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 there
2、from, 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 m
3、ay 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.org SURFACE VEHICLE STANDARD J949 APR2009 Issued 1966-03 Revised 2009-04 Superseding J949 APR2003 Test Method for Determining Stiffness of Interior Trim Materials and Substrates by a Three Point Bending Test RATIONALE Mo
5、dify title and remove all references to English units anywhere in this standard. Remove the word “machine” in 5.5. 1. SCOPE This SAE Standard presents a method of determining the stiffness of interior trim materials, substrates, and composites by a three-point bending test. 2. REFERENCES 2.1 Applica
6、ble Publications The following publications form a part of the specification to the extent specified herein. 2.1.1 ASTM Publications Available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.org. ASTM D 747 Test Method for
7、Apparent Bending Modulus of Plastics by Means of a Cantilever Beam ASTM D 790 Test Methods for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Materials 3. TEST SPECIMENS Cut three specimens each 76 x 305 mm with the long dimension in the machine direction, if a
8、pplicable. Cut three additional specimens each 76 x 305 mm, with the long dimension in the across-machine direction, if applicable. 4. CONDITIONING Unless otherwise specified, the test specimens shall be conditioned to a constant weight in a controlled atmosphere of 23 C 2 C and 50% 5% relative humi
9、dity. This test can also be conducted after soaking the specimens in water under specified conditions agreed upon by the customer and supplier to determine relative stiffness when wet. SAE J949 Revised APR2009 Page 2 of 2 5. PROCEDURE 5.1 Measure the thickness of each specimen with a micrometer to t
10、he nearest 0.25 mm at the point of load application (center of specimen) and at the support points (76 mm) on each side of the center measured in the long direction of the specimen). Determine the average of these three readings and record. 5.2 Measure the width of the specimen to the nearest 0.25 m
11、m in the same locations as given in 5.1 and determine the average of the three readings and record. 5.3 Support the flat surface of the specimen on parallel supports 152 mm apart and apply the load on a bearing parallel to the end supports. The bearing and supports shall be rounded to a radius of 10
12、 mm and shall have a minimum length of 76 mm. 5.4 Apply the load at the rate of 13 mm/min until the specimen is deflected 6.3 mm at the midspan. 5.5 Calculate and report the average stiffness for each direction, if applicable, from the following formula: EPL34 b d3Y-=(Eq. 1) where: E = stiffness = m
13、odulus of bending, Pa P = load, N L = length of span, mm = 152 mm b = width of specimen, mm d = thickness of specimen, mm Y = deflection of specimen at midspan = 6.3 mm 6. GENERAL INFORMATION This document is recommended for the quick, relative ranking of automotive trim materials and substrates. Fo
14、r more definitive determination of the flexural properties, use ASTM D 790. It should be noted that ASTM D 790 calls for a 16 to 1 thickness to span ratio. Direct comparisons of stiffness between this method and D 790 may only be valid at 10 mm specimen thicknesses. There are also other technical di
15、fferences. For determination of stiffness by the cantilever beam method, use ASTM D 747. 7. NOTES 7.1 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 iss
16、ue 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 TEXTILES AND FLEXIBLE PLASTICS COMMITTEE
