The Analysis of Electromagnetic Radiation at Destruction of Structural Materials

With the destruction of structural materials (hereinafter simply materials) of different origin,
electromagnetic radiation (EMR) arises, which is generated by inhomogeneities (cracks, microcracks,
structural elements) of different scale levels formed in the process of destruction and cracking.
The formation of electromagnetic radiation in this case, due to the following processes: the gap
interatomic, interstitial bonds, the appearance of free electrons and vacancies, the movement of
charges at the tops and on the banks of the resulting cracks. There is a universal connection between
the duration of the release of elastic energy and the size of cracks formed under load, which is that
the rise time of the longitudinal component of the elastic wave is proportional to the length of the
crack.
This relationship exists on a scale from nanometers to thousands of kilometers. A similar relationship
exists for electromagnetic radiation it is proportional to the duration of the leading edge of an
electromagnetic pulse, the characteristic size of the inhomogeneity responsible for the generation of
this pulse. The physics of EMR signal formation determines the presence in its spectrum of
information about the parameters of inhomogeneities responsible for the formation of this signal.
In this regard, there is a problem that has both a purely scientific and practical significance, which is to
establish quantitative relationships between the parameters of the EMR signal and the parameters of
inhomogeneities involved in the generation of this signal. The solution of such a task allows real-time
observation (control) of the processes occurring in a destructible object.
The methods of analyzing EMR signals, developed and used by the author, are based on the timeand-
spectrum method, the essence of which lies in the construction of time-and-spectrum tables
(TST) and subsequent analysis of the contents of these tables. The rows of TST correspond to the
moments of time, and the columns correspond to the frequencies of the spectral components. Thus,
each rows represents the processes occurring at the corresponding points in time.
In this direction, the author has developed the following methods:
1) The method of constructing time-and-spectrum tables, which made it possible to visualize the
structure of the EMR signal
2) The method of estimating the magnitude of the surface damage is based on the study of the
spectrum of electromagnetic radiation using an analogue of the statistics of the normalized span of
Hurst in the coordinates: "normalized range - frequency." It uses a modification of the method of
normalized range. It is shown that the study of the evolution of dependencies of the statistics of the
normalized range in logarithmic coordinates: “normalized range - frequency” allows us to identify their
behavioral traits, which can be interpreted as a transition to the final stage of the formation of the
surface of destruction.
3) A model has been developed for the quantitative determination of the parameters of an ensemble
of microcracks, that represents the transformation of the method of time-and-spectrum analysis into a
space–and-time method. The tables obtained in this case were called space-and-time tables (STT).
The adequacy of the method was tested using Zhurkov's concentration test.