Undergraduate Teaching 2017-18

Engineering Tripos Part IIA, 3C7: Mechanics of Solids, 2015-16

Engineering Tripos Part IIA, 3C7: Mechanics of Solids, 2015-16

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Professor V.S. Deshpande


Prof S.D. Guest, Professor V.S. Deshpande

Lab Leader

Dr F. Cirak

Timing and Structure

Michaelmas Term, 16 lectures




The aims of the course are to:

  • Provide students with an understanding of how the stresses and strains within engineering components are related to both the loads and displacements imposed at their boundaries and to any thermal or inertial loadings to which they are subjected.
  • Introduce analytical methods, predominantly for two-dimensional geometries and for both elastic and plastic response
  • Illustrate the methods with a number of engineering case studies.


As specific objectives, by the end of the course students should be able to:

  • Calculate the stresses in an elastic or plastic axisymmetric system subjected to various loads.
  • Use Airy and Prandtl stress functions to find analytical solutions to elastic problems.
  • Apply upper- and lower-bound theorems to solid mechanics problems.


Two-Dimensional Elasticity (6L) - Dr S.D. Guest

  • Revision of stress and strain in 2D; Mohr's circle.
  • Elastic constitutive relationship.
  • Concepts of plane stress and plane strain.
  • Equilibrium and compatibility equations in 2D; Cartesian and polar coordinates.
  • Analysis of problems with circular symmetry: thick-walled tube, spinning disk, thermo-elastic problems.

Torsion, Stress Functions and Plasticity (3L)

  • Elastic torsion of prismatic bars: Prandtl stress function.
  • Plastic torsion of prismatic bars.
  • Airy stress function in Cartesian and polar coordinates.
  • Stress distribution in an infinite plate with a circular hole or crack.
  • Analysis of contact stresses; half-plane under line and distributed loads.

Stress analysis in 3D and Plasticity (6L)

  • Stress analysis in 3D: principal stresses; stress invariants; hydrostatic and deviatoric stresses; deviatoric stress invariants.
  • Yield locus,  pi-plane; symmetry; convexity; normality.
  • Tresca and von Mises yield criteria; associated flow rules.
  • Upper-Bound and Lower-Bound theorems.
  • Applications of Upper-Bound and Lower-Bound theorems: thick-walled tubes; rotating disks.
  • Revision of rigid block mechanisms: application to forming problems. Elasto-plastic analysis of a thick-walled tube.

Examples papers

There will be four Examples Papers, directly related to the lectures.


Use the photo-elasticity method to determine stress concentration at the edge of a hole in a finite plate.

There is no Full Technical Report (FTR) associated with this module.


Please see the Booklist for Part IIA Courses for references for this module.

Examination Guidelines

Please refer to Form & conduct of the examinations.


The UK Standard for Professional Engineering Competence (UK-SPEC) describes the requirements that have to be met in order to become a Chartered Engineer, and gives examples of ways of doing this.

UK-SPEC is published by the Engineering Council on behalf of the UK engineering profession. The standard has been developed, and is regularly updated, by panels representing professional engineering institutions, employers and engineering educators. Of particular relevance here is the 'Accreditation of Higher Education Programmes' (AHEP) document which sets out the standard for degree accreditation.

The Output Standards Matrices indicate where each of the Output Criteria as specified in the AHEP 3rd edition document is addressed within the Engineering and Manufacturing Engineering Triposes.

Last modified: 27/09/2015 17:12