ИСТИНА

Numerical modeling was performed to study the effect of plastic deformation on the stress-strain state at the crack tip under the influence of internal pressure, and the lag formation. It was shown that plastic deformation prevents the opening of a crack segment not filled with fluid. In this case, the lag size is much smaller than in the elastic medium. With the same differential pressure in the crack and compressive load, the ratio between horizontal (closing) and vertical stresses significantly affects the lag size, crack opening, and plastic deformation at the tip. The greatest opening of the crack and the largest lag size are observed at equal horizontal and vertical stresses. The pressure distribution pattern slightly affects the lag size.