Wyniki wyszukiwania - BazTech

1

Design and analysis of cementless hip-joint system using functionally graded material

Asiri Saeed

Archive of Mechanical Engineering

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2022

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LXIX, nr 1

129--146

EN

Functionally Graded Materials (FGM) are extensively employed for hip plant component material due to their certain properties in a specific design to achieve the requirements of the hip-joint system. Nevertheless, if there are similar properties, it doesn’t necessarily indicate that the knee plant is efficiently and effectively working. Therefore, it is important to develop an ideal design of functionally graded material femoral components that can be used for a long period. A new ideal design of femoral prosthesis can be introduced using functionally graded fiber polymer (FGFP) which will reduce the stress shielding and the corresponding stresses present over the interface. Herein, modal analysis of the complete hip plant part is carried out, which is the main factor and to date, very few research studies have been found on it. Moreover, this enhances the life of hip replacement, and the modal, harmonic, and fatigue analysis determines the pre-loading failure phenomena due to the vibrational response of the hip. This study deals with the cementless hip plant applying the finite element analysis (FEA) model in which geometry is studied, and the femoral bone model is based in a 3D scan.

2

Model order reduction technique applied on harmonic analysis of a submerged vibrating blade

Tengs E., Charrassier F., Holst M., Storli P.

International Journal of Applied Mechanics and Engineering

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2019

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Vol. 24, no. 1

131--142

EN

As part of an ongoing study into hydropower runner failure, a submerged, vibrating blade is investigated both experimentally and numerically. The numerical simulations performed are fully coupled acoustic-structural simulations in ANSYS Mechanical. In order to speed up the simulations, a model order reduction technique based on Krylov subspaces is implemented. This paper presents a comparison between the full ANSYS harmonic response and the reduced order model, and shows excellent agreement. The speedup factor obtained by using the reduced order model is shown to be between one and two orders of magnitude. The number of dimensions in the reduced subspace needed for accurate results is investigated, and confirms what is found in other studies on similar model order reduction applications. In addition, experimental results are available for validation, and show good match when not too far from the resonance peak.

3

Time - frequency approach to analysis of time varying dynamic systems

Mikołajuk K., Staroszczyk Z.

Przegląd Elektrotechniczny

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2003

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R. 79, nr 10

764-767

PL

Praca poświęcona jest dyskusji i interpretacji układów okresowo zmiennych, traktowanych jako modele układów elektroenergetycznych. Modele zmienne w czasie lepiej opisują rzeczywiste przebiegi prądów i napięć obserwowane w układach elektroenergetycznych. Jednak modele zmienne w czasie są dużo trudniejsze do zastosowania i nalizy. Pokazano właściwości układów zmienych okresowo na przykładzie prostego układu analogowego i układów dyskretnych. Zamieszczone postawy teoretyczne i wyniki symulacji pozwalają lepiej zrozumieć wpływ zmienności układu na jego właściwości.

EN

The paper discusses a problem of description and interpretation of time-varying systems behavior as observed in power system. Accurate power system identification allows for time-varying model system description, which better describes current/ voltage relations in power system then classical linear time invariant (LTI) model. The time variant active system description makes difficult its time-varying (t-v) model identification and implementation. The presented paper presents insight into properties of periodically varying systems illustrated with simple analog and discrete examples. The theoretical background and simulation results are aimed to help in understanding time variance as a new property of linear systems.