Fatigue crack retardation by the application of hard damping coating to blades under resonance

The hard damping coating via atmospheric plasma spraying (APS) method was proposed to inhibit crack propagation of blade specimens in this paper. The fatigue test of uncoated and coated thin-walled blade specimens was carried out under resonance, and experimental results show that hard damping coating has the ability of crack retardation. Then, the finite element (FE) model of standard blade specimens with breathing crack was established and verified by natural frequency change of blade specimens with crack propagation. Furthermore, the crack propagation model was introduced. The crack tip stress intensity factors (SIFs) of uncoated and coated blade specimens under different crack lengths were calculated, and the crack retardation mechanism of coating was explained. Finally, the crack propagation curves of the blade specimens were calculated, and the effects of the thickness, elastic modulus and density of the coating on the crack growth were discussed. The influence of coating treatment in different stages on crack propagation was analyzed. The effects of crack depth and crack angle on crack propagation were discussed, which can help optimize coating layout. Experimental and numerical analysis show that hard damping coating can effectively delay the crack propagation, which is a practical technology in engineering application of crack propagation retardation.

Automated summary

This paper proposes a hard damping coating via atmospheric plasma spraying (APS) method to inhibit crack propagation of blade specimens. Fatigue tests show that the hard damping coating has the ability to retard crack growth. A finite element (FE) model of standard blade specimens with breathing crack is established and verified, and the crack propagation model is introduced. The effects of coating thickness, elastic modulus, and density on crack growth are discussed, as well as the influence of coating treatment on crack propagation in different stages.