Mechanics |
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1996, No. 2
V.I. Astafev, L.K. Shiryaeva
CRACK GROWTH IN EMBRITTLED ELASTIC-PLASTIC MEDIA
The mathematical model for description f crack growth in embrittled elastic-plastic media is proposed. Crack growth is modeled by using of some damage parameter. Leonov-Panasuk fracture criterion is used as the local criterion to describe the crack initiation and growth. The model proposed was used to investigate the problems of semi-infinite crack growth in embrittled hydrogen-contained media. Conditions of non-propagated crack or crack arrest are determined and the value of the threshold stress intensity factor KISCC for the crack in embrittled elastic-plastic media is found.
E.N. Kozhevnikov, N.G. Dolmatova
NONSIMMETRY OF STRESSES IN VISCOUS WAVES IN NLC
Viscoelastic stress tenzor is founded on the base of microscopic model of nematic liquid crystal. There are determined moments and stresses due to rotation of a molecular, macroscopic stresses are derived from microstresses averaged by equilibrium angular distribution of molecular axes orientation. It is shown that the account of forth angular distribution moments results in nonsymmetry of stress tenzor in viscous waves and Rapini equality destruction. The theory of the effect is compared with experimental data.