PSI - Issue 18

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A. Vshivkov et al. / Procedia Structural Integrity 18 (2019) 608–615 Author name / Structural Integrity Procedia 00 (2019) 000–000

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where A τ – applied stress amplitude which determines the diameter of yield surface, a 1 , a 2 – several coefficient. The process of heat dissipation is determined by the plastic work. This relationship could be complex due to the peculiarities of energy storage in material structure but taking into account the simplicity of equation (17) we will use the linear dependence of heat dissipation versus energy of plastic deformation for the first approximation of experimental results. Figures 6, 7 present the comparison of approximation (2) and results of the contact heat flux sensor. The equation (2) gives a good qualitative description of peculiarities of heat dissipation.

Fig. 6: Energy dissipation histories during uniaxial fatigue test (Solid line – experimental results, dotted line –approximation (2)).

Power of heat flux, W

Fig. 7: Energy dissipation histories during biaxial fatigue test (Solid line – experimental results, dotted line –approximation (18)).

where a1 =4e-18 [W/Pa 2 ] and a2 =5e-9 [W/(Pa 2 *m)] for both uniaxial and biaxial loading. 5. Conclusion In this work, experimental and theoretical studies of energy dissipated at fatigue crack tip in AISE 304 steel were carried out under biaxial loading with different biaxial coefficient.