Inhomogeneity

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1 - اثر ناهمگنی مصنوعی دانسیته بر مدول‌برشی دینامیک چوب بلوط بلند مازو (<i>Quercus castaneifolia</i>)
مصطفی کهن ترابی امیر هومن حمصی محمد طلایی پور مهران روح نیا بهزاد بازیار

10.30495/jrnr.2021.18360

در این تحقیق به بررسی تاثیر ایجاد ناهمگنی مصنوعی دانسیته در ناحیه ابتدایی و میانی تیرهای بلوط بلند مازو (Quercus castaneifolia) با بررسی تغییرات حاصل در مدول‌برشی دینامیک حاصل از روش ارتعاش خمشی آزاد در تیر دو سر آزاد پرداخته ‌شده است. بدین منظور تعداد 10 آزمونه از گون أکثر

در این تحقیق به بررسی تاثیر ایجاد ناهمگنی مصنوعی دانسیته در ناحیه ابتدایی و میانی تیرهای بلوط بلند مازو (Quercus castaneifolia) با بررسی تغییرات حاصل در مدول‌برشی دینامیک حاصل از روش ارتعاش خمشی آزاد در تیر دو سر آزاد پرداخته ‌شده است. بدین منظور تعداد 10 آزمونه از گونه بلوط با ابعاد 720× 40× 20 میلی &lrm;‌ متر (طولی، شعاعی و مماسی) جهت تعیین مدول‌برشی در تیرهای اولیه مورد آزمون ارتعاش خمشی آزاد در تیر دو سر آزاد قرار گرفتند. پس ‌از آن آزمونه‌ ها به دو گروه تقسیم ‌شده و از گروه اول بلوک‌ هایی به ابعاد 40×40×20 میلی متر از قسمت ابتدایی و از گروه دوم بلوک‌ هایی با ابعاد ذکرشده از قسمت میانی استخراج ‌شده و توسط چسب پلی وینیل استات به یکدیگر متصل شده و پس از برقراری اتصال آزمون ارتعاش خمشی آزاد مجددا بر روی آزمونه‌ ها صورت پذیرفت. پس ‌از آن بلوک‌ های بلوط از محل اتصال خارج ‌شده و در دو مرحله بلوک‌هایی از دو گونه صنوبر (Populus nigra) و انجیلی (Parrotia persica) در آنها جایگزاری شده و به‌منظور تاثیر ناهمگنی ایجاد شده توسط هر یک از بلوک ‌های جایگزین شده بر مقادیر مدول‌برشی، آزمون ارتعاش خمشی بر روی آنها صورت پذیرفت. نتایج حاکی از آن بود که ایجاد ناهمگنی مصنوعی دانسیته در ناحیه ابتدایی تیر توسط هر سه گونه بلوط، صنوبر و انجیلی تاثیر معنی‌ داری بر مقادیر مدول ‌‌برشی دینامیک ندارد، درحالی‌که ایجاد ناهمگنی در قسمت میانی تیر باعث افت معنی‌ دار مقادیر حاصل از این فاکتور شده است. تیرهای ناهمگن شده توسط گونه انجیلی بیشترین و تیرهای ناهمگن شده توسط گونه بلوط با کمترین درصد افت در مقادیر مدول ‌برشی دینامیک مواجه شدند. تفاصيل المقالة

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2 - An Analytic Study on the Dispersion of Love Wave Propagation in Double Layers Lying Over Inhomogeneous Half-Space
A Mandi S Kundu P Chandra Pal P Pati

10.22034/jsm.2019.666690

In this work, attempts are made to study the dispersion of Love waves in dry sandy layer sandwiched between fiber reinforced layer and inhomogeneous half space.Inhomogeneity in half space associated with density and rigidity and considered in exponential form. Displacem أکثر

