The article is devoted to the organization of the structural health monitoring of a walking dragline excavator using the acoustic emission (AE) method. Since the dragline excavator under study is a large and noisy industrial facility, preliminary prospecting researches were carried out to conduct effective control by the AE method, including the study of AE sources, AE waveguide, and noise parameters analysis. In addition, AE filtering methods were improved. It is shown that application of the developed filtering algorithms allows to detect AE impulses from cracks and defects against a background noise exceeding the useful signal in amplitude and intensity. Using the proposed solutions in the monitoring of a real dragline excavator during its operation made it possible to identify a crack in one of its elements (weld joint in a dragline back leg).

Dynamic characteristics of changes in the diameter of larch forests in the Lower Angara region are being analyzed. Larch stands of the herbal group of fox types is the object of the present research. This research is based on the data of field inventory 858 forest areas with larch predominance. The structure of the forest average diameter is approximated by the exponential function, statistical analysis of which has been carried out using a non-linear least-squares method and simulation methods by conducting 50000 statistical tests. Regularities of error distribution, parameters and calculation accuracy of approximating function have been defined. Estimations of parameter correlations approximating function have been suggested. Holetsky’s method helped to receive two dimensional parameter generator. The defined regularities of the dynamics of average diameters allow to design economic activities in forest stands of larch herbal groups types in the region under study.

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The paper is devoted to the study of the possibility of detecting cracks in railway rails by the acoustic emission (AE) method. An experimental study of AE signals under cyclic compression loading of rail fragments, which simulates the rail operating load, has been carried out. Fragments of rails without defects, as well as fragments containing pre-grown fatigue cracks, were studied. It was found that AE signals generated by a rail with a crack have higher activity compared to signals from defect-free specimens. It is shown that the AE signals during the loading of defect-free specimens have a short duration and low amplitude and may be caused by the deformation of non-metallic inclusions. The crack presence leads to an increase in the AE hits rate and changes the nature of the distribution of the AE hits amplitudes. It is shown that the crack location has no effect on the reliability of its detection by the AE method. Criteria of crack detection by AE testing are offered as a result of this study.