COMSOL Multiphysics^® 6.4 Release Highlights

For users of the MEMS Module, COMSOL Multiphysics^® version 6.4 introduces automatic contact modeling, symmetry support for terminals, and a new default plot showing total stored energy. Learn more about these updates below.

Automatic Contact Modeling with Many Objects

To easily create models with a large number of possible contact interactions, a new General Contact feature has been introduced that automatically sets up contact conditions between many objects arbitrarily.

A piezoelectric valve in closed position with a high stress region (red) indicating contact. The settings of the Contact Model node, a subfeature of the new General Contact feature, are shown. 

Symmetry for Terminals

The Terminal feature now supports an area multiplication factor (available in the Advanced Settings section after enabling Advanced Physics Options). This accounts for symmetry by scaling the terminal area so connected circuits or loads will perceive the full device even when only part is modeled. For example, a factor of 2 should be used if the model represents half the device. The update is available for the Electrostatics interface, the Electric Currents interface, and the Magnetic and Electric Fields interface.

A model representing half of a Lamb wave resonator. The new area multiplication factor is shown in the Settings window of the Boundary Terminal feature.

Default Plot of Total Energy

To visualize the frequency response and identify the resonance peaks of an electromechanical system, a new default plot of total stored energy, Wh_tot, is available for Frequency Domain studies with electromechanics or a piezoelectricity coupling.

In this model of a thin-film bulk-acoustic-wave (BAW) resonator, a plot of total stored energy, Wh_tot , is created when solving a Frequency Domain study. The default plot requires either the Piezoelectricity or Electromechanics coupling.

New and Updated Tutorial Models

COMSOL Multiphysics^® version 6.4 brings several new and updated tutorial models to the MEMS Module.

Birdbath Resonator Gyroscope

The resonator’s axisymmetric dome shape enables coupling between drive and sense modes. This design minimizes cost, weight, size, and power consumption while delivering higher accuracy and stability. Shown are the displacement fields with (left) and without (right) Coriolis excitation, demonstrating how angular motion produces a measurable distortion.

Application Library Title:
birdbath_resonator_gyroscope
Download from the Application Gallery

Velocity Calculation for SAW Unit Cell

This model calculates the surface-acoustic-wave (SAW) velocity and related parameters, such as the electromechanical coupling coefficients, k² and k_p, for different unit cell configurations of the 128° YX-cut LiNbO₃ crystal. These parameters are useful for various analytical and semianalytical methods of SAW device design. The displacement and electric field in the x direction are shown.

Application Library Title:
saw_velocity_calculation
Download from the Application Gallery

Uncertainty Quantification Analysis of Piezoelectric Energy Harvester

The Uncertainty Quantification Module is used to study how manufacturing uncertainties introduce variation into the output power of an energy harvester. In this tutorial model, a sequence of uncertainty quantification (UQ) studies is performed, starting from screening and continuing to uncertainty propagation. Pictured here are the surrogate models for eight distinct frequency values that relate the energy harvester output power to two input parameters.

Application Library Title:
piezoelectric_energy_harvester_uncertainty_quantification
Download from the Application Gallery

SAW Euler Angle Rotation

This model demonstrates how Euler angle rotations are applied to modify the default material properties when cut-specific data is not available. This example uses three configurations of the 128° YX-cut LiNbO₃ to calculate eigenfrequencies and eigenmodes. The displacement and potential (left) and displacement and piezoelectric strain (right) in the x direction are shown.

Application Library Title:
saw_euler_angle_rotation
Download from the Application Gallery

Shape Optimization of Microphone Diaphragm

This tutorial model demonstrates how to use the Shape Optimization study to precisely tune the natural frequency of a MEMS microphone diaphragm. The changes in the shape of the spring suspension when the natural frequency is lowered from 145 kHz to 115 kHz are shown.

Application Library Title:
microphone_diaphragm_shape_optimization
Download from the Application Gallery