Cohesion-magneto-mechanical coupling model-based interface crack evaluation method

Abstract

The invention discloses a cohesion-magneto-mechanical coupling model-based interface crack evaluation method. According to the method, the traction force and magnetic mechanical effect of the cohesionunit of a coating interface are combined, so that a cohesion-magnetic mechanical coupling model is established; the initial opening displacement of the cohesion unit is obtained through finite element simulation; fitting relationships between a magnetic field intensity threshold value, the maximum magnetic field growth speed of the cohesion unit and crack propagation speed during the growth of the fatigue crack of the interface are calculated through the cohesion-magnetic mechanical coupling model on the basis of the initial opening displacement; and the maximum magnetic field intensity of acquired self-generated magnetic signals at the interface is compared with the magnetic field intensity threshold value, so that whether the crack grows can be judged; the crack propagation speed of theinterface under the action of different fatigue circulation cycles and the crack propagation length of the interface during the fatigue service process of a coating can be obtained according to the fitting relationships. With the method of the invention adopted, the evolution behavior of the fatigue crack of the coating interface can be accurately evaluated.

Description

technical field [0001] The invention relates to a spontaneous magnetic flux leakage non-destructive detection method, in particular to a detection method for evaluating the evolution behavior of fatigue cracks at the ferromagnetic coating interface. Background technique [0002] Coatings prepared by advanced surface engineering technologies such as laser cladding, plasma surfacing, and supersonic flame spraying have good wear resistance, corrosion resistance, and high temperature resistance, and are widely used in high-end equipment. As a metastable material structure system, the coating / substrate has a large difference in mechanical properties of heterogeneous materials on both sides of the interface, and fatigue cracks are prone to appear at the interface during the service process. Carrying out relevant coating interface damage detection and evaluation for The safe operation of high-end equipment is of great significance. [0003] As a new non-destructive testing method,...

AI Technical Summary

Problems solved by technology

However, due to the discontinuity of the coating / substrate structure and the heterogeneity of the material, the stress field distribution at the interface is very complicated, and there are problems such as stress singularity and yield at the crack tip, so only the traditional force-magnetic constitutive It is difficult to effectively describe the spontaneous magnetic flux leakage evolution law of interface damage

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