Course detail

Mechanics of Composite Materials

FSI-RMOAcad. year: 2011/2012

Introduction, basic terminology. Mechanical properties of the most used fibres and matrix materials. Stiffness of unidirectional fibre composites (lamina) in longitudinal and transversal direction. Critical and minimum fibre volume fraction. Short fibre composites, theory of load transport. Transport and critical fibre length. Siffness and strength. Orthotropic behaviour as a result of the fibre composite structure. Hooke's law of the anisotropic, orthotropic and transversal orthotropic material in principal material directions. Hooke's law for 2-D fibre composite (lamina) in arbitrary direction, strength conditions. Constitutive relations of the laminated thin wall and thin plate. Construction of stiffness matrix, strength analysis. Application to the thin-wall pressure vessel.

Language of instruction

Czech

Number of ECTS credits

5

Mode of study

Not applicable.

Guarantor

prof. RNDr. Ing. Jan Vrbka, DrSc., dr. h. c.

Department

Institute of Solid Mechanics, Mechatronics and Biomechanics (ÚMTMB)

Learning outcomes of the course unit

Students will have a clear idea of the directional behaviour of composite material and of methods used in stress-strain analysis and strength control of selected structures made of composite materials.

Prerequisites

Knowledge of basic terms of theory of elasticity (stress, principal stress, deformation, strain, general Hooke's law), membrane theory of shells. Fundamentals of FEM and basic handling of ANSYS system.

Co-requisites

Not applicable.

Planned learning activities and teaching methods

Teaching methods depend on the type of course unit as specified in the article 7 of BUT Rules for Studies and Examinations.

Assesment methods and criteria linked to learning outcomes

The credit conferment is based on the successful disputation of the final project, dealing with computational modelling of mechanical behaviour of a defined structure made of composite material using FEM program ANSYS. The exam consists of a written review test and of an oral interview.

Course curriculum

Not applicable.

Work placements

Not applicable.

Aims

The objective of the course is to make students familiar with basic knowledge of mechanical behaviour of composite materials, especially of fibre composites. Elastic and strength characteristics of the composite are determined from the known mechanical properties of components and from their geometrical structure. Students get acquainted with methods used in evaluation of stresses, strains and safety factor of typical structures made of composite materials.

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

Participation in seminars is required. In a justified case an absence from the seminar can be compensated by individual projects controlled by the tutor.

Recommended optional programme components

Not applicable.

Prerequisites and corequisites

Not applicable.

Basic literature

Agarwal,B.D., Broutman,L.J.: Vláknové kompozity, SNTL, Praha, 1987
Jones,R.M.: Mechanics of composite materials. Hemisphere Publishing Corporation, New York, 1975
Krishan K. Chawla: Composite materials. Science and Engineering. Springer-Verlag, New York, Berlin, Heidelberg, 1998

Recommended reading

Not applicable.

Classification of course in study plans

  • Programme N3901-2 Master's

    branch M-IMB , 2 year of study, winter semester, compulsory

Type of course unit

 

Lecture

26 hod., optionally

Teacher / Lecturer

prof. RNDr. Ing. Jan Vrbka, DrSc., dr. h. c.

Syllabus

1.Definition and basic terms. Classification of composite materials based on their structure and materials of their components.
2.Mechanical properties of typical fibres and of matrix materials. Chemical composition, way of production.
3.Unidirectional long-fibre composite. Elasticity modulus and strength in longitudinal direction.
Critical and minimal volume of fibres.
4.Unidirectional long-fibre composite. Elasticity modulus and strength in transversal direction.Shear modulus and Poisson’s ratio.
5.Failure mechanisms of long-fibre composites under longitudinal and transversal, tensional and compressive loading.
6.Short-fibre unidirectional composite. Theory of load bearing. Stress distribution in fibres. Transmission and critical length.
7.Short-fibre unidirectional composite. Elasticity modulus and strength in transversal and longitudinal directions. Strength in transversal and longitudinal directions.
8.Modelling of mechanical properties of composites within the framework of solid mechanics. 9.Principal axes of orthotropy. Hook’s law for isotropic, orthotropic and transversally isotropic materials in principal material directions.
10.Hook’s law for plane orthotropic material in general directions. Directional stiffness matrix. Balanced oriented lamina.
11.Strength conditions for a plane composite material: maximal stress, maximal strain and Tsai-Hill energetic conditions.
12.Constitutive relations for a composed laminate wall and plate.
13.Calculation of stresses and strength control of a cylindrical laminate wall.

Computer-assisted exercise

13 hod., compulsory

Teacher / Lecturer

prof. Ing. Jiří Burša, Ph.D.

Syllabus

1.FEM simulation of tensile test of fibre composite specimen in longitudinal direction.
2.FEM simulation of tensile test of composite specimen in transversal direction.
3.FEM simulation of shear test of fibre composite specimen.
4.FEM simulation of tensile test of composite specimen in transversal plane.
5.Evaluation of the stress concentration factor under tranversal load.
6.FEM simulation of tensile test of specimen in oblique direction.
7.Practical demonstration of production and testing of composite materials.
8.FEM simulation of bending test.
9.Orthotropic material model in ANSYS system, input of elastic constants.
10.Simulation of basic mechanical tests using orthotropic model of material properties.
11.Modelling of a general body of orthotropic material.
12.Formulation of final projects.
13.Evaluation of final projects, credit.

E-learning texts

Vrbka, J.; Mechanika kompozitů; ÚMTMB, FSI, VUT v Brně; 2014
FSI-UMT-ucebni text-Mechanika kompozitů-121217.pdf 4.03 MB