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--- team:gdeliege:mems [2015/08/12 17:23] – geoffrey
+++ team:gdeliege:mems [2016/03/30 15:23] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
-===== Micro Electro-Mechanical Systems =====
+===== Microelectromechanical systems =====
 === Background ===
@@ Line 21: / Line 21: @@
 the extremities of the beams are clamped so as to maintain the structure
 a few microns above the base of the chip.
-A square electrode is fixed to the chip under the plate.
+The square holes are imposed by the manufacturing process.
-The square holes are imposed by manufacturing constraints.
+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 |}}
 //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.//
-[[http://www.open-engineering.com/|Open Engineering]]
+=== 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 |}}
-//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 |}}
 //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]]