Course detail

Nonlinear Problems of Mechanics in FEM

FSI-RNUAcad. year: 2014/2015

The course is a follow-up to basic lectures in solid mechanics, which are traditionally limited to linear problems, and introduces the basic nonlinearities. Material nonlinearity is represented by several models of plastic behaviour.
Next, contact problems, large displacement and large strain problems are presented. Although some classical solutions to selected nonlinear problems are mentioned (Hertz contact, deformation theory of plasticity), attention is given to numerical solution. Above all, the relation between stability and convergence of numerical solution and physical interpretation of the analysed problem is thoroughly inspected in seminars.

Language of instruction

Czech

Number of ECTS credits

5

Mode of study

Not applicable.

Guarantor

prof. Ing. Jindřich Petruška, CSc.

Department

Institute of Solid Mechanics, Mechatronics and Biomechanics (ÚMTMB)

Learning outcomes of the course unit

Students learn how to classify basic types of nonlinear behaviour in solid mechanics, they will learn their characteristics and classical solutions for some
types of problems. They can prepare numerical computational model, solve it using some of the commercial FE systems and make a rational analysis of
typical problems with divergence of the iterative process of solution.

Prerequisites

Mathematics: linear algebra, matrix notation, functions of one and more variables, calculus, ordinary and partial differential equations.
Others: basic theory of elasticity, theory and practical knowledge of the FEM.

Co-requisites

Not applicable.

Planned learning activities and teaching methods

The course is taught through lectures explaining the basic principles and theory of the discipline. Exercises are focused on practical topics presented in lectures.

Assesment methods and criteria linked to learning outcomes

The graded course-unit credit requirements :
- active participation in seminars,
- good results in the written test of basic knowledge,
- individual preparation and presentation of seminar assignments.

Course curriculum

Not applicable.

Work placements

Not applicable.

Aims

The aim of the course is to provide students with theoretical knowledge and elementary experience with the solution of most frequent types of nonlinear
problems of solid mechanics.

Specification of controlled education, way of implementation and compensation for absences

Attendance at seminars is required. The absence (in justified cases) is compensated by additional assignments according to the instructions of the tutor.

Recommended optional programme components

Not applicable.

Prerequisites and corequisites

Not applicable.

Basic literature

D.R.J.Owen, E.Hinton: Finite Elements in Plasticity, Pineridge Press, 1980
G.A.Holzapfel: Nonlinear Solid Mechanics, Wiley, 2000
K.-J.Bathe: Finite Element Procedures, K.-J.Bathe, 2014
M.A.Crisfield et al.: Non-linear Finite Element Analysis of Solids and Structures, Wiley, 2012

Recommended reading

M.Okrouhlík, editor: Mechanika poddajných teles, numerická matematika a superpocítace, Ústav termomechaniky AV CR, Praha, 1997

Classification of course in study plans

  • Programme N3901-2 Master's

    branch M-IMB , 1 year of study, summer semester, compulsory

Type of course unit

 

Lecture

26 hod., optionally

Teacher / Lecturer

prof. Ing. Jindřich Petruška, CSc.

Syllabus

1. Introduction to nonlinear problems of solid mechanics
2. Deformation theory of plasticity in analytical and numerical solutions
3. Incremental theory of plasticity and its implementation in FEM systems
4. Rigid-plastic analysis of forming problems - flow formulation
5. Plastic hinge and plastic collaps
6. Residual stress
7. Contact problems - classical solution
8. Strategy of contact solution in FEM, characteristics of contact elements
9. Geometrical nonlinearity - alternative formulations of strain tensors
10. Geometrical nonlinearity - continued
11. Stability of thin-walled structures as a nonlinear problem of mechanics
12. Explicit formulation of FEM in nonlinear problems of mechanics
13. Convergence of numerically solved nonlinear problem

Computer-assisted exercise

26 hod., compulsory

Teacher / Lecturer

prof. Ing. Jindřich Petruška, CSc.

Syllabus

1. Convergence of iterative solution of nonlinear problem - numerical demonstrations
2. Analytical solution of elastoplastic state of thick-walled cylindrical pipe
3. Plasticity in FEM - solution of selected tasks
4. Start of seminar project
5. Plastic collaps
6. Residual stress
7. Tutorial of seminar project
8. Solution of contact problem by FEM
9. Tutorial of seminar project
10. Solution of large displacement problem by FEM
11. Solution of stbility of shell
12. Example of an explicit FEM solver
13. Presentation of seminar projects