L4 - MEMS Dynamics Flashcards
(10 cards)
What does the term ω0 represent in the context of a mass-spring-damper system?
ω0 = √(k/m)
It is the natural frequency of the system.
Define the damping factor γ in a mass-spring-damper system.
γ = c/(2mω0)
The damping factor quantifies the level of damping in the system.
c is the dampening constant?
How does the damping factor γ affect the resonance peak in a lightly damped system?
As γ increases, the height and sharpness of the resonance peak decrease.
This relationship is crucial for the design of resonant systems.
What is an example application of a mass-spring-damper system in devices?
Accelerometer
Used in car air-bags and mobile phones to detect sudden decelerations.
What causes damping in resonant microstructures?
Viscous damping dominates losses in micromachined mechanical resonators operated in air.
Structural damping is usually small for devices made from single-crystal silicon.
What happens to a beam under thermal mismatch between its microstructure and substrate?
Mismatch between thermal expansion coefficients (CTE) of microstructure (αM) and substrate (αS) leads to Temperature-dependent axial loads are generated.
This can lead to stress and deformation in the beams.
True or False: The overall quality factor Q of a resonator is independent of the various damping processes involved.
False
The overall Q is given by 1/Q = Σ1/Qi, where Qi are the Qs of different processes.
Fill in the blank: The effect of _______ mismatch leads to temperature-dependent axial loads in beams.
thermal expansion coefficient
This mismatch can significantly affect the mechanical properties of microstructures.
What effect does a compressive axial load have on a beam?
The beam will buckle at a certain critical load.
This phenomenon is vital for understanding structural stability.
What is residual stress in the context of microengineering?
Stress remaining in a material after the manufacturing process, leading to deformation.
It can be useful for characterizing deposited materials.
