Electromagnetic
radiation (EMR) occurs when structural materials (hereinafter simply materials)
of different origin are destroyed, caused by inhomogeneities (cracks,
microcracks, structural elements) of different scale levels created during the
destruction and cracking phase. In this situation, the production of
electromagnetic radiation is attributable to the following processes: the
interatomic distance, interstitial bonds, the appearance of free electrons and
vacancies, the movement of charges at the top and on the banks of the resulting
cracks. There is a universal relation between the duration of elastic energy
release and the size of cracks created. Under load, that is, the rise time of
the elastic wave's longitudinal component is proportional to the crack length.
On a scale from nanometers to thousands of kilometres, this relationship
occurs. For electromagnetic radiation, a similar relationship occurs that is
proportional to the leading edge length of an electromagnetic pulse, the
characteristic scale of the inhomogeneity responsible for producing this pulse.
The existence of knowledge on the parameters of inhomogeneities responsible for
the formation of this signal in its spectrum is determined by the physics of
EMR signal formation. In this regard, the problem of defining quantitative
relationships between the parameters of the EMR signal and the parameters of
inhomogeneities involved in the generation of this signal has both purely
scientific and practical significance. The solution of such a task enables the
observation (control) of the processes that occur in a destructible object in
real time. The methods developed and used by the author to analyse EMR signals
are based on the time-and-spectrum method, the essence of which lies in the
time-and-spectrum tables (TST) construction and subsequent analysis of the
contents of these tables. The TST rows are the moments of time, and the columns
are the frequencies of the spectral elements. The processes occurring at the
corresponding points in time are thus expressed by each row. In this regard,
the author has developed the following methods: (1) The method of constructing
time-and-spectrum tables to visualise the structure of the EMR signal; (2) The
method of estimating the magnitude of surface damage is based on the study of
the electromagnetic radiation spectrum using an analogue of the Hurst
normalised span statistics for the coo-span. The analysis of the evolution of
the dependencies of the normalised range statistics in logarithmic coordinates
shows that: 'Normalized range - frequency' helps us to classify their
behavioural features, which can be viewed as a transition to the final stage of
the destruction surface. 3) For the quantitative determination of the
parameters of an ensemble of microcracks, a model has been developed which
represents the transformation of the time-and-spectrum analysis method into a
space-and-time method. In this situation, the tables obtained were called
space-and-time tables (STT). The adequacy of the approach was tested using a
concentration test by Zhurkov. This approach examined the electromagnetic
radiation signals obtained under laboratory conditions by the destruction of a
sample of marble and diabase. A phenomenon called "High Frequency
Trace" has been found. The most interesting property of this phenomenon is
that the number of microcracks depends on their characteristic dimensions in a
nearly linear, inversely proportional way. Regions with logarithmic scale
invariance have this phenomenon. A wide variety of nonlinear oscillations and
waves, including a kink, were also found (topological soliton, dislocation in
the Frenkel - Kontorova model). 4) We studied the microscale phenomenon of the
logarithmic invariant dependence of the number (concentration) of microcracks
on their characteristic sizes during the destruction of marble and diabase
samples, named "High-Frequency Trace" in the early works of the
author, within the context of the testing of the model described above. The
ratios of the characteristic sizes of microcracks are determined at the points
where their concentration is increased. The notion of the fracture coefficient
is implemented by electromagnetic radiation. The self-organization phenomenon
of an ensemble of microcracks was discovered. The law, which obeys the law, is
shown to be An analogue of the Gutenberg-Richter rule for microscales is a
portion of the dependence of the number of microcracks on their characteristic
sizes in logarithmic coordinates for the "High Frequency Trace"
phenomenon.
Author (s) Details
Victor D. Borisov
Department of Mechanical Engineering,
Teplosnabzhenie, Belovo, Russia.
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