Mechanical Engineering, Indian Institute of Science, Bangalore 560 012, India
Think big abut small things.
ME 237 and NE 211
Mechanics of Microsystems : Micro/nano Mechanics
Aug.-Dec., 2014
Instructor: G. K. Ananthasuresh, Room 106, ME Building, suresh at mecheng.iisc.ernet.in

Topics covered and supplementary notes

Week Dates Topics Notes/References Assignments
1 Aug. 5: The structure of micromechanical elements: why is it the way it is?
Aug. 7: Slender elements in micro/nano mechanical elements
Essential concepts in mechanics: exemplification to an axially loaded bar.
Start of the slender beam theory
Read Glimpses of MEMS History for a quick overview of microsystems and microfabrication.
A pioneering paper by Roylance and Angell
Chapter 4 in MaSS book .
Homework #1
2 Aug. 12: Beam theory and solving problems with it.
Analyzing micromechanical suspensions.
Aug. 14: Static indterminacy and resolving it.
Energy methods in mechanics.
Chapter 4 in MaSS book
Steps in deformation analysis of beams
Homework #2
3 Aug. 19: Multi-axial stiffness analysis of compliant suspensions using beam finite element code
Aug. 21: Multi-axial stffness analysis (contd.): resolving static indeterminacy
Chapter 4 in MaSS book . Steps in deformation analysis of beams
Beam finite element code in Matlab
Analysis of pin-wheel suspension
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4 Aug. 26: Strain energy in axial and bending modes of deformation; Castigliano's theorems; Maxwell's reciprocity theorem; Betti-Maxwell theorem
Aug. 28: Illustration of the use of Castigliano's theorems
State of stress in a beam; shear stress concept; Poisson effect and the derivation of the shear modulus; Derivation of the static equilibrium equations of elastic continuum in 2D.
Chapter 4 in MaSS book .
Proof of Castigliano's theorems
Derivation of the governing differential equations of an elastic continuum
Homework #3
5 Sep. 2: State of stress in a beam subjected bending and shear; reconciliation of the beam theory with the continuum theory; comparison of strain energies associated with bending, shear, and axial modes of deformation
Sep. 4: Coordinate transformation of stress, strain, and inertia tensors; Mohr's circle; concept of tensors; torsion, shear and twist.
Chapter 4 in MaSS book .
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6 Sep. 9: Residual stress, thermal stress, and heterogeneous layered beams
Sep. 11: Residual stress gradient and ensuing curling; helical beams; concept of buckling
Chapter 4 in MaSS book .
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7 Sep. 16: Midterm examination (open book, open notes for 90 min from 8:30 am to 10:00 am in the class room)
Sep. 18: Electrostatics and its coupling with mechanics using a beam actuated with a pair of charges; stability analysis using force-balance method; pull-in concept.
Chapter 6 in MaSS book .
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8 Sep. 23: Equations of electrostatics.
Sep. 25: Discritization of coupled electrostatic-elastostatic equations; compuation using beam finite elemenet codes.
Chapter 6 in MaSS book .
3D FEA beam code
Homework #4
9 Sep. 30: Energy approach to understand the electrostaic and elastostatic equations
Oct. 2: Maxwell stress tensor and body force; solving coupled equations
Chapter 6 in MaSS book .
Coupled electrostatic-elastostatic code using beam elements
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10 Oct. 7: Equations of electrostatics and their coupling with equations of elasto-statics;
Energy method; static and dynamic pull-in voltages.
Oct. 9: Dynamic pull-in voltage; energy landscape ofelectromechanics.
Chapter 6 in MaSS book .
2D Electrostatic analysis code in Matlab with GUI
Pull-in analysis code with GUI.
Re-submission of hand-written midterm solutions by Oct. 14. 2014.
11 Oct. 14: Dynamics of electrostatically actuated micromechanical structures

Oct. 16: Lumped modeling of inertia (mass)
Squeezed film effects and lumped modeling
Chapter 6 in MaSS book .
Coupled electrostatic-elastostatic dynamic analysis code using beam elements
Homework #5
One-page project proposal
12 Oct. 21: Computing effective mass of slender beams
Couette flow and dmaping on translating plates
Suqeeze film effects on micromechanical structures
Oct. 23: HAPPY Deepavali! (Holiday; no class)
Chapter 6 in MaSS book .
Slides on squeeze-film effects
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13 Oct. 28: Circuit model for squeeze-film damping; electrothermal actuators.
Oct. 30: Electro-thermal-elastic coupled analysis; free and forced vibrations; magnetic actuation
Oct. 31: Self-heated piezoresistor problem
Chapter 6 in MaSS book .
Free and forced vibrations of a 1-dof system
Electro-thermal microactuators
Coupled electromechanics
FEA for solving the electrostatics problem
Simple notes for understanding finite element method for linear elastic problems
Self-heated piezoresistor problem
Homework #6
14 Nov. 4: Happy Moharram!(Holiday, no class)
Nov. 6: Happy Gurunanak Jayanthi! (Holiday, no class again)
Nov. 7: Tutorial class converted to lecture class from 5:30 pm to 6:50 pm
Magnetic microactuators
Chapter 6 in MaSS book .
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15 Nov. 11: Magnetic actuators (contd.)
Circuit modeling: effort and flow variables; generalized resistor, capacitor, inductor, gyrator, and transformer; two-port elements
Nov. 13: Piezoresistive effect and its coupeld modeling
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16 Nov. 18: Piezoeresistive effect modeling (contd.)
Piezoelectric equations
Nov. 20: Scaling effects in MEMS
Scaling MEMS -
17 Nov. 20: Thermoelastic damping-a quick overview of the phenomenon and equations - -
18 Nov. 29: Project presentations from 9 am to 1 pm and then 2 pm to 3:30 pm
Dec. 3: Final examination: 2 to 5 pm in TF-10 in thr CeNSE building
See details on project presentations and supplementary files
Final exam of 2010
Final exam of 2011 (Comsol software-based)
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