1、_SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising theref
2、rom, is the sole responsibility of the user.”SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions.Copyright 2016 SAE InternationalAll rights reserved. No part of this publi
3、cation may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE.TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada)Tel: +1 724-776-4970 (out
4、side USA)Fax: 724-776-0790Email: CustomerServicesae.orgSAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedback on thisTechnical Report, please visithttp:/standards.sae.org/ARP5448/1AAEROSPACERECOMMENDED PRACTICEARP5448/1 REV. AIssued 2004-07Reaffirmed 2010-06Revised 2016-11Super
5、seding ARP5448/1Plain Bearing Radial Limit and Ultimate Load TestsRATIONALEThis revision updates document formatting and document references to align with the latest publications.1. SCOPE1.1 PurposeThis test method outlines the recommended procedure for performing radial limit load and ultimate load
6、 tests on low speed airframe and high speed helicopter rotor head bearings.1.2 ClassificationBearings covered by this test method shall be plain sleeve or spherical type in either annular or rod end configuration.2. REFERENCES2.1 Applicable DocumentsThe following publications form a part of this doc
7、ument to the extent specified herein. The latest issue of SAE publications shall apply. The applicable issue of other publications shall be the issue in effect on the date of the purchase order. In the event of conflict between the text of this document and references cited herein, the text of this
8、document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained.2.1.1 ASTM PublicationsAvailable from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585,
9、www.astm.org.ASTM E4 Standard Practices for Force Verification of Testing MachinesASTM E83 Standard Practice for Verification and Classification of Extensometer SystemsSAE INTERNATIONAL ARP5448/1A Page 2 of 82.1.2 ANSI PublicationsCopies of these documents are available online at http:/webstore.ansi
10、.org/.ANSI/NCSL Z540.3 Requirements for the Calibration of Measuring and Test Equipment2.1.3 ISO PublicationsAvailable from International Organization for Standardization, ISO Central Secretariat, 1, ch. de la Voie-Creuse, CP 56, CH-1211 Geneva 20, Switzerland, Tel: +41 22 749 01 11, www.iso.org.ISO
11、 10012 Measurement Management Systems Requirements for Measurement Processes and Measuring Equipment2.2 DefinitionsPERMANENT SET: Permanent set is the displacement of the bearing in the load path during one excursion from a specified pre-load to limit load and return to pre-load.RADIAL LIMIT LOAD: T
12、he radial limit load is the maximum load that should be applied to the bearing. A defined limit for permanent set is established corresponding to the specified limit load.RADIAL ULTIMATE LOAD: The radial ultimate load is 1.5 multiplied by the radial limit load. After application of the radial ultima
13、te load there may be significant permanent deformation of the bearing components. There shall not, however, be any cracked or broken components.3. GENERAL REQUIREMENTS3.1 Test Apparatus3.1.1 Testing MachineThe testing machine shall be capable of applying the required radial load at a controlled rate
14、. The calibration system for themachine shall conform to ANSI/NCSL Z540.3 and ISO 10012. Its accuracy shall be verified every 12 months by a method complying with ASTM E4. The limit and ultimate loads of the bearings tested shall be within the loading range of the testing machine as defined in ASTM
15、E4.3.1.2 Deflection Measuring DeviceThe measuring device shall be a mechanical or electronic linear indicator with a definition of 0.0002 inch and an accuracy of 0.0001 inch, or an extensometer with a precision of at least 1% of the indicated joint deflection at the limit load being applied. If usin
16、g an electronic linear indicator, an autographic recorder with an accuracy of 0.5% of the indicated joint deflection at the limit load should be used in conjunction with it, and be calibrated in accordance with ASTM E83. If using adial indicator to measure deflection, sufficient data points should b
17、e recorded to plot a load versus deflection curve manually. Load and deflection ranges shall be used which give the initial part of the load extension curve a slope ideally between 45 and 60 degrees. The measuring device does not need to be attached directly to the fixtures.3.1.3 Test FixturesThe te
18、st fixtures shall be as shown in Figure 1a thru 1d. The test housing and strut shall be fabricated from steel and heat treated to a hardness of 40 HRC minimum. The test pin shall be fabricated from high strength tool steel or equivalent, heattreated to a hardness of 50 HRC minimum. For economy it is
19、 permissible to use adapter housings and bushings that permit one housing and strut assembly to be used for a variety of bearing sizes. Other techniques are acceptable provided that they can be calibrated to account for fixture deflection.SAE INTERNATIONAL ARP5448/1A Page 3 of 83.2 Specimen3.2.1 Qua
20、ntityThe number of test specimens shall be as specified in the referencing document.3.2.2 Disposition after Test3.2.2.1 Bearings Subjected to Limit and Ultimate Load TestsUnless otherwise specified by the applicable specification or contract, bearings that have been subjected to these tests may have
21、 deformed components and shall not be shipped.4. DETAILED REQUIREMENTS4.1 Installation4.1.1 SleevesThe sleeve shall be installed in the test fixture as shown in Figure 1a or 1b (as applicable) using a 0.0000 to 0.0011 inch interference fit with the housing for steel bearings, 0.0001 to 0.0016 inch i
22、nterference fit for aluminum bearings, and a 0.002 to 0.004 inch loose fit with the pin. The use of differential temperatures for installation is acceptable.4.1.2 Plain Spherical BearingsThe bearing shall be installed in the test fixture as shown in Figure 1c using a 0.0000 to 0.0010 inch loose fit
