Guided Wave in Engineering Structures Using Non-Contact Electromagnetic Acoustic Transducers: A Numerical Approach for the Technique Optimisation
S. Soua, A. Raude, and T-H. Gan
NDT Technology Group, TWI Ltd, Cambridge, United Kingdom
There are over 10 million kilometers of pipes and pipelines around the world that carry hazardous fluids and gases. Fluids include oil, oil products, chemicals such as solvents, caustics, acids, corrosives and combustibles often at high pressure and temperature. These pipes are susceptible to corrosion if they are not protected properly by the environment or the contents. Inspection of pipes is ...
G. Rosi, L. Teresi, A. DiCarlo, and F. dell'Isola
LaMS - Università degli Studi Roma Tre, Roma, Italy
Università degli Studi di Roma "La Sapienza", Roma, Italy
Liquid crystals - as all liquids - are generally modelled as incompressible media. In fact, mass-density changes occurring in these mesophases are minuscule and inconsequential in most regimes of interest. However, liquid crystals exhibit also phenomena that call for a more refined theory. In particular, it is experimentally well established that the Fréedericksz transition - i.e., the sudden ...
O. D. D. Couto Jr. , A. C. T. Covacevice ,
 Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, Campinas, SP, Brazil
In this contribution, we simulate the optical response of piezoelectric planar optical microcavities (POMCs) under the modulation introduced by a propagating surface acoustic wave (SAW). The physical picture of the model is shown in Figure 1. A metallic interdigital transducer (IDT) is placed on the sample surface and, via inverse piezoelectric effect, is responsible for the generation of SAWs ...
N. Chowdhury, Z. Liao, and L. Zhao
Department of Electrical & Computer Engineering, Ryerson University, Toronto, ON, Canada
Department of Architectural Science, Ryerson University, Toronto, ON, Canada
Acoustic wave propagation due to the breakage or slippage of reinforced wire in water-filled prestressed concrete cylinder pipe (PCCP) attracts interest in non-destructive pipe testing. Current practice of acoustic emission (AE) detection and wire-break related events (WRE) recognition is based on field data analysis. This work deals with the theoretical investigation of WRE signal from ...
G.D. Cole, M. Aspelmeyer, and I. Wilson-Rae
University of Vienna, Vienna, Austria
Technical University Munich, Munich, Germany
Micro-and nanoscale mechanical resonators have recently emerged as ubiquitous devices for use in advanced technological applications, for example in mobile communications and inertial sensors, and as novel tools for fundamental scientific endeavors. We report a significant advancement towards understanding and controlling support-induced losses through the demonstration of an efficient numerical ...
Design and Simulation of an Orbiting Piezoelectric MEMS Gyroscope Based on Detection of Phase-Shift Signals - new
S. Gorelick, J. R. Dekker, B. Guo, H. Rimminen
 VTT Technical Research Centre of Finland, Espoo, Finland
The feasibility of phase-sensitive detection of angular-rates using bi-directional orbiting piezoresonators suspended by thick annular springs with thin-film aluminium nitride piezoactuators on top of them was investigated. The ring-shaped flexures are more suitable for supporting the orbiting motion due to their angle-dependent spring constant. The response of the orbiting resonators to ...
SRM University & BITS Pilani University, Chennai, Tamil Nadu, India
Vibration analysis of perforated plates is extremely important when designing structures where resonance is the possible mode of failure. This paper deals with the vibration analysis of rectangular perforated plates with three different types of perforations. Vibration analysis is to be carried out by both COMSOL Multiphysics® Software and Experimental set-up. The applications of perforated ...
R.Christensen, and U. Skov
A compression driver is a certain type of electrodynamic loudspeaker which has a phase plug with slits in front of the diaphragm. The slits are narrow enough that the so-called viscothermal effects are of significant importance. In this paper a 2D axisymmetric finite element model of a commercial compression driver is established where the vibroacoustic behavior can be evaluated. The ...
M. A. B. Andrade , N. Pérez , J. C. Adamowski ,
 Instituto de Física, Universidade de São Paulo, São Paulo, SP, Brasil
 Centro Universitario de Paysandú, Universidad de la República, Paysandú, Uruguai
 Departamento de Engenharia Mecatrônica e Sistemas Mecânicos, Escola Politécnica, Universidade de São Paulo, São Paulo, SP, Brasil
Este trabalho apresenta a simulação numérica de um sistema de levitação acústica para manipulação de partículas em ar. O sistema de levitação consiste de dois transdutores de ultrassom e um refletor de face plana. Através da simulação é calculado o potencial da força de radiação acústica que atua numa esfera. Os resultados da simulação são verificados experimentalmente através da comparação da ...
陆晓 , 温周斌 ,
使用 COMSOL Multiphysics® 仿真轴对称扬声器一般可采用 2D 轴对称模型，但在这种坐标系下无法建立扬声器测量中常用的矩形障板模型，而选择计算安装在无限大障板上扬声器的声特性，其仿真计算结果又与常见的标准障板上的测量结果在中低频段存在较大差异。 为了使无限大障板上的仿真结果与标准障板（或其它有限大障板）上的测量结果相一致，提出一种方法，利用 COMSOL 软件的 Parameter Sweep 功能，通过多次进行 2D 轴对称的电磁场、结构力学和声学三场耦合的扬声器仿真计算及相应后处理，得到安装在有限大障板上的扬声器正前方的声特性。 采用该方法可在较短时间内比较准确地计算得到安装在任意形状的有限大障板上的扬声器的声压级和谐波失真等特性。如图1和图2所示，采用该方法得到的声压级和总谐波失真曲线（红色），与测量结果（黑色）趋势和细节都比较一致。 ...