To help users get familiar with modelling cMUTs in OnScale, and the more advanced techniques involved in constructing these models, a series of progressive examples have been compiled. These examples comprise all the elements discussed in the previous sections, moving from simple to more complex.
These models introduce the user to the concept of Static and Dynamic analysis in a single run, and how to implement this type of simulation.
The models are well commented with thorough descriptions in the headings and command implementations - Please read the comments in the input files carefully!
Example 1- Basic axisymmetric model. Implemented entirely in continuum elements and operating in a void environment (air).
Example 2 - Expands on Example 1 by including a fluid load. This model introduces users to the concept of removing load elements in the Static Phase, and bringing them back in for the Dynamic phase.
Example 3 - Adds Contact interaction (collapse mode) and Atmospheric pressure to the model. The geometry has been modified slightly to ensure contact will be induced. This is done by reducing the gap and widening the diameter of the cavity.
Example 4 - Implements the full model in Example 3, but with Shell elements replacing the continuum elements for the membrane. This results in a much faster simulation due to the reduction in elements (no longer dominated by membrane thickness), and timestep.
CMUT Collapse Shells - A more practical example of Example 4, with some additional analysis included, such as extrapolation boundaries for beam profiles, harmonic mode shapes for analysis frequency behavior.
CMUT NoCollapse Shells- Similar to the collapse example but with Bias levels reduce to avoid driving the membrane into collapse mode.
Membrane Only - This example has no electrostatic effects included in the solution.
- The timings have been modified slightly to remove the Bias stage which is no longer required.
- BOND and the 'fake' dielectric material remain in place, but only for display purposes
- A symmetrical boundary command is applied at the XMAX of the model to simulate a plane wave better
- The FUNC is altered to generate a pulse of 1 MPa with a delay to allow it to be used after the static phase
- Contact elements remain the same
- MODS for DRLX of fluid remains the same
- BIAS running procedure removed
- FUNC and PLOD are applied after the application of the atmospheric pressure
How do I process my CMUT results?
Here is a Review File that can be altered (insert file name where specified) to work with all the examples above in order to extract metrics such as Impedance Profiles and Pressure Spectra in the load.
Further Examples (Input & Review Files)