Stress intensity factors of cracks in finite plates subjected to thermal loads

Abstract

In the framework of cracked plate thermoelastic problems, the perturbation effects caused by the presence of a crack on thermal stresses, displacements and stress intensity factors in an isotropic linear elastic medium with varying crack surface heat conductivity under uniform heat flow are studied. The disturbance due to the crack results in a non-smooth temperature modification of the original field and induces singular character of the thermal stresses near the crack tip. This disturbing temperature distribution is solved numerically by using the distributed dipole method. Finite element solutions under the above temperature distribution are presented. Numerical results of mixed mode stress intensity factors are given for various geometric cases of a plate. It is shown that, for the case of a crack situated in the finite plate center subjected to a uniform heat flow, the geometry does not affect the mode I thermal stress intensity factor KI significantly, and KI is negligible compared with the mode II thermal stress intensity factor KII. Only the mode II thermal stress intensity factor KII is significant and shows a very localized phenomenon in the near-field region of a crack. For all cases studied here, the values of the mode II thermal stress intensity factor in a smaller plate are dependent on the geometric size of the plate. As the geometric size of the plate increases, the value of KII is close to the solution of an infinite plate. © 1992.