In this work, attempts are made to study the dispersion of Love waves in dry sandy layer sandwiched between fiber reinforced layer and inhomogeneous half space.Inhomogeneity in half space associated with density and rigidity and considered in exponential form. Displacement components for fiber reinforced layer, dry sandy layer and inhomogeneous half-space have been obtained by using method of separable variables. Boundary conditions are defined at the free surface of the fiber reinforced layer and at the interfaces between layers and half space. The dispersion equation has derived in closed form. Numerical calculations for dispersion equation are performed. The study results show the effect of parameters on the velocity of Love waves and presented graphically. Graphs are plotted between wave number and phase velocity to show the effect of reinforced parameter, sandiness parameter and inhomogeneity on the phase velocity of Love waves. From the graphs it can be concluded that phase velocity decreases with respect to wave number. تفاصيل المقالة

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3 - Dispersion of Torsional Surface Wave in a Pre-Stressed Heterogeneous Layer Sandwiched Between Anisotropic Porous Half-Spaces Under Gravity
R.M Prasad S Kundu

10.22034/jsm.2019.668609

The study of surface waves in a layered media has their viable application in geophysical prospecting. This paper presents an analytical study on the dispersion of torsional surface wave in a pre-stressed heterogeneous layer sandwiched between a pre-stressed anisotropic أکثر

The study of surface waves in a layered media has their viable application in geophysical prospecting. This paper presents an analytical study on the dispersion of torsional surface wave in a pre-stressed heterogeneous layer sandwiched between a pre-stressed anisotropic porous semi-infinite medium and gravitating anisotropic porous half-space. The non-homogeneity within the intermediate layer and upper semi-infinite medium is assumed to rise up, because of quadratic variation and exponential variation in directional rigidity, pre-stress, and density respectively. The displacement dispersion equation for the torsional wave velocity has been expressed in the term of Whitaker function and their derivatives. Dispersion relation and the closed-form solutions have been obtained analytically for the displacement in the layer and the half-spaces. It is determined that the existing geometry allows torsional surface waves to propagate and the observe exhibits that the layer width, layer inhomogeneity, frequency of heterogeneity in the heterogeneous medium has a great impact on the propagation of the torsional surface wave. The influence of inhomogeneities on torsional wave velocity is also mentioned graphically by means plotting the dimensionless phase velocity against non-dimensional wave number for distinct values of inhomogeneity parameters. تفاصيل المقالة

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4 - Dispersion of SH-Wave in a Heterogeneous Orthotropic Layer Sandwiched Between an Inhomogeneous Semi-Infinite Medium and a Heterogeneous Elastic Half-Space
R.M Prasad S Kundu

10.22034/jsm.2021.1876032.1479

The aim of this paper is to investigates the existence of the dispersion of SH-wave in a heterogeneous orthotropic layer lying over a heterogeneous elastic half-space and underlying an inhomogeneous semi-infinite medium. Hyperbolic variation in upper semi-infinite assoc أکثر

The aim of this paper is to investigates the existence of the dispersion of SH-wave in a heterogeneous orthotropic layer lying over a heterogeneous elastic half-space and underlying an inhomogeneous semi-infinite medium. Hyperbolic variation in upper semi-infinite associated with directional rigidities and density has been considered while linear variation in the intermediate layer associated with initial stress, density, shear moduli and lower half-space associated with rigidity and density has been considered. The dispersion equation of SH-wave has been obtained in a closed form by using variable separation method. The effects of inhomogeneities of the assumed media are illustrated by figures using MATLAB programming. The Earth's composition is heterogeneous that incorporates extremely hard layers. The propagation of SH-wave across crustal layer of the Earth very much depends upon heterogeneity and orthotropic properties. In fact, the observation reveals that the phase velocity of SH-wave is directly proportionate to inhomogeneity parameter, orthotropic parameter and heterogeneity parameter. That means as inhomogeneity parameter and heterogeneity orthotropic parameter increases, the phase velocity of SH-wave increases proportionately. Moreover, the obtained dispersion equation of SH-wave coincides with the classical result of Love wave as initial stress, inhomogeneities, and the upper semi-infinite medium is neglected. This analysis may be helpful to expound the nature of the dispersion of seismic waves in elastic media. تفاصيل المقالة

