(ISO 7797 International Standard INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEKAYHAPOAHAR OPrAH3ALWA nO CTAHAAPTW3ALWWOORGANISATION INTE RNATIONALE DE NORMALISATION Cross-country skis - Determination of breaking load and deflection at break with quasistatic load Skis de fond -- Détermination de la charge de rupture et de la déformation a la rupture sous charge quasi-statique First edition -- 1985-08-01 UDC 685.362.2 : 620.174.2 Ref. No. 1SO 7797-1985 (E) 7797-1985 Descriptors : sports equipment, skis, cross country skis, tests, determination, breaking load, test equipment. Copyright International Organizationfor Standardization Price based on 3 pages Isefrom IHS Not for Resale 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. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the ISO Council. They are approved in accordance with ISO procedures requiring at least 75 % approval by the member bodies voting. International Standard ISO 7797 was prepared by Technical Committee ISO/TC 83, Sports and recreational equipment. International Organization for Standardization, 1985 Printed in Switzerland ted without license from IHS Not for Resale INTERNATIONAL STANDARD ISO 7797-1985 (E) Cross-country skis - Determination of breaking load and deflection at break with quasistatic load Scope and field of application 3.3 breaking load of the centrepart, FB2: Load which causes failure of the ski (breaking, delamination, buckling, etc.) This International Standard specifies a method for determina- when applied at the load application point midway between tion of the resistance of defined parts of cross-country skis to two supports 500 mm apart as described in 5.2. breaking when quasistatically loaded. Test apparatus A load applied to a ski usually leads to a predominantly elastic deformation followed by a sudden break. The optimum stiff- The general arrangement of the test apparatus is shown in ness distribution, breaking strength and deflection at break de- figure 1. pend on the application for which the ski is designed. These ap- plications demand variations from stiff skis with high breaking The test machine, usually a tensile tester with special bending strength, but relatively low deflection at break, to soft skis fixture, shall comprise which can withstand large deflections, but have a relatively low strength. Consequently, the values of the breaking strength a) two supports, with adjustable distance in longitudinal and breaking deflection cannot be directly related to the direction, at least one of which shall be a low friction roller ; characteroftheski. b) a load cell having a range of at least 10 000 N for measurement of loads FB1 and FB2; The test is applicable to all sizes of cross-country skis for adults, juniors and children. c) a displacement measurement gauge for measurement of the deflection fB1; This test procedure shall not be used for determination of d) a ram plate as shown in figure 2, which shall consist of breaking load of ski structures with relatively high plastic defor- a steel plate, 4 mm thick, and a hard rubber layer, 3 mm mation (for example skis with steel edges or skis with thick and having a Shore A hardness of 95 ± 5 (see aluminium skins). ISO 868) ; e) a load-displacement recorder for recording of the load- 2 References deflection curve on graph-paper. Iso 868, Plastics - Determination of indentation hardness by Determination of the load a