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1、A Reference number ISO 3324-2:1998(E) INTERNATIONAL STANDARD ISO 3324-2 Second edition 1998-02-01 Corrected and reprinted 1999-02-01 Aircraft tyres and rims Part 2: Test methods for tyres Pneumatiques et jantes pour aronefs Partie 2: Mthodes dessai des pneumatiques Copyright International Organizati
2、on for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 22:29:17 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 3324-2:1998(E) ISO 1998 All rights reserved. Unless otherwise specified, no p
3、art of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Organization for Standardization Case postale 56 CH-1211 Genve 20 Switzerland Internetcen
4、traliso.ch X.400c=ch; a=400net; p=iso; o=isocs; s=central Printed in Switzerland ii ContentsPage 1Scope.1 2Normative references.1 3Definitions.1 4Symbols.1 5Tyre preparation/break-in 2 6Static tests.2 7Dynamometer tests 6 Annex A (informative) Bibliography14 Copyright International Organization for
5、Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 22:29:17 MDTNo reproduction or networking permitted without license from IHS -,-,- ISOISO 3324-2:1998(E) iii Foreword ISO (the International Organization for Standardizati
6、on) 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 re
7、presented on that committee. International organizations, governmental and non- governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Sta
8、ndards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO 3324-2 was prepared by Technical Committee ISO/TC 31, Tyres, rims and
9、 valves, Subcommittee SC 8, Aircraft tyres and rims. This second edition cancels and replaces the first edition (ISO 3324-2:1979), of which it constitutes a technical revision. ISO 3324 consists of the following parts, under the general title Aircraft tyres and rims: Part 1: Specifications Part 2: T
10、est methods for tyres Annex A of this part of ISO 3324 is for information only. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 22:29:17 MDTNo reproduction or networking permitte
11、d without license from IHS -,-,- Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 22:29:17 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL
12、STANDARD ISOISO 3324-2:1998(E) 1 Aircraft tyres and rims Part 2: Test methods for tyres 1 Scope This part of ISO 3324 specifies test methods for new and retreaded civil aircraft tyres in the following categories: a)low-speed tyres: for ground speeds up to and including 104 kn; b)high-speed tyres: fo
13、r ground speeds above 104 kn. NOTE 1 kn = 1,85 km/h = 1,15 mile/h. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of ISO 3324. At the time of publication, the editions indicated were valid. All standards are
14、 subject to revision, and parties to agreements based on this part of ISO 3324 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 3324-1:1), Air
15、craft tyres and rims Part 1: Specifications. ISO 4223-1:2), Definitions of some terms used in the tyre industry Part 1: Pneumatic tyres. 3 Definitions For the purposes of this part of ISO 3324, the definitions given in ISO 4223-1 apply. 4 Symbols L0= tyre load at start of takeoff (greater than or eq
16、ual to the rated load), in pounds L0= tyre load at start of takeoff for the operational load curve, in pounds L1= test tyre load at rotation, in pounds 1) To be published. (Revision of ISO 3324-1:1993) 2) To be published. (Revision of ISO 4223-1:1989) Copyright International Organization for Standar
17、dization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 22:29:17 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 3324-2:1998(E) ISO 2 L1 = operational tyre load at rotation, in pounds L2 = tyre load at li
18、ftoff, in pounds S0 = speed at start of takeoff, in miles per hour S1 = speed at rotation, in miles per hour S2 = tyre speed at liftoff, in miles per hour (greater than or equal to the rated speed) T0 = time at start of takeoff, in seconds T1 = time at constant test load, in seconds T2 = time to rot
19、ation, in seconds T3 = time to liftoff, in seconds 5 Tyre preparation/break-in 5.1 Tyre conditioning Before break-in of the tyre, it shall be conditioned by mounting on its design rim and inflating it to the rated inflation pressure. It shall be allowed to remain in this condition for 24 h at an amb
20、ient temperature between 16 C and 32 C. 5.2 Tyre inflation and ambient temperature After the tyre has been soaked for 24 h on the design rim as indicated in 5.1, the tyre pressure shall be adjusted to the rated pneumatic inflation pressure with a gauge which can be calibrated to within one percent.
21、All tests shall be carried out at ambient temperatures between 16 C and 32 C. 5.3 Break-in procedure: static This method of tyre break-in is to prepare the test tyre by inflating it to rated inflation pressure and loading the tyre under direct vertical load against a hard flat unyielding surface unt
22、il the tyre deflection measures 50 % of the section height. The load is then removed. This load deflection test is to be carried out at two locations equally spaced around the tyre, with the centreline of the contact patch being located at 180 intervals around the circumference of the tyre. 5.4 Brea
23、k-in procedure: dynamic or alternate static testing This method of tyre break-in is to prepare the test tyre by inflating it to rated inflation pressure, then performing five rated load takeoff cycles with a load-speed-time curve representative of the applicable aircraft. 6 Static tests 6.1 Burst pr
24、essure (pressure proof test) Mount the tyre on a test wheel of adequate strength, and inflate it hydraulically at a slow rate to the minimum specified burst pressure. Maintain the tyre at this pressure for 3 s without failure. Continue inflating the tyre at a slow rate until burst. Burst pressure te
25、sts of tubeless tyres may be conducted with an inner tube fitted. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 22:29:17 MDTNo reproduction or networking permitted without lice
26、nse from IHS -,-,- ISO ISO 3324-2:1998(E) 3 6.2 Bead seating pressure Determine the bead seating pressure by a suitable method. Two procedures, currently adopted, which may be used are the following. Procedure 1: Carbon paper The bead seating pressure is determined by placing a sheet of carbon paper
27、 between two sheets of thin paper and placing these sheets between the flanges of the wheel and the bead of the tyre. The tyre is inflated and the pressure at which the heel of the bead touches the vertical face of the rim flange, as shown on the thin paper, is considered as the bead seating pressur
28、e. Procedure 2: Electrical The contact area of the wheel is cleaned to expose the metal surface. Three pieces of shim copper or steel, 120 from each other, are fixed to one tyre bead. The shims are held in place with light gauge non-conducting adhesive tape (see figure 1). The tape insulates the shi
29、ms from the top of the rim flange. This procedure calls for the use of a battery, fitted with two leads, one of which is a fixed lead containing a lamp or ohmmeter, the other lead is used as the probe lead to make contact with the three shims in turn. The tyre is inflated in increments, and after ea
30、ch increment, the probe lead is placed on the shims in turn. When the lamp lights or the ohmmeter reading is zero, at all three shim locations, the bead is considered to be fully seated on the wheel at the recorded inflation pressure, and that pressure is considered to be the bead seating pressure.
