1、BS ISO16402:2008ICS 11.040.40NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDImplants for surgery Acrylic resin cement Flexural fatiguetesting of acrylicresin cements used inorthopaedicsThis British Standardwas published under theauthority of the StandardsPolicy
2、 and StrategyCommittee on 28 February2009 BSI 2009ISBN 978 0 580 60521 5Amendments/corrigenda issued since publicationDate CommentsBS ISO 16402:2008National forewordThis British Standard is the UK implementation of ISO 16402:2008.The UK participation in its preparation was entrusted to TechnicalComm
3、ittee CH/150/1, Materials for surgical implants.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correct application.Compliance with a
4、 British Standard cannot confer immunityfrom legal obligations.BS ISO 16402:2008INTERNATIONALSTANDARDISO16402First edition2008-05-15Reference numberISO 16402:2008(E) ISO 2008Implants for surgery Acrylic resin cement Flexural fatigue testing of acrylic resin cements used in orthopaedicsImplants chiru
5、rgicaux Ciment base de rsine acrylique Essais de fatigue flexurale des ciments base de rsine acrylique utiliss en orthopdieBS ISO 16402:2008ISO 16402:2008(E)ii ISO 2008 All rights reservedPDF disclaimerThis PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this fil
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10、1 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 16402:2008ISO 16402:2008(E) ISO 2008 All rights reserved iiiForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies(ISO member bodies). The wo
11、rk of preparing International Standards is normally carried out through ISOtechnical committees. Each member body interested in a subject for which a technical committee has beenestablished has the right to be represented on that committee. International organizations, governmental andnon-government
12、al, in liaison with ISO, also take part in the work. ISO collaborates closely with the InternationalElectrotechnical Commission (IEC) on all matters of electrotechnical standardization.International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.The main t
13、ask of technical committees is to prepare International Standards. Draft International Standardsadopted by the technical committees are circulated to the member bodies for voting. Publication as anInternational Standard requires approval by at least 75 % of the member bodies casting a vote.Attention
14、 is drawn to the possibility that some of the elements of this document may be the subject of patentrights. ISO shall not be held responsible for identifying any or all such patent rights.ISO 16402 was prepared by Technical Committee ISO/TC 150, Implants for surgery, Subcommittee SC 1,Materials.BS I
15、SO 16402:2008.iv BS ISO 16402:2008INTERNATIONAL STANDARD ISO 16402:2008(E) ISO 2008 All rights reserved 1Implants for surgery Acrylic resin cement Flexural fatigue testing of acrylic resin cements used in orthopaedics1ScopeThis International Standard applies to resin cements based on poly(methacryli
16、c acid esters) and specifies theprocedure for determining the fatigue behaviour of the polymerized cement.This International Standard does not cover the hazards associated with the use of the cement in respect ofeither the patient or the user of the cement.2 Normative referencesThe following referen
17、ced documents are indispensable for the application of this document. For datedreferences, only the edition cited applies. For undated references, the latest edition of the referenced document(including any amendments) applies.ISO 5833:2002, Implants for surgery Acrylic resin cementsISO 16428, Impla
18、nts for surgery Test solutions and environmental conditions for static and dynamiccorrosion tests on implantable materials and medical devices3 Test methodThe tests make use of rectangular bar-shaped test specimens. The method for preparing these specimens isdescribed in Clause 5.The bending strengt
19、h of the resulting test specimens is determined by means of a four-point bend test underquasi static and cyclic loading conditions. Under cyclic loading conditions two test methods are described. Thefirst one follows the Whler method (S/N curve method) and determines the behaviour over the full rang
20、e ofstress levels. The second one (low stress method) determines the behaviour at lower stress levels only. Theselower stress levels, which are specified, are thought to correspond to stress levels expected to be encounteredin clinical use.4 Apparatus4.1 Equipment for mixing cement, as recommended b
