For the analysis of cracks in three-dimensional isotropic thermoelastic media, a temperature and displacement discontinuity boundary element method is developed. The Green functions for unit-point temperature and displacement discontinuities are derived, and the temperature and displacement discontinuity boundary integral equations are obtained for an arbitrarily shaped planar crack. Our boundary element method is based on the Green functions for a triangular element. As an application, elliptical cracks are analyzed to validate the developed method. The influence of various thermal boundary conditions is studied. Keywords: boundary element method, boundary integral equation method, displacement and temperature discontinuity, Green function, isotropic thermoelastic medium, planar crack, stress intensity factor, thermal boundary condition, triangular element.
INTRODUCTIONMuch research has been conducted in the analysis of cracks in thermoelastic materials using analytical or numerical methods [1][2][3][4]. Because solving complicated practical problems analytically is difficult, numerical methods are needed. Among the various numerical methods, the boundary element method is very convenient and efficient in such analyses, and many studies have adopted this method to analyze crack problems in thermoelastic media [2][3][4]. Furthermore, the subsequent displacement discontinuity boundary integral equation and boundary element method are more efficient in studying crack problems, as they grasp the basic characteristic of crack problems; specifically, fields are discontinuous across crack faces. The displacement discontinuity method was first proposed by Crouch [5] to study two-dimensional crack problems, and was then extended to three-dimensional elastic media, piezoelectric media, and magnetoelectroelastic media [6][7][8][9], where the electric and magnetic potential discontinuities were introduced across crack faces. Based on previous work, this paper develops the temperature and displacement discontinuity boundary integral equation and boundary element method for which the temperature distribution across the crack faces is assumed discontinuous. The Green functions for unit-point temperature and displacement discontinuities are derived, and the temperature and displacement discontinuity boundary integral equations are obtained for an arbitrarily shaped planar crack. The singular fields ahead of the crack front are discussed, and the stress intensity factors are obtained. For numerical simulations, the Green functions for a triangular element are obtained, and an elliptical crack is analyzed to validate the correctness of the analytical solution and the proposed numerical method. The influence of the temperature and different thermal conditions are also discussed.