last modified 01/07/2002

Coursecode: wb1409
Coursename: Theory of Elasticity

DUT creditpoints: 2
ECTS creditpoints:
3

Faculty of Mechanical Engineering and Marine Technology

Lecturer(s): Keulen, prof.dr.ir. A.

Tel.: 015-27 86515

Catalog data:
Stress and strain tensors, elastic constitutive equations, linear theory of elasticity, energy principles, energy theorems, stress functions, composite theory, homogenization

Course year: MSc 1st year
Semester:
1A / 1B
Hours p/w:
2
Other hours:
2
Assessment:
Exercises + oral exam
Assessm.period(s):
By appointm.
(see academic calendar)

Prerequisites: wb1410

Follow up: wb1400, b20, wb1402A, wb1402B, wb1405A, wb1405B

Detailed description of topics:
This course deals with the theory of elastic deformations of continuous bodies, including a number of important engineering applications. This field is the actual basis of essentially all strength of materials tools in mechanical engineering, marine technology and aerospace engineering. The elastic behaviour of engineering materials can, as a first approximation, often be considered to be linear and then determines the flexibillity of structures and the allowable stresses, as long as in-elastic behaviour (plasticity and creep) or facture does not occur. This course intends to deepen the knowledge of elastic deformations of engineering components build up during the first and second year courses. At the same time, it is the starting point for advanced courses on elasticity such as those dealing with buckling of structures, or plates and shells. Following a brief review of the fundamental notions from continuum mechanics, the general three-dimensional theory for elastic boundary value problems is developed. From this, the governing equations for the linear theory are deduced. Then, a number of important energy principles are discussed, which form the basis for numerical methods for problems of elasticity, in particular the finite element method. Subsequently, the analytical solutions for a number of typical two- and three-dimensional elasticity problems are discussed in depth. The elastic behaviour of composite materials is discussed, with emphasis on the internal state in the composite. Finally, the theory for large elastic deformations is considered for application to rubber materials.
The contents of the course are as follows:

Review of continuum mechanics: strain-displacement relations, equilibrium conditions, (thermo-) elastic constitutive equations;
Energy principle of the linear theory of elasticity: potential energy; complementary energy; mixed principles; relation with Rayleigh-Ritz methods;
Two-dimensional elastic problems: equations of Navier-Cauchy; stress functions; stress concentrations; cracks, stress intensity factors;
Three-dimensional elastic problems: thick-walled tubes/spheres; stress concentration around spherical hole; contact; wave propagation;
Inhomogeneous materials: inclusions; inhomogeneities;
Finite strain elasticity: hyperelastic material.

Course material:
Specific parts from:

  • Y.C. Fung, Foundations of Solid Mechanics, Prentice Hall, New York, 1965.
  • M.E. Gurtin, An Introduction to Continuum Mechanics, Mathematics in Science and Engineering, vol. 158, Academic Press, New York, 1982.
  • I.S. Sokolnikoff, Mathematical Theory of Elasticity, McGrawHill, 2nd ed., New York, 1956.
  • R.W. Ogden, Nonlinear elastic deformations, Ellis Horwood Ltd., 1984.

References from literature:

Remarks (specific information about assesment, entry requirements, etc.):
Oral examination

Goals:
The objective of this course is to offer a sound basis for the treatment of a wide range of problems of elasticity. To that end, the governing equations of the theory of elasticity are discussed, based on general continuum mechanics, and specific methods of solution are considered for the linear theory.
The solution of a number of typical engineering elasticity problems are pressented in detail, partly to illustrate the adopted solution strategy, and partly because they provide model problems that are key to several related fields of engineering.

Computer use:
Most applications of the theory of elasticity require numerical techniques. This course includes the common basic concepts on which the Finite Element Method is based. Specific numerical aspects are dealt with in b20.

Laboratory project(s):

Design content:
The theory of elasticity is the foundation for the analysis of stresses and the flexibility in the design of structures and components. This holds for the initial design stages, where "rough" estimates are made based on simple models (beams, etc.), as well as for the final, detailed designs where advanced numerical tools are used.

Percentage of design: 50%