Mechanical Engineering, Indian Institute of Science, Bengaluru, 560 012, India
"The more you think, the less material you need"
ME260
Structural Optimization
Size, Shape, and Topology

Aug. 2026 to Nov. 2026
Instructor: G. K. Ananthasuresh, Room 106, ME Building, suresh at iisc.ac.in
Teaching assistant: To be decided, M2D2 lab in mecheng, someone at iisc.ac.in
Lectures: Tu, Th: 08:30 AM - 10:00 AM; Venue: ME MMCR

Timeline and lecture notes

Week Dates Topics Notes Others
1 - 6 Module 1: Structural design with finite-variable optimization
1 Aug. 6, 2026: Overview of the course (Size, shape and topology optimization)
Template of a structural optimization problem: What we need to learn and how to formulate problems
Identifying size, shape, and topology optimization problems
Finite variable optimization vs. calculus of variation; and how they relate to structural optimization
ME260 course appetizer
Lecture notes 1
Lecture notes 2
Lecture notes 2A
Lecture notes 3
Article on strctural hierarchy by Prof. Lakes
Article on Eiffel's optimal structures
2 Aug. 11, 2026: Unconstrained and constrained minimization
Aug. 13, 2026: KKT conditions; fmincon to solve constrained minimization problems
Truss FEA; size and shape optimization in Matlab.
Lecture notes 4
Lecture notes 5
Matlab files for three-bar truss optimization
Quiz 1
Quiz 2
3 Aug. 18, 2026: Constrained minimization; duality; two-bar truss optimization
Aug. 20, 2026: Multi-bar truss optimization
Lecture notes 6
Lecture notes 6 extra (duality)

Quiz 3
Quiz 4
4 Aug. 25, 2026: Size (and topology) optimization of trusses and the optimality criteria algorithm
Aug. 27, 2026: Dual formulation of truss optimization for statically determinate trusses
Concepts of states of self stress and Maxwell's rule
Simultaneous geoemtry and material optimization of trusses
Lecture notes 7a
Lecture notes 7b
Lecture notes 8a
FEA theory notes (trusses and beams)
Matlab truss analysis code
Matlab truss optimization code
Quiz 5
Quiz 6
5 - 11 Module 2: Structural optimization in the framework of calculus of variations
5 Sep. 1, 2026: Genesis of calculus of variations
Sep. 3, 2026: Formulating variational problems in geometry and mechanics
Genesis of calculus of variations
Geometry and mechanics problems cast as calculus of variations problems
Quiz 7
6 Sep. 8, 2026: Mathematical preliminaries of calculus of variations: vectors spaces, function spaces, etc.
Sep. 10, 2026: Gateaux (first) variation, Frechet differential, etc.
Fundamental lemma of calculus of variations
Some examples to practise taking variation
Mathematical preliminaries to calculus of variations; functional and function spaces
Banach, Sobolev, etc., spaces
First variation of a functional
Fundamental lemma of calculus of variations
Quiz 8: https://connections.swellgarfo.com/game/-P0vA_0qCK_yBboQL7sb
Quiz 9
Read Ted Chiang's "Story of Your Life".
Try to watch Arrival, the movie, if you can find the time.
7 Sep. 15, 2026: Variational derivative and derivation of Euler-Lagrange equations in the manner apparently done by Euler without using the concept of variation
Minimum potential energy principle, Principle of virtual work, and force-balance: equivalence established through calculus of variations
Sep. 17, 2026: Static equilibrium of a beam and interpreting the boundary conditions.
EL equations for the case of multiple derivatives and multiple functions
Three ways for dynamic equilibrium: Hamilton's principle, D'Lambert's principle, and Newton's second law
Dynamic equilibrium of a bar to motivate functionals of two independent variables
Euler-Lagrange equations in multiple functions and multiple derivatives but in a single domain variable
Quiz 10
Quiz 11
8 Sep. 22, 2026: Generalization of Euler-Lagrnage equations to multiple functions and multiple derivatives; subtleties in Gateaux variation
Sep. 24, 2026: Discussion of the mini-project: various aspects of truss design
Mini project
Quiz 12
9 Sep. 29, 2026: Euler-Lagrage equations with global (functional) and local (function) constraints
Two examples: Compliant design problem of a beam and contact problem with a beam
Oct. 1, 2026: Euler-Lagrange equations and boundary conditions for 2D and 3D domains.
Euler-Lagrange euqations for global (or functional) constraints
Euler-Lagrange euqations for local (or function) constraints
Euler-Lagrange equations in two and three independent variables
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10 Oct. 6, 2026: Review for the midterm
Oct. 8, 2026: Midterm examination
Taking variation when there is shorthand notation with vectors
Midterm questions of variational methods course ME 256 from 2005 to 2018
Midterm questions of ME 260 from 2021 to 2025

