Wyniki wyszukiwania - Biblioteka Nauki

1

Experimental and Simulation Investigations of the Cantilever Beam Energy Harvester

100%

Nowak R.

Machine Dynamics Research

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2017

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tom Vol. 41, No. 3

95--103

EN

Machines, cars and other constructions often generates harmful vibrations, which can be used as the excitement signal for the energy harvesting structures. Waste mechanical energy can be converted into the electrical energy using piezoelectric element. The harvester described in the present paper consists of cantilever steel beam with both side glued piezoelectric elements. The excitation is realized as a support harmonic movement, where the amplitude is assumed as constant. Two types of research methods are used: experiment and finite element simulations. In the first one method the harvester is attached to the electrodynamic shaker. The generated voltage and acceleration of the selected point are measured. The finite element model is proposed with material and geometrical parameters similar to the laboratory examined harvester. Also, the generator patch model takes into account the three-dimensional piezoelectric effect instead of one-dimensional, which are popular especially in mathematical modeling. The major case specified in this paper is comparison of the experiment and FEM calculations results, what ensures the correctness of the FE model. The acquired amplitude frequency and time domain characteristics of the displacement and the generated voltage are compared and discussed. The proposed and verified FE model will be used in more advanced simulations.

2

Blast wave and suspension system interaction - numerical approach

88%

Baranowski P. , Małachowski J.

Journal of KONES

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2011

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tom Vol. 18, No. 2

17-24

EN

The main aim of this paper is to present the effective example of coupled experimental and numerical tests. Moreover, a development process of a numerical model of a terrain vehicle suspension system is presented. Experimental tests were carried out on the machine Instron 8802 with an assistance of the high-speed camera Phantom v12. Obtained stress-strain curves were applied into the FE model to estimate material constants for Mooney-Rivlin constitutive rubber model and for numerical failure criterion. Geometry of the tire and other suspension elements were achieved using reverse engineering technology. Due to the fact that a tire is such a complex structure to be represented with numerical methods, it was important to develop a discrete model of tire as much similar to the real one as possible. Consequently, an exact tire cords pattern was implemented into the FE model of the tire, which was obtained by the assistance of a microscope and X-ray device. In the next step, numerical analyses were performed simulating the TNT explosion under the suspension system with a simplified motor-car body. Nonlinear dynamic simulations were carried out using the explicit LS-Dyna code, with central difference scheme with modified the time integration of the equation of motion. In order to simulate the blast wave propagation the Smoothed Particle Hydrodynamics (SPH) method and Arbitrary Lagrangian-Eulerian formulation with Jones Wilkins Lee (JWL) equation defining the explosive material were used. Finally, results from both approaches were compared.

3

Selected modeling problems of monopile foundations used in the energy industry

75%

Labocha S. , Paluszyński J.

Budownictwo o Zoptymalizowanym Potencjale Energetycznym

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2021

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tom Vol. 10 Nr 2

77--87

EN

The paper presents selected practical aspects of the construction of monopile foundations used in the onshore power sector and analysis the effect of these solutions on the design of such structures. The basis for the evaluation of load capacity of such foundations was briefly discussed and the key factors that determine the ability to transfer loads from the structure to the ground were indicated. The main problem presented in the paper was to assess the impact of the reinforced concrete stay-in-place formwork piles built using the well technology. The considerations were supplemented with a computational example illustrating the thesis presented in the paper. A positive effect of prefabricated formwork rings on the load capacity of the foundation was demonstrated.

4

Wyznaczenie charakterystyk montażowych modeli fundamentowych złączy śrubowych z podkładką stalową i odlaną z tworzywa

75%

Grudziński P. , Grzejda R.

Przegląd Mechaniczny

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2016

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tom nr 5

35--38

PL

Przedstawiono modelowanie i obliczenia fundamentowych złączy śrubowych stosowanych w przypadku posadawiania ciężkich maszyn i urządzeń. Opisano charakterystyki odkształceń elementów łączonych fundamentowego złącza śrubowego dla przyjętych modeli na etapie jego montażu. Charakterystyki obliczeniowe porównano z charakterystykami otrzymanymi doświadczalnie. Sformułowano wnioski o podstawowym znaczeniu dla praktyki inżynierskiej.

EN

The paper deals with modelling and calculations of foundation bolted joints used in the case of seating of heavy machines or devices. Characteristics of the loads and deformations for the adopted models at the assembly stage are presented. The computational characteristics are compared respectively with the results of experimental studies. Conclusions of paramount importance to the engineering practice are formed.

5

Finite element model for analysis of characteristics of shrouded rotor blade vibrations

63%

Zinkovskii A. , Savchenko K. , Onyshchenko Y. , Polishchuk L. , Nazerke A. , Zhumazhanov B.

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tom T. 12, nr 4

11--16

EN

The paper presents the approaches to FE modelling of blade airfoil, contact between the shrouds and operational damage. The regularities are established concerning the influence of the finite element type, finite element mesh and model of contact interaction on the spectrum of natural frequencies of blade assemblies. The use of the developed computational models is substantiated to determine the forced vibration characteristics of the selected objects of investigation. Based on the performed numerical experiments it was substantiated of finite element model selection for analysis of characteristics of shrouded rotor blade vibrations.

