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Calculation Model of Materials Dynamic Destruction

#1208


Investigation of the Dynamic Destruction of Materials in Wide Longevity Ranges Aimed at Creating a Process Calculation Model

Tech Area / Field

  • PHY-SSP/Solid State Physics/Physics

Status
8 Project completed

Registration date
22.01.1998

Completion date
06.06.2005

Senior Project Manager
Tyurin I A

Leading Institute
VNIIEF, Russia, N. Novgorod reg., Sarov

Project summary

Both in natural phenomena and in laboratory experiments there are realized deferent possibilities of pulse effects on a solid state material leading to wave medium movement, what may cause its destruction.

The problem of the dynamic destruction process description including the investigation of dynamic effects, defining the behavior of materials at high pressures and temperatures (characteristic times of mechanical pulse operation t ~ 10-6 ё 10-10 sec), represents one of the most difficult problems of modern physics and it is also urgent for the solution of many applied questions of modern engineering. In recent years of considerable interest there has become the study of nonlinear dissipative media. In the course of their investigation it has been noted, that there often occurs in them they number decrease of the degrees of freedom (with their help one can efficiently describe the system). In some cases one can manage to single out some degrees of freedom, to which all the others are added.

In this connection of particular value is the investigation of simplest nonlinear models or the investigation of specific dissipative systems for detection a set of general regularities. The decrease of the system dynamics speaks for the fact that there take place in the system self-organization. The investigations demonstrated that in many cases the regimes stated in the dissipative media possess the invariant-group structure, for example, the appearing cascade of destruction centers. The law of storing damages is universal in various longevity are of fundamental character.

In the problem of material dynamic failure widely discussed in literature the most interesting phenomenon is a dynamic failure at different types of pulse loading.

Besides the explosive and shock-wave types of loading, there are applied loadings with the use of, electron beams for the purpose of considering the problems of independence of the destruction process on the method of loading (method of energy input). Pulse electron accelerators represent a unique tool for dynamic failure investigation.

While striking a solid body the electrons interact with its electron subsystem. In the time of the electron-ion relaxation tei (for metals tei – 10-11 s) the energy of electron subsystem excitation is transferred to the ion one. If the energy input is accomplished rapidly then while increasing the temperature the body isn't able to expand; a compressing pressure appears in it (thermal shock) due to potential will asymmetry. To relax the pressure the body (for example, a plane layer) expands in both directions, it is similar, to rarefaction wave propagation into a heated material. When the rarefaction wave meet a negative pressure forms in the substance that could cause a failure.

The research methods developed at present allow studying temperature-temporal reqularities of the dynamic failure of solid materials (in particular, determination of coordinates t P, T).

Basing on the results of experiments, fractography researches with the use of calculation means, application of fractal geometry methods and percolation theory, one can predict the topology state of object with increasing concentration of destruction centers - up to its macrodestruction. This will allow to make up a "pattern" of the process of dynamic destruction in a wide temperature-time range, to predict the behaviour of uninvestigated materials under extreme conditions and to create the corresponding data bank.

The goal of this work is the calculation model production of the process of dynamic distraction on the basis of the investigation results of forming dissipative structures (a cascade of destruction centers), used in modern high-energy pulse facilities, which lead to macrodistruction.

The rate of energy introduction and its density are according to ITER and Tokamak programs characteristic for the determination of the thermonuclear reactor first wall. The average energy flux of plasma pinch, affecting the first wall of the thermonuclear reactor TOKAMAK-ITEF, constitutes 2-3 MW/m2, while its affect to the plate pertor-7 MW/m2 (Kadomtsev B.B. Basics of tokamak plasma physics./Science and Engineering Achievements. series Plasma Physics. VINITU, 1991, v.10, No l, pl-148. Topilski L.N. Estimation of the first wall ITER service life. VANT, series Thermonuclear synthesis). It heats the wall and decreases its dynamic strength. At the shift of plasma pinch from the stationary orbit, owing to the influence of high-temperature plasma and outcoming electrons there increase the loads to the thermal shock in the near-surface layer of the wall material. In this case the pulsed pressures in the heated material can be as high as - 1GPa and they can lead to its thermomechanical destruction.

The goal of this work is the calculation model production of the process of dynamic destruction on the basis of the investigation results' of forming dissipative structures (a cascade of destruction centers), used in modern high-energy pulse facilities, which lead to macrodistruction.

The results of this work can be specifically used both at designing accelerators of charged particles and at investigating the problems of high energy concentrations in of magnetic cumilation phenomena as well as at the solution of a set of other problems.

After the completion of the works on-the given project we are going to continue the work on the setting up of the decisive stages and on the simplification of its description.

Publication


1. A.Ya.Uchaev, Bonyushkin, S.A.Novikov, N.I.Zavada. "The choption metal failure in the mode of rapid volume heating". Review. Moscow TsNIIAtominform, 1991, 85p.
2. A.I.Pavlovskii, E.K.Bonyushkin, A.Ya.Uchaev, S.A.Novikov, V.A.Tsukerman, N.I.Zavada, I.R.Trunin. "Peculiarities of temperature-temporal regularities of dynamic failure of some metals in the mode of rapid volume heating". DAN, 1991, v.317, N 6, p.1376.
3. E.K.Bonyshkin, N.I.Zavada, L.A.Platonova, N.I.Serchenkova, A.Ya.Uchaev. Fractal nature of dynamic failure process. In coll. book Fractal in applied physics. VNIIEF publishing house 1995, p. 123-174.
4. B.L.Glushak, I.R.Trunin, S.A.Novikov, A.I.Ruzanov. Numerical simulation of metals decomposition destruction. In coll. book Fractal in applied physics. VNIIEF publishing house 1995, p. 59-122.

Potential Role of Foreign Collaborators:


- Coordination of the schedule of activities;
- Discussion of current results;
- Joint discussion of project results;
- Joint analysis, joint publications.


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