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Vol 52, No 2 (2016)
- Year: 2016
- Articles: 7
- URL: https://journals.rcsi.science/1061-8309/issue/view/11280
Acoustic Methods
53-59
Two approaches to the solution of problems of ultrasonic flaw metering: Analysis of a high-quality image of reflectors and correlation analysis of measured echo signals
Abstract
The problem of ultrasonic flaw metering consists in the obtainment of information on the reflector type, its dimensions, and the coordinates of its location. As the accuracy of determining the parameters of a discontinuity increases, the results of ultrasonic testing become more reliable. A highquality image of reflectors, which is reconstructed using the C-SAFT method with consideration for multiple reflections of pulses from the boundaries of a test object that makes it possible to determine the types and dimensions of reflectors, can be considered as one of the tools of flaw metering. However, the C-SAFT method disregards the features of reflections from discontinuities with nonuniform scattering indicatrices. As a development of flaw-metering methods, it is proposed to determine the parameters of a discontinuity from the results of comparison of the measured echo signals and estimated echo signals, which are calculated as functions of the discontinuity parameters. The results of using the proposed methods of ultrasonic flaw metering in numerical and model experiments, which demonstrate the working capacity of the proposed approach, are presented.
60-77
Factors that affect the excitation effectiveness of torsional waves during waveguide inspection of pipes
Abstract
The results of theoretical and experimental studies of the features and excitation effectiveness of torsional waves in pipes depending on the parameters of excitation, the properties of the pipe material, and the dimensions of an object are given. The results can be used for the evaluation of the possibility of waveguide quality control of pipelines during the development of inspection procedures using torsional waves.
78-84
Eddy-Current Methods
An initial-boundary value problem of structurescopy of a nonferromagnetic metal solid with foreign dielectric inclusions using the residual field of an instantaneously cut-off extraneous current
Abstract
An initial-boundary value problem of electrodynamics is considered for the structurescopy of a nonferromagnetic metal with foreign dielectric inclusions; it is assumed that structurescopy is carried out using the residual electromagnetic field of an instantaneously cut-off extraneous current. Under the fairly sweeping assumptions on the electric conductivity of the solid, the dielectric permittivity of the foreign inclusions, and the smoothness of the boundaries of the solid and the inclusions, it has been proven that the initial-boundary value problem of electrodynamics under consideration has a unique solution, which depends continuously on the initial conditions.
85-94
The probabilistic characteristics of estimation of the residual strength and operation lifetime of steel wire rope based on the results of non-destructive testing
Abstract
This article describes a procedure for the probabilistic estimation of the strength indices of steel wire ropes on the basis of the data of magnetic non-destructive testing. The proposed method for the determination of probabilistic characteristics undetection an existing fault of a heterogeneous wire rope structure and the false detection of a fault. The obtained probabilistic estimates of errors of nondestructive testing have been applied for calculations of high-risk and conservative scenarios of the variation of the strength and remaining lifetime of wire rope during its non-fault operation lifetime.
95-101
Integrated Methods
Integrated quality control of the rotor discs of gas turbines of gas-compressor units by eddy-current and dye penetrant nondestructive testing
Abstract
The features of the integrated diagnostics of the discs of gas turbines of gas-compressor units using eddy-current and dye-penetrant testing are considered. The effectiveness of the detection of the crack-type defects in HPT and LPT discs under the first tooth of the fir-tree slots of the discs along the contact line of the teeth of the comb and blade butt are demonstrated. The calculations of the stress–strain state allowed the estimation of the occurrence of cracks in the fir-tree slots of discs, as well as the service life of discs up to crack formation at extraordinary operating temperatures. Integrated quality control by eddy-current and color capillary nondestructive testing provides reliable crack detection in details without serious costs for mechanical preparation of items for inspection along with a substantial reduction of the labor-intensiveness and depth of the inspection.
102-111
An instrument for simultaneous visual and thermal testing of microelectronic devices
Abstract
The problem of simultaneous visual and thermal testing of microobjects is considered. For this purpose, a mirror–lens optical system is proposed and constructed. The system has no movable elements and provides identical scales of images in spectral ranges of 0.4–0.8 and 8–14 μm. The technique for calculating its dimensions and an experimental setup on the basis of this scheme are described. The results of its testing using an example of investigating microelectronic devices are presented.
112-117