electrostatic actuated beam optimization case study · optimization problem definition what do we...
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Coupling modeFRONTIER with ANSYS
Electrostatic Actuated Beam OptimizationCase Study
www.ozeninc.com/[email protected]
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Electrost
atic clamp
ed beam an
alysis
SEP 17 2009
15:02:33
VOLUMES
TYPE NUM
2
Problem Description:
• An electrostatic structural analysis is performed to determine the deflection of a silicon beam for a MEMS switch.
• A clamped beam for an RF MEMS switch device is modeled to compute the center deflection for an applied voltage.
• Forces generated by the electrostatic field will bend the beam towards a ground plane.
Electrostatic Actuated Beam Model
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FE Geometry & Boundary Definition
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Electrostatic clamped beam analysis
SEP 17 2009
15:31:49
VOLUMES
TYPE NUM
U
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Electrostatic clamped beam analysis
SEP 17 2009
15:31:49
VOLUMES
TYPE NUM
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1
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Electrostatic clamped beam analysis
SEP 17 2009
15:31:49
VOLUMES
TYPE NUM
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Boundary Conditions
Surface Interface, Voltage and Ground Potential Locations
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Electrostatic clamped beam analysis
SEP 17 2009
15:51:37
ELEMENTS
VOLT
FSIN
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Optimization Problem Definition What do we want to improve?
Objectives
To determine the optimized geometric configuration of the Electrostatic Actuated Beam Model when subjected to a multi objective optimization:
Maximize Displacement, Minimize Electric Potential, Minimize Volume
Why to Maximize Displacement
• In order to maximize the performance of the system.
Why to Minimize Electric Potential• Higher operating voltages exponentially decrease the operating lifetime of the switch.
Why to Minimize Volume
• Minimize the Mass and Material Cost.
Create workflow in modeFRONTIER
• Define the Inputs and their Domains
• Set Ansys as an Application Node
• Set the Logic flow
• Set the Outputs
• Set the Objectives:
• Maximize Displacement
• Minimize Electric Potential
• Minimize Volume
Parameter Domain
Beam Length 135 - 160 mm
Beam Width 2.5 - 4 mm
Beam Height 1.5 – 2.5 mm
Voltage 80 – 140 V
Multi- Objective Electrostatic Actuated Beam Optimization Problem Definition In modeFRONTIERTM
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Electrostatic clamped beam analysis
SEP 17 2009
16:00:56
ELEMENTS
BeamHeight
Multi- Objective Electrostatic Actuated Beam Optimization Problem Definition In modeFRONTIERTM
SOBOL as DOEMOGA-II as Scheduler
Multi Objective(functions to be maximized
or minimized)
Input variablesof the parametric
model
ANSYS
OutputVariables
Postprocessing – Bubble Plot
Maximize Displacement
Min
imiz
e E
lect
ric
Po
ten
tial
• The Bubble plot shown is a 3D view of the scatter.
• It compares the design points with respect to different factors (e.g. Displacement, Electric Potential, Volume).
• All the computed Design configurations are shown in the Bubble plot.
• Around 1000 configurations were computed
• ModeFRONTIER identifies designs that are Pareto (non-dominated)
• Total CPU time required for the optimization: circa 28 hours
ParetoFrontier
Postprocessing – Parallel Coordinate Chart
The Parallel Chart allows the viewing of all designs simultaneously, with one vertical axis for each variable or output
It is most useful for Filtering Designs, especially in cases with multiple, conflicting, objectives
Each Jagged Line across the Chart represents one Design Configuration
Moving the sliders up or down, hides all designs outside the range, allowing the selection of Designs of interest (RED LINE)
Optimum Design• The chart represents all the Pareto designs.
• By sliding the Volume Objective, the designs can be filtered.
Postprocessing – Parallel Coordinate Chart
• Sliding the other objectives will further filter designs which doesn’t satisfy the criteria.
Postprocessing – Parallel Coordinate Chart
• Final Design can be chosen from the parallel co-ordinate chart by further sliding the Max Displacement objective towards the higher end.
#371
Postprocessing – Parallel Coordinate Chart
ANSYS Postprocessing – Final Design
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MN
MX X
Y
Z
Electrostatic clamped beam analysis
-.958366-.851881
-.745396-.638911
-.532425-.42594
-.319455-.21297
-.1064850
SEP 17 2009
15:05:03
NODAL SOLUTION
STEP=12
SUB =1
TIME=120
UY (AVG)
RSYS=0
DMX =.958366
SMN =-.958366
1
MN
MX X
Y
Z
Electrostatic clamped beam analysis
-.958366-.851881
-.745396-.638911
-.532425-.42594
-.319455-.21297
-.1064850
SEP 17 2009
15:05:03
NODAL SOLUTION
STEP=12
SUB =1
TIME=120
UY (AVG)
RSYS=0
DMX =.958366
SMN =-.958366
1
MN
MX X
Y
Z
Electrostatic clamped beam analysis
-.958366-.851881
-.745396-.638911
-.532425-.42594
-.319455-.21297
-.1064850
SEP 17 2009
15:05:03
NODAL SOLUTION
STEP=12
SUB =1
TIME=120
UY (AVG)
RSYS=0
DMX =.958366
SMN =-.958366
1
MNMX
X
Y
Z
Elect
rostat
ic cla
mped b
eam an
alysis
0 12
24 36
48 60
72 84
96 108
SEP 17
2009
15:10:
19
NODAL
SOLUTI
ON
STEP=1
2
SUB =1
TIME=1
20
VOLT
(AV
G)
RSYS=0
DMX =.
949166
SMX =1
08
1
MNMX
X
Y
Z
Electrostatic clamped beam analysis
012
2436
4860
7284
96108
SEP 17 2009
15:10:19
NODAL SOLUTION
STEP=12
SUB =1
TIME=120
VOLT (AVG)
RSYS=0
DMX =.949166
SMX =108
1
MNMX
X
Y
Z
Electrostatic clamped beam analysis
012
2436
4860
7284
96108
SEP 17 2009
15:10:19
NODAL SOLUTION
STEP=12
SUB =1
TIME=120
VOLT (AVG)
RSYS=0
DMX =.949166
SMX =108
Y-Displacement Electric Potential
Conclusions
• In few hours modeFRONTIER tested several configurations, the same task would have taken days for a single operator
• modeFRONTIER created an automatic procedure: once the parametric model is set, the optimizator will keep iterating it till it finds the best configurations
• modeFRONTIER finds the optimum solutions (pareto frontier), therefore the need of testing only the best configurations reducing the experimental phase and controlling the spending
Conclusions
• ModeFRONTIER found the optimum designachieving improvement for all the parameter specified except the Electric Potential Objective
• In this case the Displacement and Volume objectives are improved at the expense of Electric Potential
• Displacement increase of 14.2% from the initial design
• Electric potential increase of 1.84% from the initial design
• Volume reduction of 16.1% from the initial design
MCDM Multivariate AnalysisStatistical Analysis
Process Integration
Response Surface Tool
Design of Experiments Optimization Algorithms Robust Design
modeFRONTIER Capabilities
Stay Ahead During Challenging Times
• To learn more about how Ozen Engineering can help you incorporate simulation into your design and testing processes, please visit us at www.ozeninc.com
• For more Design Optimization case studies visit: http://ozeninc.com/OptimizationCaseStudies
• If you would like us to create a demo for your specific case or for any other question, please contact us at: [email protected]