PL

W artykule przedstawiono podejścia do modelowania elementów skończonych płata łopaty, styku osłon oraz uszkodzeń eksploatacyjnych. Ustalono prawidłowości dotyczące wpływu typu elementu skończonego, siatki elementów skończonych oraz modelu interakcji stykowej na widmo częstotliwości drgań własnych zespołów łopatek. Uzasadnione jest wykorzystanie opracowanych modeli obliczeniowych do wyznaczania charakterystyk drgań wymuszonych wybranych obiektów badań. Na podstawie przeprowadzonych eksperymentów numerycznych uzasadniono wybór modelu elementów skończonych do analizy charakterystyk drgań osłoniętych łopat wirnika.

6

Poprawa sztywności belki wzmocnienia tylnych drzwi samochodu osobowego

63%

Stadnicki J. , Wróbel I.

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tom R. 91, nr 7

561--563

PL

Aby chronić pasażerów przed skutkami zderzenia bocznego, w drzwiach samochodów osobowych montuje się wzmocnienia – belki drzwiowe, których sztywność sprawdza się podczas prób stanowiskowych. Opisano model MES do symulowania takiego testu, a po sprawdzeniu wykorzystano go do poprawy sztywności belki wzmacniającej tylne drzwi.

EN

To protect passengers against consequences of side crash side door beams are assembled to doors of passenger cars. Their stiffness is examined during stand tests. The FE model to simulate such a test is described. After verification the model has been applied to improve of rear door side beam stiffness.

7

Deep drawing and redrawing of solution-treated Cu-Cr-Zr-Ti alloy sheets and post-forming characterization of the redrawn cup wall

63%

Behera D. R. , Katiyar B. S. , Das S. , Panda S. K. , Kar S. K. , Murty S. V. S. N.

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2023

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tom Vol. 23, no. 3

art. no. e217, 2023

EN

Recently, space research organizations are interested in investigating multistage deep drawing of Cu-Cr-Zr-Ti alloy sheets for the fabrication of large-depth thrust chamber liners used in cryogenic engine of satellite launch vehicles. Hence, an attempt was made for the first time to design and develop a laboratory scale two-stage deep drawing setup to successfully draw cylindrical cups of solution-treated Cu-0.5Cr-0.05Zr-0.05Ti (wt. %) sheets of 1.7 mm thickness. The finite element (FE) model with Marciniak–Kuczynski forming limit diagram (MK-FLD) was implemented to design the above two-stage deep drawing setup, and two different anisotropic models, namely Hill48 and Barlat89, along with solid and shell element formulations were used to capture the deformation behavior. After setup design, the two-stage deep drawing experiments were conducted, and successful redrawn cups with overall drawing ratio of 2.94 with maximum cup depth of 58.5 mm was achieved. The strain evolution during deformation was analyzed in polar effective plastic strain (PEPS) locus, and it was also observed that the surface roughness of cup wall and corner was significantly increased to 2.73 μm and 3.16 μm, respectively, due to accumulation of plastic strain and evolution of texture. Further, the orientation gradient inside the grains at both cup wall and corner regions was observed, and evolution of Copper {112} < 111> and Y{111} <112> texture components were identified in the cup wall. However, the marginal increase in roughness of cup corner as compared to that of the cup wall might be due to the development of Brass {110} < 112 > texture. Finally, the aging behavior of redrawn cup wall was analyzed, and it was found that the peak aging occurred at 500 °C for 2 h. with a hardness of 98 ± 4 VHN due to the formation of fine Cr-rich precipitates.

8

On the reconstruction method of ceramic foam structures and the methodology of Young modulus determination

51%

Nowak M. , Nowak Z. , Pęcherski R. B. , Potoczek M. , Śliwa R. E.

Archives of Metallurgy and Materials

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2013

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tom Vol. 58, iss. 4

1219--1222

EN

In the present paper a finite element model was used to investigate the mechanical properties such as Young’s modulus of open-cell ceramic foam. Finite element discretization was derived from real foam specimen by computer tomography images. The generated 3D geometry of the ceramic foam was used to simulate deformation process under compression. The own numerical procedure was developed to control finite element mesh density by changing the element size. Several numerical simulations of compression test have been carried out using commercial finite element code ABAQUS. The size of the ceramic specimen and the density of finite element mesh were examined. The influence of type and size of finite element on the value of Young’s modulus was studied, as well. The obtained numerical results have been compared with the results of experimental investigations carried out by Ortega [11]. It is shown that numerical results are in close agreement with experiment. It appears also that the dependency of Young’s modulus of ceramic foam on density of finite element mesh cannot be ignored.

PL

W pracy przedstawiono metodę określania własności mechanicznych np. modułu Younga porowatych pianek ceramicznych o otwartych komórkach. Wykorzystując obrazy z tomografii komputerowej rzeczywistej struktury pianki otrzymano siatkę elementów skończonych. Przestrzenny obraz geometrii pianki wykorzystano do symulacji numerycznej procesu deformacji w próbie ściskania. Opracowano własną procedurę numeryczną do generowania elementów skończonych o różnej wielkości i kontroli gęstości siatki elementów. Przeprowadzono szereg symulacji numerycznych procesu ściskania pianek z wykorzystaniem programu elementów skończonych ABAQUS. Ustalono wpływ rodzaju i wielkości elementów skończonych jak również wielkości samej próbki na wartość modułu Younga wyliczonego dla próby jednoosiowego ściskania. Otrzymane numerycznie wartości modułów Younga porównano z wartościami z doświadczeń opublikowanych w pracy Ortegi [11]. Otrzymane rezultaty z symulacji numerycznych są w dobrej zgodności z doświadczeniem. Ustalono, ze wartości modułu Younga dla porowatych pianek ceramicznych zależy od gęstości siatki elementów skończonych i nie może być pomijana.