PSI - Issue 28

A. Vshivkov et al. / Procedia Structural Integrity 28 (2020) 1839–1845 Author name / Structural Integrity Procedia 00 (2019) 000–000

1843

5

dl

dl









2

2

(2)

, U W r W r     ,

 

 

1

2

p

p

p

dN

dN

Constants in equation (2) was determined by experimental data (α = 3.6e-17 [W/Pa2]; β = 3.3e-12 [W/(Pa2*m)]). This let us to suggest relation which can describe heat dissipation for uniaxial and biaxial loadings. Figures 5, 6 present comparison between experimental results and theoretical calculations of heat dissipation at fatigue crack tip.

0 0.2 0.4 0.6 0.8 1 1.2

sp1, measure sp1, calculation sp2, measure sp2, calculation sp3, measure sp3, calculation sp4, measure sp4, calculation sp5, measure sp5, calculation sp6, measure sp6, calculation sp7, measure sp7, calculation

0

0.5

1

1.5

2

2.5

Time, s

10 4

Fig. 5. Experimental measurement and theoretical calculation of heat dissipation during uniaxial fatigue tests.

Fig. 6. Experimental measurement and theoretical calculation of heat dissipation during biaxial fatigue tests.

Normalization of heat dissipation was conducted according to the following equation:

Q dl

(3)

*

Q

2    



dN

As a result, we have obtained a universal relation between heat flux and crack growth rate. The character of this relation does not depend from loading conditions (see figure 7).