Dept. Mechanical Engineering, University of California, Santa Barbara, CAWouldn't it be a great service for the diagnosing and treating genetic of diseases if physicians had a disposable instrument for detecting DNA that worked...
The model performs a static analysis on a piezoelectric actuator based on the movement of a cantilever beam, using the Piezoelectric Devices predefined multiphysics interface. Inspired by work done by V. Piefort and A. Benjeddou, it...
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...
The thermal stress in a layered plate is studied in this example. A plate consisting of two layers, a coating and a substrate layer is stress and strain free at 800 degrees C. The temperature of the plate is reduced to 150 degrees C and...
This model demonstrates how to set up a fluid-structure interaction problem in COMSOL Multiphysics. It illustrates how fluid flow can deform solid structures and how to solve for the flow in a continuously deforming geometry. The...
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...
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...
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...
The elastic cantilever beam is one of the elementary structures used in MEMS designs. This model shows the bending of a cantilever beam under an applied electrostatic load. The model solves the deformation of the beam under an applied...
Capacitive comb drives are commonly used both as actuators and position sensors. The following model focuses on position measurement. Many approaches exist for positional measurements with MEMS devices, of which capacitance measurement is...
A capacitive pressure sensor is simulated. This model shows how to simulate the response of the pressure sensor to an applied pressure, and also how to analyze the effects of packing induced stresses on the sensor performance.
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...
Active microvalves are common components in microfluidic systems. In a thermomechanically actuated microvalve, an electric current generates movement by resistively heating the actuator structure, thereby causing mechanical stress and...
This example shows how to set up a piezoelectric transducer problem following the work of Y. Kagawa and T. Yamabuchi. The composite piezoelectric ultrasonic transducer has a cylindrical geometry that consists of a piezoceramic layer, two...
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...
This model analyzes the thermal expansion in a MEMS device, such as a microgyroscope, where thermal expansion should be minimized. The device is made from the copper-beryllium alloy UNS C17500 and uses temperature-dependent material...
Squeezed-film gas damping is a critical aspect of many MEMS transducers and actuators. In accelerometers, for example, inertia produces a motion that the device detects. A typical structure connects a large proof mass to surrounding...
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...
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...
An electrostatically actuated MEMS resonator is simulated in the time and frequency domains. The device is driven by an AC + DC bias voltage applied across a parallel plate capacitor. The dependence of the resonant frequency on DC bias is...
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,...
This is an overview presentation on the elastic waves and piezoelectric modeling features of COMSOL Multiphysics. The focus here is on piezo-features and especially COMSOL's strength in that you are allowed to mix dielectric, elastic,...
A surface acoustic wave (SAW) is an acoustic wave propagating along the surface of a solid material. Its amplitude decays rapidly, often exponentially, through the depth of the material. SAWs are utilized in many kinds of electronic...
AT cut quartz crystals are widely employed in a range of applications, from oscillators to microbalances. One of the important properties of the AT cut is that the resonant frequency of the crystal is temperature independent to first...
Bulk Acoustic Wave (BAW) resonators can be used as narrow band filters in radio-frequency applications. The chief advantage compared with traditional ceramic electromagnetic resonators is that BAW resonators, thanks to the acoustic...
This tutorial model of a two-hot-arm thermal actuator couples three different physics phenomena: electric current conduction, heat conduction with heat generation, and structural stresses and strains due to thermal expansion. In this...
Piezoresistive pressure sensors were some of the first MEMS devices to be commercialized. Compared to capacitive pressure sensors, they are simpler to integrate with electronics, their response is more linear and they are inherently...
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...
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...
