HIRANWAR P.C.1, KHOBRAGADE N.W.2*
1Department of Mathematics, RTM Nagpur University, Nagpur-440033, MS, India
2Department of Mathematics, RTM Nagpur University, Nagpur-440033, MS, India
* Corresponding Author : khobragadenw@gmail.com
Received : 18-06-2012 Accepted : 25-06-2012 Published : 27-06-2012
Volume : 3 Issue : 2 Pages : 109 - 113
J Stat Math 3.2 (2012):109-113
We apply integral transformation techniques to study thermoelastic response of a hollow cylinder in general, in which sources are generated according to the linear function of the temperature, with boundary conditions of the radiation type. Numerical calculations are carried out for a particular case of a hollow cylinder made of Aluminum metal and result are depicted graphically.
Transient Response, Hollow Cylinder, Temperature Distribution Thermal Stress, Integral Transform.
Nowacki has determined steady state thermal stresses in a thick circular plate subjected to an axisymmetric temperature distribution on the upper face with zero temperature on the lower face and circular edge. Wankhede has determined the quasi - state thermal stresses in circular plate subjected to arbitrary initial temperature on the upper face with lower face at zero temperature. However, there are not many investigation on transient state. S.K. Roy Choudhary has succeeded in determining the quasi - static thermal stresses in a circular plate subjected to transient temperature along the circumference of circular upper face with lower face at zero temperature and the fixed circular edge thermally insulated. In the recent work, some problems have been solved by Noda and Deshmukh. In all aforementioned investigations an axisymmetrically heated plate has been considered. Recently, Nasser proposed the concept of heat sources in generalized thermoelasticity and applied to the thick plate problem.. Khobragade et al. studied an inverse unsteady state problem of finite length hollow cylinder. They have not considered any thermoelastic problems with boundary conditions of radiation type, in which sources are generated according to the linear functions of radiation type, in which sources are generated according to the linear function of the temperature, which satisfies the time dependent heat conduction equation. From the previous literature regarding finite length hollow cylinder as considered it was observed by the author that no analytical procedure has been established considering internal heat source generation within the body.
This paper is concerned with the transient thermoelastic problem of a hollow cylinder in which sources are generated according to the linear function of temperature, occupying the space with radiation type boundary conditions.
Consider a hollow cylinder of length 2h in which sources are generated according to linear function of temperature. The material is isotropic, homogeneous and all properties are assumed to be constant. Heat conduction with internal source and prescribed boundary conditions of the radiation type are considered. The equation for heat conductions is , the temperature in cylindrical coordinate is
where is the source function and being the thermal conductivity of the material, is the density and is the calorific capacity, assumed to be constant.
For convenience, we consider the under given functions as the superposition of the simpler function.
and
Consider
Substituting equations (2) and (3) in the heat conduction equation (1), one obtain
where k is the thermal diffusivity of the material of the cylinder (which is assumed to be constant). Subject to the initial and boundary condition
for all
for all
for all
for all
The most general expression for these conditions can be given by
where the prime denotes differentiation with respect to are the Dirac Delta functions having is constants. is the additional sectional heat available on its surface at and are radiation constants on the upper and lower surface of cylinder respectively.
The radiation and axial displacement U and W satisfy the uncoupled thermoelastic equation as (Sierakowski and Sun) are
Where is the volume dilatation.
And
The thermoelastic displacement function as (Nowacki) is governed by the Poisson’s equation
With at and .
Where ,
And are poisons ratio and the linear coefficient of thermal expansion of the material of the cylinder respectively.
The stress functions are given by
Where P1 and P0 are the surface pressure assumed to be uniform over the boundaries of the cylinder. The stress functions are expressed in terms of displacement components by the relations
Where is the Lame’s constant, is the shear modulus and U and W are the displacement components.
The equations (1) to (18) constitute the mathematical formulation of the problem under consideration.
In order to solve fundamental differential equation (5) under the boundary conditions (7) and (8), we firstly introduce the integral transform of order 0 over the variable r. Let n be the parameter of the transform, then the integral transform and its inversion theorem is written as
where is the transformation of with respect to nucleus .
The kernel function can be defined as
with
for and in which and are Bessel’s functions of the first and second kind of order respectively.
Applying the transformation defined in equation (19) to the equations (5) (6) and (9) and using equation (7) and (8) one obtains
Where X =
Where is the transformed is function of and is the transformed parameter. The Eigen values are the positive roots of the characteristic equation.
.
We introduce another integral transformation that respond to the radiation type boundary conditions
Further apply the transformation defined in equation (24) to the equation (20) and using (22) and (23) one obtains.
where
where is the transformed function of and is the transformed parameter. The symbol (*) means a function in the transform domain and the nucleus is given by the orthogonal functions in the interval as
where
The eigen values are the positive roots of the characteristic equation
After performing some calculations on the equation (25), the reduction is made to linear first order differential equation as
The transformed temperature solution is
Where
Applying the inversion of transformation rules defined in equations (19) and (24) the temperature solution is shown as follows
Taking into account of the first equation of equation (3), the temperature distribution is finally represented by
The equation (31) represents the temperature at any instant and at all points of the hollow cylinder when there are radiation type boundary conditions.
Substituting value of from (31) in (14) one obtains the thermoelastic displacement function as
Substituting the value of from equation (32) in (12) and (13) one obtains.
Now making use of two displacement components the volume dilatation is established as
The stress components can be evaluated by substituting the values of thermoelastic displacement from equations (33) and (34) in equations (15), (16), (17) and (18) one obtains.
Set
Applying Marchi-Fasulo transform to equation (40), we obtain,
, . Substitute this values in (15), one obtains
In this paper we study thermoelastic response of finite length hollow cylinder in which sources are generated according to linear function of temperature, with boundary conditions of the radiation Marchi - Zgrablich transform and March - Fasulo transform techniques are used to obtain numerical results. The temperature, displacement and stresses that are obtained can be applied to the design of useful structures or machines in engineering applications.
The authors are thankful to University Grant Commission, New Delhi for providing the partial financial assistance under major research project scheme.
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