1、raising standards worldwide NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BSI Standards Publication BS ISO 6772:2012 Aerospace Fluid systems Impulse testing of hydraulic hose, tubing and fitting assembliesBS ISO 6772:2012 BRITISH STANDARD National foreword This British Stand
2、ard is the UK implementation of ISO 6772:2012. It supersedes BS 2M52:1989 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee ACE/69, Aerospace hydraulic systems, fluids and components. A list of organizations represented on this committee can be obtained
3、 on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2012. Published by BSI Standards Limited 2012 ISBN 978 0 580 67897 4 ICS 49.080; 83.140.40 Compl
4、iance with a British Standard cannot confer immunity from legal obligations. This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 2012. Amendments issued since publication Date Text affectedBS ISO 6772:2012 ISO 2012 Aerospace Fluid sys
5、tems Impulse testing of hydraulic hose, tubing and fitting assemblies Aronautique et espace Systmes de fluides Essai dimpulsion des tuyauteries flexibles, tubes et raccords INTERNATIONAL STANDARD ISO 6772 Third edition 2012-10-01 Reference number ISO 6772:2012(E)BS ISO 6772:2012ISO 6772:2012(E) ii I
6、SO 2012 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2012 All rights reserved. Unless otherwise specified, no part 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
7、 either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in SwitzerlandBS ISO 6772:2012ISO 6772:2012(E) ISO 2012 All righ
8、ts reserved iii Contents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references 1 3 Terms and definitions . 1 4 Requirements 1 4.1 Shape of impulse trace . 1 4.2 Calculation of pressure rise . 2 4.3 Preparation of specimens 2 4.4 Test fluid . 3 5 Principle of test 3 6 Test method . 3 7 I
9、ntended use 4 7.1 Standard 4 7.2 Reference . 4 Bibliography 6BS ISO 6772:2012ISO 6772:2012(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 carrie
10、d 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, governmental and non-governmental, in liaison with ISO, also take part in the work. IS
11、O collaborates closely with the International Electrotechnical 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 task of technical committees is to prepare Internatio
12、nal Standards. Draft International Standards 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. Attention is drawn to the possibility that some of the ele
13、ments of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 6772 was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles, Subcommittee SC 10, Aerospace fluid systems and components. This third edi
14、tion cancels and replaces the second edition (ISO 6772:1988), which has been technically revised. The main changes are as follows: 3.2: definition has been modified; Clause 5: new paragraph has been added; Tables 1, 2 and 3 have been modified to cover additional classes J and K. iv ISO 2012 All righ
15、ts reservedBS ISO 6772:2012ISO 6772:2012(E) Introduction In hydraulic systems, power is transmitted through the hydraulic fluid under pressure with a network of tubing and hoses, and their attendant fitting assemblies. In order to demonstrate that these transmission elements are fit for purpose in t
16、erms of the prevention of premature failures due to fatigue, it is necessary to conduct appropriate impulse pressure testing. This document provides the overall requirements for pressure impulse testing of hydraulic system distribution elements. ISO 2012 All rights reserved vBS ISO 6772:2012BS ISO 6
17、772:2012Aerospace Fluid systems Impulse testing of hydraulic hose, tubing and fitting assemblies 1 Scope This International Standard specifies the requirements and the procedures for impulse testing of hose, tubing, and fitting assemblies for use in aerospace hydraulic systems. Requirements may appl
18、y, when appropriate, to components used in other aerospace fluid systems. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated refe
19、rences, the latest edition of the referenced document (including any amendments) applies. ISO 6771, Aerospace Fluid systems and components Pressure and temperature classifications ISO 8575, Aerospace Fluid systems Hydraulic system tubing 3 Terms and definitions For the purposes of this document, the
20、 following terms and definitions apply. 3.1 rate of pressure rise slope of the pressure/time curve in the straight portion of the pressure increase portion NOTE For the purpose of this definition, the rate of rise is determined between 10 % of the total rise above back-pressure and 10 % of the total
21、 rise below peak pressure. 3.2 peak pressure maximum value for an operating pressure of short duration ISO 8625-1:1993, 1.25 4 Requirements 4.1 Shape of impulse trace When observed on an oscilloscope, the impulse traces show as approximate pressure/time cycles. It is mandatory that these pressure/ti
22、me curves be confined to the shaded area indicated in Figure 1. The dynamic impulse trace produced by the test machine shall be in conformity with the trace illustrated in Figure 1. INTERNATIONAL ST ANDARD ISO 6772:2012(E) ISO 2012 All rights reserved 1BS ISO 6772:2012ISO 6772:2012(E) Key X Percent
23、of one cycle Y Percentage of nominal pressure 5 % 1 The slope of this portion of curve, between 10 % and 90 % of peak pressure, gives the rate of rise (see 4.2) 2 Peak pressure (see Table 1 or 2). Only one pressure peak is allowed above 110 % of operating pressure and it must be within the first 15
