Numerical modelling of the interaction macro–multimicrocracks in a plate under tensile stress

In this work, the evaluation of the stress intensity factor of a macrocrack in interaction with one or several microcracks in a material containing a geometrical defect was investigated. Several configurations were considered in order to apprehend the mechanisms induced by the interaction effect and in particular the effects of reduction and/or amplification of the stress field between macro and single or multiple microcracks. The obtained results show that, macro–microcrack spacing is an important parameter if the microscopic cracks is relatively close to the macrocrack tip. The macrocrack has the tendency to accelerate as it propagates towards the microcrack. When the relative distance characterizing this spacing is higher than 0.2, the interaction effect can be neglected and the stress intensity factor remains unchanged for both defect types. When this ratio is lower than 0.2, the interaction between the two defects becomes significant and the stress intensity factor at the macrocrack tip strongly increases. For an inclined microcrack configuration, the interaction becomes significant and cannot be neglected.

► We modeled the interaction effect of macro and multi-microcrack parallel and in series.
► The plastic zones are compressed by modifying interaction stress and the extension of macrocrack.
► The SIF increases linearly when h/a < 10 and d/a → 0
► The stress interaction causes the coalescence of macrocrack and microcracks at its vicinity.