1、Designation:F251408(Reapproved 2014)Standard Guide forFinite Element Analysis(FEA)of Metallic Vascular StentsSubjected to Uniform Radial Loading1This standard is issued under the fixed designation F2514;the number immediately following the designation indicates the year oforiginal adoption or,in the
2、 case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.INTRODUCTIONThis guide establishes general requirements and considerations for using finite element anal
3、ysistechniques for the numerical simulation of metallic stents subjected to uniform radial loading.Thesestents are intended for use within the human vascular system.1.Scope1.1 PurposeThis guide establishes general requirementsand considerations for the development of finite elementmodels used in the
4、 evaluation of the performance of a metallicvascular stent design under uniform radial loading.Suggestedcriteria are provided for evaluating the typical cases of metallicstents under uniform radially oriented and pulsatile loading.Recommended procedures for checking and validating thefinite element
5、model(s)are provided as a means to assess themodel and analysis results.Finally,the recommended contentof an engineering report covering the mechanical simulations ispresented.1.2 Limits:1.2.1 This guide is limited in discussion to the finite elementstructural analysis of metallic stents of the foll
6、owing types:1.2.1.1 Plastically deformable metal stents.1.2.1.2 Self-expanding metal stents.1.2.1.3 Plastically deformable metal portions of coveredstents.1.2.1.4 Metal portions of self-expanding covered metalstents.1.2.2 The emphasis of the techniques described in this guideis intended for both ela
7、sto-plastic materials such as stainlesssteel,and superelastic materials such as nitinol.Unique con-cerns associated with stents designed for shape memorybehavior are not addressed within this guide.1.2.3 This guide does not consider changes to possible timevarying conditions or different loadings re
8、lated to vascularremodeling.1.2.4 This guide is restricted to cases that involve theapplication of uniform radially oriented loading.1.2.5 This guide does not provide guidance in the applica-tion or interpretation of FEA in determining fatigue life.1.2.6 This guide is not intended to include complet
9、e de-scriptions of the finite element method,nor its theoretical basisand formulation.1.3 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.2.Terminology2.1 Definitions:2.1.1 balloon expandable stent,na stent that is expandedat th
10、e treatment site by a balloon catheter.The purpose of theballoon is to plastically deform the stent material such that thestent remains expanded after the deflation of the balloon.2.1.2 conceptual model,nmodel produced by analyzingand observing the physical system of interest composed ofmathematical
11、 models and equations representing that system.2.1.3 computational model,nimplementation of a concep-tual model in software.2.1.4 crimp,vto secure the stent on a delivery system byradially compressing the stent into a delivery device such as acatheter or onto an expanding delivery device such as aba
12、lloon.2.1.5 delivery system,na mechanical system that is usedto deliver and deploy a stent at a target site.2.1.6 elasto-plastic material,na material behavioralmodel that exhibits elastic behavior(recoverable)up to itsyield point and plastic behavior(irrecoverable)above its yieldpoint.2.1.7 enduranc
13、e limit,nstress or strain level at which thematerial is considered to have“infinite”life.1This guide is under the jurisdiction of ASTM Committee F04 on Medical andSurgical Materials and Devices and is the direct responsibility of SubcommitteeF04.30 on Cardiovascular Standards.Current edition approve
14、d March 1,2014.Published April 2014.Originallyapproved in 2008.Last previous edition approved in 2008 as F2514 08.DOI:10.1520/F2514-08R14.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 2.1.8 finite element analysis(FEA),n a general purpo
15、senumerical technique.2.1.8.1 DiscussionIn this guide,the structural continuumis discretized into regions known as elements,in which themechanical behavior is defined.Continuity is enforced at thevertices of the elements where node points are defined.Themechanical behavior of the continuum is then d
16、efined accord-ing to mathematical expressions of physical laws at the nodepoints.This results in the definition of a set of simultaneousequations that are solved for state variables from which suchimportant quantities as displacements,stresses,and strains canbe derived.2.1.9 geometrical nonlinearity,na type of nonlinearityrelated to structural deformation where the relation betweenstrain and displacement are not linearly proportional.2.1.10 linear elastic material,na material in which thestress
