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 reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 2009 SAE International All rights reserved. No part of this publication ma
3、y 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: 724-776-4970 (outside USA)
4、Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.orgSURFACEVEHICLERECOMMENDEDPRACTICEJ2694 SEP2009 Issued 2009-09 Anti-Noise Brake Pads Shims: T-pull Test RATIONALEThis recommended practice standardizes the measurement of the bond strength between the anti-noise shims a
5、nd the disc brake pads. The development of sufficient bond strength is necessary for the correct performance of bonded anti-noise shims. 1. SCOPE This recommended practice covers the attachment of bonded anti-noise brake pad shims only. Mechanically attached shims (those without bonding) are not cov
6、ered by this procedure. 1.1 Purpose To measure the strength of the adhesive bond for the attachment of anti-noise shims to disc brake pads or a test specimen to a standard steel plate. Its primary use is as a quality tool.2. REFERENCES 2.1 Applicable Publications The following publications form a pa
7、rt of this specification to the extent specified herein. 2.1.1 DIN Publications Available from Deutsches Institut fr Normung e.V., Burggrafenstrasse 6, 10787 Berlin, Germany, www.din.de.DIN 53 282 Winkelschlversuch (T-peel Test) DIN 50 014 Standard Climatic Conditions 2.1.2 ASTM Publications Availab
8、le from ASTM International, 100 Barr Harbor Dr., P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.org.ASTM D 618 Standard Practice for Conditioning Plastics for Testing ASTM D 1876 Standard Test Method for Peel Resistance of Adhesives (T-Peel Test) SAE J2694 Issued SEP200
9、9 Page 2 of 73. DEFINITIONS 3.1 Pull Strength The pull strength (P) or initial peel resistance of the shim adhesive is defined as the force per width (N/mm) which is needed to pull a shim from the backing plate of a pad at a 90 angle. b/FP = (Eq. 1) where F is the peak pull force (N) and b is the sh
10、im bend width (mm). This value is used to assess the bond quality. 3.2 Shim Bend Width The shim bend width is the width of the adhesive bond at the start of the test. Area AArea BShim bend line away from spigot holes and semi shears etc.Fig. 1.The shim pull widthSpigot holes andsemi shearsFIGURE 1 -
11、 SHIM WITH BEND LINE AND SHIM BEND WIDTH SAE J2694 Issued SEP2009 Page 3 of 7Clamp moving member oftensile test apparatus onto shimShimPad backplateFriction materialDirection of pull at the test velocityShim bent at 90qclose to centreline avoiding spigot holes, semi shears etc.Clamp bar appliesforce
12、 F to hold thepad to the testmachine.Tensile test machine bedFqFIGURE 2 - 90 PULL TEST SETUP 3.3 Peak Force The peak pull force F is the intial force necessary to start the peel of the adhesive. See Figure 3. FIGURE 3 - LOAD VS. TRAVEL CHART DEFINING PEAK PULL FORCE (F) SAE J2694 Issued SEP2009 Page
13、 4 of 73.4 Failure Mode The failure mode of the assembly describes the visual inspection of the bonding interface and of the adhesive layer after separation. For example, the adhesive can remain completely on the pad back plate, be found in patches on both back plate and shim, or remain completely o
14、n the shim. 4. TEMPERATURE AND HUMIDITY FOR TESTING The ambient condition for the test is 23 C 2 C. In critical cases, standard climatic conditions (according to agreed specifications such as ASTM D 618 or DIN 50 014-23/50-2) should be applied. 5. EQUIPMENT AND APPARATUS 5.1 Testing Machine This tes
15、t can be conducted on a universal tensile test machine or specifically designed test equipment. The load measurement accuracy required for peak pull force (F) is 1% of full range, and 0.5 N for force ranges less than 100 N. Preferably, the load vs. travel should be recorded. The moving member veloci
16、ty shall be 50 mm/min 10%. The travel range of the moveable member should be a minimum of 5 mm. However, travel must be sufficient to overcome the peak pull force as shown in Figure 3.6. TEST SAMPLES 6.1 Testing During the Development Phase “Test specimen” samples are standard shim samples, 40 mm wi
17、de and 100 mm long, bonded to a steel block, sufficiently sized to accommodate the shim sample, with a minimum thickness of 5 mm.The steel block shall be either steel with a defined surface finish approximating a production steel pad back plate, or plates cut from the same type of steel as used for
18、the back plates. The steel block must be either de-greased or treated in the same process as the standard pads/backing plates before the shims are mounted, such as painted or otherwise coated. 6.2 Testing as a Production Check The test has to be completed with the intended or series back plate and s
19、him. Production or production intent conditions apply.7. BONDING Both during development and production, bonding of the shim to the supporting plate has to be performed according to a bonding specification. During the development phase, the bonding should be performed as intended for production. Dur
