Coupling of in‐plane and out‐of‐plane waves in thick flat plate structure subjected to a transverse load.

1992 ◽  
Vol 91 (4) ◽  
pp. 2418-2418 ◽  
Author(s):  
J. M. Cuschieri
Keyword(s):  
Flat Plate ◽  
Plane Waves ◽  
Transverse Load ◽  
Plate Structure ◽  
Out Of Plane

Optimization of Phononic Crystals for the Simultaneous Attenuation of Out-of-Plane and In-Plane Waves

2011 ◽  
Author(s):  
Osama R. Bilal ◽  
Mahmoud I. Hussein
Keyword(s):  
Genetic Algorithm ◽  
Phononic Crystal ◽  
Plane Waves ◽  
Phononic Crystals ◽  
Gap Size ◽  
Two Dimensional ◽  
Dispersion Characteristics ◽  
Out Of Plane ◽  
Optimization Methodology ◽  
Application Specific

The topological distribution of the material phases inside the unit cell composing a phononic crystal has a significant effect on its dispersion characteristics. This topology can be engineered to produce application-specific requirements. In this paper, a specialized genetic-algorithm-based topology optimization methodology for the design of two-dimensional phononic crystals is presented. Specifically the target is the opening and maximization of band gap size for (i) out-of-plane waves, (ii) in-plane waves and (iii) both out-of-plane and in-plane waves simultaneously. The methodology as well as the resulting designs are presented.

Thin Film Characterization Using the Point-Deflection Method

2001 ◽  
Vol 695 ◽  
Author(s):  
Ning Tang ◽  
Roxann L. Engelstad ◽  
Edward G. Lovell
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Transverse Load ◽  
Internal Stresses ◽  
Boundary Constraints ◽  
Thin Film Characterization ◽  
Out Of Plane ◽  
Average Internal Stress ◽  
Low Sensitivity ◽  
Plane Displacement

ABSTRACTThe Point-Deflection Method is a potentially useful technique for measuring the internal stresses of freestanding thin films. By applying a small concentrated transverse load at the center of a pre-stretched film, and measuring the corresponding out-of-plane displacement at appropriate locations, the average internal stress can be readily determined. The load-deflection relationship has been derived for both circular and rectangular shapes. The method involves no additional micromachining in sample preparation and has low sensitivity to the variations in boundary constraints. Its feasibility has been further substantiated with finite element simulations from a variety of perspectives, as well as experimental correlations from the stress measurements of a photomask pellicle film.

scholarly journals Robust separation of topological in-plane and out-of-plane waves in a phononic crystal

2022 ◽  
Vol 5 (1) ◽  
Author(s):  
Myung-Joon Lee ◽  
Il-Kwon Oh
Keyword(s):  
Elastic Wave ◽  
Phononic Crystal ◽  
Plane Waves ◽  
Degree Of Freedom ◽  
Wave Separation ◽  
Simultaneous Control ◽  
Accidental Degeneracy ◽  
Out Of Plane ◽  
Wave Path ◽  
The Rich

AbstractValley degree of freedom, associated with the valley topological phase, has propelled the advancement of the elastic waveguide by offering immunity to backscattering against bending and weak perturbations. Despite many attempts to manipulate the wave path and working frequency of the waveguide, internal characteristic of an elastic wave such as rich polarization has not yet been utilized with valley topological phases. Here, we introduce the rich polarization into the valley degree of freedom, to achieve topologically protected in-plane and out-of-plane mode separation of an elastic wave. Accidental degeneracy proves its real worth of decoupling the in-plane and out-of-plane polarized valley Hall phases. We further demonstrate independent and simultaneous control of in-plane and out-of-plane waves, with intact topological protection. The presenting procedure for designing the topologically protected wave separation based on accidental degeneracy will widen the valley topological physics in view of both generation mechanism and application areas.

scholarly journals Adhesive Bond Imaging by Noncontact Measurements With Single-Sided Access

2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Shogo Nakao ◽  
Takahiro Hayashi
Keyword(s):  
Flat Plate ◽  
Adhesive Bonding ◽  
Imaging Technique ◽  
Laser Doppler Vibrometer ◽  
Adhesive Bond ◽  
Scanning Laser ◽  
Laser Source ◽  
Adhesive Bonds ◽  
Plate Structure ◽  
Noncontact Measurements

Adhesive bonding, an effective joining technique for platelike structures in aircraft and automobiles, requires postbond inspection preferably with noncontact and single-sided access. The present study discusses the application of an imaging technique with a scanning laser source (SLS) to evaluate adhesive bonds in a platelike structure. When a laser Doppler vibrometer (LDV) is used as a receiver, the SLS technique realizes noncontact measurements with single-sided access. The imaging experiments that used narrowband burst waves and broadband chirp waves indicated that the imaging technique is appropriately applied to adhesive bonds and that the use of broadband chirp waves provides clearer images and reduces spurious images due to resonance. Furthermore, images of adhesive bonds were clearly obtained for a complex plate structure that consisted of a top-hat section and a flat plate, and this demonstrates that the imaging technique can be widely applied to evaluate various adhesive bonds.

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