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MEMS Stress sensor
MEMS stress sensor
MEMS stress sensor changes its shape under mechanical stress. The electrode plates comes close and the variation in electrical capacitance is detected.
Problem type:
Planeparallel problem of electrostatics and stress analysis .
Geometry:
Given:

Young's modulus 
Poisson's ratio 
Silicon 
130 GPa 
0.1 
Copper 
140 GPa 
0.34 
Task:
Calculate the sensor deformation and electrical capacitance in initial and deformed states.
Solution:
Initially the electrostatic problem is simulated to calculate the native capacitance of the sensor.
Then deformed sensor profile is calculated in stress analysis problem. The profile is exported into the separate geometry model file using Stress Deform tool. That deformed shape model is then used to run another electrostatic analysis to calculate the deformed state capacitance.
Results:
Initial capacitance value 0.0026 pF
Capacitance in deformed state 0.0028 pF (+10%)
Electric field distribution in the deformed stress sensor
Download video:
Calculation of deformed shape using QuickField Stress Analysis module
Translation of the deformed shape to the geometry model using the StressDeform tool
Initial capacitance calculation using Electrostatics module
Deformed state capacitance calculation..
Watch online on YouTube.
View simulation report in PDF.
Download simulation files (files may be viewed using any QuickField Edition).