Galleria dei Modelli
Radially Polarized Piezoelectric Transducer
This tutorial model shows how a user-defined coordinate system can be used to create any type of directional polarization of a piezoelectric material. Results are shown for the case of radial polarization of a piezoelectric disk. The piezoelectric material is PZT-5H. The example shows a static analysis. Visualization of the cylindrical coordinate system as well as the stress/strain in that system ...
Surface Micromachined Accelerometer
This model shows how to simulate a capacitively actuated surface micromachined accelerometer, using the Electromechanics Interface. It is based on a case study from the book Microsystem Design by Stephen D. Senturia (Kluwer Academic Publishers, 5th Edition, 2003, pages 513-525).
Pull-in of an RF MEMS Switch
This model analyzes an RF MEMS switch consisting of a thin micromechanical bridge suspended over a dielectric layer. A DC voltage greater than the pull-in voltage is applied across the switch, causing the bridge to collapse onto the dielectric layer with a resulting increase in the capacitance of the device. A penalty based contact force is implemented to model the contact forces as the bridge ...
Microresistor Beam
This example illustrates the ability to couple thermal, electrical, and structural analysis in one model. This particular application moves a beam by passing a current through it; the current generates heat, and the temperature increase leads to displacement through thermal expansion. The model estimates how much current and increase in temperature are necessary to displace the beam. Although the ...
A Piezoceramic Tube
This example involves a static 2D axisymmetric analysis of a piezoelectric actuator using the Piezoelectric Devices physics interface. It models a radially polarized piezoelectric tube, as described by S. Peelamedu and co-authors. An application area where radially polarized tubes are employed is in nozzles for fluid control in inkjet printers.
Piezoelectric Actuated Microgripper
This tutorial models a piezoelectrically actuated microgripper with mechanical contact. The microgripper contains a piezoelectric actuator that operates in the longitudinal mode. Elongation in the longitudinal direction creates a lifting movement to the structure. Simultaneous contraction in the transversal direction closes the gripper and allows it to move objects. The model uses the ...
An Electrostrictive Disc
This tutorial shows how you can use the Electromechanics interface in COMSOL's MEMS Module to model Electrostriction. Electrostrictive materials (e.g. PMN-PT) exhibit nonlinear strain as a function of electric field. This 2D axisymmetry model uses a parametric sweep of voltage to exhibit the nonlinear mechanical response to a linear variation in the electrical input. Note that the ...
Gecko Foot
In nature, geckos use dry adhesion forces to climb walls. They have inspired researchers to develop synthetic gecko foot hairs to be used in, for example, robot applications. This model contains the nano/micro hierarchy of a synthetic gecko foot hair, where cantilever beams both in nano and micro scales describe the seta and spatula parts of one spatula stalk attached to a gecko foot. The ...
Capacitive Micromotor
This tutorial shows how to model a 2D capacitive micromotor. The motor consists of a rotor and a stator made of polysilicon. The cogs of the stator are subjected to a time-varying pulsed voltage such that the voltage on adjacent cogs vary by a phase difference of 2p/3. As a result, a time-varying torque acts on the rotor thereby rotating it about its center. This model shows how to use an ...
Squeeze Film Disc
This benchmark model computes the total force acting on a vibrating disc in the frequency and time domains and compares both results with expressions derived analytically. When the vibration amplitude is small enough that the system is linear the frequency and time domain results agree well with theory. Larger amplitude vibrations, which result in a non-linear response that cannot be modeled in ...
