Course code LauZ3167

Credit points 3

Strength of Materials I

Total Hours in Course120

Number of hours for lectures24

Number of hours for seminars and practical classes16

Number of hours for laboratory classes8

Independent study hours72

Date of course confirmation16.02.2016

Responsible UnitInstitute of Mechanics

Course developers

author prof.

Aivars Kaķītis

Dr. sc. ing.

author lect.

Mārtiņš Dauvarts

Bc. sc. ing.

Prior knowledge

Fizi2021, Physics I

Mate1029, Mathematics I

Mate1030, Mathematics II

Meha4008, Theoretical Mechanics I

Course abstract

The aim of the study course is to acquire basic knowledge about the strength of materials and methods of its determination, as well as about the methods of calculation of the basic elements of structures. In this part of the course the factors of internal forces and construction of their diagrams, combined stress state, strength theories, strength calculations in basic loads of structures, tensile, compressive, shear, torsion, bending are mastered.

Learning outcomes and their assessment

Knowledge - knows the principles of engineering calculations of strength, durability and deformation of materials and structures. There is an understanding of the construction and application of epics. Assessment of knowledge - tests and defense of independent work.
Skills - ability to look at the conditions of strength, stability and deformation of various engineering structures in an abstract and analytical way. Assessment - defense of laboratory works and independent works.

Competence - the ability to use the basic principles of material resistance in practical and scientific work, as well as in the invention and implementation of technically innovative processes. Able to independently solve engineering problems, create calculation schemes for real structures and perform the necessary calculations for equipment design work. Assessment - defense of laboratory work and independent work.

Course Content(Calendar)

1. Introduction. Basic hypotheses of material resistance - (1h L; 1h PstD).
2. Geometric characteristics of section areas, their calculations - (2h L; 2h PrD; 8h PstD).
3. Slicing method. Internal force factors for epic base loads. Bending of differential relations - (2h L; 2h PrD; 8h PstD).
4. Slicing method. Internal force factor epithelial base loads - (2h PstD), (Test 1)
5. Stress. Tensile (compressive) load. Hooke's Law - (1h L; 2h PrD; 6h PstD).
6. Tensile testing of steel - (2h LabD; 2h PstD) (Laboratory work 1)
7. Tensile diagram for plastic and brittle materials. Permissible voltage. Tensile strength calculation. Surface press - (2h L; 2h PrD; 4h PstD).
8. Determination of modulus of elasticity and Poisson's ratio - (2h LabD; 2h PstD), (2nd laboratory work).
9. Stresses in sections of drawn bar. Compound voltage state. Voltage-state of the plane and space - (2h L; 1h PrD; 4h PstD).
10. Stresses in stretched / extruded bar sections - (1h PstD), (Test 2)
11. Generalized Hooke's law. Deformation spaces in the stress state - (2h L; 1h PrD; 2h PstD).
12. Pure shear load. Calculations of welded and riveted joints - (2h L; 1h PrD; 2h PstD).
13. Strength theories - (2h L; 2h PstD).
14. Torsional loading. Round bar torsion. Calculation of torsional strength - (2h L; 1h PrD; 6h PstD).
15. Torsional loading. Round bar torsion. Calculation of torsional strength - (1h PstD) (Test 3)
16. Determination of shear modulus in torsion - (2h LabD; 4h PstD) (3. Laboratory work).
17. Bending load. Bending normal and tangential stresses - (2h L; 1h PrD; 6h PstD).
18. Bending tangential stresses. Bending strength calculations. Rational cross section of the beam - (2h L; 1h PrD; 4h PstD).
19. Determination of stresses in net bending - (2h LabD; 2h PstD) (4. Laboratory work).
20. Beam curved axis differential equation and its integration - (2h L; 2h PrD; 4h PstD).

21. Bending load. Bending normal and tangential stresses. (1h PstD) (Test 4)

Requirements for awarding credit points

The course ends with a test. In order to pass the test, independent work and laboratory works must be defended and tests must be written.

Description of the organization and tasks of students’ independent work

During the independent work students study in depth the topics discussed in the lectures and perform independent work:
1. Independent work: Calculate the geometrical characteristics of the section area for a composite beam.
2. Independent work: Calculate the internal force diagrams of a curved beam.
3. Independent work: Calculate the flat frame internal force diagrams.
4. Independent work: Perform a torsional strength calculation.

5. Independent work: Calculate the bending strength of the beam.

Criteria for Evaluating Learning Outcomes

The student explains the calculation process and justifies it with the principles of theory.

Compulsory reading

1. Ziemelis I., Kaķītis A., Dominieks L. Materiālu pretestība. Jelgava: LLU, 2008. 376 lpp.

2. Russell Hibbeler. Statics and Mechanics of Materials. Pearson; 5th edition, 2016. 936 p.

Further reading

1. Lavendelis E. Materiālu pretestība. Rīga: Zvaigzne,1986. 341 lpp.

2. Auzukalns J. Materiālu pretestība uzdevumos. Rīga: Zvaigzne, 1973. 742 lpp.

Periodicals and other sources

1. Gere J. M. Mechanics of Materials. 6th ed. [tiešsaiste] [skatīts 13.12.2020.]. Pieejams:


The study course is included in the Compulsory part of the Bachelor’s study program “Agricultural Engineering”. 2nd study year 4th semester.