3. Answer the following questions:

1. What method did Mohr use in developing his theory of strength?

2. What is principal circle?

3. What do you know about criterion of failure?

4. What is shear stress criterion?

5. What is stress space?

6. What other strength theories do you know?

7. Speak about Mohr's theory.

4. Finish the following sentences:

1. The reason for his students' interest in his lectures stemmed from …….

2. Tresca criterion assumed that the critical value of the shear stress …….

3. Voigt came to the conclusion that the question of strength is too …….

4. In the special case of metallic materials with the same strength …….

5. By using a thick walled cylinder of high-grade steel …….

6. He designed and constructed a special device for producing …….

7. Photographs of geometric models of such surfaces corresponding …….

5. Translate the following words and word combinations into Ukrainian:

stress circle method, theory of strength, engineering mechanics, creation of the science, strength of materials, failure, fracture, stress, shear, assumption, decisive measure, impending failure, brittle materials, plane, criterion, successful application, structural materials, special device, compression of a cubic specimen, perpendicular directions, various yield criteria.

6. Put these words in to the right order to make sentences:

1. of, more, Mohr, the, made, complete, strength, materials, study, a, of.

2. criterion, referred, the, Mohr-Coulomb, now, strength, to, theory, is, as, This.

3. number, tests, made, stresses, A, with, view, checking, with, Mohr's, to, theory, were, of, combined, a.

4. He, that, isotropic, withstand, high, condition, that, very, material, found, an, could, in, pressure.

5. advantage, space, in, simplicity, presentation, of, lies, and, visual, such, The, its.

6. yield, the, surface, space, transformed, space, The, stress, be, into, can, in, strain, the.

7. A, strength, expressions, presented, lot, after, theories, Mohr, and, were, of.

6. Complete the sentences with the appropriate words from the text.

   1. Mohr always tried to bring something fresh and _______ to the students' attention.

   2. He considered failure in broad senses; that is, it can be yielding of the _______ or fracture.

   3. Both criteria were based on the assumption that the maximum shear stress is the only decisive _______ of impending failure.

   4. The strength of _______ under a complex stress state can be determined by the corresponding limiting principal circle.

   5. He found that an isotropic material could withstand very _______ pressure in that condition.

   6. A comparison of various strength _______ applied in machine design before the 1930s was given by Marin.

   7. Since then the study of strength theory has been developing on a more reliable _______ basis.

8. Match English words with their Ukrainian equivalents:

1. comparison a)припущення

2. specimen b)пружність

3. application c)простота

4. tension d)порівняння

5. simplicity e)поломка

6. assumption f)зразок

7. failure g)застосування