scholarly journals An asymptotic model for solving mixed integral equation in some domains

2020 ◽  
Vol 28 (1) ◽  
Author(s):  
Mohamed Abdella Abdou ◽  
Hamed Kamal Awad
Keyword(s):  
Integral Equation ◽  
Potential Function ◽  
Theory Of Elasticity ◽  
Asymptotic Model ◽  
Logarithmic Function ◽  
Integral Term ◽  
Special Cases ◽  
Generalized Potential ◽  
Carleman Function ◽  
Axisymmetric Problems

Abstract In this paper, we discuss the solution of mixed integral equation with generalized potential function in position and the kernel of Volterra integral term in time. The solution will be discussed in the space $$L_{2} (\Omega ) \times C[0,T],$$ L 2 ( Ω ) × C [ 0 , T ] , $$0 \le t \le T < 1$$ 0 ≤ t ≤ T < 1 , where $$\Omega$$ Ω is the domain of position and $$t$$ t is the time. The mixed integral equation is established from the axisymmetric problems in the theory of elasticity. Many special cases when kernel takes the potential function, Carleman function, the elliptic function and logarithmic function will be established.

scholarly journals New Model for Solving Mixed Integral Equation of the First Kind with Generalized Potential Kernel

2017 ◽  
Vol 9 (5) ◽  
pp. 18
Author(s):  
Shareefa Eisa Ali Alhazmi
Keyword(s):  
Integral Equation ◽  
Potential Function ◽  
Mixed Boundary ◽  
Mixed Boundary Conditions ◽  
Contact Problems ◽  
Three Dimensions ◽  
Function Form ◽  
Special Cases ◽  
Generalized Potential ◽  
Carleman Function

New technique model is used to solve the mixed integral equation (\textbf{MIE}) of the first kind, with a position kernel contains a generalized potential function multiplying by a continuous function and continuous kernel in time, in the space $L_{2} (\Omega )\times C[0,T],\, 0\leq T<1$, $\Omega$ is the domain of integration and $T$ is the time. The integral equation arises in the treatment of various semi-symmetric contact problems, in one, two, and  three dimensions, with mixed boundary conditions in the mechanics of continuous media. The solution of the \textbf{MIE }when the kernel of position takes the potential function form, elliptic function form, Carleman function and logarithmic kernel are discussed and obtain in  this work. Moreover, many special cases are derived.

scholarly journals Fredholm-Volterra integral equation with potential kernel

2001 ◽  
Vol 26 (6) ◽  
pp. 321-330
Author(s):  
M. A. Abdou ◽  
A. A. El-Bary
Keyword(s):  
Integral Equation ◽  
Continuous Function ◽  
Volterra Integral Equation ◽  
Fredholm Integral Equation ◽  
Integral Term ◽  
Potential Kernel ◽  
Generalized Potential ◽  
Potential Form

A method is used to solve the Fredholm-Volterra integral equation of the first kind in the spaceL2(Ω)×C(0,T),Ω={(x,y):x2+y2≤a},z=0, andT<∞. The kernel of the Fredholm integral term considered in the generalized potential form belongs to the classC([Ω]×[Ω]), while the kernel of Volterra integral term is a positive and continuous function that belongs to the classC[0,T]. Also in this work the solution of Fredholm integral equation of the second and first kind with a potential kernel is discussed. Many interesting cases are derived and established in the paper.

Spectral relationships of the integral equation with logarithmic kernel in some different domains

2014 ◽  
Vol 4 (3) ◽  
pp. 610-622
Author(s):  
M. I. Youssef ◽  
M. A. Abdou
Keyword(s):  
Integral Equation ◽  
Contact Problem ◽  
Potential Theory ◽  
Fredholm Integral Equation ◽  
Theory Of Elasticity ◽  
Theory Method ◽  
Logarithmic Kernel ◽  
Special Cases ◽  
Plane Theory Of Elasticity ◽  
Potential Theory Method

In this work, the Fredholm integral equation (FIE) with logarithmic kernel is investigated from the contact problem in the plane theory of elasticity. Then, using potential theory method (PTM), the spectral relationships (SRs) of this integral equation are obtained in some different domains of the contact. Many special cases and new SRs are established and discussed from this work.

