The stress-strain curves of polimetilmetakrilat (PMMA) and polytetrafluoroethylene (PTFE) in a wide range of change of strain-rates are obtained. It is found, that at irreversible deformation PMMA and PTFE jerky flow arises, at least, at three scale levels and has a periodic character. The region of existence of jumps of different scale levels is revealed. The statistical analysis of jumps of pressure on stress-strain curves is carried out. The results make it possible to track the tendencies of change of the character of jerky flow as a function of strain-rates. The obtained statistical data allows one to make a conclusion on scale invariance of jerky flow of the investigated polymers. The connection of peculiarity of jerky flow with mechanisms of irreversible deformation is discussed.
|
