ИСТИНА

The bridged crack approach is used for modeling of cracked structures self-healing. In the frames of this approach is assumed: 1) there is a crack in a structure after service loading; 2) there are bonds between surfaces of a crack (which are induced by a healing mechanism, the interface layer); 3) this layer is considered as a part of the crack with distributed nonlinear spring-like bonds between surfaces of crack (bridged zone). The bonds properties define the stresses at the crack bridged zone, its size and, hence, the fracture toughness of the material. The main goal of the modeling consists in the computational analysis of the bridging stresses distribution and in the computing of the stress intensity factors which are the main characteristics of self-healing efficiency. The mathematical background of the stress problem solution is based on the singular integral-differential equations method and the boundary elements method. Different self-healing methods (microcapsules filled with a self-healing agent, microvascular fibers, mendable polymers) with various mechanisms of self-healing are analyzed. The thermo-fluctuation kinetic Zurkov’s model is used to evaluate the regeneration and formation of the crack bridged zone. The healing time and efficiency are dependent on the chemical reaction rate of the healing agent, crack size and the external loads. The model can be used for the evaluation of composite materials healing and durability.