This model of a vibrating micromirror surrounded by air uses the thermoacousticshell interaction user interface to model the fluidsolid interaction, and it thus includes the correct viscous and thermal damping of the mirror from the surrounding air. In order for the motion to be periodic, the damping ratio must be limited to the range 0 \le \zeta comsol conference in cambridge air damping simulation of mems torsional paddle n. Anthony1 1school of mechanical engineering, university of birmingham corresponding author. Analyze viscous and thermal damping in a vibrating micromirror with. I am looking for a free not only as in freedom alternative to comsol multiphysics. Pdf modeling and simulation of mr damper using comsol. Modeling natural and forced convection in comsol multiphysics. The measured air velocity then used as an input in simulation work which used comsol multiphysics software. Thermal management of buildings hardware and simulation software modeling. Analytical and numerical modeling of squeezefilm damping in. How do i make a nonlinear solver converge in comsol multiphysics. Classical hydraulic dampers are flexible devices that are used to attach a component to a mounting base. Excessive air damping can be detrimental to the performance of oscillating. Analyzing the viscous and thermal damping of a mems micromirror.
Modeling technique of material damping properties in ansys. Air damping analysis in comb microaccelerometer wu zhou, yu. Magnetic field comsol multiphysics modeling software. Mems micromirror oszillation air damping comsol multiphysics. Modeling and simulation of mr dampers using comsol. Viscous damping and spring force calculation of regularly. This software was originally produced by comsol ab. Comsol multiphysicstm was previously used successfully for air damping simulations in angular combdrive micromirrors. Mufflers are often located in exhaust systems or on heat, ventilation, and air conditioning hvac systems, where their key functionality is to. The slits are narrow enough that the socalled viscothermal effects are of significant importance. Cfd software for simulating fluid flow applications. Multiphysics analysis of thermoelastic damping effects on rf. Mems microphone, corrugated diaphragm, perforated diaphragm 1.
This might be a question better suited for the software recommendations side of s. Simulation of room airflow using comsol multiphysics software. Micromirrors are used in certain mems devices to control optic elements. The most popular versions among comsol multiphysics users are 4. Viscous damping and spring force in periodic perforated. Modeling and simulation of damping resistance of a cantilever. Complex systems, such as structures in preetched cavities or angular combdrive scanning mirrors, typically require simulations to reliably evaluate the air damping. Apr 28, 2017 whenever we have a heated or cooled part exposed to air, there is some transfer of heat from the part to the air via convection. Solution below, you can see a table with the first and fourth natural frequencies in khz of beams in vacuum, air, and water.
Air damping of oscillating mems structures comsol multiphysics. The acoustics module is an addon to the comsol multiphysics software that provides tools for modeling acoustics and vibrations for applications such as speakers, mobile devices, microphones, mufflers, sensors, sonar, and flow meters. A homogeneous, unstructured mesh was employed for most of the domain with areas of refinement in the gap region and around the reentrant. Explicit specification of damping constant posted 21. Using comsol multiphysics, it is possible to estimate your material parameters from experimental measurements through optimization. From the analysis it is clear that at some particular.
Simulation of surface pressure distribution and damping analysis was carried out for different mirror plate materials. Analyzing the viscous and thermal damping of a mems. For instance, the thermoviscous acoustics, transient interface generates the full details for the viscous and thermal damping of the micromirror from the surrounding air. It needs to vibrate with a high qfactor in the horizontal plane and a low one along the transverse plane 4.
Excessive air damping can be detrimental to the performance. Modeling acoustic damping processes comsol multiphysics. Oct 15, 20 the total viscous damping of a cell consists of the squeezefilm damping due to the motion of the air in the gap and the resistance of the hole. To evaluate the applicability of the fluidstructure interaction interface of comsol multiphysicstm for estimation of the air damping for a variety of other mems devices, the experimental and simulated. For porous materials, the challenge may be even higher, as data provided by manufacturers is often sparse. Various mems devices, resonators and sensors are designed to operate in air and viscous fluids. You can use the specialized features to visualize acoustic fields and build virtual prototypes of devices or. A compression driver is a certain type of electrodynamic loudspeaker which has a phase plug with slits in front of the diaphragm. The simulationbased results on vibration and acoustics analysis are very sensitive to the description and input methods of damping properties. Since the absence of accurate measuring technologies makes it impossible to acquire the real structural parameters of sensing capacitors, the comsol software and whole sensor tests are proposed in this paper to study the dependence of damping coefficients on the fabrication errors including dimension deviation and etching angle. Comsol provides an ide and unified workflow for electrical, mechanical, fluid, acoustics and chemical applications. Evaluation of squeezefilm damping effects in mems perforated.
The version of lmgrd must be the same or higher than the flexnet version used by the comsol software. The fluidstructure interaction interface of comsol multiphysics software is used to study the 2d interaction of torsional paddle resonator with air and evaluate the damping torque and quality factor. I was very happy to calculate the damping loss rather than wander around trying random values for damping loss in comsol. In order for the motion to be periodic, the damping ratio must be limited to the range 0 \le \zeta air and gas damping mechanisms that comsol multiphysics has to offer. Thinfilm thickness influence on anisotropic mems damping. Air damping significantly influences the dynamical characteristics of. The analysis results are presented and compared with microphone structure having perforated back plate.
