Zero group velocity longitudinal modes in an isotropic cylinder

Zero group velocity （ZGV） modes are studied in an isotropic cylinder. The L （0, 2） mode behaves anomalously for the materials with a value of the bulk velocity ratio, to, in the range √2 〈 κ 〈 2.64 and normally otherwise. All higher modes, except the first few, have no ZGV point for all isotropic materials. This is explained analytically by finding the slope of phase velocity dispersion curves of modes first when the phase velocity equals κ and then at their initial state.

Fluid flow and fluid shear stress in canaliculi induced by external mechanical loading and blood pressure oscillation

The paper studies the problem of fluid flow and fluid shear stress in canaliculi when the osteon is subject to external mechanical loading and blood pressure oscillation.The single osteon is modeled as a saturated poroelastic cylinder. Solid skeleton is regarded as a poroelastic transversely isotropic material. To get near-realistic results, both the interstitial fluid and the solid matrix are regarded as compressible. Blood pressure oscillation in the Haverian canal is considered. Using the poroelasticity theory, an analytical solution of the pore fluid pressure is obtained. Assuming the fluid in canaliculi is incompressible, analytical solutions of fluid flow velocity and fluid shear stress with the Navier-Stokes equations of incompressible fluid are obtained. The effect of various parameters on the fluid flow velocity and fluid shear stress is studied.

ElasticWaves in Generalized Thermo-Piezoelectric Transversely Isotropic Circular Bar Immersed in Fluid

In this paper,a mathematical model is developed to study the wave propagation in an infinite,homogeneous,transversely isotropic thermo-piezoelectric solid bar of circular cross-sections immersed in inviscid fluid.The present study is based on the use of the three-dimensional theory of elasticity.Three displacement potential functions are introduced to uncouple the equations of motion and the heat and electric conductions.The frequency equations are obtained for longitudinal and flexural modes of vibration and are studied based on Lord-Shulman,Green-Lindsay and Classical theory theories of thermo elasticity.The frequency equations of the coupled system consisting of cylinder and fluid are developed under the assumption of perfectslip boundary conditions at the fluid-solid interfaces,which are obtained for longitudinal and flexural modes of vibration and are studied numerically for PZT-4 material bar immersed in fluid.The computed non-dimensional frequencies are compared with Lord-Shulman,Green-Lindsay and Classical theory theories of thermo elasticity for longitudinal and flexural modes of vibrations.The dispersion curves are drawn for longitudinal and flexural modes of vibrations.Moreover,the dispersion of specific loss and damping factors are also analyzed for longitudinal and flexural modes of vibrations.

A Refined Theory of Axisymmetric Poroelastic Circular Cylinder

A refined theory of axisymmetric deformation of an isotropic poroelastic circular cylinder in a steady-state is presented directly by utilizing the general solutions and Lur＇e method without any advance hypothesis.The refined equations are derived under non-homogenous boundary conditions,and the approximate solutions are obtained by omitting higher-order terms.The all-inclusive refined equations and approximate solutions constitute the refined theory of circular cylinders.Correlative examples are brought up to analyze influences of liquid-solid coupling properties on the mechanical behavior of poroelastic materials.Moreover,the present results are converted into those of homologous pure elastic problem directly.