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Of the two values n , determined by (6.18) is less than the

desired value.
In asymmetric torsion cycles similarly we obtain
 
n   1 , n  T .
 k  k (6.19)
        
a  m a m
   
   
In the joint action of bending torsion at present Gough-Polard’s
empirical relationship is generally used
n n
n    . (6.20)
2
n  n 2
 

Questions for self-assessment

1. What is the essence of the phenomenon of fatigue of
the material?
2. What is cycle stress?
3. Which cycles of stress do you know?
4. What parameters characterize the stress cycle?
5. How can you build a Wohler curve for the given
material?
6. What is the limit of endurance?
7. Which value is called the base number of cycles?
8. What is the diagram of the limiting amplitudes and
what is its purpose?
9. How do you schematize the diagram of limiting
amplitude?
10. Which factors affect the fatigue strength of materials?
11. Which measures can reduce the impact of harmful
factors on the fatigue strength of materials?
12. What is small cyclic fatigue?

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