COMSOL 6.4 - Coupling to Other Physics Interfaces

Coupling to Other Physics Interfaces

The MEMS Module connects to COMSOL Multiphysics and other add-on modules in the COMSOL Multiphysics product line. You can view and modify the models in terms of the underlying PDEs. Table 1-1 summarizes the most important MEMS couplings and other common devices you can model using this module.

The first column of the table lists phenomena, couplings, and devices that are often associated with the word electromechanical in the narrow and literal meaning of MEMS. The devices in this category are usually various kinds of actuators and sensors. The microfluidic devices, although using some of the same manufacturing and miniaturizing techniques, form a totally different application area. The Fluid-Structure Interaction column lists various techniques and phenomena that are useful for both electromechanical and microfluidic applications, where movement and deformation of solids are of concern.

This table, however, shows only the tip of the iceberg — our view of the most important applications where you can use the MEMS Module. In your hands, the multiphysics combinations and applications are unlimited.

Table 1-1: Examples Of Coupled Phenomena and Devices You Can Model Using the MEMS Module.
	Electromechanical	Fluid-structure Interaction
Phenomenon/ coupling	Electrostructural Electrothermal Thermomechanical Thermal-electric-structural Piezoelectric Piezoresistive Prestressed modal analysis Stress stiffening	Moving boundary using ALE technique Squeeze-film damping
Devices	Cantilever beams Comb drives Resonators Micromirrors Thermomechanical actuators Inertial sensors Pressure sensors	Mechanical pumps and valves

The MEMS Module Study Capabilities by Physics Interface

This section lists the physics interfaces, the physical quantities they solve for, and the standard abbreviation each one uses. The physical quantities in these physics interfaces are:

•

The structural displacements or the velocity components u, v, and w

•

The film pressure variation, pf

•

The electric scalar potential, V

•

The concentration, c

Table 1-2 lists the physics interfaces specific to MEMS modeling and this module.


	When using the axisymmetric physics interfaces, the horizontal axis represents the r direction and the vertical axis the z direction. The geometry in the right half plane must be created, that is, only for positive r.


	Studies and Solvers in the COMSOL Multiphysics Reference Manual

Table 1-2: MEMS Module Interface Dependent Variables and Preset Study Options.
Physics Interface	Name	Dependent variables	Preset Study Options
			Stationary	Time Dependent	Time-Dependent Modal	Eigenfrequency	small-signal analysis, frequency domain	Frequency Domain	Frequency-Domain Modal	Prestressed Analysis, Eigenfrequency	Prestressed Analysis, Frequency. Domain
AC/DC
Electrostatics	es	V	√	√
Electric Currents	ec	V	√
Electrical Circuit	cir	none	√	√				√
Fluid Flow
Thin-Film Flow	tff	pf	√	√		√		√
Thin-Film Flow, Domain	tff	pf	√	√		√		√
Fluid-Structure Interaction	—	u, v, w p	√	√
Fluid-Structure Interaction, Fixed Geometry	—	u, v, w p	√	√
Structural Mechanics
Solid Mechanics	solid	u, v, w	√	√	√	√	√	√	√	√	√
Piezoelectricity	—	u, v, w V	√	√	√	√	√	√	√	√	√
Thermal Stress	—	u, v, w T	√	√	√					√	√
Thermoelasticity	te	u, v, w T		√		√		√
Joule Heating and Thermal Expansion	—	u, v, w, T, V	√	√	√		√			√	√
Electromechanics	emi	u, v, w V	√	√						√	√
Piezoresistivity, Domain Currents	pzrd	u, v, w V	√	√	√		√	√	√	√	√
Piezoresistivity, Boundary Currents	pzrb	u, v, w V	√	√	√		√	√	√	√	√
Piezoresistivity, Shell	pzrs	u, v, w V, ar	√	√	√		√	√	√	√	√