21、y the cement manufacturer.4.2 Moulds, made of a suitable material to produce rectangular bar-shaped specimens directly in their finalshape with the dimensions of length, width and depth. If preferred, one or more mouldsto produce plates of thickness may be used and the specimens subsequently cut to
22、size using a saw.All surfaces of the moulds which come into contact with the cement shall be finely finished with 400 gradeemery paper.NOTE Materials with sufficient stiffness, as for example aluminium alloys or stainless steel, have been found to be suitable.4.3 Flat, smooth plates, (two for each m
23、ould) of a suitable material and size to cover the upper and lowersurfaces of the moulds (4.2).75 mm 10 mm 3,3 mm3,3 mmBS ISO 16402:2008ISO 16402:2008(E)2 ISO 2008 All rights reserved4.4 Mould release agent, to facilitate separation of the specimens from the moulds.NOTE Teflon-spray, vacuum grease o
24、r beeswax have been found to be suitable.4.5 Polyester film, to cover the plates of the mould.4.6 C-clamp(s) or other device(s), for clamping the mould(s) between the top and bottom plates.4.7 Bend test machine, capable of applying loads up to which optionally can increase linearly or cancycle sinus
25、oidally over a range of loads between and the selected value at a frequency of , and whichis equipped with a device for measuring, controlling and recording the load to an accuracy of .4.8 Four-point bend test rig, having the dimensions shown in Figure 1 (corresponding to ISO 5833:2002,Annex F) with
26、 means of preventing initial misalignment, changes of alignment and walking-off of the testspecimen on the supports during the test. The loading points should be of the rolling type and have a diameterof . The test rig should be such that equal loads are applied to all loading points.4.9 Water bath,
27、 to maintain the test specimen and the loading fixtures at a temperature of .4.10 Saw.4.11 Emery paper, 400 grade.5 Preparation of test specimens5.1 General conditionsThe mould(s) (4.2), plates (4.3), mixing equipment (4.1) and the cement to be used (both powder and liquidcomponents) shall be mainta
28、ined at for at least before casting the test specimen(s). Thespecimen(s) shall be cast at .5.2 Preparation procedure5.2.1 Cover the surfaces of the mould which come into contact with the cement, with a thin film of the mouldrelease agent (4.4).5.2.2 Cover the bottom plate of the mould with polyester
29、 film (4.5). Place the mould on top of the film-coveredplate.5.2.3 Mix the components of cement, following the manufacturers instructions. Use a sufficient quantity ofcement to make the required number of specimens.NOTE A good procedure is the following: obtain a large batch of cement powder and a l
30、arge batch of cement liquid fromthe manufacturer. Subdivide these batches into smaller units of powder and liquid, then store. Mix the number of thesesmaller units which is needed to make the required number of specimens. If possible, make all the specimens to be testedfrom a single batch of cement
31、powder and a single batch of cement liquid. If this is not possible, use the minimum possiblenumber of cement batches. In both cases record the batch numbers.5.2.4 Fill the mould(s) with the cement immediately after the mixing is completed, cover with a sheet of thepolyester film, add the top plate
32、and clamp the top and bottom plates to the mould(s).5.2.5 After approximately remove the clamp(s) (4.6), the top plate and the top polyester film and apply amark to the top of the specimen near one end, to identify the top surface. Remove the specimen(s) from theirmould(s). Wet grind the edges and t
33、he faces of the specimens which were in contact with the mould or whichresult from cutting with a saw (4.10), using 400 grade emery paper (4.11). The rectangular bar-shaped testspecimens shall have a length of , width of , and thickness of .200 N0N 5Hz2N3mm(37 1)C(23 2)C 2h(23 2)C1h(75 0,2) mm (10 0
34、,2) mm (3,3 0,2) mmBS ISO 16402:2008ISO 16402:2008(E) ISO 2008 All rights reserved 35.2.6 Measure the specimen thickness and width to an accuracy of taking readings for at least threecross-sections of the specimen and calculate the mean values.5.2.7 Examine the specimens with the naked eye. Do not e
35、xclude specimens with internal pores. Excludespecimens with discernable defects or scratches on the specimen surface.Pores generated by the mixing procedure are unavoidable. Such pores are a feature of bone cements andinfluence the strength behaviour of the material. For this reason specimens with i
