Wyniki wyszukiwania - BazTech

1

Modelowanie i migracja sekcji czasowych zero-offsetowych w ośrodkach TTI metodą pseudospektralną

Kostecki A., Żuławiński K.

Nafta-Gaz

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2014

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R. 70, nr 12

855--860

PL

W publikacji przedstawiono pseudospektralną metodę modelowania czasowych sekcji zero-offsetowych w anizotropowych ośrodkach TTI (Tilted Transverse Isotropy), opartą na jednostronnym pseudoakustycznym równaniu falowym. Równanie pseudoakustyczne wyprowadzono z dokładnej formuły dyspersyjnej dla ośrodka TTI. Rozpatrzone zostały obydwa przypadki akwizycji pomiarów, to jest „pod upad” i „z upadem” dla antyklinalnego modelu TTI.

EN

In this paper we present a pseudospectral method of the modeling of zero-offset seismic time-sections in anisot-ropic media of the TTI (Tilted Transverse Isotropy) type, based on one-wave pseudoacoustic equation. This equation was derived from a precise dispersion relation for 2D TTI media. Both cases for the acquisition of data along directions for „up-dip” and „down-dip” for two-dimensional anticlinal model TTI were considered. Obtained results were verified by depth migration MG(F-K) in wave number (k) – frequency (f) domain.

2

Tetragonal or hexagonal symmetry in modeling of failure criteria for transversely isotropic materials

Ganczarski A., Adamski M.

Acta Mechanica et Automatica

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2014

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Vol. 8, no. 3

125--128

EN

Present work deals with modeling of failure criteria for transversely isotropic materials. Analysis comprises two classes of symmetry: Tsai-Wu tetragonal and new Tsai-Wu based hexagonal. Detail analysis of both classes of symmetry with respect to their advantages as well as limitations is presented. Finally, simple comparison of differences between limit curves corresponding to cross sections by planes of transverse isotropy, orthotropy and shear plane is done.

3

Analysis of wave motion in transversely isotropic generalized thermoelastic diffusive plate

Kumar R., Kansal T.

Journal of Technical Physics

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2009

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Vol. 50, no 1

17-40

EN

The present investigation deals with the propagation of plane harmonic thermoelastic diffusive waves in a homogeneous, transversely isotropic, thin elastic plate of finite width, in the context of generalized theory of thermoelastic diffusion. Lord and Shulman(L-S) theory, in which thermal and thermo-mechanical relaxation is governed by a time constant and diffusion relaxation is governed by other different time constant, is selected for the study. According to the characteristic equation, three quasi-longitudinal waves, namely: quasi-elastodiffusive(QED-mode), quasi-massdiffusive(QMD-mode) and quasi-thermodiffusive(QTD-mode), can propagate in addition to quasi-transverse waves(QSV-mode), and the purely quasi-transverse motion(QSH-mode), which is not affected by thermal and diffusion vibrations, gets decoupled from the rest of the motion of wave propagation. The secular equations corresponding to the symmetric and skew-symmetric modes of the plate are derived. The amplitudes of displacements, temperature change and concentration for symmetric and skew-symmetric modes of vibration of plate are computed numerically. Anisotropy and diffusion effects on the phase velocity, attenuation coefficient and amplitudes of wave propagation, are presented graphically in order to illustrate and compare the analytical results. Some special cases of frequency equation are also deduced from the present investigation.

4

On the contact problem in piezoelectroelasticity

Kaliński W., Rogowski B.

International Journal of Applied Mechanics and Engineering

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2009

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Vol. 14, no 1

157-174

EN

The problem of electroelasticity for piezoelectric materials is considered. The fundamental solutions for the axi-symmetric problem of piezoelasticity are utilized to solve a smooth contact problem. Exact solutions are obtained for elastic and electric fields in the contact problem. If the contact region is an annular three-part then the mixed boundary value problem is considered. In this case the solution is approximated as series solution.

5

A note on tensile instabilities and loss of ellipticity for a fiber-reinforced nonlinearly elastic solid

Merodio J., Neff P.

Archives of Mechanics

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2006

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Vol. 58, nr 3

293-303

EN

In this paper we examine the loss of ellipticity and the associated failure of fiber-reinforced compressible nonlinearly elastic solids under deformations leading to fiber extension. In particular, the analysis concerns a material model that consists of an isotropic base material augmented by a reinforcement depending on the fiber direction and referred to as a reinforcing model. We examine a reinforcement that introduces additional stiffness under simple shear deformations in the fiber direction. In previous contributions it was shown for this material that loss of ellipticity under uniaxial tensile loading in the fiber direction requires a non-convex reinforcing model. Here we generalize this result and show that loss of ellipticity under plane deformations not associated with uniaxial loading in the fiber direction but also creating fiber extension may occur for convex reinforcing models.

6

On the contact problem for a smooth punch in piezoelectroelasticity

Dyka E., Rogowski B.

Journal of Theoretical and Applied Mechanics

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2005

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Vol. 43 nr 4

745--761

EN

The problem of electroelasticity for piezoelectric materials is considered. For axially symmetric states, three potentials are introduced, which determine displacements, electric potential, stresses, components of the electric field vector and electric displacements in the piezoelectric body. These fundamental solutions are utilized to solve a smooth contact problem. Exact solutions are obtained for elastic and electric fields in the contact problem. The numerical results are presented graphically to show the influence of applied mechanical and electrical loading on the analyzed quantities and to clarify the effect of anisotropy of piezoelectric materials. It is also shown that the influence of anisotropy of the materials on these fields is significant.

PL

Rozpatrzono osiowo symetryczne zagadnienie clektrosprężystości dla materiałów piezoelektrycznych. Wprowadzono trzy potencjały opisujące przemieszczenia, naprężenia, elektryczny potencjał, składowe wektora pola elektrycznego i elektrycznych przemieszczeń. Znalezione fundamentalne rozwiązania wykorzystano do analizy zagadnienia kontaktowego gładkiego stempla. Znaleziono ścisłe rozwiązania opisujące sprężyste i elektryczne pola w rozpatrywanym zagadnieniu kontaktowym. Wyniki obliczeń przedstawiono na wykresie w celu pokazania wpływu mechanicznych i elektrycznych obciążeń na analizowane wielkości. Efekt anizotropii materiałów piezoelektrycznych w omawianym zagadnieniu jest znaczący.

7

Modelling elastic behaviour of soft tissues. P.1. Transverse isotropy

Jemioło S., Telega J. J.

Engineering Transactions

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2001

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Vol.49, iss.2/3

241-281

EN

New constitutive relationships for hyperelastic transversely isotropic materials have been proposed. The well-known isotropic hyperelastic model due to Ogden [I.58] has been extended to transverse isotropy. It has been shown that some models intended to describe the nonlinear elastic behaviour of soft tissues are oversimplified and lead to incorrect results. An overview of soft tissue modelling, being a continuation of the one started in [48], has also been given. .