Numerical Study On Stress Intensity Factor Of Cracks In Coating/Substrate System

With the fast development of coating technology, coated materials are extensively used in many areas. Study on the fracture strength of coating/substrate system has important theoretical significances, and can provide foundations for the design and preparation of coated materials. In this dissertation, finite element software ANSYS is applied to analyze contact stress and stress intensity factor of crack in coating/substrate system numerically.For the contact stress of coating/substrate system under cylindrical indenter, the distribution of the contact normal and shear stress with different material and different coating thickness are discussed. The contact width under different contact load is also analyzed.Stress intensity factor of crack in coating/substrate system under Hertz pressure and cylindrical indenter is investigated respectively. Then, the variations of stress intensity factors of single and double surface crack(s) with different coating/substrate materials, different crack length, and different crack position are analyzed respectively.For the interface crack of coating/substrate system, the stress field of crack tip and the related displacement near crack tip of corresponding point are analyzed. The stress intensity factor is calculated with a series of equations. Results of the bimaterial plate with a central interface crack are presented to confirm the accuracy of the above method. Furthermore, the stress intensity factors of single and double interface crack(s), under the Hertz pressure and cylindrical indenter with different coating/substrate material, different crack length, and different crack position are analyzed.