Mechanical Engineering, Indian Institute of Science, Bengaluru, 560 012, India
"Be flexible and strong."
ME254 Compliant Mechanisms Jan. 2024 - Apr. 2024
Instructor: G. K. Ananthasuresh, Room 106, ME Building, suresh at iisc.ac.in
Lectures: Tu, Th: 08:30 AM - 10:00 AM; Venue: ME MMCR

Timeline and lecture notes

Week Dates Topics Notes Codes, etc.
1 - 5
Module 1: Principles and Concepts
1 Jan. 4, 2024: The spirit of compliant mechanisms: an overview of compliant mechanisms and their applications. Prof. Ashok Midha's thoughts on compliant mechanisms and mechanisms in general
Overview of compliant mechanisms
Spirit of compliant design
Applications of compliant mechanisms
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2 Jan. 9, 2024: Introducing Matlab and COMSOL finite element software to analyze compliant mechanisms.
Familiarization with beam finite element codes in Matlab (linear and nonlinear)
Jan. 11, 2024: In-class hands-on practice with Matlab and COMSOL to understand how compliant mechanisms work.
Subtleties in using finite element analysis of compliant mechanisms. Matalb code linear finite element analysis with beams
Matalb code geometrically nonlinear finite element analysis with beams
3 Jan. 16, 2024: Mobility analysis; how to identify the degrees of freedom
and the number of required actuators
Reinforcing the concept of virtual rigid segments in the extended Gurbler's formula
Jan. 18, 2024: Maxwell's rule and Calladine's extension
How to compute and interpret DoF of compliant mechanisms using the extended Grubler's formula
Mobility analysis of compliant mechanisms
Delineating DoFs (degrees of freedom) and SoSSs (states of self-stress)
Grubler's formula extended for compliant mechanisms
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4 Jan. 23, 2024: Degrees of freedom and states of self-stress (contd.)
Jan. 25, 2024: How to delineate DoF and SoSS using compatibility and force-equilibrium matrices of a truss.
Matlab program for the mobility analysis of 2D and 3D trusses; nullspace interpretation of DoF and SoSS modes.
- Matalb code and data files for planar truss mobility analysis
5 Jan. 30, 2024: Classification of compliant mechanisms
Characterizing the stiffness of elastic pairs
Compliant hingers and sliders; folded-beam suspension mechanism
Myosotis method for beam deformation analysis
Feb. 1, 2024: Myosotis method (contd.) with examples
Multi-axis stiffness of the folded-beam suspension
Elastic pairs 3D beam fea code (linear)
6 Feb. 6, 2024: Micromechanical suspensions
A case study of a micromachined accelerometer
Feb. 8, 2024: Instant centre method of design of compliant mechanisms
Examplification of the instant centre method in multiple stages
Instant center method
Micromachined accelerometers
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7 Feb. 13, 2024: Mechanical advantage aspects of compliant mechanisms
Three types of mechanical advantages and their implication
Feb. 15, 2024: Spring-lever (SL) model of compliant mechanisms for abstraction of static behaviour
kci, kco, and n
The equivalence with two DoF (single-input-single-output) model of CMs
Mechanical advanatges aspects of CMS by Salomon and Midha
Spring-lever modeling of CMs
8 Feb. 20, 2024: Elastica analysis
Feb. 22, 2024: Elastica analysis and PRB
Burns and Crossley's kinematic approximation of a cantilever with a rigid bar of shortened length
Howell and Midha's kinetostatic approximation of a cantilever with a rotation spring of constant stiffness
Elastica analysis
Elastica similarity analysis 1
Elastica similarity analysis 2
Pseudo-rigid-body (PRB) kinematic model
Pseudo-rigid-body (PRB) kinetoelastic model
In-class 30-min quiz on Feb. 20.
9 Feb. 27, 2024: Principle of virtual work and force-equilibrium equation
Kinetoelastic equations and precision point synthesis for torque-angle specifications
Feb. 29, 2024: Discussion of homework problems
Force-equilibrium equation using PRB -
10 Mar. 5, 2024: Synthesis equations for constant-force compliant mechanism
Mar. 7, 2024: Mid-term examination
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11 Mar. 12, 2024: Precision point synthesis: variable, equations, free choices
Mar. 14, 2024: Kinetoelastic synthesis using PRB and precision points synthesis
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12 Mar. 19, 2024: Spring-mass-lever model; energetic approach to arrive at m_ci and m_co
Mar. 21, 2024: Selection-based design of compliant mechanisms using spring-lever and spring-mass-lever models
Static balancing with zero-free-length springs
Spring-mass-lever models
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13 Mar. 26, 2024: Static balancing: force-force; force-spring; and spring-spring
Concept of constant potential energy and zero-free-length springs
Mar. 28, 2024: Bistability, snap-through; analysis of shallow arches; energy method
An ME project on static balancing
Static balancing using auxiliary springs
Static balancing techniques applied to compliant mechanisms
Static balancing of cognates of the four-bar linakge with a spring load
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14 Apr. 2, 2024: Topology optimization of compliant mechanisms
Topology optimization using YinSyn
Apr. 4, 2024: Quiz 2 (8:30 AM to 9:30 AM); open everyting
Topology optimization of compliant mechanisms using beam elements and mutual strain energy and strain energy formulation
Topology optimization of compliant mechanisms with distributed compliance
YinSyn: topology optimization code for compliant mechanisms and stiff structures
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15 Apr. 9, 2024: Non-dimensional models of beams undergoing large displacements
Non-dimensional modeling of compliant mechanisms
Building block method of designing compliant mechanisms; compliance ellipsoid

Apr. 11, 2024: Comparison of design methods for compliant mechanisms
Non-dimensionalization of compliant mechanisms response
Building block method of compliant mechanisms
Comparison of several design methods of compliant mechanisms
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16 Apr. 16, 2024: Advanced applications of compliant mechanisms - -