Abstract
The presence of defects in the structure requires noticeable attention and understanding of fracture mechanisms in brittle materials has to be established. Defects in the form of holes, macro- and micro-cracks are the main interest of this paper. This work investigates the dual role of holes and micro-crack arrays on toughening and degradation mechanisms in concrete structures. An ordinary state-based peridynamics (PD) model is utilized to analyse the fracture problem at the micro-level. The application of PD shows its advantage in crack-hole, macro- and micro-crack interaction problems since PD can accurately predict the contribution of defects on structural behaviour. The study of the three-point bending problem with five types of holes existing in the structure showed the crack arrest phenomena at the hole boundary and the “attraction” of the crack to propagate towards the hole. For the study of the macro- and micro-cracks interaction problem, various cases of the micro-crack distribution and inclination angles are considered and validated with analytical studies. The PD quasi-static simulations show good agreement with analytical solutions. Moreover, PD dynamic solutions show the capability of PD to capture complex crack propagation paths. It is observed that the presence of micro-cracks and holes ahead of the main crack can suppress its further propagation as well as have an influence on the crack propagation direction. The numerical results demonstrate the efficiency of the PD modelling of multiple crack interaction problems.
Highlights
The failure of engineering structures has always been a topic of engineering practice
The parameter KI/K0 is helpful to identify if micro-cracks enhance or suppress the macro crack propagation and is very useful for understanding the complex structural behaviour with defects
When the plate consists of both macro- and micro-cracks, micro-cracks can have influence on the main crack propagation behaviour where the main crack follows the orientation of micro-cracks
Summary
The failure of engineering structures has always been a topic of engineering practice. Brittle materials can consist of randomly distributed small-size defects such as voids, micro-cracks and holes [5] These defects can have a significant influence on the propagation behaviour of macro-cracks. PD formulation allows to deal with complex crack interaction problems where multiple cracks of arbitrary shapes can be introduced in the structure, and tracking of the crack tip location and crack behaviour is not necessary For this reason, original “bond-based” PD has been successfully applied to brittle fracture problems to predict crack nucleation and propagation [31,32,33,34] as well as the main crack interacting with micro-cracks [35, 36]. Ordinary state-based PD model is used to investigate the influence of smallsize defects on the propagation of macro-cracks in brittle materials.
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