31、Other procedures may be used if these are recognized and approved by the certification or airworthiness authority. In all procedures the test shall be conducted without the use of lubricant on the tyre bead or rim. Key 1 Tyre bead 2 Steel or copper shims 0,05 mm (0,002 in) 3 Non-conducting adhesive
32、tape, thin gauge 4 Gap in tape 5 Wheel Figure 1 Bead seating pressure: electrical method Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 22:29:17 MDTNo reproduction or networking
33、 permitted without license from IHS -,-,- ISO 3324-2:1998(E) ISO 4 6.3 Air retention: tubeless tyres After an initial 12 h minimum stabilization period at rated inflation pressure, the tyre shall be capable of retaining pressure with a loss of pressure not exceeding 5 % in 24 h. Ambient temperature
34、shall be measured at the start and finish of the test to assure that the pressure change was not caused by an ambient temperature change. 6.4 Tyre dimensions Mount the tyre on the specified rim, inflate it to its maximum rated inflation pressure and allow it to stand for a minimum of 12 h at normal
35、room temperature. After this lapse of time, readjust the inflation to the original value. Following the pressure adjustment, measure and record the following tyre dimensions: overall diameter; overall width; shoulder diameter; shoulder width. When a tyre does not have a readily identifiable shoulder
36、 point, measure the shoulder width at the maximum specified shoulder diameter. 6.5 Load-deflection curves 6.5.1 Tyre mounting Mount the tyre and inflate as specified in 6.4 Install the tyre and wheel in the testing machine. Make every attempt to remove all the looseness (slop) between the wheel, axl
37、e, bushings, etc., so that an accurate zero point can be determined. 6.5.2 Vertical load deflection curves 6.5.2.1 To obtain the zero load and deflection point, move the tyre until it barely touches the flat plate. Do not pre- load. Vertical load deflection curves shall be obtained on the inflated t
38、yre by applying a vertical load and measuring the corresponding deflection between the wheel flange and the unyielding flat surface against which the tyre acts. The load shall be applied beginning from the point of contact of the tyre with the flat surface until the tyre bottoms, with continuous rec
39、ording of load and corresponding deflection. The load shall then be reduced until its value reaches zero once more, again continuously monitoring load and corresponding deflection. The total load deflection loop or curve shall be presented as indicative of the vertical load deflection characteristic
40、s of the tyre. The tyre pressure should be recorded throughout the test. This test shall be carried out at two locations around the tyre, each separated by 180. Each vertical load deflection test shall be performed at the location which is opposite from the location of the last loading, in order to
41、minimize the effect of a flat spot. The time rate of the tyre deflection shall be not more than 50,8 mm/min. 6.5.2.2 Method for determining bottoming point 6.5.2.2.1 The tyre bottoming point is when the tyre has fully deflected its sidewall and is beginning to compress the lower sidewall structure.
42、This is recognized by a noticeable change in the slope of the load deflection curve occurring at a high load and deflection. The bottoming point is the load and deflection at that point. 6.5.2.2.2 For the purposes of approximating the bottoming load for a given tyre with a given inflation pressure,
43、the bottoming load shall be considered as that load at which the rate of loading (kg/25 mm) is 2,2 times the average rate of loading between 28 % and 48 % radial deflection. 6.5.2.2.3 The bottoming load is determined as follows (see figure 2): Copyright International Organization for Standardization
44、 Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 22:29:17 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO ISO 3324-2:1998(E) 5 a)Conduct the load deflection test in usual manner, obtaining sufficient data
45、to plot a representative curve for the inflation pressure required. (This should be carried slightly beyond the point described in 6.5.2.2.2.) b)Plot the load deflection curve. c)Calculate the inverse slope (kg/25 mm) between 28 % and 48 % deflection. EXAMPLE 9 000 kg/36 mm = 6 250 kg/25 mm d)Constr
46、uct a straight line (A-A) having a slope (kg/25 mm) equal to 2,2 times that calculated in c). EXAMPLE 2,2 6 250 = 13 750 kg/25 mm e)Draw line B-B parallel to A-A and tangent to the load deflection curve in the bottoming area. f)The bottoming load will be considered that which occurs at the point of
47、the tangency P (approximately 30 500 kg in the example given above). NOTE Values given for illustrative purposes (see 6.5.2.2.3). Figure 2 Determination of bottoming load 6.5.3 Lateral load deflection curves 6.5.3.1 The lateral deflection of the tyre is defined as the relative lateral displacement b
48、etween the wheel flange at a point immediately above the centreline of the contact patch and the loading plate, parallel to the loading plate surface. 6.5.3.2 The surface of the plate which is in contact with the tyre shall be covered with a material designed to prevent tyre slippage. Lateral load deflection curves shall be obtained by first loading the inflated tyre to the rated deflection under rated load conditions, followed by lateral displacement o