Wyniki wyszukiwania - BazTech

1

Influence of material distribution and damping on the dynamic stability of Bernoulli-Euler beams

Garus Sebastian, Garus Justyna, Sochacki Wojciech, Nabiałek Marcin, Petru Jana, Borek Wojciech, Šofer Michal, Kwiatoń Paweł

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

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Vol. 71, nr 4

art. no. e145567

EN

The study analyzed the influence of materials and different types of damping on the dynamic stability of the Bernoulli-Euler beam. Using the mode summation method and applying an orthogonal condition of eigenfunctions and describing the analyzed system with the Mathieu equation, the problem of dynamic stability was solved. By examining the influence of internal and external damping and damping in the beam supports, their influence on the regions of stability and instability of the solution to the Mathieu equation was determined.

2

Mechanical vibrations: recent trends and engineering applications

Garus Sebastian, Błachowski Bartłomiej, Sochacki Wojciech, Jaskot Anna, Kwiatoń Paweł, Ostrowski Mariusz, Šofer Michal, Kapitaniak Tomasz

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2022

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Vol. 70, nr 1

art. no. e140351

EN

Although the study of oscillatory motion has a long history, going back four centuries, it is still an active subject of scientificr esearch. In this review paper prospective research directions in the field of mechanical vibrations were pointed out. Four groups of important issues in which advanced research is conducted were discussed. The first are energy harvester devices, thanks to which we can obtain or save significant amounts of energy, and thus reduce the amount of greenhouse gases. The next discussed issue helps in the design of structures using vibrations and describes the algorithms that allow to identify and search for optimal parameters for the devices being developed. The next section describes vibration in multi-body systems and modal analysis, which are key to understanding the phenomena in vibrating machines. The last part describes the properties of granulated materials from which modern, intelligent vacuum-packed particles are made. They are used, for example, as intelligent vibration damping devices.

3

Meshless local Petrov-Galerkin method for rotatingRayleigh beam using Chebyshev and Legendre polynomials

Panchore Vijay

Archive of Mechanical Engineering

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2022

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LXIX, nr 2

301-–318

EN

The numerical solutions are obtained for rotating beams; the inclusion of centrifugal force term makes it difficult to get the analytical solutions. In this paper, we solve the free vibration problem of rotating Rayleigh beam using Chebyshev and Legendre polynomials where weak form of meshless local Petrov-Galerkin method is used. The equations which are derived for rotating beams result in stiffness matrices and the mass matrix. The orthogonal polynomials are used and results obtained with Chebyshev polynomials and Legendre polynomials are exactly the same. The results are compared with the literature and the conventional finite element method where only first seven terms of both the polynomials are considered. The first five natural frequencies and respective mode shapes are calculated. The results are accurate when compared to literature.

4

Support with mechanical vibrations of welding processes - review of own research

Krajewski Arkadiusz, Kołodziejczak Paweł, Cegielski Paweł, Grześ Jarosław

Welding Technology Review

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2021

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R. 93, nr 3

57--73

EN

The article discusses the most important original achievements in the use of high-power mechanical vibrations with low and ultrasonic frequency in various welding processes such as (131) MIG, (135) MAG, (141) TIG, (21) RW, (522) LW, (45) diffusion welding and (924) brazing in relation to various basic materials such as structural steel and aluminum alloys. Mechanical vibrations were introduced by means of ultrasonic vibrating systems and using the shot-blasting process, as well as acoustic influence. As part of the comparative research, the structure and hardness analysis of HV0.1 was presented. The obtained results indicate that both low-frequency and ultrasonic frequency vibrations significantly change the properties of the resulting structures affected by mechanical vibrations. The scale of these changes varies depending on the frequency and parameters specific to each of the welding processes used. The obtained results allow us to conclude that the skilful application of mechanical vibrations accompanying welding processes can contribute to the reduction of grain sizes, to change the depth or width of penetration and to lowering hardness in the sensitive heat affected zone area.

PL

W artykule omówiono najważniejsze oryginalne osiągnięcia w zakresie stosowania drgań mechanicznych wysokiej mocy o niskiej i ultradźwiękowej częstotliwości w różnych procesach spajania takich jak (131) MIG, (135) MAG, (141) TIG, (21) RW, (522) LW, (45) zgrzewanie dyfuzyjne i (924) lutowanie w odniesieniu do różnych materiałów podstawowych takich jak stal konstrukcyjna oraz stopy aluminium. Drgania mechaniczne wprowadzano za pomocą ultradźwiękowych układów drgających oraz stosując proces śrutowania, a także akustyczne oddziaływanie. W ramach badań porównawczych przedstawiono analizę struktury i twardości HV0.l. Uzyskane wyniki wskazują, że zarówno drgania o niskiej częstotliwości, jak i o częstotliwości znacznie zmieniają własności powstających struktur, na które oddziałują drgania mechaniczne. Skala tych zmian bywa różna w zależności od częstotliwości oraz parametrów specyficznych dla każdego ze stosowanych procesów spawalniczych. Uzyskane wyniki pozwalają stwierdzić, że umiejętne zastosowanie drgań mechanicznych towarzyszących procesom spawalniczym mogą przyczynić się do zmniejszenia rozmiarów ziaren, do zmiany głębokości czy szerokości wtopienia oraz do obniżenia twardości w newralgicznym obszarze SWC.

5

Perturbation method in the analysis of manipulator inertial vibrations

Szumiński P.

Mechanics and Mechanical Engineering

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2011

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Vol. 15, nr 2

149-160

EN

An analysis of inertial component of mechanical vibrations induced during a motion of the MAR industrial manipulator is presented. The mathematical analysis of vibrations is based on the perturbation method. The presented considerations include an analytical description of inertial vibrations as well as results of the numerical analysis for the RPP-type manipulator.