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5 - Mathematical Modeling of Thermoelastic State of a Thick Hollow Cylinder with Nonhomogeneous Material Properties
V. R Manthena N.K Lamba G.D Kedar

The object of the present paper is to study heat conduction and thermal stresses in a hollow cylinder with nonhomogeneous material properties. The cylinder is subjected to sectional heating at the curved surface. All the material properties except for Poisson’s ra أکثر

The object of the present paper is to study heat conduction and thermal stresses in a hollow cylinder with nonhomogeneous material properties. The cylinder is subjected to sectional heating at the curved surface. All the material properties except for Poisson’s ratio and density are assumed to be given by a simple power law in the axial direction. A solution of the two-dimensional heat conduction equation is obtained in the transient state. The solutions are obtained in the form of Bessel’s and trigonometric functions. For theoretical treatment, all the physical and mechanical quantities are taken as dimensional, whereas we have considered non-dimensional parameters, for numerical analysis. The influence of inhomogeneity on the thermal and mechanical behaviour is examined. The transient state temperature field and its associated thermal stresses are discussed for a mixture of copper and tin metals in the ratio 70:30 respectively. Numerical calculations are carried out for both homogeneous and nonhomogeneous cylinders and are represented graphically. تفاصيل المقالة

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6 - Thermoelastic Analysis of a Rectangular Plate with Nonhomogeneous Material Properties and Internal Heat Source
V. R Manthena N.K Lamba G.D Kedar

This article deals with the determination of temperature distribution, displacement and thermal stresses of a rectangular plate having nonhomogeneous material properties with internal heat generation. The plate is subjected to sectional heating. All the material propert أکثر

This article deals with the determination of temperature distribution, displacement and thermal stresses of a rectangular plate having nonhomogeneous material properties with internal heat generation. The plate is subjected to sectional heating. All the material properties except Poisson’s ratio and density are assumed to be given by a simple power law along x direction. Solution of the two-dimensional heat conduction equation is obtained in the transient state. Integral transform method is used to solve the system of fundamental equation of heat conduction. The effects of inhomogeneity on temperature and thermal stress distributions are examined. For theoretical treatment, all the physical and mechanical quantities are taken as dimensional, whereas for numerical computations we have considered non-dimensional parameters. The transient state temperature field and its associated thermal stresses are discussed for a mixture of copper and zinc metals in the ratio 70:30 respectively. Numerical calculations are carried out for both homogeneous and nonhomogeneous cases and are represented graphically. تفاصيل المقالة

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7 - Shear Waves Through Non Planar Interface Between Anisotropic Inhomogeneous and Visco-Elastic Half-Spaces
B Prasad P Chandra Pal S Kundu

A problem of reflection and transmission of a plane shear wave incident at a corrugated interface between transversely isotropic inhomogeneous and visco-elastic half-spaces is investigated. Applying appropriate boundary conditions and using Rayleigh’s method of ap أکثر

A problem of reflection and transmission of a plane shear wave incident at a corrugated interface between transversely isotropic inhomogeneous and visco-elastic half-spaces is investigated. Applying appropriate boundary conditions and using Rayleigh’s method of approximation expressions for reflection and transmission coefficients are obtained for the first and second order approximation of the corrugation. Further, closed form formulae of these coefficients are presented for a corrugated interface of periodic shape (cosine law interface). Numerical computations for this particular type of corrugated interface are performed and a number of graphs are plotted to illustrate the effect of different parameters of the both half-spaces on the reflection and transmission coefficients. It is found that these coefficients depend upon the amplitude of corrugation of the boundary, angle of incidence and frequency of the incident wave and are strongly influenced by the anisotropy, inhomogeneity and visco-elasticity of the half-spaces. Some special cases are also derived. تفاصيل المقالة