Vibration amplitude reduction can be achieved by improving the old technique of suspension by bringing in application of magnetorheological or electrorheological fluid in it. The measurement of air velocity was taken using davis anemometer at random point in the room. In this paper, the consideration of vibration damping using software. The proposed structure is modeled and studied using comsol multiphysics software. Mar 19, 2018 watch this webinar to get a 20minute introduction to vibration and noise analysis in comsol multiphysics and learn about modeling acoustic applications like gearbox systems, gear trains. Vibrating micromirror with viscous and thermal damping. Comsol multiphysics software is used for applications that have coupled physics problems and is a unique tool that is used for the designing and analysis phase of the magnetorheological damper. In this paper, squeeze film damping analysis was performed on a micromirror using comsol multiphysics software. Comsol multiphysics is a crossplatform finite element analysis, solver and multiphysics simulation software. I was able to find the damping loss to introduce in comsol based on quality factor given in my piezoelectric harvester specifications. Even if many of them have been validated by means of numerical simulations, nobody seems to have discussed about the accuracy of numerical approaches in this field. Iiii complex 3d geometry construction using basic mathematics l7 duration.
Squeezefilm gas damping of a vibrating disc comsol. Design and multiphysics analysis of mems capacitive microphone. The effect of resonance frequency by changing the torsional spring on air damping is investigated. The simulation process begins by building up geometry of the room, assigning constant parameters, meshing the geometry of the room, and finally run the solver analysis. Warning your internet explorer is in compatibility mode and may not be displaying the website correctly. In a second part, we propose a numerical approach based on the fem multiphysics comsol software to define the dimensionless elastic and viscous damping forces in circular cmut with flexible plate. It allows conventional physicsbased user interfaces and coupled systems of partial differential equations pdes. Comsol multiphysicstm was previously used successfully for air damping simulations in angular combdrive micromirrors 4. School of mechanical engineering, university of birmingham, edgbaston, b15 2tt. In order to decrease the total viscous damping, a larger hole density is required. In the comsol multiphysics software any number of physics can be combined in one and the same simulation.
Simulating a permanent magnet in solidworks with ems by emworks. The combination of comsol products required to model your application. This means that the comsol license server needs to be upgraded to comsol 5. See firsthand how the comsol software works in an interactive online demo tailored to discuss your needs.
The majority of mems microphones use flat diaphragms along with a perforated back plate. The present study is aimed to predict the damping measured as qfactor of a single mass cantilever energy harvester structure as shown in figure 1 at various cavity pressure using comsol multiphysics commercial finite element software. Squeeze film damping and stiffening in circular cmut with air. The analysis result are presented and compared with microphone structure having perforated back plate. Squeeze film air damping analysis is done on the fixedfixed beam membrane for. This discussion is about an older version of the comsol multiphysics software. Discussion closed this discussion was created more than 6 months ago and has been closed. Comsol multiphysics is compatible with windows xp7810 environment, 32 and 64bit versions. In acoustics, knowing the damping properties of fluids and structures can be challenging. The comsol software automatically formulates the energy equation coupled to the momentum and mass balance equations for ideal gases. Comsol multiphysics and comsol are either registered trademarks or trademarks of comsol ab.
Excessive air damping can be detrimental to the performance of oscillating mems components. Comsol multiphysics alternatives and similar software. The effect of different air gap height on the damping was also studied. The combination of comsol products required to model your application depends on several. The movement of the air can be either forced, via a fan, or free, as a result of the natural buoyancy variations due to changes in the air temperature. In a second part, we propose a numerical approach based on the fem multiphysics. In both cases, when meshing these models, automatic mesh refinement resolves the shock pattern by refining around the regions with very high velocity and pressure gradients. For high squeeze number, typical for cmut operation, air spring constants for piston and flexible membrane are similar. Comsol webinar modeling coils and electric devices youtube. The measured air velocity then used as an input in simulation work which used comsol multiphysics. Dec 29, 2011 the literature includes a variety of analytical and semianalytical models to describe squeezefilm damping in mems perforated structures. Yang 1 the damping effect of enveloping air would be.
Compression driver simulation including air damping in. There are many types of structural damping that you can implement in your finite element analyses. The resulting model includes some of the most advanced air and gas damping mechanisms that comsol multiphysics has to offer. In the present paper, we apply both the main analytical models and a commercial finite. Comsol multiphysics is an engineering, design, and finite element analysis software environment for the modeling and simulation of any physicsbased system.
Comsol software to define the dimensionless elastic and viscous damping. The comsol software automatically detects the solidfluid boundary and applies the necessary boundary conditions at the solidfluid interface. Comsol webinar vibration and noise analysis in comsol. For microstructures having a small number of holes per unit area u 2, the squeezefilm damping is the dominant part.