Boundary Integral Equation Formulation in Generalized Linear Thermo-Viscoelasticity With Rheological Volume

2003 ◽  
Vol 70 (5) ◽  
pp. 661-667 ◽  
Author(s):  
A. S. El-Karamany
Keyword(s):  
Integral Equation ◽  
Rheological Properties ◽  
Boundary Integral Equation ◽  
Relaxation Times ◽  
Fundamental Solutions ◽  
Boundary Integral ◽  
Phase Lag ◽  
Integral Equation Formulation ◽  
Special Cases ◽  
The Given

A general model of generalized linear thermo-viscoelasticity for isotropic material is established taking into consideration the rheological properties of the volume. The given model is applicable to three generalized theories of thermoelasticity: the generalized theory with one (Lord-Shulman theory) or with two relaxation times (Green-Lindsay theory) and with dual phase-lag (Chandrasekharaiah-Tzou theory) as well as to the dynamic coupled theory. The cases of thermo-viscoelasticity of Kelvin-Voigt model or thermoviscoelasticity ignoring the rheological properties of the volume can be obtained from the given model. The equations of the corresponding thermoelasticity theories result from the given model as special cases. A formulation of the boundary integral equation (BIE) method, fundamental solutions of the corresponding differential equations are obtained and an example illustrating the BIE formulation is given.

Edge Crack in an Elastic Strip on a Liquid Foundation

1989 ◽  
Vol 33 (03) ◽  
pp. 214-220
Author(s):  
Paul C. Xirouchakis ◽  
George N. Makrakis
Keyword(s):  
Stress Intensity Factor ◽  
Integral Equation ◽  
Fourier Transform ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Edge Crack ◽  
Applied Pressure ◽  
Theory Of Elasticity ◽  
Elastic Strip ◽  
Pressure Loading

The behavior of a long elastic strip with an edge crack resting on a liquid foundation is investigated. The faces of the crack are opened by an applied pressure loading. The deformation of the strip is considered within the framework of the linear theory of elasticity assuming plane-stress conditions. Fourier transform techniques are employed to obtain integral expressions for the stresses and displacements. The boundary-value problem is reduced to the solution of a Fredholm integral equation of the second kind. For the particular case of linear pressure loading, the stress-intensity factor is calculated and its dependence is shown on the depth of the crack relative to the thickness of the strip. Application of the present results to the problem of flexure of floating ice strips is discussed.

Stresses and Displacements in a Rotating Conical Shell

1943 ◽  
Vol 10 (2) ◽  
pp. A53-A61
Author(s):  
J. L. Meriam
Keyword(s):  
Conical Shell ◽  
Body Force ◽  
Theory Of Elasticity ◽  
Common Type ◽  
The Body ◽  
Surface Loading ◽  
Thin Walled Structures ◽  
Special Cases ◽  
Engineering Problems ◽  
Rotating Conical Shell

Abstract The analysis of shells is an important subdivision of the general theory of elasticity, and its application is useful in the solution of engineering problems involving thin-walled structures. A common type of shell is one which possesses symmetry with respect to an axis of revolution. A theory for such shells has been developed by various investigators (1, 2, 3, 6) and applied to a few simple cases such as the cylindrical, spherical, and conical shapes. Boundary conditions, for the most part, have been simple static ones, and conditions of surface loading have been included in certain special cases. This paper extends the theory of axially symmetrical shells by including the body force of rotation about the axis and applies the results to the rotating conical shell. The analysis follows a pattern established by several investigators (1, 2, 3, 6) and for this reason is abbreviated to a considerable extent. Only where the inclusion of the body force makes elucidation advisable or where a slightly different method of approach is used are the steps presented in more detail.

scholarly journals Some Applications of Eigenvalue Problems for Tensor and Tensor–Block Matrices for Mathematical Modeling of Micropolar Thin Bodies

2019 ◽  
Vol 24 (1) ◽  
pp. 33 ◽  
Author(s):  
Mikhail Nikabadze ◽  
Armine Ulukhanyan
Keyword(s):  
Boundary Value Problems ◽  
Anisotropic Medium ◽  
Eigenvalue Problems ◽  
Constitutive Relations ◽  
Boundary Value ◽  
Initial Boundary ◽  
Theory Of Elasticity ◽  
Initial Boundary Value Problems ◽  
Special Cases ◽  
Initial Boundary Value

The statement of the eigenvalue problem for a tensor–block matrix (TBM) of any orderand of any even rank is formulated, and also some of its special cases are considered. In particular,using the canonical presentation of the TBM of the tensor of elastic modules of the micropolartheory, in the canonical form the specific deformation energy and the constitutive relations arewritten. With the help of the introduced TBM operator, the equations of motion of a micropolararbitrarily anisotropic medium are written, and also the boundary conditions are written down bymeans of the introduced TBM operator of the stress and the couple stress vectors. The formulationsof initial-boundary value problems in these terms for an arbitrary anisotropic medium are given.The questions on the decomposition of initial-boundary value problems of elasticity and thin bodytheory for some anisotropic media are considered. In particular, the initial-boundary problems of themicropolar (classical) theory of elasticity are presented with the help of the introduced TBM operators(tensors–operators). In the case of an isotropic micropolar elastic medium (isotropic and transverselyisotropic classical media), the TBM operator (tensors–operators) of cofactors to TBM operators(tensors–tensors) of the initial-boundary value problems are constructed that allow decomposinginitial-boundary value problems. We also find the determinant and the tensor of cofactors to the sumof six tensors used for decomposition of initial-boundary value problems. From three-dimensionaldecomposed initial-boundary value problems, the corresponding decomposed initial-boundary valueproblems for the theories of thin bodies are obtained.

