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 entirelyvoluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefro
2、m, is the sole responsibility of the user.”SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions.QUESTIONS REGARDING THIS DOCUMENT: (724) 772-8512 FAX: (724) 776-0243TO PLACE A DOCUMENT
3、 ORDER; (724) 776-4970 FAX: (724) 776-0790SAE WEB ADDRESS http:/www.sae.orgCopyright 1990 Society of Automotive Engineers, Inc.All rights reserved. Printed in U.S.A.SURFACEVEHICLE400 Commonwealth Drive, Warrendale, PA 15096-0001RECOMMENDEDPRACTICESubmitted for recognition as an American National Sta
4、ndardJ1528ISSUEDJUN90Issued 1990-06FATIGUE TESTING PROCEDURE FOR SUSPENSION-LEAF SPRINGSForewordThis Document has not changed other than to put it into the new SAE Technical Standards BoardFormat.1. Scope1.1 Test MaterialOnly fully processed new springs which are representative of springs intended f
5、or the vehicleshall be used for the tests. No complete spring or separate leaf shall be used for more than one test.2. ReferencesThere are no referenced publications specified herein.3. Report ContentTo obtain uniform documentation, every report shall include detailed information on thefollowing poi
6、nts, when applicable:3.1 GeometryOverall dimensions, location and dimensions of fracture sections including the location of thefracture initiation point shall be described in writing or by photographs.3.2 Material and Manufacturing ProcessThe type of material, as well as essential steps in the manuf
7、acturingwhich may affect the test results, shall be specified. As examples, type of hardening, shot-peening understress at given level, etc., can be mentioned.The hardness shall be checked on critical surfaces, and the hardness distribution through the section shall bemeasured. Shot peen coverage an
8、d the microstructure shall be evaluated.3.3 FractographyFracture surfaces shall be shown on photographs and the type of fracture discussed. Theextension of fatigue fracture shall be measured and the crack starting points shall be examined.3.4 Test Result PresentationThe individual test results may b
9、e clearly stated. Even noncritical events likecracks in secondary leaves must be recorded.The results of the fatigue testing of a group of springs should be subjected to statistical analysis. The Weibulldistribution is recommended. Also, it is recommended that minimum fatigue performance requirement
10、s bespecified in terms of B10 life and population slope.COPYRIGHT Society of Automotive Engineers, Inc.Licensed by Information Handling ServicesSAE J1528 Issued JUN90-2-4. Vertical Loading Methods4.1 General Directions4.1.1 EQUIPMENTThe test machine shall be able to maintain the maximum and minimum
11、specified force within2%. This can be accomplished by force control or control of deflection calibrated against a static force. Inthe latter case, dynamic and static spring rates must be considered.4.1.2 CLAMPINGThe spring shall be clamped at the center to simulate its installation in the vehicle. T
12、he clampingparts and assembly requirements must be specified by the vehicle manufacturer.The clamping hardware shall be tightened to the torque values specified and verified throughout the test.The bolt torque should be measured and brought up to specification more frequently at the beginning of the
13、test. Measurements are to be taken at 2000, 5000, and 10 000 cycles; then at 10 000 cycle intervals up to50 000 cycles and every 50 000 cycles until completion of the tests are recommended.4.1.3 TEST MOUNTINGSUnless otherwise specified, springs with eyes shall be free to move in the direction of the
14、datum line; springs with slipper ends shall be tested on fixed mountings. The vehicle manufacturer shallspecify the mountings on springs with other end configurations.4.1.4 RATE OF TESTINGSprings shall be cycled at a rate of between 0.5 and 2 Hz. The cyclic rate shall be chosenso that surface temper
15、ature on the spring does not exceed 90 C. Fans may be used to provide cooling air.4.2 Test Procedure4.2.1 STATIC LOAD TESTThe spring shall be loaded from zero up to the prescribed maximum deflection and backto zero. It is acceptable to apply the load in steps.The force shall be measured at the cente
16、r clamp. The vertical deflection of the spring center shall also bemeasured. The relation between the force and the deflection during a full cycle may be plotted in a diagram.4.2.2 FATIGUE TESTThe spring shall be loaded from 1/2 g (g = design load) to maximum load experienced underactual vehicle con
17、ditions, typically 2 g.For validation, six springs for each design, shall be tested to failure or to the number of cycles specified.Position limit switches shall be placed so that the test is terminated when the spring deflection has increaseda prescribed distance (see 5.1).In the case of a deflecti
18、on controlled test, the spring rates shall be measured at uniform intervals during thetest on at least one specimen in a test batch.If the spring rate increased more than 5% during the test, the deflection should be corrected to keep the testpeak forces constant. Regarding a corresponding decrease,
19、see 5.1. If it is necessary to correct thedeflection during the test as shown by the measurement of the spring rate, this shall be recorded and done inthe same way, including the number of cycles, for all springs in the batch.Measure the load at rated load position at 50 000 cycle intervals to deter
20、mine load loss due to permanentset.COPYRIGHT Society of Automotive Engineers, Inc.Licensed by Information Handling ServicesSAE J1528 Issued JUN90-3-5. Fatigue Failure Criteria5.1 Inability of Spring to Sustain LoadNormally, this is said to happen when deflection has increased 5 to10% above the maxim
21、um total deflection at the test start or load loss at 50 000 cycles exceeds 5% of the loadat test start.5.2 Visible Crack in #1 Leaf or Visible Cracks in More Than Two Supporting Leaves.PREPARED BY THE SAE TRUCK AND BUS CHASSIS COMMITTEECOPYRIGHT Society of Automotive Engineers, Inc.Licensed by Info
22、rmation Handling ServicesSAE J1528 Issued JUN90RationaleNot applicable.Relationship of SAE Standard to ISO StandardNot applicable.ApplicationOnly fully processed new springs which are representative of springs intended for the vehicleshall be used for the tests. No complete spring or separate leaf shall be used for more than one test.Reference SectionThere are no referenced publications specified herein.Developed by the SAE Truck and Bus Chassis CommitteeCOPYRIGHT Society of Automotive Engineers, Inc.Licensed by Information Handling Services
