Shear fracture of the main crack in the presence of rigid inclusions and an accompanying crack closure

Abstract

Earlier, a paper devoted to the planar problem of the interaction between the main crack and the field of small rigid inclusions under tensile loading was published [1]. The present investigation is concerned with the problem when a similar crack-inclusions set is affected by shear loading. Attention has been paid to the analysis of the possible macrocrack edge contact. Recent investigations of macro-microcrack interaction under shear loading [2, 3] and heat flux [4, 5] have revealed that, depending on the location and orientation of the small cracks, the main crack could be partially or completely closed and the macrocrack tip stress intensity factor K I could be negative. Therefore, in order to obtain the correct stress intensity factor K I the presence of the contact zones has been taken into account. This phenomena, for the shear loading of dissimilar materials with cracks, was revealed in the 1960s and references can be found in [61. In recent years, effect of crack closure is taken into account for different investigations (see e.g. [7, 8]). The problem of interaction between the main crack and small rigid inclusions is very close to the macro-microcrack problem. So, applying the method of singular integral equations [9] and the small parameter method [10, 3], the problem of crack-microinclusions interaction under shear loading can be solved with the following assumptions: 1) one opening zone with an unknown length 2c is located within the macrocrack;