The transient analysis of a CMUT model can effectively be broken down into 2 stages:
- Static: Bias loading and/or Atmospheric pressure
- Dynamic: Application of Impulse drive signal
For most FEA packages this requires two separate solvers, however, in OnScale both types of analysis can be performed in a single simulation, hence providing truly non-linear results.
Before discussing the particulars of performing these analysis types in Dynamic Relaxation and Model Excitation, it is important to look how to drive the model in suitable manner for performing these two phases in a single simulation.
Users can combine drive functions from both data hist and func using func hist.
- DC Bias can be created with a data hist command, either defined explicitly, or read in from an external time-amplitude file
- Func can be used to generate the Impulse drive via its in-built functionality, or again it can be read in from an external file
- 'Add' the two signals together with the correct timings using func hist
This capability allows user to drive the model with distinctly different signals at the different phases of the models, while maintaining continuity in the drive signal throughout the simulation. The is very similar to how these devices would be excited in practice, and OnScale is designed to emulate reality.