Nonlinear magnetoelastic deformations of porous solids

2021 ◽  
pp. 108128652198896
Author(s):  
Pei Zheng ◽  
Xiong Tang ◽  
Ding Ding

A magnetoactive porous solid comprises a porous polymer matrix with embedded magnetizable particles. The connected porous space of the polymer matrix is filled with a fluid. Under externally applied magnetic fields, the magnetoactive porous solid can undergo large deformations in the elastic regime, triggering diffusive flow in the interconnected pores. The coupled hydromagnetomechanical behavior of such materials has recently received considerable attention. In this paper, the effective stress principle is applied to the constitutive modeling of the material at finite strains. In contrast to previous works, the Lagrangian porosity is no longer treated as an independent constitutive variable in the proposed formulation. To investigate the effect of the magnetic field on the mechanical response of the material, as well as to illustrate the theory, the problem of inflation of a circular cylindrical tube in the presence of a uniform axial magnetic field is formulated and solved. Computational results are presented graphically.

2017 ◽  
Vol 23 (6) ◽  
pp. 950-983 ◽  
Author(s):  
Prashant Saxena

A thick-walled circular cylindrical tube made of an incompressible magnetoelastic material is subjected to a finite static deformation in the presence of an internal pressure, an axial stretch and an azimuthal or an axial magnetic field. The dependence of the static magnetoelastic deformation on the intensity of the applied magnetic field is analysed for two different magnetoelastic energy density functions. Then, superimposed on this static configuration, incremental axisymmetric motions of the tube and their dependence on the applied magnetic field and deformation parameters are studied. In particular, we show that magnetoelastic coupled waves exist only for particle motions in the azimuthal direction. For particle motion in radial and axial directions, only purely mechanical waves are able to propagate when a magnetic field is absent. The wave speeds as well as the stability of the tube can be controlled by changing the internal pressure, axial stretch and applied magnetic field that demonstrates the applicability of magneto-elastomers as wave guides and vibration absorbers.


2000 ◽  
Author(s):  
Ray W. Ogden ◽  
Christian A. J. Schulze-Bauer

Abstract In this paper we present some new data from extension-inflation tests on a human iliac artery and then, on the basis of the nonlinear theory of elasticity, we examine a possible model to represent this data. The model considers the artery initially as a thick-walled circular cylindrical tube which may consist of two or more concentric layers. In order to take some account of the architecture (morphological structure), each layer of the material is regarded as consisting of two families of mechanically equivalent helical fibers symmetrically disposed with respect to the cylinder axis. The resulting material properties are then orthotropic in each layer. General formulas for the pressure and the axial load in the symmetric inflation of an extended tube are obtained. The starting point is the unloaded circular cylindrical configuration, but (in general unknown) residual stresses are included in the formulation. The model is illustrated by specializing firstly to the case of a single layer so that the consequences of the hypothesis of uniform circumferential stress in the physiological state can be examined theoretically. This enables the required residual stresses to be calculated explicitly. Secondly, the equations are specialized for the membrane approximation in order to show how certain important characteristics of the experimental data can be replicated using a relatively simple anisotropic membrane model.


Author(s):  
J. Wolowski ◽  
J. Badziak ◽  
P. Parys ◽  
E. Woryna ◽  
J. Krasa ◽  
...  

Author(s):  
Le Sun ◽  
Zhejun Luo ◽  
Jun Hang ◽  
Shichuan Ding ◽  
Wei Wang

2021 ◽  
Vol 76 (3) ◽  
pp. 265-283
Author(s):  
G. Nath

Abstract The approximate analytical solution for the propagation of gas ionizing cylindrical blast (shock) wave in a rotational axisymmetric non-ideal gas with azimuthal or axial magnetic field is investigated. The axial and azimuthal components of fluid velocity are taken into consideration and these flow variables, magnetic field in the ambient medium are assumed to be varying according to the power laws with distance from the axis of symmetry. The shock is supposed to be strong one for the ratio C 0 V s 2 ${\left(\frac{{C}_{0}}{{V}_{s}}\right)}^{2}$ to be a negligible small quantity, where C 0 is the sound velocity in undisturbed fluid and V S is the shock velocity. In the undisturbed medium the density is assumed to be constant to obtain the similarity solution. The flow variables in power series of C 0 V s 2 ${\left(\frac{{C}_{0}}{{V}_{s}}\right)}^{2}$ are expanded to obtain the approximate analytical solutions. The first order and second order approximations to the solutions are discussed with the help of power series expansion. For the first order approximation the analytical solutions are derived. In the flow-field region behind the blast wave the distribution of the flow variables in the case of first order approximation is shown in graphs. It is observed that in the flow field region the quantity J 0 increases with an increase in the value of gas non-idealness parameter or Alfven-Mach number or rotational parameter. Hence, the non-idealness of the gas and the presence of rotation or magnetic field have decaying effect on shock wave.


2020 ◽  
Vol 65 (1) ◽  
pp. 95-104
Author(s):  
H. Wu ◽  
Y. L. Chang ◽  
Alexandr Babkin ◽  
Boyoung Lee

1990 ◽  
Vol 44 (1) ◽  
pp. 167-190 ◽  
Author(s):  
Alf H. Øien

Collisions in a cylindrically symmetric non-neutral (electron) plasma, where the Larmor radius is much smaller than the Debye length, and the consequent particle transport, are studied. The plasma is confined radially by a strong axial magnetic field and axially by electric potentials. Hence two particles may interact repeatedly. Eventually they drift too far away from each other poloidally to interact any more, owing to shear in the E × B drift. The consequent build-up of correlation is limited by correlational disintegration due to collisions with ‘third particles’ between the repeated interactions. A kinetic equation including these effects is derived, and the cross-field particle transport along the density gradient is found. An associated equilibration time is shown to scale as B and to be in good agreement with the experimentally obtained values of Briscoli, Malmberg and Fine.


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