Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Soliton models of dislocation and acoustic emission in metallic materials

Pawełek A., Pilecki S.

Archives of Acoustics

2000

Vol. 25, no. 3

331-358

In this paper the analysis of the dislocation models and the possibilties of their appliacation to the description of the acoustic emission (AE) sources, which are acting during plastic deformation of metallic materials are presented. Especially the one-dimensional atomic Frenkel-Kontorova model pf dislocation (model FK) has been discussed with particular reference to its nonlinear properties which determine the movement of the dislocation kink along the dislocation line as a solitary wave process. At the same time the equivalence of the FK model with the string model of dislocation (S model) has been demonstrated. In consequence, the FK model has been generalized by the consideration of new terms of higher order responsible for the anharmonic (nonlinear) interaction between the atoms (including also the second coordination zone). A new class of nonlinear partial differential equations (NLPD equations), which may play a role in the theory of lattice vibration of the crystal with dislocation as well as in the theory of dislocations, has been obtained. The results are discussed in the context of rich experimental data (obtained at IMIM) which establish the correlations between the measured AE parameters and the plastic deformation mechanisms as well as microstructure evolution accurring in fcc single and polycrystals subjected to channel-die compression, especially at the liquid nitrogen temperature.

Acoustic Emission Data on Mechanism Fracture of Unidirectional Fiber Reinforced Composites

Leksowskij A., Abdumanonov A., Pilecki S., Ranachowski P.

Molecular and Quantum Acoustics

1999

Vol. 20

135-141

The investigation of fiber's break process was carried out by acoustic emission method under tensile loading of AL-B and carbon fibers reinforced composites. The experiment has shown that final act of macrofacture is preceding by sequence of single breaks, which time interval are shortened impetuously. The analysis interval of time sequence point out that the fiber breaks are correlated and the distribution of local stress by relaxation process. It is established that Weibull's distribution of B-fibers strength is not homogeneous and has characteristic modes. lt is shown that Zweben's model on determination of strength of unidirectional fibers reinforced composites gives satisfactory agreement with an experiment under taking into account lowering of coefficient stress concentration on fiber, neighboring to broken (at the expense of relaxation effect) and using the parameter of width distribution not on the whole, but without weak one.