Propagation of flexural waves in phononic crystal thin plates with linear defects

2010 ◽  
Vol 11 (10) ◽  
pp. 827-834 ◽  
Author(s):  
Zong-jian Yao ◽  
Gui-lan Yu ◽  
Yue-sheng Wang ◽  
Zhi-fei Shi ◽  
Jian-bao Li
Keyword(s):  
Phononic Crystal ◽  
Thin Plates ◽  
Flexural Waves ◽  
Linear Defects

Flexural Vibration in a Ternary Locally Resonant Phononic Crystal Thin Plate with Defects

2010 ◽  
Vol 150-151 ◽  
pp. 1282-1285
Author(s):  
Zong Jian Yao ◽  
Gui Lan Yu ◽  
Yue Sheng Wang ◽  
Jian Bao Li
Keyword(s):  
Point Defect ◽  
Thin Plate ◽  
Mass Density ◽  
Phononic Crystal ◽  
Flexural Vibration ◽  
Defect Mode ◽  
Expansion Method ◽  
Flexural Waves ◽  
Filling Fraction ◽  
Linear Defects

The improved supercell plane wave expansion method is applied to theoretically study the propagation of flexural waves in a ternary locally resonant phononic crystal thin plate with a point defect and linear defects. The thin concrete plate composed of a square array of steel cylinders hemmed around by rubber is considered here. Absolute band gaps in low frequency are obtained. For the point defect, the defect mode is localized around the defect, and the magnitude of the resonant defect mode is strongly dependent on the defect filling fraction, mass density and Young’s modulus of the defect cylinder. For the straight linear defects, several resonant linear defect bands appear inside the absolute band gap. And the displacement distributions show that the flexural waves could well propagate along the linear defects.

scholarly journals Numerical Assessment of the Performance of Elastic Cloaks for Transient Flexural Waves

2020 ◽  
Vol 7 ◽  
Author(s):  
Marco Rossi ◽  
Daniele Veber ◽  
Massimiliano Gei
Keyword(s):  
Finite Element ◽  
Thin Plates ◽  
Winkler Foundation ◽  
Finite Element Code ◽  
Flexural Waves ◽  
Transient Waves ◽  
Mathematical Transformation ◽  
Plane Body ◽  
Numerical Assessment ◽  
Subgrade Modulus

A relevant application of transformation elastodynamics has shown that flexural waves in a Kirchhoff-Love plate can be diverted and channeled to cloak a region of the ambient space. To achieve the goal, an orthotropic meta-structural plate should be employed. However, the corresponding mathematical transformation leads to the presence of an unwanted strong compressive prestress, likely beyond the buckling threshold of the structure, with a set of in-plane body forces to warrant equilibrium. In addition, the plate must possess, at the same time, high bending stiffnesses, but a null twisting rigidity. With the aim of estimating the performance of cloaks modelled with approximate parameters, an in-house finite element code, based on a subparametric technique, is implemented to deal with the cloaking of transient waves in orthotropic thin plates. The tool allows us to explore the sensitivity of specific stiffness parameters that may be difficult to match in a real cloak design. In addition, the finite element code is extended to investigate a meta-plate interacting with a Winkler foundation, to confirm how the subgrade modulus should transform in the cloak region.

scholarly journals Poisson-like effect for flexural waves in periodically perforated thin plates

2018 ◽  
Vol 144 (2) ◽  
pp. 1053-1058 ◽  
Author(s):  
Penglin Gao ◽  
José Sánchez-Dehesa ◽  
Linzhi Wu
Keyword(s):  
Thin Plates ◽  
Flexural Waves

Active control of flexural waves in a phononic crystal beam with staggered periodic properties

Wave Motion ◽  
2020 ◽  
Vol 93 ◽  
pp. 102481 ◽  
Author(s):  
Ping Chen ◽  
Yi-Ze Wang ◽  
Yue-Sheng Wang
Keyword(s):  
Active Control ◽  
Phononic Crystal ◽  
Flexural Waves

Finite Element Method for Analysis of Flexural Vibration Propagating in Ternary Phononic Crystal Thin Plates

2012 ◽  
Vol 256-259 ◽  
pp. 596-599
Author(s):  
Zong Jian Yao ◽  
Gui Lan Yu ◽  
Yue Sheng Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Point Defect ◽  
Phononic Crystal ◽  
Flexural Vibration ◽  
Expansion Method ◽  
Square Lattice ◽  
Thin Plates ◽  
Response Curves ◽  
Element Method

Propagation of flexural vibration in a ternary phononic crystal thin plate with a point defect are explored using finite element method. The thin concrete plate is composed of steel cylinders hemmed around by rubber with a square lattice. Absolute band gaps, point defect bands and transmission response curves with low frequency are investigated. Comparing the results of finite element method with that of improved plane wave expansion method, precise identifications are obtained to identify the point defect states. The results show that the finite element method is suitable for the exploring of flexural vibration propagating in ternary phononic crystal thin plates.

scholarly journals Experiments on cloaking in optics, thermodynamics and mechanics

2015 ◽  
Vol 373 (2049) ◽  
pp. 20140357 ◽  
Author(s):  
Muamer Kadic ◽  
Tiemo Bückmann ◽  
Robert Schittny ◽  
Martin Wegener
Keyword(s):  
Three Dimensional ◽  
Thin Plates ◽  
Visible Range ◽  
Flexural Waves ◽  
Discrete Lattices ◽  
Mechanical Metamaterials ◽  
Visible Frequency ◽  
Transient Thermal ◽  
Thermal Cloaking ◽  
Static Core

Spatial coordinate transformations can be used to transform boundaries, material parameters or discrete lattices. We discuss fundamental constraints in regard to cloaking and review our corresponding experiments in optics, thermodynamics and mechanics. For example, we emphasize three-dimensional broadband visible-frequency carpet cloaking, transient thermal cloaking, three-dimensional omnidirectional macroscopic broadband cloaking for diffuse light throughout the entire visible range, cloaking for flexural waves in thin plates and three-dimensional elasto-static core–shell cloaking using pentamode mechanical metamaterials.

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