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No 5 (2023)
Articles
Ultrasonic tomography using sparse antenna arrays and frequency domain post-processing
Abstract
Currently, an important problem for industrial ultrasonic tomography using post-processing of matrix phased arrays signals is the improving restoration speed of results in the form of images of flaws in inspected objects. One of the approaches aimed at solving this issue is the application of sparse matrix antenna arrays. In this paper, we consider the use of the sparse matrix probes operating in a separate mode of signals acquisition together with the post-processing algorithm using the calculations in frequency-domain. Considered algorithm is based on the application of non-uniform fast Fourier transform. The efficiency of the considered approach is verified via in-situ experiments.
Defektoskopiâ. 2023;(5):3-11
3-11
Acoustic and electromagnetic properties of a martensitic-aging ferro-nickel alloy with the addition of copper under mechanical tension
Abstract
The paper presents the results of a study of the effect of mechanical longitudinal uniaxial stretching on the velocity of longitudinal and transverse waves in XM-12 steel samples. During the research, an acoustic mirror-shadow method was used on multiple reflections of the control using an electromagnetic acoustic transducer and a piezoelectric transducer based on a polyvinylidene fluoride film to excite and receive waves. The elastic modules of the studied samples and the coefficients of acoustoelasticity are calculated.
Defektoskopiâ. 2023;(5):12-20
12-20
Algorithms of hysteresis interference
Abstract
The calculated distribution of the electric voltage U at the output of the magnetic head (MG) scanning the magnetic carrier (MN) along the x coordinate is presented. The coordinates and amplitudes of the first maxima of hysteresis interference (HI) obtained in a pulsed magnetic field were found. Calculations with repeated use of the initial branch of the residual magnetization of the MN when constructing hysteresis interference are proposed. An analysis of the initial and hysteresis branches of signals for MH and other information carriers, signal converters and control systems has been carried out. The use of the obtained results allows to improve the quality of control of the properties of materials and objects.
Defektoskopiâ. 2023;(5):21-31
21-31
Calculation of the magnetic field strength from a semi-infinite cylinder placed in an arbitrary external field
Abstract
In the model of the semi-infinite cylinder the formulas and the corresponding algorithm for finding the magnetic field strength inside and outside the homogeneous cylinder placed in the external magnetic field of arbitrary configuration are deduced. Testing the results of calculations on these formulas for their correspondence with known physical laws, as well as on their coincidence with well-known analytical answers in the limiting private cases of the forms of magnetics were carried out.
Defektoskopiâ. 2023;(5):32-44
32-44
Debonds and water-filled defects detection in honeycomb sandwich composites based on pulse infrared thermography ndt technique
Abstract
Honeycomb Sandwich Composites (HSCs) have been extensively used in aerospace, automotive and shipbuilding industries due to their light weight, high temperature resistance, high strength and fatigue resistance. In this study, the infrared thermography was used to detect debonds and water-filled defects in HSCs specimens under pulsed thermal stimulation. To improve the efficiency of defects detection, dynamic thermal tomography (DTT), principal component analysis (PCA) and total harmonic distortion (THD) techniques were applied to the raw infrared image sequences. The results show that, in the inspection of HSCs, the defect identification results can be improved by using the image processing techniques mentioned above, while the signal-to-noise ratio (SNR) can be significantly improved by means of the THD technique. It is confirmed that debonds and water-filled defects in the HSCs can reliably be detected and identified by using the technique of pulse infrared thermography nondestructive testing.
Defektoskopiâ. 2023;(5):45-53
45-53
The novel procedure of active thermal ndt: combining heating and forced cooling
Abstract
A novel technique of active thermal nondestructive testing is proposed. It involves consecutive heating and forced cooling of the surface of test objects. The results of numerical modeling and experiments have demonstrated efficiency of this technique in case of test materials, which are characterized by a high level of emission/absorption noise. Optimization of such test procedure requires correctly choosing power and turn-on time of forced cooling to stimulate increase of temperature contrast over defects at particular times. An additional advantage of forced cooling is decrease of a thermal load on test materials that may be important in case of composites.
Defektoskopiâ. 2023;(5):54-63
54-63