Wyniki wyszukiwania - BazTech

1

Peridynamic Simulation of Crushing Processes in Copper Open-Cell Foam

Postek E., Pęcherski R. B., Nowak Z.

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 4

1603--1610

EN

In the last 20 years, a new meshless computational method has been developed that is called peridynamics. The method is based on the parallelized code. The subject of the study is the deformation of open-cell copper foams under dynamic compression. The computational model of virtual cellular material is considered. The skeleton structure of such a virtual cellular material can be rescaled according to requirements. The material of the skeleton is assumed as the oxygen free high conductivity (OFHC) copper. The OFHC copper powder can be applied in additive manufacturing to produce the open-cell multifunctional structures, e. g., crush resistant heat exchangers, heat capacitors, etc. In considered peridynamic computations the foam skeleton is described with the use of an elastic-plastic model with isotropic hardening. The dynamic process of compression and crushing with different impact velocities is simulated.

2

Application of the elastic-plastic model in the analysis of the displacement in a rock mass

Marczak Halina

Advances in Science and Technology. Research Journal

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2018

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Vol. 12, no 2

188--196

EN

The concern of this article is the analysis of the impact of increased volume (dilation) and decreased strength of the rock material in the plastic zone on the displacement field in the vicinity of the roadway. Elastic-plastic model of the behaviour of the rock material and the strength criterion of Coulomb-Mohr were assumed. The volume change of the rock material is controlled by the angle of dilation ψ, which determines dilation parameter β that is taken into account in the analysis. The influence of parameter β and the strength of the rock material, after crossing the border state of stress, in the field of displacements in the vicinity of the excavation and rock pressure on the elastic support of the excavation was proved. The relationships determining displacement fields in the plastic zone which were obtained with consideration to in this zone of both the elastic and plastic displacement, as well as the relationships which were obtained without elastic deformations was discussed. The exact form of the equation for the displacement field in the plastic zone depends on how the elastic deformation in the plastic zone is defined. There are three ways of describing these deformations. In the first method it is assumed that in plastic deformation area the elastic deformation constants are equal to the deformation constants at the plastic and elastic border. The second method of description is based on the assumption that the plastic zone is a thick-walled ring whose edges: internal and external have been appropriately debited. In the third method, elastic deformations in the plastic zone were made dependent on the state of stress in the zone. The results are illustrated in a form of response curves of the rock mass.

3

The interaction features of the multi-level retaining walls with soil mass

Boyko I., Skochko L., Zhuk V.

Civil and Environmental Engineering Reports

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2017

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No. 26(3)

179--190

EN

The interaction features of multi-level retaining walls with soil base were researched by changing their geometric parameters and locality at the plan. During excavation of deep foundation pits it is important to choose the type of constructions which influences on the horizontal displacements. The distance between the levels of retaining walls should be based on the results of numerical modelling. The objective of this paper is to present a comparison between the data of numerical simulations and the results of the in-situ lateral tests of couple piles. The problems have been solved by using the following soil models: Coulomb-Mohr model; model, which is based on the dilatation theory; elastic-plastic model with variable stiffness parameters.

PL

W pracy są analizowane właściwości interakcji pomiędzy wielopoziomowymi murami oporowymi, a gruntem. Analiza polega na sterowaniu parametrami geometrycznymi i lokalizacją ścian oporowych. Przy głębokich wykopach ważny jest wybór odpowiedniego rodzaju konstrukcji zabezpieczającej przed wpływem sił poziomych tj. ścian oporowych. Odległość między poziomami ścian oporowych powinna opierać się na wynikach analiz numerycznych. Celem pracy jest porównanie wyników symulacji numerycznych z wynikami badań polowych. Problem rozwiązano numerycznie z zastosowaniem trzech modeli sprężysto-plastycznych gruntu.

4

Wpływ spójności górotworu na jego zachowanie się w otoczeniu wyrobisk korytarzowych

Marczak H.

Wiadomości Górnicze

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2013

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R. 64, nr 1

15-21

PL

W artykule przedstawiono równania wyrażające naprężenia i przemieszczenia w ośrodku skalnym w sąsiedztwie wyrobiska korytarzowego. Przyjęto sprężysto-plastyczny model ośrodka skalnego i uwzględniono spadek parametrów wytrzymałościowych materiału skalnego po osiągnięciu warunku stanu granicznego. Zastosowano kryterium stanu granicznego Coulomba. Przemieszczenia wyznaczono przy uwzględnieniu przyrostu naprężeń zaistniałych w następstwie wykonania wyrobiska. Przedstawiono wyniki analizy wpływu spójności ośrodka skalnego na jego zachowanie w sąsiedztwie wyrobiska korytarzowego.

EN

The paper presents equations expressing the stresses and displacements in the rock body's cohesion in the vicinity of a roadway. Elastic-plastic model of the rock body was assumed, and a decrease of rock body's strength parameters after reaching of the limit state condition was included. The Coulomb criterion of the limit state was applied. Displacements were determined, taking into account the inerease in stresses occurring as a result of the working's execution. The results of the analysis of the impact of the rock body's cohesion on its behavior in the vicinity of a roadway.

5

Effect of ring notch radius on the decohesion mode in AlSi alloys

Piekło J., Maj M.

Archives of Foundry Engineering

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2009

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Vol. 9, iss. 2

25-28

EN

The article discusses the effect of the, determined by tensile test, non-linear characteristics of AlSi alloys on the value of the shape factor k for the three different sizes of the radius of the ring notch made on round specimens. Applying a numerical solution, the changes of stress in the notch plane were determined in function of the notch configuration and the value of instantaneous load. Tensile tests were carried out on round bars with ring notches. The appearance of fractures was examined on scanning images. Differences in notch effect observed in the linear-elastic and elastic-plastic model of material hardening in a non-linear mode were described.

6

Analiza numeryczna wzmocnionego podłoża gruntowego pod centrum handlowym sarni stok

Gaszyński J., Gwóźdź-Lasoń M.

Prace Naukowe Instytutu Geotechniki i Hydrotechniki Politechniki Wrocławskiej. Konferencje

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2007

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Vol. 76, nr 42

221-228

PL

W prezentowanej pracy, przedstawiono problematykę modelowania numerycznego wzmocnionego podłoża gruntowego. Analizie poddano wyniki symulacji numerycznych zestawione z danymi pozyskanymi z badań terenowych dla zrealizowanych obiektów inżynierskich. Przedstawiono tutaj opis numerycznej procedury modelowania ośrodka gruntowego z elementami wzmacniającymi w postaci kolumn żwirowych wykonywanych w technologii wibrowymiany. Niniejsze rozważania są uogólnieniem i kontynuacją wcześniej opublikowanych prac, między innymi [2], [3], [4] i [5], gdzie opisano szereg przeprowadzonych analiz procedury wykonanych symulacji numerycznych przy użyciu MES i programu Z_Soli zakładając sprężysto-plastyczny model ośrodka gruntowego.

EN

The paper considers the issue of ground-medium reinforcement. Based on generally accepted principles the author presents numerical modeling patterns of subsoil reinforced by gravel-columns. She compares the outcome of the numerical simulations with the measured load capacity of gravel columns located under shopping center in Bielsko - Biala, South of Poland. The paper constitutes an attempt to summaries and generalise earlier research which involved FEM numeric procedures and the Z_Soil package, and utilized an elastic-plastic model of a ground medium. Theoretical instigation, simulation and empirical experiment are closely related and none of these cognitive methods should be applied separately. A simulation, i.e. analytical or numerical solving of model equations, can generate full and credible results only if it is theoretically and empirically verified.