DYNAMIC CALCULATION OF PRISMATIC SYSTEMS TAKING INTO ACCOUNT INTERNAL FRICTION

The paper shows a possibility of including a frequency-independent viscoelastic design resistance in calculation models representing composite structures with distributed parameters. Diff erential equations of the system motion include parameters of complex rigidity. The research puts forward a solution which helps solve stationary and non-stationary dynamic problems taking internal friction into account. This solution is found by using the calculation algorithm for prismatic shells involving the use of topological matrices. In the process of separation of variables, this approach yields a diff erential equation of linear oscillator motion with frequency-independent viscoelastic resistance.

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On: “Frequency‐independent background internal friction in heterogeneous solids” by Baxter H. Armstrong (GEOPHYSICS, June 1980, p. 1042–1054).

Geophysics ◽

10.1190/1.1441270 ◽

1981 ◽

Vol 46 (9) ◽

pp. 1314-1314 ◽

Cited By ~ 1

Author(s):

Gábor Korvin

Keyword(s):

Internal Friction ◽

Frequency Dependence ◽

Attenuation Coefficient ◽

Thermal Conduction ◽

Heterogeneous Solids ◽

Low Frequencies ◽

Novel Approach ◽

Frequency Independent ◽

Inherent Frequency

In his recent paper Dr. Armstrong proposes a novel approach based on considerations of thermal conduction and thermoelastic dissipation to explain the observed nearly constant Q behavior toward low frequencies in randomly heterogeneous solids. I feel, however, the fluctuation coefficient R defined by his equation (22) does have an inherent frequency dependence introduced through the [Formula: see text] factors so that the attenuation coefficient A might be a more complicated function of frequency than suggested by equation (24).

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Reactions of composite structures, with concentrated and distributed parameters, to seismic action (vertical vibrations)

Soviet Mining Science ◽

10.1007/bf02594874 ◽

1976 ◽

Vol 12 (3) ◽

pp. 296-300

Author(s):

I. M. Mirzaev

Keyword(s):

Composite Structures ◽

Seismic Action ◽

Distributed Parameters ◽

Vertical Vibrations

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Elementary Models for Frequency-Independent Internal Friction

Role of Internal Friction in Dynamic Analysis of Structures ◽

10.1201/9780203740408-4 ◽

2021 ◽

pp. 94-117

Author(s):

A.I. Tseitlin ◽

A.A. Kusainov

Keyword(s):

Internal Friction ◽

Frequency Independent

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On the Disintegration of Bodies of (Granular) Materials Governed by the Coulomb Rule

Journal of Applied Mechanics ◽

10.1115/1.3629563 ◽

1964 ◽

Vol 31 (1) ◽

pp. 1-4 ◽

Cited By ~ 2

Author(s):

H. H. Bleich

Keyword(s):

Boundary Layer ◽

Internal Friction ◽

Granular Materials ◽

Mechanical Model ◽

The Body ◽

Dynamic Problems ◽

Angle Of Internal Friction

For the purposes of analysis, granular materials are frequently idealized by stating that slip will occur when the stresses satisfy a relation depending on the angle of internal friction and cohesion. States of stress violating this rule are not permitted. From a simple mechanical model it is concluded that in dynamic problems the possibility of disintegration of the body must be considered, and that disintegration, if it occurs, is a boundary-layer phenomenon.

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A convenient analytical method for solution of dynamic problems in one-dimensional distributed-parameters systems

Applied Mathematical Modelling ◽

10.1016/0307-904x(94)90183-x ◽

1994 ◽

Vol 18 (1) ◽

pp. 51-54

Author(s):

Yuri A. Ermolin

Keyword(s):

Analytical Method ◽

Dynamic Problems ◽

One Dimensional ◽

Distributed Parameters

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Dispersion of polarized shear waves in viscous liquid over a porous piezoelectric substrate

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x18758190 ◽

2018 ◽

Vol 29 (9) ◽

pp. 2040-2048 ◽

Cited By ~ 6

Author(s):

Juhi Baroi ◽

Sanjeev A Sahu ◽

Manoj Kumar Singh

Keyword(s):

Viscous Liquid ◽

Composite Structures ◽

Graphical Representation ◽

Mass Density ◽

Separation Of Variables ◽

Piezoelectric Medium ◽

Horizontal Wave ◽

Two Phases ◽

Acoustic Wave Devices ◽

Shear Horizontal

This article aims to study the propagation of polarized shear horizontal waves in viscous liquid layer resting over a porous piezoelectric half-space. An analytical solution is proposed using the separation of variables method. The dispersion relation is obtained using the proper boundary conditions for both electrically open and short cases in determinant form. The numerical example and graphical representation are provided in support of the findings. Dynamic response of affecting parameters (e.g. layer’s width, mass density, piezoelectric constant, dielectric constant, viscous coefficient, and dielectric coupling between the two phases of the porous aggregate) has been presented through graphs. It is observed that the phase velocity of considered wave remarkably affected by these parameters. Moreover, obtained result is matched with the existing result. Findings may contribute significantly toward optimization of surface acoustic wave devices and other liquid sensors. Moreover, this study may be utilized to frame a theoretical model for the problems of shear horizontal wave propagation in composite structures, involving piezoelectric medium.

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In Situ microscopy of the anodic etching of silicon

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100137537 ◽

1995 ◽

Vol 53 ◽

pp. 232-233

Author(s):

Frances M. Ross ◽

Peter C. Searson

Keyword(s):

Composite Structures ◽

High Surface ◽

High Surface Area ◽

Chemical Properties ◽

Selective Etching ◽

Silicon On Insulator ◽

Second Phase ◽

Porous Layers ◽

New Class ◽

Porous Semiconductors

Porous semiconductors represent a relatively new class of materials formed by the selective etching of a single or polycrystalline substrate. Although porous silicon has received considerable attention due to its novel optical properties1, porous layers can be formed in other semiconductors such as GaAs and GaP. These materials are characterised by very high surface area and by electrical, optical and chemical properties that may differ considerably from bulk. The properties depend on the pore morphology, which can be controlled by adjusting the processing conditions and the dopant concentration. A number of novel structures can be fabricated using selective etching. For example, self-supporting membranes can be made by growing pores through a wafer, films with modulated pore structure can be fabricated by varying the applied potential during growth, composite structures can be prepared by depositing a second phase into the pores and silicon-on-insulator structures can be formed by oxidising a buried porous layer. In all these applications the ability to grow nanostructures controllably is critical.

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