# Application Gallery

The Application Gallery features COMSOL Multiphysics® tutorial and demo app files pertinent to the electrical, structural, acoustics, fluid, heat, and chemical disciplines. You can use these examples as a starting point for your own simulation work by downloading the tutorial model or demo app file and its accompanying instructions.

Search for tutorials and apps relevant to your area of expertise via the Quick Search feature. To download the MPH-files, log in or create a COMSOL Access account that is associated with a valid COMSOL license. Note that many of the examples featured here can also be accessed via the Application Libraries that are built into the COMSOL Multiphysics® software and available from the File menu.

### 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 ...

### Residual Stress in a Thin Film Resonator - 3D

Surface micromachined thin films are often subject to residual stress. This COMSOL Multiphysics example describes a thin film resonator with straight or folded cantilever beam springs. The resonance frequencies of the resonator are affected by thermal stress. Using folded springs relieves this effect. The example is made up of four models: two thin film resonators with folded cantilever beam ...

### 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 ...

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 ...

### 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 ...

### 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 ...

### 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. ...

### 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/)".

### Thermoelastic Damping in a MEMS Resonator

Thermoelastic damping, which arises when you subject a material to cyclic stress, is an important factor when designing MEMS resonators. The stress brings about deformation, where materials heat under compressive stress and cool under tensile stress. Thus, due to the resulting heat flux, energy is lost to bring about this damping. The magnitude of the energy loss depends on the vibrational ...

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