Quantification of Arterial Stiffness Reduced Effect of Vessel Geometry

2008 ◽  
Author(s):  
Shinichiro Ota ◽  
Toshitaka Yasuda ◽  
Takashi Saito
Keyword(s):  
Mechanical Properties ◽  
Cylindrical Shell ◽  
Arterial Stiffness ◽  
Wall Thickness ◽  
Shell Theory ◽  
Dynamic Strain ◽  
Thin Cylindrical Shell ◽  
Inner Pressure ◽  
Latex Tube ◽  
Mechanical Factors

Arteriosclerosis is such as phenomena hardening of arteries, with thickening and loss of elasticity. Previous indexes include effect of geometric and mechanical factors as the radius, the wall thickness and mechanical properties of arteries. In this study, we proposed viscoelasticity indexes formulated by thin cylindrical shell theory estimated dynamic strain, and this index was independent of wall thickness and radius of arterial vessels. To confirm the validity of these indexes, we evaluated the parameters of viscoelasticity using the latex tube with different wall thickness of blood vessel model. We measured a radius of the latex tube and an inner pressure maintained by a pulsatile pump in a mock circuit filled with the water. Estimating the parameters of elasticity using these measured values, we concluded that a proposal index was independent of the wall thickness of the artery.

Non-Axisymmetric Dynamic Response of Imperfectly Bonded Buried Orthotropic Thin Empty Cylindrical Shell Due to Incident Shear Wave (SH Wave)

2011 ◽  
Vol 2 (2) ◽  
pp. 40-56
Author(s):  
Rakesh Singh Rajput ◽  
Sunil Kumar ◽  
Alok Chaubey ◽  
J. P. Dwivedi
Keyword(s):  
Cylindrical Shell ◽  
Dynamic Response ◽  
Shear Wave ◽  
Shell Theory ◽  
Surrounding Medium ◽  
Sh Wave ◽  
Thin Cylindrical Shell ◽  
Sh Waves ◽  
Stiffness And Damping ◽  
Thin Shell Theory

Non-axisymmetric dynamic response of imperfectly bonded buried orthotropic thin empty pipelines subjected to incident shear wave (SH-wave) is presented here. In the thin shell theory the effect of shear deformation and rotary inertia is not considered. The pipeline has been modeled as an infinite thin cylindrical shell imperfectly bonded to surrounding. A thin layer is assumed between the shell and the surrounding medium (soil) such that this layer possesses the properties of stiffness and damping both. The degree of imperfection of the bond is varied by changing the stiffness and the damping parameters of this layer. Although a general formulation including P-, SV-, and SH-wave excitations are presented, numerical results are given for the case of incident SH-waves only. Comparison of axisymmetric and non-axisymmetric responses are also furnished.

Axial Leakage Flow-Induced Vibration of a Thin Cylindrical Shell With Respect to Lateral Vibration

2003 ◽  
Vol 125 (2) ◽  
pp. 158-164 ◽  
Author(s):  
Katsuhisa Fujita ◽  
Atsuhiko Shintani ◽  
Masakazu Ono
Keyword(s):  
Cylindrical Shell ◽  
Shell Theory ◽  
Beam Theory ◽  
Navier Stokes ◽  
Leakage Flow ◽  
Lateral Vibration ◽  
Thin Cylindrical Shell ◽  
Flow Induced Vibration ◽  
Navier Stokes Equation ◽  
Coupled Equations

In this paper, the stability of a thin cylindrical shell subjected to axial leakage flow is discussed. In this paper, the second part of a study of the axial leakage flow-induced vibration of a thin cylindrical shell, we focus on lateral vibration, that is, the beamlike vibration of a shell. The coupled equations between a shell and a fluid are obtained by using the Donnell’s shell theory and the Navier-Stokes equation as same as the former paper. The influence of the axial velocity on the unstable vibration phenomena is clarified concerning the beamlike vibration mode of a shell. The numerical results on shell theory are compared with the ones on beam theory which have been already reported by the authors; and the numerical parameter studies are done for various dimensions of a shell and a fluid.

