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 ...
Electromagnetic Force Calculation Using Virtual Work and Maxwell Stress Tensor
The model compare the electromagnetic force calculated by *virtual work* and *maxwell stress tensor* methods on the axial magntic bearing. The forces is evaluated by studying the effect of a small displacement on the electromagnetic energy of the system. This is done by using the *Magnetic Fields*, *Deformed Geometry* and *Sensitivity* physics interfaces.
Pull-in Voltage for a Biased Resonator-2D
Silicon micromechanical resonators have long been used for designing sensors and are now becoming increasingly important as oscillators in the consumer electronics market. In this series of models, a surface micromachined MEMS resonator, designed as part of a micromechanical filter, is analyzed in detail. The Stationary Analysis of a Biased Resonator model performs a stationary analysis of ...
Piezoelectric Valve
Piezoelectric valves are frequently employed in medical and laboratory applications due to their fast response times and quiet operation. Their energy efficient operation, also dissipates little heat, which is often important for these applications. This model shows how to model a piezoelectric valve in COMSOL. The valve is actuated by a stacked piezoelectric actuator. A hyper-elastic seal is ...
Piezoelectric Rate Gyroscope
This model shows how to analyze a tuning fork based piezoelectric rate gyroscope. The direct piezoelectric effect is used to drive an in-plane tuning fork mode. This mode is coupled to an out of plane mode by the Coriolis force and the resulting out of plane motion is sensed by the reverse piezoelectric effect. The geometry of the tuning forks is designed so that the eigenfrequencies of the ...
Prestressed Micromirror
One method of creating spring-like structures or inducing curvature in thin structures is to plate them to substrates that are under the influence of residual stresses. The plating process can control this stress even for similar materials. One such device is the electrostatically controlled micromirror. It is typically quite small, and arrays of such devices can be implemented in projectors. ...
Adhesion and Decohesion of Indenting Ball
A steel ball is pressed down against a rubber membrane. When the contact pressure exceeds a certain value, the two parts start sticking together. When the ball is retracted, the membrane is pulled upwards in the bonded region. During the retraction, the bond is partially broken. This happens when the stresses exceed the limits specified in the decohesion law.
Microresistor Beam
Microresistors allow for quick and accurate actuation or structural movement directly related to the electricity that is applied to them. Microresistors can be used in many applications where small perturbations or deflections are required to be applied to devices, almost instantaneously. The Microresistor Beam app illustrates the importance of fully coupled, multiphysics simulations. An ...
Applying a Current-Voltage Switch to Models
This example exemplifies how to model the switching between current and voltage excitations in *Terminal* boundary conditions. A more detailed description of the phenomenon and the modeling process can be seen in the blog post "[Control Current and Voltage Sources with the AC/DC Module](https://www.comsol.com/blogs/control-current-and-voltage-sources-with-the-acdc-module/)".
Simulation of RF Tissue Ablation
This example exemplifies how to model tissue ablation through applying RF radiation. A more detailed description of the phenomenon, and the modeling process, can be seen in the blog post "[Study Radiofrequency Tissue Ablation Using Simulation](https://www.comsol.com/blogs/study-radiofrequency-tissue-ablation-using-simulation/)".
