Mechanics |
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1997, No. 2
B.I. Astafev, L.V. Stepanova
Stress, strain rate and damage fields near the growth crack tip in coupled creep-damage approach for the linear-fractional constitutve relations are analyzed. It is found that the damage accumulation tends to the appearance of damage zone adjacent to the crack surfaces where all components of stress tensor are equal to zero and damage parameter is equal to unit (so-named failed or fully damage zone). Also the influence of damage tends to vanishing of strain rate singularity.
E.N. Kozhevnikov, N.G. Dolmatova
FREDERIKS TRANZITION IN HOMEOTROPICALY ORIENTED NLC
Nonstationary nonlinear stresses and moments in Nematic Liquid Crystal under sound action are constructed on the base of statistical approach by nonequilibrium angular distribution and time averagerating of microstresses and micromoments caused by molecular rotation. Microscopic description is made in the frame of nonequilibriun thermodynamics; nonequilibrium densisty distribution is determined from Fokker-Plank equation. It is shown that stationary stresses and moments result in structural deformation of homeotropicaly oriented NLC-layer under sound incidence to it. The effect is of a threshold character (acoustical Frederiks trazition). Theoretical results are compared with experiemental data.