Stress singularity of nonhomogeneous body with crack in thermal stress fields

In this investigation, singular fields of stresses and heat fluxes at the tip of a crack in a nonhomogeneous body, or functionally gradient material (FGM), are studied under both elastic and plastic conditions. It is found that the crack tip fields have the same forms as those in the homogeneous material, provided that the material properties of FGM are continuous. The heat fluxes have a square-root singularity at the crack tip, and the elastic crack tip stress field is characterized by the K-field of linear fracture mechanics and the plastic singular field is the HRR field for a power-law material. The relationship between stress intensity J factors and the path-independent integral proposed by Aoki, Kishimoto, Matsumoto, Tachihara and Sakata is discussed. (author)