Radial Force Calculation at the Start of Drilling Operation Using the SPG Method

Each component of a drug-eluting stent (DES) contributes to the safety of the device. Continuous efforts are being dedicated to the search of the optimal compromise between facility of use, safety and long-term efficacy. Shorter balloons reduce the vascular trauma beyond the stent struts; the metallic composition of the stent platform and the platform itself interact with the vascular wall in a long-lasting equilibrium between radial force, vessel patency and reparative cellular regrowth. The modality of drug elution is largely regulated by the chosen drug carrier, rather than by the chemical properties of the drug itself. Drug elution can be accomplished by permanent polymers that remain in the vessel wall forever, by biodegradable polymers that leave the naked metallic structure behind after their complete absorption, or even by direct release of the drug from stent reservoirs. The clinical performance of DESs has been exhaustively assessed in a large number of studies that have showed rapid and continuous improvements, from the first-generation DESs to the latest devices, based on substantial changes in stent design and polymer composition.

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Finite Element Analysis of Nonuniformity of Tires with Imperfections5

Tire Science and Technology ◽

10.2346/1.2768607 ◽

2007 ◽

Vol 35 (3) ◽

pp. 226-238 ◽

Cited By ~ 1

Author(s):

K. M. Jeong ◽

K. W. Kim ◽

H. G. Beom ◽

J. U. Park

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Three Dimensional ◽

Element Model ◽

Radial Force ◽

Element Analysis ◽

The Finite Element Analysis ◽

Dimensional Finite Element ◽

Force Variation ◽

Three Dimensional Finite Element

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.

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Influence of Rim Run-Out on the Nonuniformity of Tire-Wheel Assemblies

Tire Science and Technology ◽

10.2346/1.2139538 ◽

1994 ◽

Vol 22 (2) ◽

pp. 99-120 ◽

Cited By ~ 1

Author(s):

T. B. Rhyne ◽

R. Gall ◽

L. Y. Chang

Keyword(s):

Finite Element ◽

Radial Force ◽

Membrane Model ◽

Model Experiments ◽

Force Variation ◽

One To One ◽

The One

Abstract An analytical membrane model is used to study how wheel imperfections are converted into radial force variation of the tire-wheel assembly. This model indicates that the radial run-out of the rim generates run-out of the tire-wheel assembly at slightly less than the one to one ratio that was expected. Lateral run-out of the rim is found to generate radial run-out of the tire-wheel assembly at a ratio that is dependent on the tire design and the wheel width. Finite element studies of a production tire validate and quantify the results of the membrane model. Experiments using a specially constructed precision wheel demonstrate the behavior predicted by the models. Finally, a population of production tires and wheels show that the lateral run-out of the rims contribute a significant portion to the assembly radial force variation. These findings might be used to improve match-mounting results by taking lateral rim run-out into account.

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