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team:gdeliege:mems [2015/08/12 16:23] geoffreyteam:gdeliege:mems [2016/03/30 15:23] (current) – external edit 127.0.0.1
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-===== Micro Electro-Mechanical Systems =====+===== Microelectromechanical systems =====
  
 === Background === === Background ===
  
- +I worked on a research project over microelectromechanical systems (MEMS) 
-[[http://www.open-engineering.com/|Open Engineering]]+in the Aerodynamics group of Prof. Essers. 
 +This project was a collaboration between several research groups of the Université de Liège: 
 +Aerodynamics, Mechanical Vibrations (Prof. Golinval) and Applied and Computational Electromagnetics 
 +(W. Legros). 
 +My objective in this project was to simulate the deformation of microactuators 
 +taking into account the damping effect of air. 
 +These microactuators had to be manufactured by [[http://www.imtek.de/laboratories/mems-applications/mems_home?set_language=en|IMTEK]] and tested in the vibrations lab.
  
 === Problem description === === Problem description ===
 +
 +I designed the geometry of the actuators together with Véronique Rochus and Guillaume Sérandour from the Mechanichal Vibrations group.
 +The shape and dimensions of the actuators were strongly limited by manufacturing constraints.
 +Therefore, we started with a microplate as suggested by IMTEK specialists.
 +An example of such plates is shown in Fig. 1;
 +although this is not represented in the drawing,
 +the extremities of the beams are clamped so as to maintain the structure
 +a few microns above the base of the chip.
 +The square holes are imposed by the manufacturing process.
 +The vibration of the plate is induced by the electric potential difference
 +between the plate and the square electrode which is fixed to the chip.
  
 {{ :team:gdeliege:arc03.png?500 |}} {{ :team:gdeliege:arc03.png?500 |}}
 //Figure 1. Geometry of the micro-actuator (length=300$\mu m$, width=100$\mu m$, thickness=2$\mu m$). The aluminium plate is 2$\mu m$ above the electrode.// //Figure 1. Geometry of the micro-actuator (length=300$\mu m$, width=100$\mu m$, thickness=2$\mu m$). The aluminium plate is 2$\mu m$ above the electrode.//
  
 +=== Numerical simulations ===
  
-=== Simulations ===+My first task was to design an automated way to calculate the mesh deformation of the air domain 
 +when the actuator moves. 
 +The difficulty was to keep an acceptable aspect ratio of the deformed mesh elements, which was of course critical between the plate and electrode. 
 +I also had to couple the different programs needed to make the coupled simulations: 
 +  * a fluid dynamic finite volume software written in C by Didier Vigneron, parallelized with MPI (distributed memory); 
 +  * a mechanical finite element software, OOfelie, written in C++ by [[http://www.open-engineering.com/|Open Engineering]]; 
 +  * a C++ code of my own, which calculated the electrostatic force and the mesh deformation. 
 +An external script called the different codes in turn and converted the input/output files to ensure data compatibility. 
 +Fig. 2 shows results of the electric simulation on a quarter of the plate. 
 +Electromechanical simulations were performed at different excitation frequencies (Fig. 3, left) and a full electromechanical-fluid simulation was made at the resonance frequency (Fig. 3, right).
  
 {{ :team:gdeliege:arc01.png |}} {{ :team:gdeliege:arc01.png |}}
-//Figure 2. Electric scalar potential and electric force acting on the plate, calculated with my own code and visualized with [[http://www.geuz.org/gmsh|Gmsh]].//+//Figure 2. Electric scalar potential and electric force acting on the plate, calculated with my own code (mesh and visualization with [[http://www.geuz.org/gmsh|Gmsh]]).//
  
 {{ :team:gdeliege:arc02.png |}} {{ :team:gdeliege:arc02.png |}}
 //Figure 3. Vertical displacement of the plate : (left), electromechanical simulation (OOfelie+my code) for an excitation frequency equal to $0.5\,\nu_r$, $\nu_r$ and $2\,\nu_r$, where $\nu_r$ is the resonance frequency; (right), electromechanical simulation with/without fluid coupling (OOfelie+my code+Didier Vigneron's code) at the resonance frequency.// //Figure 3. Vertical displacement of the plate : (left), electromechanical simulation (OOfelie+my code) for an excitation frequency equal to $0.5\,\nu_r$, $\nu_r$ and $2\,\nu_r$, where $\nu_r$ is the resonance frequency; (right), electromechanical simulation with/without fluid coupling (OOfelie+my code+Didier Vigneron's code) at the resonance frequency.//
 +\\
 +\\
 +[[team:gdeliege|Back to main page]]
team/gdeliege/mems.1439389438.txt.gz · Last modified: 2016/03/30 15:22 (external edit)

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