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.

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### Waveguide Iris Bandpass Filter

A conductive diaphragm, an iris, placed transverse to a waveguide aperture causes a discontinuity and generates shunt reactance. Bandpass frequency response can be achieved from cascaded cavity resonators combined with these reactive elements which can be created by inserting a series of iris elements inside the waveguide. This model consists of a X-band waveguide WR-90 and symmetrical inductive ...

### Squeeze-Film Gas Damping of a Vibrating 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 ...

### Coupled-Line Bandpass Filter

It is possible to realize a narrowband bandpass filter using cascaded microstrip coupled lines. In this example, a design composed of cascaded microstrip lines, each approximately a half wave length in size at the resonant frequency, is analyzed. The model is solved for the S-parameters and a very narrow bandwidth is observed.

### Combining Elastoplastic and Creep Material Models

This model shows how to combine different types of material nonlinearity, such as creep and elastoplasticity. In this specific example you will perform a stress and nonlinear strain analysis on a thick cylinder under a nonproportional loading: an initial temperature increase followed by a fluctuating pressure applied to the internal surface of the cylinder. This load case involves two ...

### Postbuckling Analysis of a Hinged Cylindrical Shell

The model studied is a benchmark for a hinged cylindrical panel subjected to a point load at its center. A linear buckling analysis predicts the critical buckling load. Such an analysis will however not give any information about what happens at loads higher than the critical load. Tracing the solution after the critical load is called a postbuckling analysis. This model uses the Shell interface.

### Linear Buckling Analysis of a Truss Tower

Trusses are commonly used to create light structures that can support heavy loads. When designing such a structure, it is important to ensure its safety. For a tower made of bars, buckling can cause the structure to collapse. This model shows how to compute the critical buckling load using a linear buckling analysis. The solution is compared with an analytical expression for critical load ...

### Defining a Mapped Dielectric Distribution of a Material (Wave Optics)

In this example, the properties of an engineeredmaterial are modeled by a spatially varying dielectric distribution. Specifically, a convex lens shape is defined via a known deformation of a rectangular domain. The dielectric distribution is defined on the undeformed, original rectangular domain and is mapped onto the deformed shape of the lens. Although the lens shape defined here is convex, ...

### Small Signal Analysis of a MOSFET

This model shows how to compute the AC characteristics of a MOSFET. Both the output conductance and the transconductance are computed as a function of the drain current.

### Powder Compaction of a Cup

The fabrication of a cup through powder compaction is simulated in this tutorial model. The powder compaction process is becoming common in the manufacturing industry, due to its potential for producing components of complex shape and high strength. Combining the Fleck-Kuhn-McMeeking (FKM) model with the Gurson-Tvergaard-Needleman (GTN) model for porous plasticity makes it possible to cover a ...

### Eigenfrequency Shifts Caused by Temperature Changes

This example explores the shift in natural frequencies caused by changing the temperature. One study investigates a doubly clamped beam where both ends are fixed, while the other study looks at a cantilever beam where only one end is fixed. The following effects are studied: * Stress stiffening * Change in size * Constraint effects * Temperature-dependent Young's modulus Results show that the ...