Abstarct: In this thesis، a finite orthotropic environment under heat shock is studied. Coupled dynamical thermoelasticity equations baxsed on Green-Naghdi thermoelasticity theory are considered، as well as the finite element method developed for discretization in space and the implicit Newmark method for temporal integration. Mechanical and temperature enrichment functions have been used to model the crack in the finite element method. Stress intensity coefficients were calculated using the interaction integral method and compared for different angles of fibers in an orthotropic material. The results are also investigated for several different integral radii. In the following، the temperature distribution around the crack tip which causes the temperature distribution to be perturbed is compared baxsed on two type-III and III-Green theory. The stress intensity coefficients of the two modes I and II for an edge cracked plate for different angles of the fibers have been validated by Mohammadi's paper. The results are very accurate. Also، the stress intensity coefficients in two modes I and II for a plate having a smooth internal crack for an orthotropic material under mechanical loading were validated with the results of the Sanchez paper which results were highly accurate. The results have been investigated for two smooth and inner rim edges under uniform heat shock for different angles of fibers.