150 9585 90 EOTSh 0100225 ISO INTERNATIONAL STANDARD 9585 First edition 1990-12-15 Implants for surgery --- Determination of bending strength and stiffness of bone plates la rigidite des plaques pour os Reference number IsO 9585:1990(E) opyright International Organizationfor Standardizatior ISo 9585 90 E06tS9h 2.9220010 ISO 9585:1990(E) Foreword Iso (the International Organization for Standardization) is a worldwide federation of national standards bodies (isO member bodies). The work of preparing International Standards is normally carried out through isO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, govern- mental and non-governmental, in liaison with iso, also take part in the work. Iso collaborates closely with the International Electrotechnica! Commission(lEC)onallmatters ofelectrotechnicalstandardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an Inter- national Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard Iso 9585 was prepared by Technical Committee ISO/TC 150, Implants for surgery. C ISO 1990 All rlghts reserved, No part of this publicatlon may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and mlcrofilm, without permlsslon inwritingfromthepubilisher, International Organizatlon for Standardization CasePostale56·CH-1211Geneve20·Switzerland PrintedinSwitzerland Not for Resale 958590 4851903 0100227 4 ISO 9585:1990(E) INTERNATIONAL STANDARD Implants for surgery --- Determination of bending strength and stiffness of bone plates Scope 2.5 equivalent bending stiffness: Stiffness of the 1 plate calculated from the dimensions of the test configuration and the slope Softhe linearpartof the This International Standard describes a test method load/deflection diagram defined by the mechanical for determining the bending strength and stiffness test. of straight bone plates. It may also be used to test plates having a small initial curvature intended to Unit: N-m2 produce pre-loading of the bone when fitted and to test the straight portion of angled plates. This test NOTE 2 This equivalent bending stiffness takes account method isnotrecommended forplates oflengthless of the holes or slots in the plate. than 50 mm nor for plates designed to be used with, or forming parts of, intramedullary devices. 3 Apparatus NOTE 1 A test method for plates of length less than 3.1 Test'rig, to produce a loading system in ac- 50 mm is in preparation. cordance with figure 1, the four rollers (indicated by hatched circles) being so constrained that their axes remain parallel. 2 Definitions 3.2 Rollers, of cylindrical form and of equal diam- For the purposes of this International standard, the eters within the range of 8 mm to 13 mm, or of pro- following definitions apply. filed form corresponding to the cross-section of the plate to be tested, and having a mean diameter 2.1 moment: Turning effect ofa force about an axis, within the range 8 mmto 13 mm.It is desirable that expressed numerically by the product of the force F one of the rollers be secured to the specimen to re- and the distance h measured perpendicularly from strain longitudinal movement and that all rollers are the axis to the line of action of the force. secured to maintain their relative position. Unit: N-m 3.3 Means of applying forces, e.g. a mechanical 2.2 bending moment, Mp: Moment acting about an testing machine. axis perpendicular to the long axis of a body and generally producing lateral deflection. 3.4 Device(s), for measurement of relative displacement(s). Unit: N-m Procedure 4 2.3 deflection: Linear displacement due to bending measured perpendicular to the original axis of the 4.1 General plate. Unit: m Conduct bending tests u