Refer also to early homework problems of ME 256 as practice for the midterm
11 Oct. 13, 2026: Variable end conditions in Calculus of Variations; transversality conditions; broken extremals; Weirstrass-Erdmann conditions
Examples: Fermat's refraction problem and the generalization of the tractrix problem
Oct. 15, 2026: Bar optimization
Principle of optimality for light-stiff structures
Optimization of a bar (a dozen problems)
Bar optimization code in Matlab and the optimality criteria algorithm
Variable end conditions of a functional
A dozen optimization problems of a bar
Solutions of two bar optimization problems
Quiz 13: Grading ChatGPT's solution to the midterm on a printed copy with everything closed except one's mind, to find the mistakes, inconsistencies, and misinterpretations.
Bar optimization code
12 Oct. 20, 2026: Beam optimization problem for stiffness, strength, and flexibility
Beam optimization code in Matlab
2D frame optimization
Oct. 22, 2026: Homogenization method and its role in topology optimization; 1D homogenization using asymptotic expansion method
Power law and material interpolation, and SIMP
Playing with 99-line code to understand the influence of the penalty parameter and sensitivity filter
Practice with YinSyn code for stiff structures and compliant mechanisms
Lecture notes 9
Lecture notes 8b
Many beam optimization problems
Solution to beam optmization for stiffness and flexibility
2D frame optimization problem
Beam optimization for strength
Homogenization of a 1D problem
Beam optimization code
99-line code for 2D stiff-structure optimization
YinSyn 2D code for topology optimization of structures and compliant mechanisms
13 - 16 Module 3: Multiphysics design problems; Sensitivity analysis for shape and topology optimization
13 Oct. 27, 2026: Material-property interpolation for topology optimization for electro-elasto-statics, fluids, etc.
Pressure load problem and electro-thermal-elastic problem
Oct. 29, 2026: Introduction to topology optimization using COMSOL and nTop
Papers sent by email as a zip file.
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14 Nov. 3, 2026: Ananlytical expressions for sensitivity in the Calculus of Variations framework
Sensitivity of dynamic compliance; electro-thermal-elastic analysis
Reversal of the sequence of design sensitivity of adjoint variables in electro-thermal-elastic problems
Nov. 5, 2026: Verification of sensitivity using finite-difference methods and its pitfalls and a remedy
Coupled electrostatic and elastostatic problem
Topology optimization of coupled electrostatic and elastostatic problem
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15 Nov. 10, 2026: Sensitivity analysis: parameter, shape; 1D and 2D; Jacobian and its derivatives (material and space derivatives)
Nov. 12, 2026: Shape sesitivity and shape optimization
Parameter sensititvity of a functional
Shape derivative with a 1D example
Derivatives of the Jacobian and its other forms
Shape optimization in 2D
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16 Nov. 17, 2026: Numerical optimization techniques for topology optimization
Convex linearization leading to the method of moving asymptotes (MMA)
Nov. 19, 2026: Topological derivatives and their use
Numerical optimization techniques
ConLin, MMA, and GCA papers
Topological derivative
Optimization with topological derivative
Instructions for the term paper
Project presentation template
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Schedule of lectures in previous years

Lecture notes of 2025 offering of this course

Lecture notes of 2024 offering of this course

Lecture notes of 2023 offering of this course

Lecture notes of 2022 offering of this course

Lecture notes of 2021 offering of this course

Lecture notes of 2020 offering of this course