24、% of cycle 3 Back pressure in pressure classes B, D, E: (345 170) kPa / (50 25) psiBack pressure in pressure classes J, K: (700 350) kPa / (100 50) psi Figure 1 Impulse trace 4.2 Calculation of pressure rise The rate of pressure rise shall be calculated using the following formula: wherep is the pea
25、k pressure, in kilopascals;t at 0,9 p is the time, in seconds, at 0,9 p;t at 0,1 p is the time, in seconds, at 0,1 p. 4.3 Preparation of specimens The preparation of test specimens shall be defined in the detail design specification of the component. Specimens shall be subjected to the relevant trea
26、tments and production test requirements of the component specification. 2 ISO 2012 All rights reservedBS ISO 6772:2012ISO 6772:2012(E) 4.4 Test fluid The test fluid shall be the specified aircraft system fluid or another hydraulic fluid which is compatible with the item being tested. 5 Principle of
27、test This method of testing is intended to determine the ability of flexible hose assemblies, tubing and fitting assemblies to withstand hydraulic impulse for qualification testing under simulated conditions. 6 Test method For testing of hose, tubing and fitting assemblies, including boss or port fi
28、ttings, the cycle rate shall be (70 5) cycles/min. Unless otherwise specified, the peak pressure and the rate of pressure rise shall be as specified in Tables 1 and 2. Unless otherwise specified, the assembly shall be tested in the sequence shown in Table 3. The sweep rate on the oscilloscope or rec
29、order shall be adjusted so that the slope of the pressure rise shall take advantage of the full size of the screen. The trace and photographs of the impulse cycle shall be an accurate record of the impulse cycle and show a grid or other means to permit accurate checking. The end-to-end accuracy and
30、sampling rate of the data acquisition system and sensors should ensure that the impulse measurement uncertainty is within the pressure waveform specifications of this document. The accuracy of the measurements shall be traceable to international standards. Unless otherwise specified in the detail or
31、 procurement specification, the total number of cycles shall be 200 000. After the temperature has stabilized at the maximum or minimum, as specified in Table 3, a minimum soak time of 1 h is required before that portion of the test sequence is begun. If temperature control is required by the procur
32、ement specification, the fluid temperature shall be measured at the test manifold and the ambient temperature shall be measured approximately 150 mm from the test specimens. The peak pressure shall be measured at the test manifold. Table 1 Peak pressure and rate of pressure rise SI-metric units of m
33、easure Hoses, tubing and fitting assemblies Peak pressure Minimum rate of pressure rise Maximum rate of pressure rise Pressure class a Nominal outside diameter b kPa % kPa/s kPa/s B 10 500 DN14 and smaller 125 126 000 700 000 DN16 to DN25 (incl.) 520 000 DN32 340 000 DN40 and over 280 000 D 21 000 A
34、ll diameters 150 315 000 2 100 000 E 28 000 420 000 J 35 000 525 000 K 55 000 135 525 000 4 590 000 aPressure classes in accordance with ISO 6771. bNominal outside diameters in accordance with ISO 8575. DN = nominal outside diameter in mm, example: DN16 = nominal outside diameter of 16 mm. ISO 2012
35、All rights reserved 3BS ISO 6772:2012ISO 6772:2012(E) Table 2 Peak pressure and rate of pressure rise Imperial units of measure Hoses, tubing and fitting assemblies Peak pressure Minimum rate of pressure rise Maximum rate of pressure rise Pressure class a Nominal outside diameter b psi % psi/s psi/s
36、 B 1 500 08 and smaller 125 18 000 100 000 10 through 12 75 000 20 50 000 24 and over 40 000 D 3 000 All diameters 150 45 000 300 000 E 4 000 60 000 J 5 000 75 000 K 8 000 135 75 000 650 000 aPressure classes in accordance with ISO 6771. bNominal outside diameters in accordance with ISO 8575. Dash s
37、ize is the equivalent of the diameter in 1/16 inch, example: - 06 = 6/16 inch diameter. Table 3 Sequence and duration of impulse testing at temperature aSequence No. Number of cycles as a percentage of the total number of cycles Temperature (ambient and fluid) 1 50 Maximum 2 24 From 15 C to 35 C/60
38、F to 95 F 3 1 Minimum 4 5 Maximum 5 20 Ambient and fluid: any of the above. These cycles may be added to any one sequence or divided among them. aUnless otherwise specified in the detail or procurement specification. 7 Intended use 7.1 Standard This test is intended to promote standardization of imp
39、ulse test requirements, procedures and equipment for the standard qualification and evaluation impulse testing of hydraulic hose assemblies, tubing and fittings. 7.2 Reference If reference is made to this International Standard in a specification as part of the requirements, the following additional
40、 requirements shall be specified: a) nominal pressure; 4 ISO 2012 All rights reservedBS ISO 6772:2012ISO 6772:2012(E) b) operating temperature limits; c) design of specimens. ISO 2012 All rights reserved 5BS ISO 6772:2012ISO 6772:2012(E) Bibliography 1 ISO 8625-1:1993, Aerospace Fluid systems Vocabu
41、lary Part 1: General terms and definitions related to pressure 2 SAE AIR 1228, Standard Impulse Machine Equipment and Operation 6 ISO 2012 All rights reservedBS ISO 6772:2012BS ISO 6772:2012 ISO 6772:2012(E) ISO 2012 All rights reserved ICS 49.080, 83.140.40 Price based on 6 pagesThis page deliberat
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