Crack opening and closure under the action of mechanical and thermal loads

Under general loading conditions, there is no guarantee that the crack surfaces will be fully open. Complete or partial closure of the crack could occur if the surrounding material is compressed. Such a phenomenon is illustrated for the situation of a single crack engulfed by a remote but uniform compressive stress field while tensile forces are applied at isolated points so that the material can counteract against the compressive field. Examples are provided illustrating partial crack closure with or without symmetry about the mid-plane normal to the crack surface. Considered will be mechanical and thermal loadings.