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Обзорная статья "Теория электронного типа разрушения твердых тел (1993)" и новые позиции авторов
Review report 'Theory of the electron fracture mode in solids' in 'Journal of Applied Physics - N12,v.74-93' and new author's ideas

Текст статьи - авторы (authors) Genady P. Cherepanov College of Engineering and Design, Florida International University, Miami, Florida 33199 (Formerly at Division of Applied Sciences, Harvard University, Cambridge. MA 02138.) Andrew A. Borzykh * Kursk Polytechnic Institute, Kursk, Russia, CIS (Received 11 January 1993; accepted for publication 26 August 1993)

Комментарии 1999 - Comments * Kursk Innovations-Consulting Center (with 1992) This text was the step of our generalization of investigation the group of phenomena and their math&physics models. The paper was finished until 1988 years, but we sent to magazine the text in this form in the 1992 years only.

Текст статьи - Abstract The theoretical model serving to explain and describe the phenomenon of the electron fracture mode (EFM) discovered experimentally nearly 20 years ago is advanced. EFM is characterized by the brittle cleavage of common plastic crystals proceeding with supersonic velocities independently of initial cracks when subjected to high-intensity electron beams. Using the invariant r integral of an electromagnetic deformable medium, it is proven that two electrons moving faster than the phase speed of light attract one another, as distinct from the common Coulomb's law. Self-packing of such relativistic electron beams is studied using a periodic chain model. It is suggested that during irradiation of a solid by a high-intensity electron beam, some electron clusters are formed, which act as wedges cutting the crystalline specimen. The dynamic problem of supersonic cutting by a thin wedge is studied, and the drag is calculated. The length of the resulting crack is computed. The theoretical results are confirmed by available experimental data.

Комментарии 1999 - Comments And we were intrigued that our mathematical models for interactions in electron beams easy transformed for similar dynamic problems in theory of supersonic cutting, in theory of optic-acoustic effects and others .

Текст статьи - I.INTRODUCTION In the mid 1960s, high-power pulse electron-beam accelerators having a voltage of some millions of volts were invented and later used to fracture various materials. Experimental data analysis enabled discovery of a new mode of fracture in several ductile crystals caused by a specific energy supply to the crack tip. The mode differs from the well-known thermomechanical modes of fracture caused by the "heat-thermostress-crack" mechanism. We call this new mode the electron fracture mode (EFM). It is char-acterized by the following three special features: (i) iInitial macrocracks in a specimen do not affect the threshold of fracture; in other words, the value of the beam intensity at which the specimen breaks; (ii) fracture of different mate-rials, which can be very ductile under usual mechanical loads, occurs in a brittle manner; that is, the specimen usually splits by a crack without any residual deforma-tions; (iii) the splitting cracks propagate with supersonic velocities. These data are controversial from the point of view of fracture mechanics and, hence, they cannot be un-derstood or explained with traditional theories. The purpose of the present study is to create a simple practical model of the EFM. Our basic viewpoint can be briefly summarized as follows: During irradiation of a solid by a high-intensity electron beam, some electron clusters are formed and act as "blades" or "wedges," cutting the crystalline specimen. In this section, experimental data on the EFM are analyzed and discussed, while the peculiarities of the EFM are specified. As a result, we can conclude that the pro-cesses caused by the EFM are unusual from the point of view of common fracture mechanics. In Sec. II, the invariant Г integrals of an electromagnetic -deformable medium are modified for supersonic singularities. The basic model and some problems explaining and describing the EFM are formulated. In Sec. III the relativistic electron interactions in beams are considered. Using Г integrals, we derive the law of the interaction of two moving relativistic charges; that is, the generalized Coulomb's law for relativistic charges. In particular, when two relativistic electrons e move with the same velocity v, one behind the other along a rectilinear trajectory, the force F acting upon the rear electron is equal to Here R is the distance between the electrons, c is the speed of light in vacuum, and a is the phase speed of light in a medium having electromagnetic constants, ? , ?, and ?'. It appears that two electrons moving faster than the phase speed of light attract each other, as distinct from the com-mon Coulomb's law; hence, the beams of such relativistic electrons tend to self-pack and self-compress. The latter problem is studied using a periodic chain model of the electron beam. In Sec. IV the dynamic elastic problem of supersonic cutting by a thin wedge is formulated and solved, and the drag force is calculated. In Sec. V the problem of deceleration of the moving wedge is solved in quasi-steady approximation. The length of a resulting cut, that is, the final crack, is determined. Some applications of the analytical solutions are given. In Sec. VI the theoretical results are analyzed and compared with experimental results. The role of relativistic electrons is estimated and some parameters of solid-state electron clusters are defined. The necessity of further study of this mysterious phenomenon is emphasized in Sec. VII.

Комментарии 1999 - Comments And we were intrigued that our mathematical models for interactions in electron beams easy transformed for similar dynamic problems in theory of supersonic cutting, in theory of optic-acoustic effects and others .

Under constructing, excuse us.
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