scholarly journals A New Generalized Morse Potential Function for Calculating Cohesive Energy of Nanoparticles

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3323 ◽  
Author(s):  
Omar M. Aldossary ◽  
Anwar Al Rsheed
Keyword(s):  
Potential Function ◽  
Cohesive Energy ◽  
Morse Potential ◽  
Attractive Force ◽  
Repulsive Interaction ◽  
Additional Parameter ◽  
Generalized Potential ◽  
The Stability ◽  
Experimental Values ◽  
Generalized Morse Potential

A new generalized Morse potential function with an additional parameter m is proposed to calculate the cohesive energy of nanoparticles. The calculations showed that a generalized Morse potential function using different values for the m and α parameters can be used to predict experimental values for the cohesive energy of nanoparticles. Moreover, the enlargement of the attractive force in the generalized potential function plays an important role in describing the stability of the nanoparticles rather than the softening of the repulsive interaction in the cases when m > 1.

scholarly journals Tolerance and asymptotic modelling of dynamic thermoelasticity problems for thin micro-periodic cylindrical shells

Meccanica ◽  
2020 ◽  
Vol 55 (12) ◽  
pp. 2391-2411 ◽  
Author(s):  
Barbara Tomczyk ◽  
Marcin Gołąbczak
Keyword(s):  
Cell Size ◽  
Constitutive Relations ◽  
Cylindrical Shells ◽  
Theory Of Elasticity ◽  
Asymptotic Model ◽  
Dynamic Thermoelasticity ◽  
Oscillating Coefficients ◽  
Stationary Action ◽  
A Cell ◽  
Model Equations

AbstractThe problem of linear dynamic thermoelasticity in Kirchhoff–Love-type circular cylindrical shells having properties periodically varying in circumferential direction (uniperiodic shells) is considered. In order to describe thermoelastic behaviour of such shells, two mathematical averaged models are proposed—the non-asymptotic tolerance and the consistent asymptotic models. Considerations are based on the known Kirchhoff–Love theory of elasticity combined with Duhamel-Neumann thermoelastic constitutive relations and on Fourier’s theory of heat conduction. The non-asymptotic tolerance model equations depending on a cell size are derived applying the tolerance averaging technique and a certain extension of the known stationary action principle. The consistent asymptotic model equations being independent on a microstructure size are obtained by means of the consistent asymptotic approach. Governing equations of both the models have constant coefficients, contrary to starting shell equations with periodic, non-continuous and oscillating coefficients. As examples, two special length-scale problems will be analysed in the framework of the proposed models. The first of them deals with investigation of the effect of a cell size on the shape of initial distributions of temperature micro-fluctuations. The second one deals with study of the effect of a microstructure size on the distribution of total temperature field approximated by sum of an averaged temperature and temperature fluctuations.

Mean dyadic Green's function of a randomly rough surface

1994 ◽  
Vol 72 (1-2) ◽  
pp. 20-29 ◽  
Author(s):  
Saba Mudaliar
Keyword(s):  
Integral Equation ◽  
Green’S Function ◽  
Multiple Scattering ◽  
Rough Surface ◽  
Green's Function ◽  
Diagram Method ◽  
Dyadic Green’S Function ◽  
Dyadic Green's Function ◽  
Special Cases ◽  
Randomly Rough Surface

The problem of wave propagation and scattering over a randomly rough surface is considered from a multiple-scattering point of view. Assuming that the magnitude of irregularities are small an approximate boundary condition is specified. This enables us to derive an integral equation for the dyadic Green's function (DGF) in terms of the known unperturbed DGF. Successive iteration of this integral equation yields the Neumann series. On averaging this and using a diagram method the Dyson equation is derived. Bilocal approximation to the mass operator leads to an integral equation whose kernel is of the convolution type. This is then readily solved and the results are presented in a simplified and useful form. It is observed that the coherent reflection coefficients involve infinite series of multiple scattering. Two special cases are considered the results of which are in agreement with our expectations.

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