adjusting the orientation of the reticular band structures. The phenomena of band gaps of elastic or acoustic waves can potentially be utilized for vibration-free, high-precision mechanical systems, and sound insulation.

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Generalized thermoelastic band structures of Rayleigh wave in one-dimensional phononic crystals

Meccanica ◽

10.1007/s11012-017-0747-5 ◽

2017 ◽

Vol 53 (4-5) ◽

pp. 923-935 ◽

Cited By ~ 2

Author(s):

Ying Wu ◽

Kaiping Yu ◽

Linyun Yang ◽

Rui Zhao

Keyword(s):

Rayleigh Wave ◽

Phononic Crystals ◽

Band Structures ◽

One Dimensional ◽

Generalized Thermoelastic

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Nondestructive Evaluation of Functionally Graded Subsurface Damage on Cylinders in Nuclear Installations Based on Circumferential SH Waves

Science and Technology of Nuclear Installations ◽

10.1155/2016/3035180 ◽

2016 ◽

Vol 2016 ◽

pp. 1-7

Author(s):

Zhen Qu ◽

Xiaoqin Shen ◽

Xiaoshan Cao

Keyword(s):

Mechanical Properties ◽

Phase Velocity ◽

Nondestructive Evaluation ◽

Surface Damage ◽

Subsurface Damage ◽

Functionally Graded ◽

Horizontal Shear ◽

Steel Cylinder ◽

Sh Waves ◽

Subsurface Layers

Subsurface damage could affect the service life of structures. In nuclear engineering, nondestructive evaluation and detection of the evaluation of the subsurface damage region are of great importance to ensure the safety of nuclear installations. In this paper, we propose the use of circumferential horizontal shear (SH) waves to detect mechanical properties of subsurface regions of damage on cylindrical structures. The regions of surface damage are considered to be functionally graded material (FGM) and the cylinder is considered to be a layered structure. The Bessel functions and the power series technique are employed to solve the governing equations. By analyzing the SH waves in the 12Cr-ODS ferritic steel cylinder, which is frequently applied in the nuclear installations, we discuss the relationship between the phase velocities of SH waves in the cylinder with subsurface layers of damage and the mechanical properties of the subsurface damaged regions. The results show that the subsurface damage could lead to decrease of the SH waves’ phase velocity. The gradient parameters, which represent the degree of subsurface damage, can be evaluated by the variation of the SH waves’ phase velocity. Research results of this study can provide theoretical guidance in nondestructive evaluation for use in the analysis of the reliability and durability of nuclear installations.

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A deep learning approach based on a data-driven tool for classification and prediction of thermoelastic wave’s band structures for phononic crystals

Mechanics of Advanced Materials and Structures ◽

10.1080/15376494.2021.1983088 ◽

2021 ◽

pp. 1-14

Author(s):

Shirin Javadi ◽

Ali Maghami ◽

Seyed Mahmoud Hosseini

Keyword(s):

Deep Learning ◽

Phononic Crystals ◽

Data Driven ◽

Learning Approach ◽

Band Structures

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