LV EN RU DE FR

Strength of Materials I

Course developers

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 - students learn the principles of engineering calculations of strength, durability and deformation of materials and structures. Assessment of knowledge - tests and defense of individual works.
Skills - students are able to creatively use the principles and methods and techniques of material resistance in the calculation of strength, stability and deformation of engineering structures. Assessment - defense of individual and laboratory works.

Competence - students are able to independently solve engineering problems, create calculation schemes for real structures and perform the necessary calculations for equipment design work. Assessment - defense of individual and laboratory works.

Course Content(Calendar)

1. Introduction. Basic hypotheses of material strength - 2h.
2. Geometrical characteristics of section areas, their calculations - 4h.
3. Section method. Diagrams of internal force factors for basic loads. Differential relations in bending - 4h.
4. Definition of stress. Tensile (compressive) load. Hooke's law - 2h.
5. Tensile diagram for plastic and brittle materials. Allowable stress. Tensile strength calculation. Surface compression - 2h.
6. Test on the calculation of tensile strength.
7. Tensile test diagram for steel - 2h (Laboratory work).
8. Stress state of axially loaded bars. Combined stress state. Plane stress state and general stress state - 2h.
9. Determination of modulus of elasticity and Poisson's ratio - 2h (Laboratory work).
10. Generalized Hooke's Law. Deformations of the generalized stress state - 2h.
11. Pure shear load. Calculations of welded and riveted joints - 2h.
12. Strength theories - 2h.
13. Torsional loading. Round bar torsion. Calculation of torsional strength - 2h.
14. Determination of shear modulus in torsion - 2h (Laboratory work).
15. Bending load. Normal and tangential stresses in bending - 2h.
16. Determination of stresses in pure bending - 2h (Laboratory work).
17. Tangential stresses in bending. Bending strength calculations. Rational cross section of the beam - 4h.
18. Differential equation for the curved axis of the beam and its integration - 2h.

19. Test: calculation of bending deformations using the differential equation of the curved axis.

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

A successful assessment can be obtained in the test if there are no significant errors in the calculations and the process of the calculations is explained. The student receives high marks if the tasks performed in the laboratory and independent works are completed, well-designed and the student is able to answer the questions.

Compulsory reading

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

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

Further reading

1. Lavendelis E. Materiālu pretestība: mācību grāmata augstskolu tehnisko specialitāšu studentiem. Rīga: Zvaigzne,1986. 340 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: https://docs.google.com/file/d/0B-fBr8ucz0m4ZGRmdy1yckZXSWM/edit

Notes

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