OOFELIE::Multiphysics | Transducers Design Solution | FSI Solution / Applications / Transducers / Piezoelectric devices / Vibrating Intertial Accelerometer

Vibrating Intertial Accelerometer

Vibrating Intertial Accelerometer

ONERA (Frenh Aerospace Laboratory) constructed a monolythic quartz sensor, sensitive to orthogonal acceleration. This concept efficiently decouples the vibrating beam from the outside case through a decoupling framework. OOFELIE::Multiphysics permits to maximize the vibration quality factor of the sensitive element, needed for frequency stability.

The whole device - including the sensor's package is simulated using OOFLIE::Multiphysics because of the need of strongly coupled Piezo-thermo-elastic modeling.

The resonating beam is activated through piezoelectrcity while thermo-elastic damping is critical for space (zero-gravity) and vacuum applications. At the same time thermal stresses influencing the frequency behavior need to be minimized.

For more information consult The Onera Webpage (In French)

Multiphysics model

divamechanism

The device functionality is based on the piezoelectric actuation of a beam (see red arrow) and the consequent measurement of the frequency shift due to axial stresses exercised on this beam.

impthighQ

The importance of a high Quality factor for the device sentitivity. The OOFELIE::Multiphysics strongly couple piezo-thermo-elastic simulations give an excellent fit with the experimental measurements.

Packaging effects

The sensor's behavior was simulated within a To8 package, which enables to:

  • Study the enegergy losses through the mounting parts
  • Optimize the resonance quality
  • Minimize the effectof thermal stresses on the resonance frequency.
framework

Interaction with IC

Finally the accelerator's response was optimized together with it's measurement electronic circuit (IC). The measurement circuit is designed to lock into the transducers eigen-frequency for optimizal performance, however the transducer's original response (top left) does not enable this because the electric capacitance intoduced by the structure intoduces an unwanted phase-shift. By adding an electric compensation circuit and optimizing the electric parameters of this circuit, we are able to improve the total system performance (bottom right), cancelling the phase shift, while maintaining the quality factor.

electric_cosim