Thermal fracture interference: a two-dimensional boundary element approach

Thermal loading of fractured structures is associated with the development of differential deformations along crack surfaces which result in the closure of the crack. Inherent non-linearities demand application of numerical procedures to resolve this problem. In this paper, a boundary element procedure is formulated to treat crack surface interference imposed under thermal steady-state or transient loadings. An iterative-incremental procedure is developed to deal with the non-linearity produced by the frictional contact of the crack surfaces. The open, adhesion and slip contact conditions are modeled through the utilization of the multi-domain technique. Two approaches are followed regarding the thermal boundary contact conditions along the crack region. In the first, crack surfaces are assumed to be thermally insulated. This assumption simplifies the formulation significantly. In the second, the crack surfaces are assumed to provide perfect thermal contact. Thermal stress intensity factors are evaluated from traction nodal results that adopt singular elements in the crack tip region. Numerical examples are illustrated, discussed and compared with analytical solutions, where possible. Fracture characteristics are predicted in terms of the involved parameters. As a general conclusion, peak values of thermal stress intensity factors depend on the friction conditions existing between crack faces.