36、nternal pores shall not beexcluded. Discernable defects or scratches on the surface are not a feature of bone cements and for this reasonsuch specimens shall be excluded.5.2.8 Maintain the specimens in Ringers solution according to ISO 16428 at for 4 weeks prior tothe beginning of the test series.Di
37、mensions in millimetresKey1 central loading plunger2 inner loading rollers3 test specimen4 outer loading rollersforcedistance between outer loading rollers distance between outer and inner loading rollers NOTE See also Figure F.1 of ISO 5833:2002.aAll loading points.bBetween any two loading points.F
38、igure 1 Four-point bend test rigFl1(60 1) mml2(20 1) mm0,1 mm(37 1)CBS ISO 16402:2008ISO 16402:2008(E)4 ISO 2008 All rights reserved6 Test procedure6.1 Environmental conditionsFill the water bath with Ringers solution. Place the test rig and the test specimen in the water bath and leaveuntil the tem
39、perature is . The test specimen shall be placed symmetrically in the rig so that thesurface identified as “top” in the casting procedure is subjected to compressive stress.6.2 Quasi static testingUsing the bend test machine (4.7), the four-point bend test rig (4.8) and the water bath (4.9), increase
40、 themachine test load at a uniform loading rate of until fracture occurs. Record the load at fractureto an accuracy of . If large pores (diameter ) are found on the fracture surface repeat the testusing an additional specimen. Repeat the tests until results are obtained from five specimens which do
41、not havelarge pores on the fracture surface. Test results shall be reported for all specimens (including those with largepores found on the fracture surface).6.3 Calculation and expression of the “quasi static” bending strengthFor each test specimen, calculate the bending strength, , in megapascals,
42、 from the expression:whereis the force at fracture, in newtons (also referred to as the load); is the mean measured width of the specimen, in millimetres; is the mean measured thickness of the specimen, in millimetres; is the distance between the inner and outer loading rollers ( ). Calculate the me
43、an value and standard deviation of the individual bending strengths of the five test specimens,expressed in megapascals. The mean value is the “quasi static” strength.6.4 Fatigue testing6.4.1 GeneralUsing the bend test machine (4.7), the four-point bend test rig (4.8) and the water bath (4.9), test
44、specimens arecyclically loaded until fracture occurs or, if fracture does not occur, until a predetermined upper limit of the cyclenumber is reached. Testing is performed at different stress levels.6.4.2 Loading conditionsThe cyclic load shall be applied load-controlled at a frequency of . The minim
45、um value of the forceshall be and the maximum force shall have the value that corresponds to the intended stress level. Thisvalue is calculated using the equation given in 6.3 where the width, , and the thickness, , are the mean valuesfor the specimen to be tested. The waveform of the loading cycles
46、 shall be sinusoidal between the minimum andmaximum values.The test shall be continued until fracture occurs or the requisite number of load cycles has been applied. If largepores (diameter ) are found at the fracture surface, the test shall be repeated using an additional(37 1)C(90 10) N/min2N grea
47、terorequalslant 1mmBB=3Fabh2Fbha 20 mm(5 0,5) Hz5Nb hgreaterorequalslant 1mmBS ISO 16402:2008ISO 16402:2008(E) ISO 2008 All rights reserved 5specimen. Repeat the tests until results are obtained from the requisite number of specimens which do not havelarge pores at the fracture surface. Test results
48、 shall be reported for all specimens (including those with largepores found on the fracture surface).6.4.3 Determination of the fatigue behaviour over a wide range of stress levels (S/N curve method)Where the performance of the cement is to be determined over a wide range of stress levels, the follo
49、wingprocedure shall be applied.Use five specimens per loading level and an upper limit of five million cycles. Start at a level of of the quasistatic strength. The next lower level is chosen by stepping down from the level by a fixed amount (forexample by of the quasi static strength). The next lower levels are chosen by stepping down by the samefixed amount. (In the example, the levels would then be , , , etc.).
