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1

Use of DEM to characterize damage of delicate fruit on feeders with reciprocating drive

Olejnik Tomasz P., Sobiecka Elżbieta, Kryszak Dariusz

Technologia i Jakość Wyrobów

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2023

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R. 68

171--186

EN

This article describes the modeling by DEM technology of damage to highbush blueberries, during transport on a reciprocating feeder. The modeled values of normal and tangential forces at the blueberry contact points were determined, and the effect of changing the mass output of the transported fruit on the values of normal and tangential forces was studied. It has been shown that the change in the mass output of blueberries does not exceed the permissible tangential and normal forces, interacting between the fruits.

PL

W artykule opisano modelowanie technologią DEM uszkodzeń borówki wysokiej, podczas transportu na podajniku z napędem posuwisto-zwrotnym. Określono modelowe wartości sił normalnych oraz stycznych w punktach kontaktu borówki. Przeprowadzono symulacje uwzględniające wpływ zmiany wydatku masowego transportowanych owoców na wartości sił normalnych i stycznych. Wykazano, że zmiana wydatku masowego borówki nie powoduje przekroczenia dopuszczalnych sił stycznych i normalnych, oddziałujących pomiędzy owocami.

2

Shear forces in the connection of structural elements under bending

Machelski C.

Studia Geotechnica et Mechanica

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2013

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Vol. 35, nr 3

69--83

EN

A beam consisting of elements connected flexibly along their axis is discussed in the paper. An example of a structural system, constructed with the use of different materials is a composite girder consisting of a steel beam connected with a concrete slab. Full interaction of elements connected discontinuously (discretly) along the axis of the beam is a particular (theoretical) case. Taking into account functions of shear forces and stiffness k, a connection, can be classified as rigid when k > 1400 MN/m2. In this case, the results obtained from the classic beam (homogeneous) model are sufficient for design purposes. In the cases presented in the paper, the results obtained using classic model may considerably deviate from the results obtained using layered model, considered to be the accurate one. The examples of analyses given in the paper show the possibility for the use of Fourier series in calculating shear forces in the case of discrete connections. Using this solution, a compatibility of shear forces with values calculated on the basis of design solution was proved to be valid only in the case of full interaction (no shear slip). As the connection flexibility increases, the discrepancy between the functions of shear forces along the length of a girder rises. Regular arrangements of shear connectors were considered in the paper. The function of connection stiffness k(x) can have a significant influence on the distribution of shear force t(x).

3

Experimental Results and Models of the Tire/Road Contact

Kröger M., Gäbel G., Moldenhauer P.

Machine Dynamics Problems

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2007

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Vol. 31, No. 2

84-94

EN

The contact between tire tread block and road surface is very complicated and usually unknown. The dynamic behaviour of the tread blocks is strongly influenced by the contact situation e.g. contact stiffness, local friction coefficient as well as wear which changes the tread block geometry and in hence the local contact forces. Within this paper a dynamic tread block model is presented describing the dynamic tread block behaviour using an effective reduction method. The model is built up modularly and combines the non-linear contact stiffness due to the rough surface, the local friction coefficient in dependency of the relative velocity and wear mechanisms. Measurements of the different contact phenomena which are considered in the model are shown and exemplary simulation results are presented to clarify the effectiveness of the modular model.

4

Weryfikacja doświadczalna analitycznego modelu M-F wybranych parametrów ruchu pojazdu samochodowego

Szymaniak G.

Folia Societatis Scientiarum Lublinensis

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2000

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vol. 9

75-87

PL

W opracowaniu podjęto próbę oceny przedziałów wartości współczynników modelu Magic-Formula oraz jakościowej analizy przebiegu charakterystyk sił stycznych i momentu stabilizującego w porównaniu z charakterystykami określonymi na podstawie danych laboratoryjnych. Metoda analityczno-graficzna umożliwia w prosty sposób ocenę przedziałów zmienności współczynników a1.

EN

In the paper the attempt of evaluation of intervals value of Magic-Formula model coefficients and quantitive analisis of tangential forces and self-aligning torąue comparing to the laboratory datas was presented. The analitical-graphic method enables simple estimation of intervals changebility and a1, coefficients.

5

Tangential forces on the die - workpiece contact surface during rotary forging

Balawender T., Stachowicz F.

Applied Mechanics and Engineering

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1999

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Vol. 4, no 3

495-507

EN

Theoretical considerations of the kinematic relationship between a rocking die and workpiece during rotary forging are described in here. According to friction conditions the skid or slip may cause the rising of circumferential forces at the die-workpiece interface. It was confirmed by the results of experimental invegations of the rotary forging process.