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5.4 Critical stress. The limits of applicability of the Euler’s
formula………………………………………………………… 54
5.5 Practical calculation of compressed rods stability………… 59
Questions for self-assessment…………………………………. 61
6 CALCULATIONS FOR STRENGTH AT STRESSES,
WHICH CHANGE OVER TIME……………………………... 63
6.1 The concept of fatigue……………………………………... 63
6.2 Cycles strains and their characteristics…………………….. 64
6.3 Methods for determining the boundary of endurance. Curve
fatigue…………………………………………………... 65
6.4 The main factors affecting the fatigue strength……………. 67
6.5 Diagram of boundary stresses. Fatigue safety factor……… 69
Questions for self-assessment…………………………………. 72
7 DYNAMIC PROBLEMS……………………………………. 74
7.1 Consideration of inertial forces at constant acceleration…... 74
7.2 Calculation under shock loads……………………………... 76
7.2.1 Technical theory of shock……………………………… 76
7.2.2 Longitudinal impact……………………………………. 77
7.2.3 Transverse impact……………………………………… 79
7.2.4 Twisting impact………………………………………... 80
7.2.5 Account the weight of the rod, which suffers blow……... 81
7.2.6 Strength of materials on impact…………………………. 83
7.3 Fluctuations of systems with one degree of freedom……… 85
7.3.1 Free vibrations of beams with one degree of freedom…... 86
7.3.2 Forced oscillations beam with one degree of freedom…... 89
Questions for self-assessment…………………………………. 92
8 BEAM ON ELASTIC FOUNDATION…………………….. 94
8.1 Model of elastic foundation………………………………... 94
8.2 The differential equation of beam on elastic foundation…... 95
8.3 Calculation of infinitely long beam………………………... 97
8.4 Short beams on elastic foundation…………………………. 101
Questions for self-assessment…………………………………. 104
9 THE CONCEPT OF MOMENTLESS THEORY OF
SHELLS. CALCULATION OF THICK – CYLINDER……… 106
9.1 Momentless model of axisymmetrical thin-walled shell…... 106
9.2 Stresses in axially symmetric thin-walled shell. Calculation
of the strength………………………………………………….. 107
9.3 Lame’s problem……………………………………………. 110
Questions for self-assessment…………………………………. 114
THE LIST OF SOURCES USED……………………………... 117

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