Finite Element Analysis and Applications

Module aims

The aim of the course is to teach the students to use Finite Element programs in a practical way to solve problems in linear elastic stress analysis. A student who has studied the course should be able, in a later industrial setting, to undertake the analysis of real problems with a fair understanding of sensible modelling procedures. In support of this, the course is split into two stages:

  1. Theoretical study of the Finite Element method, with emphasis on understanding what goes on inside a typical, modern, commercial program
  2. Practical experience in analysis using an industry-standard, interactive, Finite Element program.

ECTS units:    6   
Contributing to Course Elements: 6 to ME3-LCTVS or ME4-LCTVS

Learning outcomes

On successfully completing this module, students will be able to:

  • Explain the basic theoretical principles of the Finite Element method
  • Employ industry-standard software for interactive FE model generation, analysis and the post-processing of results
  • Interpret the output from the software critically and intelligently in order to yield the required information
  • Formulate the boundary conditions of a problem in a suitable form for correct analysis
  • Assess alternative strategies (of element type, mesh design, boundary condition definition etc.) for economical and accurate FE modelling of specific 2D, 3D and axisymmetric structural problems

Module syllabus

  • Introduction: with application to static stress analysis. Context and history.
  • Truss frame example: division into elements, selection of variables and shape functions, stiffness derivation, assembly of stiffness equations, application of boundary conditions, solution for displacements, computation of element stresses and strains.
  • The constant strain triangle: Continuum model and role of continuum elements; Geometry of constant strain triangle (CST), nodal variables and shape functions, stiffness derivation (plane stress and plane strain), element stress and strain computation.
  • Element forumulation: the need for more advanced and generalised procedures; element stiffness by virtual work; general procedure applied to CST; detailed derivation of linear rectangular element (Gauss quadrature, location of element integration points etc.); quadratic rectangular element, axisymmetric elements, 3-dimensional solid elements, truss and beam elements, membrane, plate and shell elements. Isoparametric elements, Jacobian mapping for arbitrarily shaped elements. Element performance: Stiffness and accuracy considerations. Nonconforming elements, reduced integration.
  • Element libraries: elements offered by commercial programs (shapes, nodes, degrees of freedom, allowable load types, etc.). Materials, loads, supports and solution: analysis procedure for modern commercial programs (definition of structure and loads, supports and other constraints, solution, post-processing); material property definitions and matrices; geometric properties (thicknesses, cross-sectional areas etc.); load types (point forces and moments, pressure, body forces, thermal) and internal conversion to nodal loads; supports, prescribed displacements, rigid links; symmetric and antisymmetric boundary conditions and their application to reduce model size; stiffness transformations to model supports or loads at arbitrary angels; stiffness matrix assembly and solution, bandwidth and its minimisation; Other types of solution (structural dynamics, material plasticity, large deflections, contact problems, fracture mechanics).
  • Guide to good modelling: Identification of appropriate domain of solution (2-/3-dimensional, axisymmetry, beams/shells etc.). Selection of elements, degrees of freedom, stress assumptions etc. Creation of mesh (refinement, shape, aspect ratios, curvature); Definition of material and geometric properties; application of loads and supports; pre-analysis checks; post-processing results - typical options; importance of verification, development of checking strategies; sources of inaccuracies and errors.

Pre-requisites

ME1-HSAN; ME2-HSAN

Teaching methods

  • Duration: Spring term (11 weeks)
  • Lectures: 5 x 3hr lectures covering the theoretical material listed in the syllabus
  • Tutorials: 6 x 1.5hr sessions in the computer room, devoted mainly to tackling the four tasks listed in the syllabus, but including some general tutorial time. Students work in groups of 2 or 3. Results of practicals are reported on brief structured forms for assessment.
  • Projects: Two tutorial sheets (not assessed), short project, both to be done mainly in own time.

Summary of student timetabled hours

Autumn

Spring

Summer

Lectures

0

15

0

Tutorials

Details of tutorials to be advised by the course leader during the course.

Other (computing)

0

9

0

Total

24

Expected private study time

3 hr per week, plus exam revision

Assessments

Written examinations:

Date (approx.)

Max. mark

Pass mark

Finite Element Analysis & Applications (3h)

A Data and Formulae handbook is provided.

This is a CLOSED BOOK Examination.

April/ May

160

n/a

 

Coursework (including progress tests, oral presentations etc.)

Submission date

Max. mark

Pass mark

Submission

Feedback

Practical task 1

Returned, with grade and written comments for discussion in tutorial

Jan-March

10

n/a

Practical task 2

Ditto

Jan-March

10

n/a

Practical task 3

Ditto

Jan-March

10

n/a

Practical task 4

Ditto

Jan-March

10

n/a

Total

200

n/a

Module leaders

Dr Ulrich Hansen