Rupture of Interatomic Bonding at the Crack Tip

Let us estimate the parameters of the crack tip proceeding from (17.17). The area of the crack tip S can be expressed as 

2) In these empirical equations the crack length is given in mm, coefficients 0.112 and 0.147 are given in mm.  

Substituting the parameters in (17.17) we obtain data listed in Table 17.2. 

The /S values are of the order of the crack-tip size. It means that the needle-like tip of the crack equals 27-85 interatomic distances. Approximately this number of interatomic bondings are destroyed in front of the growing crack simultaneously per one cycle of load vibration. 

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