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8 - Torsion of cylindrically poroelasic circular shaft with radial inhomogeneity .some exact solutions for extruder
mohammad farid khansanami Faranak Khansanami

Torsion of elastic and poroelastic circular shaft of radially inhomogeneous, cylindrically orthotropic materials is studied with emphasis on the end eﬀects example for extruder. To examine the conjecture of Saint-Venant’s torsion, we consider torsion of circular s أکثر

Torsion of elastic and poroelastic circular shaft of radially inhomogeneous, cylindrically orthotropic materials is studied with emphasis on the end eﬀects example for extruder. To examine the conjecture of Saint-Venant’s torsion, we consider torsion of circular shaft with one end ﬁxed and the other end free on which tractions that results in a pure torque are prescribed arbitrarily over the free end surface. Exact solutions that satisfy the prescribed boundary conditions point by point over the entire boundary surfaces are derived in a uniﬁed manner for cylindrically orthotropic shafts with or without radial inhomogeneity and for their coun- terparts of Saint-Venant’s torsion. Stress diﬀusion due to the end eﬀect is examined in the light of the exact solutions.The present study enables us to assess Saint-Venant’s principle as applied to anisotropic, non-homogeneous poroelastic bodies in general and to evaluate the stress diﬀusion in torsion of radially inhomogeneous, cylindrically orthotropic cylinders in particular. The following conclusions can be drawn from the analysis. تفاصيل المقالة

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9 - Torsion of cylindrically poroelasic circular shaft with radial inhomogeneity .some exact solutions for extruder
محمد فرید خان سمنی فرانک خان سمنی

Torsion of elastic and poroelastic circular shaft of radially inhomogeneous, cylindrically orthotropic materials is studied with emphasis on the end eﬀects example for extruder. To examine the conjecture of Saint-Venant’s torsion, we consider torsion of circular s أکثر

Torsion of elastic and poroelastic circular shaft of radially inhomogeneous, cylindrically orthotropic materials is studied with emphasis on the end eﬀects example for extruder. To examine the conjecture of Saint-Venant’s torsion, we consider torsion of circular shaft with one end ﬁxed and the other end free on which tractions that results in a pure torque are prescribed arbitrarily over the free end surface. Exact solutions that satisfy the prescribed boundary conditions point by point over the entire boundary surfaces are derived in a uniﬁed manner for cylindrically orthotropic shafts with or without radial inhomogeneity and for their coun- terparts of Saint-Venant’s torsion. Stress diﬀusion due to the end eﬀect is examined in the light of the exact solutions.The present study enables us to assess Saint-Venant’s principle as applied to anisotropic, non-homogeneous poroelastic bodies in general and to evaluate the stress diﬀusion in torsion of radially inhomogeneous, cylindrically orthotropic cylinders in particular. The following conclusions can be drawn from the analysis تفاصيل المقالة

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10 - PLANE WAVE PROPAGATION THROUGH A PLANER SLAB
Rajneesh Kakar

An approximation technique is considered for computing transmission and reflection coefficients for plane waves propagating through stratified slabs. The propagation of elastic pulse through a planar slab is derived from first principles using straightforward time-depen أکثر

An approximation technique is considered for computing transmission and reflection coefficients for plane waves propagating through stratified slabs. The propagation of elastic pulse through a planar slab is derived from first principles using straightforward time-dependent method. The paper ends with calculations of enhancement factor for the elastic plane wave and it is shown that it depends on the velocity ratio of the wave in two different media but not the incident wave form. The result, valid for quite arbitrary incident pulses and quite arbitrary slab inhomogeneities, agrees with that obtained by time-independent methods, but uses more elementary methods تفاصيل المقالة

فهرس المقالات Inhomogeneity

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