E173 Applied Elasticity

Harvey Mudd College

Fall 2005

(Last edited at 9:00 AM on 1 December 2005.)

Particulars:

Lectures:             Tuesday, Thursday   9:35–10:50 in TG 208

Instructor:            Prof. Clive Dym, clive_dym@hmc.edu, Parsons 2373B; 621–8853

Office Hours:       Monday, Wednesday  9:00–11:00 or drop by

Grader:                Prof. Clive Dym

Textbook:            R. D. Cook and W. C. Young, Advanced Mechanics of Materials, 2nd Edition; at Huntley Bookstore

My goals for this course are that you will:

·       develop an understanding of how the theory of elasticity can be applied to model some mechanical and structural behaviors;

·       learn the principles that underlie the energy-based modeling of engineering solids and structures;

·       obtain exact and approximate solutions for a variety of problems in solid mechanics; and

·       experience some sense of how engineers think about problems in solid mechanics. 

Course emphases:

The theory of elasticity is concerned with modeling the deformations of and stresses in continuous media characterized by linear relationships between stress and strain. Applied elasticity is about developing and applying geometry-based idealizations of real physical situations and structures. This introduction to applied elasticity will focus on:

·       introducing the three-dimensional theory of elasticity;

·       introducing minimum energy principles to derive mathematical models of the behaviors of elastic solids;

·       using kinematic assumptions and minimum energy principles to derive idealized models of elastic behavior in one- and two-dimensional solids;

·       solving a variety of solid mechanics problems exactly and approximately; and

·       developing physical intuition about mechanical behavior and its role in analyzing and designing solid bodies.

Course topics:

1  The linear theory of elasticity:  Strain, stress, constitutive laws, equilibrium and compatibility for three-dimensional solids.

2  Energy methods:  The calculus of variations; the Principle of Minimum Potential Energy; the Principle of Minimum Complementary Energy; the (two) Castigliano Theorems.

3  Failure criteria:  Criteria for different material behaviors; cracks; fatigue.

4  Two-dimensional formulations and problems:  Plane stress; plane strain; beams as plane stress problems; thick-walled cylindrical and spherical pressure vessels; rotating disks.

5  Torsion: St. Venant theory; membrane analogy; torsion with warping of thin-walled beams and tubes; torsional failure.

6  Energy methods for beams:  Deriving classical beam theory; comparison with elasticity theory solution; Timoshenko beam theory; energy-based approximate solutions for beams.

7  Column buckling: Stability; bifurcation and limit points; nonlinear and linearized models of column behavior; the elastica; Koiter’s postbuckling theory; beam-columns; energy-based approximate solutions to buckling eigenvalue problems.

8  Beams on elastic foundations (if time permits):  Motivation; derivation of equations; limits and special cases; analogy with axisymmetric deformation of circular cylindrical shells.

Course activities:

This particular introduction to applied elasticity will involve your:

·       active participation in course discussions of the concepts and their application; and

·       mastering the skills to solve solid mechanics problems in homework and exams.

Materials posted online (I): Syllabus and miscellaneous readings

On Dimensional Analysis

Beam Summary

Lecture Notes: 3 November

Lecture Notes: 15 November

 

Materials posted online (II): Homework assignments

Homework No. 1

Homework No. 1 Solutions

Homework No. 2

Homework No. 2 Solutions

Homework No. 3

Homework No. 3 Solutions

Homework No. 4

Homework No. 4 Solutions

Homework No. 5

Homework No. 5 Solutions

Homework No. 6

Homework No. 6 Solutions

 

Grading:

There will be two 75-minute exams. Dates for the two exams — one around half-way, the other at the end — will be decided as the course unfolds. These exams are likely to be closed book and notes. The components of your final course grade are weighted as follows: 30% for the homework and 35% for each exam.

Additional references (generally available at Sprague Library):

W. B. Bickford, Advanced Mechanics of Materials, Addison Wesley, 1998.

A. P. Boresi and P. P. Lynn, Elasticity in Engineering Mechanics, Prentice Hall, 1974.

A. P. Boresi, R. J. Schmidt and O. M. Sidebottom, Advanced Mechanics of Materials, John Wiley, 1993.

R. G. Budynas, Advanced Strength and Applied Stress Analysis, McGraw-Hill, 1977.

C. L. Dym, Stability Theory and Its Applications to Structural Mechanics, Noordhoff, 1974 and Dover Publications, 2002.

C. L. Dym and I. H. Shames, Solid Mechanics: A Variational Approach, McGraw-Hill, 1973.

J. M. Gere and S. P. Timoshenko, Mechanics of Materials, PWS Publishing, 1997.

H. W. Haslach, Jr., and R. W. Armstrong, Deformable Bodies and Their Material Behavior, John Wiley, 2004.

H. L. Langhaar, Energy Methods in Applied Mechanics, Krieger, 1989.

E. P. Popov, Engineering Mechanics of Solids, Prentice Hall, 1990.

H. Reisman and P. S. Pawlik, Elasticity: Theory and Applications, John Wiley, 1980.

I. H. Shames and C. L. Dym, Energy and Finite Element Methods in Structural Mechanics, Taylor and Francis, 1985.

S. P. Timoshenko, History of Strength of Materials, Dover Publications, 1983.

S. P. Timoshenko and J. N. Goodier, Theory of Elasticity, McGraw-Hill, 1970.

A. C. Ugural and S. K. Fenster, Advanced Strength and Applied Elasticity, Prentice Hall, 1995.