20、ing production the bonding shall be done to an agreed upon production specification. For improved test repeatability, the bonding method must be defined and recorded with sufficient precision, including items as pressures, temperatures and holding times. If the strength of the bond changes after the
21、 bonding operation due to subsequent curing, the samples shall be held until the curing occurs. 8. PREPARATION OF TEST SAMPLES In the description which follows, the term “pad assembly” is used inter-changeably for a bonded shim specimen and steel block or pad specimen. SAE J2694 Issued SEP2009 Page
22、5 of 78.1 Clamp the assembled damping shim in the area close to the bending point with a special clamping device (see Figure 4). FIGURE 4 - CLAMPING DEVICE TO PROVIDE A 90 ANGLE WITHOUT INFLUENCE TO THE ADHESIVE LAYER 8.2 Pry the exposed half of the shim away from the back plate, using a suitable fl
23、at-bladed utensil such as a putty knife or chisel to start the detachment, then complete the operation by hand. 8.3 Bend the unattached half of the shim until it attains an angle of 90 to the pad back plate. The shim bending radius should be in the range of 1 to 2 mm for simple shims and 2 to 4 mm f
24、or multi-layer shims. 8.4 Clamp the pad assembly in a fixture or vice in a position such that the top of the vice is as close as possible to the noise shim centerline without passing over a back plate spigot hole, indentations, alpha-numeric stamping, or semi shear. The purpose of the clamping is to
25、 prevent the shim from experiencing a preload or lifting prior to the actual test.9. TEST PROCEDURES 9.1 The tensile test rig consists of a static and a moveable cross-member. During tensile testing the test sample is attached to both the static and the moveable member. When the moveable member is m
26、oved away from the static member, tensile forces are applied to the test sample (see Figure 2). 9.2 The prepared pad assembly must be clamped to the static part of the tensile rig. A suitable method is to use a clamp bar across the exposed area of the pad assembly. No additional load or pressure sha
27、ll be exerted by this clamp bar. 9.3 The part of the shim that is bent 90 upward needs to be attached to the moveable part of the tensile test rig. Suitable methods are using a hole in the shim or by means of a clamp, where it has to be assured, that no slip should occur between the clamp and the cl
28、amped shim specimen. For repeatability of results, the attachment method needs to be defined with sufficient precision, and reported. The clamp should not be a rigid body but should provide a balance of the tangential forces by means of a chain or steel cable (see Figure 5). SAE J2694 Issued SEP2009
29、 Page 6 of 7FIGURE 5 - CLAMPING DEVICE FOR T-PULL WITHTANGENTIAL FORCE BALANCE BY CHAIN 9.4 The rig shall be operated with a moving member velocity of 50 mm/min 10%. The travel range of the moveable member should be a minimum of 5 mm. 10. OPTIONAL PRE-HEATING OF SAMPLE While the usual T-pull test is
30、 done with as produced pad assemblies, pre-conditioning of the pad assembly can be arranged. This conditioning can include: 10.1 Several cycles of brake applies on a brake test rig or friction tester, with maximum rotor temperatures up to 650 C. If the test samples are pre-conditioned in such a mann
31、er, the test procedure and brake cooling conditions used must be fully defined.11. STATISTICS Unless specified otherwise, the number of samples to be tested should be five (5). 12. RECORD The test report shall include the following: a) Technician or test operator responsible for test execution and t
32、est reporting b) Description and unique characterization of the test specimen c) Set-up, equipment, and environmental conditions of the test d) Test procedure including test velocity e) Detailed geometry of the components and the bonding interface f) If applicable: Steel block type and surface quali
33、ty g) If applicable: Surface preparation, de-greasing procedure, solvent type, painting process, etc.h) Documentation of the adhesive and the bonding instructions SAE J2694 Issued SEP2009 Page 7 of 7i) Bonding conditions including specimen preparation, temperature, pressure duration, post-curing j)
34、If applicable: Pre-conditioning parameters k) Number of samples l) P (pull strength) for each sample, average P for sample lot, and standard deviation of samples m) Load vs. Displacement Charts, if available n) Description of the failure mode of the assembly o) Date, time and specific observations o
35、f the test 13. NOTES 13.1 Marginal Indicia A change bar (I) 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 revision 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 THE SAE BRAKE LININGS STANDARDS COMMITTEE OF THE SAE BRAKE FORUM STEERING COMMITTEE