23、with the housing, and a 0.0000 to 0.0010 inch loose fit with the pin. The use of differential temperatures for installation is not allowed.4.1.3 Rod End BearingsThe bearing shall be installed in the test fixture as shown in Figure 1d using a 0.0000 to 0.0010 inch loose fit with the pin. The use of d
24、ifferential temperatures for installation is not allowed. An appropriately threaded attachment shall be installed on the rod end shank permitting a thread engagement of at least 1 times the thread pitch diameter.4.2 Radial Limit Load TestApply a preload equal to 4 to 6% of the specified radial limit
25、 load and maintain for a minimum of 3 minutes. (NOTE: Rod end bearing tests shall be performed such that the bearing load places the shank in tension.) Engage the deflection measuring device and “zero” the autographic recorder. Increase the load to the specified limit load at a rate of a minimum of
26、1% of the specified load per second. Maintain the radial limit load for a minimum of 2 minutes. Remove the load, at the same rate as during loading, to the initial preload. The permanent set shall be the deflection reading when the radial load returns to preload. NOTE: When a bearing specimen is to
27、be subjected to the radial ultimate load test, it will not be necessary to remove that bearing from the test fixture after completing the radial limit load test.4.3 Radial Ultimate Load Test(NOTE: Rod end bearing tests shall be performed such that the bearing load places the shank in tension.) Incre
28、ase the load to the specified ultimate load at a rate of a minimum of 1% of the specified load per second. Remove the load at the same rate as during loading.4.4 Test DurationTesting shall continue until the test is successfully completed (when the appropriate load rating of the bearing has been met
29、) or until failure as defined in the applicable specification has occurred.SAE INTERNATIONAL ARP5448/1A Page 4 of 84.5 Post Test Evaluation4.5.1 Radial Limit LoadThe data shall be reviewed for conformance to the performance criteria (i.e., deflection at load, permanent set, etc.) as required by the
30、applicable specification.4.5.2 Radial Ultimate LoadExamine the test specimen. Deformation of the outer race is acceptable. There shall be no cracked or broken components.5. NOTES5.1 Intended UseThis test method is intended to provide means for evaluating the performance under static loads on low spe
31、ed airframe bearings and for high speed helicopter rotor head bearings. Specific test and data requirements are given in the applicable document. The following note shall be used to reference this test method:NOTE: The bearings shall be tested in accordance with ARP5448/1.The slash number refers to
32、the specific test method.5.2 Test Data5.2.1 Test ParametersSpecific test requirements are given in the referencing document. Test requirements shall include the following test parameters as applicable:a. Test specimen design envelope.b. Shaft and housing configuration.c. Radial limit load.d. Radial
33、ultimate load.e. Loading rates for limit and ultimate load tests.f. Deflection at radial limit load.g. Permanent set.h. Test duration.i. Failure criteria (breakage, etc.).SAE INTERNATIONAL ARP5448/1A Page 5 of 85.2.2 Test RecordsA log shall be maintained during the test and shall include a record of
34、 start and stop times, loads, maintenance performed on the test facility, and any other pertinent information relating to the test. If using a dial indicator to measure deflection, data indicating the progress of the test shall be recorded at sufficient intervals to produce an accurate plot of recor
35、ded test parameters versus time. If the load versus deflection graph is recorded from an electronic plotter, the horizontal and vertical axes should be labeled, and the chart identified. Data sheets shall be filled out when data is taken during the test. Test data sheets shall be in a format similar
36、 to the sample test data sheet shown in Table 1. Readings from oscillographs, temperature controls or any other recording devices shall then be taken at specified intervals and the records maintained sufficiently tosupport recording of the test results.5.2.3 Test ReportThe recorded data shall be sum
37、marized in report form and (as applicable) shall contain the following:a. Bearing description.1. Part number.2. Lot identification.3. Manufacturer.4. A dated drawing completely describing the test bearing, including the dimensions, material and ratings.b. Test machine description.1. Model number, se
38、rial number and a brief description.2. Calibration data.c. Test parameters.d. Data sheets.e. Plots of recorded test parameters.1. Radial limit load versus deflection.2. Radial ultimate load versus deflection.f. Any test malfunction resulting in an invalid test or in an interruption in the test shall
39、 be noted.g. Results of all inspections.h. To ensure accuracy of test data, the bearing supplier (or testing laboratory) shall certify that the data presented is theperformance data for all bearings tested in the report and that no data has been deleted.SAE INTERNATIONAL ARP5448/1A Page 6 of 86. NOT
40、ES6.1 Revision IndicatorA change bar (l) located in the left margin is for the convenience of the user in locating areas where technical revisions, not editorial changes, have been made to the previous issue of this document. An (R) symbol to the left of the document title indicates a complete revis
41、ion of the document, including technical revisions. Change bars and (R) are not used in original publications, nor in documents that contain editorial changes only.PREPARED BY SAE SUBCOMMITTEE ACBG-1, PLAIN BEARING OFCOMMITTEE ACBG, AIRFRAME CONTROL BEARINGS GROUPSAE INTERNATIONAL ARP5448/1A Page 7 of 8Table 1 - Sample format of test data sheetARP5448/1Bearing P/N _Bearing Test # _Radial Load:Limit _Ultimate _Date _Machine # _Housing # _Technician _TestDuration Static Radial LoadDeflection atMaximum Load Permanent SetSAE INTERNATIONAL ARP5448/1A Page 8 of 8Figure 1 - Radial load fixtures
