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The effects of component rotation on H/V spectra: a comparison of rotational and translational data

Nawrocki Dariusz, Mendecki Maciej J., Teper Lesław

Geology, Geophysics and Environment

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2024

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Vol. 50, no. 2

145--154

EN

The presented investigation focused on site effect estimations, specifically resonance frequency and amplification. These estimations were carried out for both rotational and translational signals, using waveforms from mining-induced seismic events. Site effect parameters were calculated using the horizontal-to-vertical spectral ratio (HVSR) technique, which is commonly applied to translational records by comparing the spectral ratio between horizontal and vertical components. In this study, we also applied the horizontal-to-vertical (H/V) ratio to rotational records. However, due to the different orientations of motion propagation, we introduced the spectral H/V ratio for rotational motion as the torsion-to-rocking spectral ratio (TRSR). Furthermore, we analyzed these signals according to two approaches. First, we estimated the site effect parameters for directly registered signals, and secondly, we considered rotated components by varying the angle from 0° to 180° in 5-degree increments. Generally, the H/V curves indicated two peaks for translational motions and four peaks for rotational motions. The averaged H/V spectra and spectra obtained for different angles of component rotation showed insignificant fluctuation in amplification values for both rotational and translational motions. However, when comparing each component’s spectrum for all angles, we observed changes in the site effect parameter values for both motion types. Radar plots depicting amplification values versus rotation angles for separated components revealed characteristic fluctuations, suggesting local anisotropy. Moreover, when comparing the radar plots between rotational and translational results, it was evident that rotational resonance frequencies shifted to higher frequency values, potentially indicating shallower geological layers as their source.

2

The Impact of a Movement Type on Tribological Properties of AlTiN Coating Deposited on HS6-5-2C Steel

Kowalczyk Joanna, Madej Monika, Piotrowska Katarzyna, Radoń-Kobus Krystyna

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 2

305--316

EN

This paper investigates the effect of the type of movement on the tribological properties of an AlTiN coating applied to a disc made of HS6-5-2C steel. Tribological tests were carried out with a tribometer operating on a ball-disc friction apparatus moving in to-and-from as well as in rotary motion. The tests were carried out under technically dry friction conditions, subject to the application of a cutting fluid used during machining in grinding, turning, milling, drilling and cutting processes. A scanning microscope was used to observe the morphology of the surface, the morphology of the AlTiN coating, and to determine its chemical composition and assess wear mechanisms. The topography of the surface was analysed before and after carrying out the friction and wear tests using a confocal microscope with interferometric mode. The results of the provided tests indicate that the cutting fluid used in the tests reduced the coefficient of friction in both rotary and the sliding – reciprocating motion about 75% and 65% respectively. It has also contributed to a reduction in linear wear in the sliding – reciprocating motion about 22%. In case of rotary motion, higher values of linear wear about 40% were recorded, due to wear of the counterspecimen.

3

Thermoelastic strongly nonlinear vibration of rotating functionally graded ring plate

Hu Yu Da, Bao Hai Jun, XU Hao Ran

Journal of Theoretical and Applied Mechanics

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2021

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Vol. 59 nr 1

157--171

EN

For a metal ceramic functionally graded (FGM) ring plate, considering variations in physical properties with temperature and a power-law distribution of material components along the thickness direction, thermoelastic coupled nonlinear vibration equation in thermal environment is derived by means of Kirchhoff’s thin plate theory and the Hamiltonian principle. The transverse nonlinear vibration differential equation of the inner and outside-clamped ring plate under static load is obtained by using the Galerkin method; moreover, perturbation solution of static deflection is carried out. An improved L-P method is employed to solve the strongly nonlinear vibration equation. The vibration response and nonlinear natural frequency expression are developed. Through numerical examples, natural frequency characteristic curves of the rotating FGM ring plate are plotted. The Runge Kutta method is applied to obtain vibration response, phase and power spectrum diagrams. The influence of different parameters on natural vibration characteristics is analyzed. The results show that analytical solutions are consistent with numerical solutions, and the natural frequency decreases with an increase in the metal content and surface temperature, but grows with an increase in the rotational speed.

4

Etapy formowania się stożka osadu w zbiorniku testowym kadzi wirowej whirlpool

Jakubowski M., Sterczyńska M., Poreda A.

Inżynieria Rolnicza

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2013

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R. 17, nr 1, t. 1

83--92

PL

Artykuł stanowi prezentację wyników badań eksperymentalnych przepływu mieszaniny separowanej w zbiorniku laboratoryjnej kadzi wirowej. Przedmiotem badań były charakterystyczne etapy formowania się stożka osadu w zależności od umiejscowienia (wysokości) otworu wlotowego i prędkości napełniania. Badania eksperymentalne zostały wykonane z wykorzystaniem zbiornika modelowego kadzi wirowej (tzw. whirlpoola) o pojemności V=2 hl i średnicy D=640 mm. W wyniku przeprowadzonych doświadczeń ustalono, iż w zjawisku formowania się stożka można wydzielić pewne charakterystyczne stany. W ramach przeprowadzonych badań porównano czasy ich występowania, a poprzez ich porównanie określono najkorzystniejsze prędkości napełniania, a także najkorzystniejsze wysokości umiejscowienia otworu wlotowego.

EN

The article presents results of the experimental research on the flow of mixture separated inside a laboratory cycling vat. The specific stages of forming the sediment cone depending on the position of the inlet (the placement height) and the speed of filling were the subject of the research. The research was carried out using a cycling vat (also called a whirlpool) scale model with capacity of V = 2hl and diameter of D = 640 mm. As a result of the experiments it was determined that as a part of the phenomenon of forming the cone, a few specific stages can be distinguished. The research involved a comparison of their timing, which allowed determination of the optimal speed of filling as well as the best height of placing the inlet.

5

Slip at the surface of a general axi-symmetric body rotating in a viscous fluid

Ashmawy E. A.

Archives of Mechanics

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2011

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Vol. 63, nr 4

341-361

EN

The rotational motion of an arbitrary axi-symmetric body in a viscous fluid is discussed using a combined analytical-numerical technique. A singularity method based on a continuous distribution of a set of Sampson spherical singularities, namely Sampsonlets, along the axis of symmetry within the body, is applied to find the general solution for the fluid velocity that satisfies the general slip boundary condition. Employing a constant and linear approximation for the density functions and applying the collocation technique to satisfy the slip boundary condition on the surface of the body, a system of linear algebraic equations is obtained to be solved numerically. The couple exerted on a prolate and oblate spheroid and on a prolate and oblate Cassini ovals is evaluated for various values of the aspect ratio a/b and for different values of the slip parameter, where a and b are the major and minor semi-axes of the particle respectively. The CPU time elapsed during numerical calculations is measured and tabulated. Numerical work shows that convergence to at least six decimal places is achieved.

6

Analiza możliwości aplikacji metody sterowania ruchem obrotowym żurawi samojezdnych

Kłosiński J.

Dozór Techniczny

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2001

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z. 2

25--30, 38