MICROSONICS. Microsonics 39, rue des Granges Galand, Saint Avertin, France Phone : +(33) (0)

Transcription

1 For more News of NDT.net click: MICROSONICS The finite element method (FEM) is very suitable for structural simulation, specially when the structure is vibrating in vacuum. When the vibrating structure is submerge in an unbounded (fluid, elastic or piezoelectric solids) medium, the radiating conditions have to be taken in to account. The boundary element method (BEM) is very suitable for unbounded medium, because the radiating conditions are exact. It is often use to complete of the finite element method. Microsonics is FEM-BEM coupling tool, which is fully compatible to Ansys (FEM software package), and is accessible in ANSYS environment. It is a BEM solver which cover a wide physics area: Radiation and propagation in fluid medium (acoustic), Radiation and propagation in isotropic / anisotropic solid medium, Radiation and propagation in piezoelectric medium. Moreover, the user can define is own Green function.

2 MICROSONICS 39, rue des Granges Galand Saint Avertin France Phone : +(33) (0) or +(33) (0) didace.ekeom@microsonics.fr

3 Operating principle Microsonics is fully integrated into Ansys. Because, Microsonics input data are Script command automatically extracted from finite BEM data file elements data, using macros. Thus, Microsonics can be run in Ansys user inteface. The computation will create a Script command impedance matrix, and write it in a Ansys ANSYS (Call system) BEM module binary file (*.sub file format). The *.sub files were introduced by Ansys in order to alloy the user to interface with Ansys calulation. Thus, there is no interference Read binary file Binary file between Ansys source code and Microsonics. Note that, new Ansys version will read previous Ansys *.sub file. Thus, for Ansys user Microsonics can be easily used. It requires only the training to learn how to used a couple of additional APDL command. Several coupling FEM-BEM can be activated in the same calculation, this is very suitable for medical probe simulation.

4 Competition advantages Microsonics is add-on module fully integrated into Ansys. In consequence, there is no waste of time and no risk of data error during the transfer. An external BEM code, which will need his own pre and post processing is not necessary. Microsonics use ANSYS pre and post processing thus the global cost of the FEM-BEM solution is reduced. Microsonics FEM-BEM coupling in ANSYS covers a great number application. User Green function can be integrate and use in Ansys. Ansys-Microsonics coupling is the only tool which alloy FEM-BEM multicoupling. Multicoupling is very suitable for medical probe device (one coupling for the backing or substrate and one for the fluid) and for RF-filter (one coupling on each resonator). Microsonics is pioneer in modeling of acoustic MEMS devices (Bulk Acoustic Wave, RF-MEMS) radiating in the substrate. Thus is enable to estimate correctly the quality factor.

5 Applications areas Microsonics is suitable for most dynamic problems of structure surrounded by an unbounded domain, in particular: Vibroacoustic (noise cancellation), Underwater acoustic, Ultrasound imaging, Sensor, RF filter (BAW and SAW devices), MEMS Resonator (anchor losses), Building and industrial equipment (soil-structure coupling), Seismic.

6 Acoustic FEM-BEM coupling for ultrasound imaging Key parameters: Coupling factors, radiated pressure (or power) and bandwidth 2D or 3D simulation tool accounting for ultrasound probe radiating in water Receiving sensitivity Solution proposed: FEM-BEM coupling FEM for ultrasound probe & BEM backing and water Radiated pressure by a Medical probe FEM-BEM piezocomposite probe modelling Electrical admittance Two FEM-BEM coupling, one for the solid medium (backing) and one in fluid medium.

7 Acoustic FEM-BEM coupling for ultrasound imaging (Capacitive Micromachined Ultrasonic Transducers) Pressure on the cmut top face Key parameters: Coupling factors, collapse voltage bandwidth and cross-talk 2D or 3D simulation tool accounting for cmut radiating in water Solution proposed: FEM-BEM coupling FEM for cmut & BEM backing and water Resonance frequency : 15 MHz Collapse voltage : volts -6.0 db : >100% Radiated pressure by a cmut D. EKEOM, IEEE-UFFC Symposium 2006

8 Acoustic FEM-BEM coupling for ultrasound imaging (Capacitive Micromachined Ultrasonic Transducers) Key parameters: Coupling factors, collapse voltage bandwidth and cross-talk 2D or 3D simulation tool accounting for cmut radiating in water Solution proposed: FEM-BEM coupling FEM for cmut & BEM backing and water Acoustic BEM Elastodynamic BEM D. EKEOM, MUT Workshop 2007

9 Elastic half-space FEM-BEM coupling for Solidly Mounted resonator (Bulk Acoustic Waves - RF filter devices) Key parameters: Quality and coupling factors and purity of resonance 2D or 3D simulation tool accounting for resonator-substrate coupling Solution proposed: FEM-BEM coupling FEM for resonator+bragg reflector & BEM for substrate mod (Z) a.u. 1,E+07 1,E+06 1,E+05 1,E+04 1,E+03 1,E+02 resonator p 1,E f (MHz) 2 x Bragg reflector s 1,5 1 0,5 y ( ) BEM silicon substrate substrate modelling arg (Z) 0-0,5-1 -1, f (MHz) Quality factors and coupling coefficients Qs Qp k 2 1D Mason s model : % 2D FEM-BEM model : % (Loss less materials ) Electrical impedance of a Solidly Mounted Resonator radiating in silicon substrate Red: FEM-BEM coupling Blue: Mason Model D. EKEOM, B. DUBUS and A. VOLATIER, IEEE-UFFC Symposium 2007

10 Periodic half-space FEM-BEM coupling for Surface Acoustic Waves (RF filter devices) Key parameters: Quality and coupling factors and purity of resonance 2D or 3D simulation tool accounting for resonator-substrate coupling Solution proposed: periodic FEM-BEM coupling FEM for resonator & BEM for piezoelectric substrate User piezoelectric Green function Programmable Features Quality factors and coupling coefficients Qs Qp k 2 3D FEM-BEM model : %

11 Elastic half-space FEM-BEM coupling for MEMS resonator (Anchor acoustic losses) Key parameters: Quality factor, radiated power and purity of resonance parallel resonance frequency real & imaginary 2D or 3D simulation tool accounting for beam-substrate coupling Solution proposed: FEM-BEM coupling, FEM for beam & BEM for substrate Quality factor Qs Qp k 2 2D FEM Only : 65.4% 3D FEM-BEM model : % (Loss less materials)

12 Elastic half-space FEM-BEM coupling for MEMS resonator (Anchor acoustic losses) Key parameters: Quality factor and purity of resonance Displacement module and phase 2D or 3D simulation tool accounting for beam-substrate coupling Solution proposed: FEM-BEM coupling, FEM for beam & BEM for substrate Zoom at resonance frequency

13 Microsonics Users Bulk Acoustic Wave resonator CEA-Léti (France), EPCOS (Germany), EPFL (Switzerland), IEMN (France), STMicroelectronics (France) Surface Acoustic Wave resonator EPCOS (Germany) RF-MEMS ENSIAME (France), IEMN (France) Ultrasound Imaging Fraunhofer-IBMT (Germany)