259 Research on a lug tire model based on thin cylindrical shell theory

2009 ◽  
Vol 2009 (0) ◽  
pp. _259-1_-_259-5_
Author(s):  
Yuya FUKUDA ◽  
Katsuhide FUJITA ◽  
Mitsugu KANEKO ◽  
Takashi SAITO
Keyword(s):  
Cylindrical Shell ◽  
Shell Theory ◽  
Tire Model ◽  
Thin Cylindrical Shell ◽  
Model Based

The Application of Long and Short Cylindrical Shell Solutions for Stress and Flexibility Determination in a Single Mitred Bend

2016 ◽  
Author(s):  
Igor Orynyak ◽  
Andrii Bogdan ◽  
Iryna Selivestrova
Keyword(s):  
Cylindrical Shell ◽  
Shell Theory ◽  
Bending Moment ◽  
Axial Direction ◽  
Piping System ◽  
Structural Elements ◽  
Thin Cylindrical Shell ◽  
Straight Pipe ◽  
Pipe Bend ◽  
Short Shell

The continuous pipe bend behavior is well elaborated in literature. It is characterized by local ovalization of each cross section during bending which results in enhanced flexibility of it as compared to straight pipe. When pipe bend approaches some other structural elements of a piping system the end effect take place which can be described by so called long shell solution. This long solution is, in fact, a semi-membrane Vlasov’s solution when the derivative of any geometrical or force function in axial direction is much smaller than in the circumferential one [1]. Mitred bend is formed by conjunction by welding of two oblique sections of initially straight pipes. Its behavior during loading by pressure or bending moment is not evident and poorly described in standards. The goal of this paper is to give a set of general functions within a thin cylindrical shell theory which will give the opportunity to consider the mitred bend as an element of a piping system. Here we additionally introduce the so called short solution when the derivative of any parameter in axial direction is much bigger than that in circumferential one. Its main goal is to give the local behavior of stress in the vicinity of the oblique weld. Each of these two solutions satisfy by differential equations of forth order. The complete theoretical solution for a particular mitred bend is compared with a) existing analytical solutions and formulas; b) numerical results obtained by FEM with distinction of the zones of influence of a long as well as short shell solution; c) experimental data on real mitred bends given in the literature.

Bending Due to Ring Loading of a Cylindrical Shell With an Elastic Core

1965 ◽  
Vol 32 (1) ◽  
pp. 99-103 ◽  
Author(s):  
John C. Yao
Keyword(s):  
Cylindrical Shell ◽  
Stress Function ◽  
Shell Theory ◽  
Soft Core ◽  
Thin Cylindrical Shell ◽  
Displacement Fields ◽  
Material Constants ◽  
The Core ◽  
Stress And Displacement Fields ◽  
Classical Shell Theory

The problem of a long, thin cylindrical shell with a soft core and subjected to a radial ring load is solved with the use of the Boussinesq-Neuber stress function for the core in conjunction with classical shell theory. Numerical results for stress and displacement fields are given for various values of the cylinder geometry parameters and material constants.

Analysis of Spectral Characteristics of Sound Waves Scattered from a Cracked Cylindrical Elastic Shell Filled with a Viscous Fluid

2013 ◽  
Vol 38 (3) ◽  
pp. 335-350 ◽  
Author(s):  
Olexa Piddubniak ◽  
Nadia Piddubniak
Keyword(s):  
Viscous Fluid ◽  
Shell Theory ◽  
Elastic Shell ◽  
Spectral Characteristics ◽  
Steel Shell ◽  
Sound Waves ◽  
Thin Cylindrical Shell ◽  
Shell Surface ◽  
Theory Approximation ◽  
Directivity Patterns

Abstract The scattering of plane steady-state sound waves from a viscous fluid-filled thin cylindrical shell weak- ened by a long linear slit and submerged in an ideal fluid is studied. For the description of vibrations of elastic objects the Kirchhoff-Love shell-theory approximation is used. An exact solution of this problem is obtained in the form of series with cylindrical harmonics. The numerical analysis is carried out for a steel shell filled with oil and immersed in seawater. The modules and phases of the scattering amplitudes versus the dimensionless wavenumber of the incident sound wave as well as directivity patterns of the scattered field are investigated taking into consideration the orientation of the slit on the elastic shell surface. The plots obtained show a considerable influence of the slit and viscous fluid filler on the diffraction process.

Sign in / Sign up

Export Citation Format

Share Document