Vol 54, No 11 (2018)

Results of studying regularities in the development of cracks in glass under impact loading using the method of acoustic emission (AE) and tensometry are presented. An experimental setup has been developed that provides a single dynamic action with further damping of elastic vibrations in a test object. It has been established that the relaxation of elastic stresses occurring near the crack after the impact is described by a logarithmic dependence. The parameters of the amplitude and time distributions of AE signals have been determined. A technique is proposed for dividing the total flow of AE signals into stationary groups with an exponential distribution of time intervals between the signals.

Issues of estimating the instrumental errors of a device for in-process control of the position of a rotating plane, based on analyzing the coordinates of the points on the trajectory of movement of a luminous mark in a rotating mirror are considered. The main dependences describing the trajectory of the luminous mark in the rotating mirror are provided, the schemes in which errors are formed are considered, some assessments of these errors are given, and the main components of the errors are highlighted. Based on the research, recommendations are given on choosing the parameters of a device that implements the control of the position of the rotating plane.

The main advantages and disadvantages of universal software packages designed to solve problems of magnetostatics are indicated. The problems arising from the use of such packages are discussed, and possible ways to overcome these barriers are suggested.

The possibilities of increasing the reliability of eddy-current quality control of soldering in current-carrying copper joints of the stator windings of electrical machines and expanding the nomenclature of inspected joints by using an improved eddy current transducer with a U-shaped core are investigated. To achieve this goal, rectangular cutouts were made in the poles of the U-shaped core, made of transformer steel plates, to allow the transducer to be mounted on a tested solder joint in two mutually perpendicular directions. Using such a transducer for testing allows one to induce closedloop eddy currents in the solder joint along these two directions, thus significantly improving the reliability of testing by virtue of all soldered surfaces in the joint contributing to the eddy-current transducer signal. The use of such a transducer also significantly expands the range of tested joints due to the possibility of exciting closed-loop eddy currents perpendicular to the direction of such joints (testing the side walls of the joints). It is shown that despite local changes in the distribution of electromagnetic field in the interpole space as compared to the case of no cuts, the presence of rectangular cuts in the poles of the U-shaped core of the eddy current transducer practically does not affect the accuracy of determining the degree of soldering of tested joints along and perpendicular to their direction.

The structure and principle of operation of a heating unit intended for the thermal and radiation-thermal treatment of luminescence ionizing-radiation detectors aimed at modifying their dosimetric characteristics are described. The unit provides for linear heating of detectors in the range of 50–700°C at a given rate from 1 to 15°C/s, as well as for isothermal exposure of detectors. A description of unit operation is given as well as the results of trial tests that prove a high accuracy in reproducing the temperature and heating rate, acceptable for problems being solved.