The magnesium material is selected for numerical calculations and its thermal and mechanical data have been given in reference (Abo-Dahab et al.
[17]), where all the variables utilized in the computations has been considered in SI units, as:
In addition to the comparisons, we applied the following:
The numerical calculations of the real part values of the field of physical quantities in two dimensions as a function of distance have been divided into three categories:
(i) The first group is to study the effect of alteration the four generalized thermoelastic theories (GTET) on physical quantities when both the gravitational field ( ) and the initial magnetic field are constants. In more details, in this case, it considers the following: the other values for variables of different (GTET) given as, for (CT) theory While, for (LS) theory, But, for (GL) theory, Finally, for (GN) theory, This group is shown in Figures (1)-(7).
(ii) The second group is to examine the impact of variation the gravitational field to be as on physical quantities when both the initial magnetic field to be and the parameters of (GTET) are chosen to be fixed as: This group is displayed in Figures (8)-(14).
(iii) The third group is to illustrate the influence of change the initial magnetic field to become as on physical quantities when both the gravitational field and the variables of (GTET) are constants such as: This group is displayed in Figures (15)-(21).
In more details, one may remark the following:
Fig. 1 considers the changes on the displacement versus distance It is noted that in this case when the thermal relaxation times change, the contrast of the G-L model (green-colored curve) is completely different from the rest of the other three models. While the remaining three curves of the models (CT, L-S and G-N) exhibit similar oscillatory behavior with small variations.
Fig.1 Displacement distribution versus with four theories. |
Fig. 2 examines the variation on the displacement component as function of It is observed that the behavior of the curves in this case is very similar. For example, the curves begin with a maximum value when , then as the distance grows, these values decay to reach the value almost zero in the interval But the effect of relaxation times is the greatest possible for the G-L model, then the C-T model, after that the L-S model and finally the G-N model.
Fig.2 Displacement distribution versus with four theories. |
Fig. 3 illustrates the changes on the normal component of stress against off In this case, all the curves begin with negative values for all the models, due to the variation of the thermal relaxation times, and they are gradually enlarged linearly with similar behavior for all the curves. So, they are reaching almost a maximum value at . After that, the curves begin to decrease so that they all coincide at .
Fig.3 Stress distribution versus with four theories. |
Figs. 4 and 6 display the modifications on the components of stresses and versus The behavior of the curves in these two cases is very close. So, they start for all models from one point at , the stresses values become (-0.14). After that, they start to grow non-linearly until it reaches , then the changes become almost constant and linear for all curves until they all coincide when .
Fig.4 Stress distribution versus with four theories. |
Fig. 5 discusses the alterations on the component of stress with respect to It may be seen that all curves start at with a value of .Then, these values gradually decrease linearly to reach a minimum value in the period After that, its value increases non-linearly until they become almost constant values in the period
Fig.5 Stress distribution versus with four theories. |
Fig. 7 presents the changes in versus It is remarked that when , the values of varies according to different models, but almost all curves have similar behavior with a small difference in the values. It is remarked that the curves of the variable leads to zero when the distance is maximized.
From the second group of Figures (8-14). It is easy to see that Figs. 8 and 10 examine the variations on as and function of at different values of . It is observed that the curves start with different values at , then as the distance enlarges, these values change to reach the value almost zero at for u curves but at for curves, After that, the curves for both of and coincide until they reach the maximum value of at . It may easily be noted that inversely proportional to the gravitational field , while is directly proportional to it.
Figs. 9 and 14 give the variations on the variables and against of . It is found that all the curves in the two variables start with different values at . Then they reduce non-linearly with increasing to reach to the following values at , respectively. After that, the values of the curves diminish to coincide at . While curves of the increase almost linearly in small amounts to become stable until reach .
Figs. 11, 12 and 13 demonstrate the variety of versus at various values of . It is easy to notice that the behavior of the curves in these three cases has the same behavior as the curves in Figs 4, 5 and 7 from in the first group.
Finally, from the third group of Figures (15-21). It is remarked that Fig. 15 shows the changes on as a function of at several values of . The attitude of the curves in this case is similar. So, they start for all curves from one point at , then, they start to grow non-linearly until it reaches to its maximum at the interval After that, They reduce nonlinearly until becoming minimum almost in the period Next, they increase linearly again until they coincide at about . It may also be seen that the effect of on is an inverse proportion.
Fig. 16 considers the alteration of as a function of . It is noticed that the demeanor of the curves in this case is analogous. Therefore, the curves commencement with a maximum value when , then as the distance expands, these values reduce to reach the value almost zero at . Also, it is found that the more value of leads to increase
Fig. 17 display the change of the normal stresses as a function of . By increasing the value of , the values of curves goes up nonlinearly in the period , while after this period the changes become linear until they reach at Also, it is noted that the more value of leads to increase .
Figs. 18 and 20 display the variety of and against at various values of . It is clear that the demeanor of the curves in these two cases has the same character as the curves in Figs 4 and 6 from in the first group and Fig. 12, Fig. 13 in the second group.
Fig.6 Stress distribution versus with four theories. |
Fig.7 Temperature distribution versus with four theories. |
Fig.8 Displacement distribution versus with gravity. |
Fig.9 Displacement distribution versus with gravity. |
Fig.10 Stress distribution versus with gravity. |
Fig.11 Stress distribution versus with gravity. |
Fig.12 Stress distribution versus with gravity. |
Fig.13 Stress distribution versus with gravity. |
Fig.14 Temperature distribution versus with gravity. |
Fig.15 Displacement distribution versus with magnetic field. |
Fig.16 Displacement distribution versus with magnetic field. |
Fig.17 Stress distribution versus with magnetic field. |
Fig.18 Stress distribution versus with magnetic field. |
Fig. 19 illustrates the alterations on the component of stress with respect to at many values of It may be seen that all curves start at with a value of Then, these values gradually decrease linearly to reach a minimum value about . Then, its value increases non-linearly until they become almost constant values in the period Also, increasing the value of clearly reduces
Fig.19 Stress distribution versus with magnetic field. |
Fig.20 Stress distribution versus with magnetic field. |
Fig. 21 considers the change on the curves of versus at different values of . By increasing the value of , the values of curves goes down nonlinearly until they reach to its minimum in the interval , After that the changes become almost linear until they reach at Also, it is noticed that the more value of leads to decrease .
Fig.21 Temperature distribution versus with magnetic field. |
Generally, from Figures (1-7), it is noticed through the graphs and results which come from numerical calculations that the effect of temperature, displacement compounds and stress components when the thermal relaxation time is implicitly located in the heat equation is clearly dissimilar from that case when the thermal relaxation times are not present in the thermal equation, while they exist in the constitutive equations of the system being studied.
Finally, the results obtained in this work are more general, so one may obtain from them some results of others' research as special cases from them. For example, Othman and Lotfy
[5], Othman et al.
[36], Abo-Dahab
[41], Lotfy
[37] studied a problem of generalized magneto-thermo-elasticity without considering more theories of GTET and with different assumptions.