1、 WORLDWIDE ENGINEERING STANDARDS Test Procedure GMW14735 Determination of the Permanent Set Characteristics of Elastomeric Components Copyright 2012 General Motors Company All Rights Reserved September 2012 Originating Department: North American Engineering Standards Page 1 of 5 1 Scope Note: Nothin
2、g in this standard supercedes applicable laws and regulations. Note: In the event of conflict between the English and domestic language, the English language shall take precedence. 1.1 Purpose. The object of this test procedure is the determination of the permanent set characteristics of elastomeric
3、 components used in vehicles, subjected to a constant deformation at specified temperatures. The data given by this test procedure will also enable an indication of the state of cure of the elastomer to be obtained. 1.2 Foreword. Not applicable. 1.3 Applicability. Not applicable. 2 References. Note:
4、 Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Specifications. ISO 188 2.2 GM Standards/Specifications. GMW14734 3 Resources 3.1 Facilities. Not applicable. 3.2 Test Equipment 3.2.1 Measuring equipment for determining the heights h0, hs, and ins
5、talled height of the elastomeric component in accordance with GMW14734. 3.2.2 Test fixtures in which the test samples may be deflected to the installed height (H), and held at that deflection. 3.2.3 Air Oven. Heating oven, capable of maintaining the required temperatures within the specified toleran
6、ces (e.g., heat oven to ISO 188 Method B) and having suitable volume. 3.2.4 Cold Cabinet. Temperature range: - 30 C to 5 C continuously adjustable. Temperature variation: 2 K. Temperature change speed for the empty cabinet: 1.5 K/minute (recommended). Work space of suitable volume. 3.2.5 Timing devi
7、ce, with an indicating range of 24 h, and accurate to one (1) minute in 24 h. 3.3 Test Vehicle/Test Piece. 3.3.1 The test samples shall be elastomeric components, as to be assembled into the vehicle. 3.3.2 For determination of properties for initial samples approval and arbitration purposes, and for
8、 routine quality control purposes, at least three test pieces shall be tested. 3.4 Test Time. Not applicable. 3.5 Test Required Information. Not applicable. 3.6 Personnel/Skills. Not applicable. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleN
9、o reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARD GMW14735 Copyright 2012 General Motors Company All Rights Reserved September 2012 Page 2 of 5 4 Procedure The test samples shall be tested in accordance with the requirements of this test procedure
10、and to the values specified on the relevant part drawing or test specifications with regard to the magnitude and direction of forces applied, and method of assembling to the test fixture. 4.1 Preparation. 4.1.1 Test Sample Preparation. For initial sample approval and arbitration purposes, the time p
11、eriod between vulcanization and testing shall be seven (7) days minimum. For quality control purposes, the period shall be 72 h. The test samples shall remain at a temperature of +23 C 5 C for 8 h minimum before testing, and shall be free from strain during this period. 4.2 Conditions. 4.2.1 Environ
12、mental Conditions. 4.2.2 Test Conditions. Deviations from the requirements of this standard shall have been agreed upon. Such requirements shall be specified on component drawings, test certificates, reports, etc. 4.3 Instructions. 4.3.1 The unstressed height (h0i) and installed height (Hi) shall be
13、 determined in accordance with GMW14734, if this test procedure is required for the elastomeric component. Where the Force Deflection to GMW14734 is not required, the specified value for the installed height (Hi) shall be used. 4.3.2 The test samples shall then be allowed to recover for 24 h -1 h at
14、 + 23 C 5 C in an unstressed condition. 4.3.3 The test sample shall then be inserted into the test fixture (3.2.2) deflected to the installed height (Hi) within one (1) minute and maintained at that height. 4.3.4 The test fixture and test sample shall then be placed into the oven/cold cabinet and ma
15、intained under one of the conditions specified in Table 1. 4.3.5 After the appropriate period, the test fixture and sample shall be removed from the oven/cold cabinet and allowed to recover to + 23 C 5 C within 6 h -0.1 h. 4.3.6 Following the recovery period defined in 4.3.5, the stress shall be rem
16、oved from the test sample, and it shall be allowed a further recovery period of 60 3 minutes at +23 C 5 C. The height (hsi) shall then be measured. 4.4 Test Duration and Temperature of Storage. One of the following conditions from Table 1 shall be used as specified on the relevant elastomeric compon
17、ent drawing, test specification or material specification. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARD GMW14735 Copyright 2012 General Mo
18、tors Company All Rights Reserved September 2012 Page 3 of 5 Table 1: Conditioning and Test Temperatures Condition Code Letter Duration in Hours Temperature in C A 22 to 24 -30 3 B 22 to 24 -20 3 C 22 to 24 -10 3 D 22 to 24 +80 2.5 E 22 to 24 +100 2.5 F 22 to 24 +125 2.5 G 22 to 24 +150 2.5 H 22 to 2
19、4 +175 2.5 I 22 to 24 +200 2.5 K 22 to 24 +225 2.5 L 70 to 72 +23 2.5 M 70 to 72 +80 2.5 N 70 to 72 +100 2.5 O 70 to 72 +125 2.5 P 70 to 72 +150 2.5 Q 70 to 72 +175 2.5 R 70 to 72 +200 2.5 S 70 to 72 +225 2.5 T 166 to 168 +80 2.5 U 166 to 168 +100 2.5 V 166 to 168 +125 2.5 W 166 to 168 +150 2.5 X 16
20、6 to 168 +175 2.5 Y 166 to 168 +200 2.5 Z 166 to 168 +225 2.5 5 Data 5.1 Calculations. Not applicable. 5.2 Interpretation of Results. Not applicable. 5.3 Test Documentation. 5.3.1 Evaluation and Rating. The permanent set Xjj shall be calculated from the measured values as follows: %10000 xHh hhxj ii
21、 siii Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARD GMW14735 Copyright 2012 General Motors Company All Rights Reserved September 2012 Page
22、4 of 5 5.4 Report. With reference to this test procedure, the test report shall also include the following. Part name. Part number. Test specification number. Additional identifications. Manufacturer. Grade of elastomer. Date of manufacture. Date of test. Test sample number. The values of the follow
23、ing, rounded to one decimal point: Height h0i (mm). Installed height Hi (mm). Height hsi (mm). The value of the following rounded to the nearest whole number: Permanent set Xjj (%). Any specific observations on the test sample. Folds, cracks, other surface effects. 6 Safety This standard may involve
24、 hazardous materials, operations, and equipment. This standard does not propose to address all the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitat
25、ions prior to use. 7 Notes 7.1 Glossary. Alphabetical Subscripts: Shall identify the dimension, e.g., h0: A dimension of the unstressed elastomeric component hs: A dimension of the elastomeric component after the removal of strain at the conclusion of the test Alphabetical Suffixes: Shall identify t
26、he test conditions detailed in paragraph 4.4 generally designated by j. j may take the form A, B, C thru Z. For example, XB indicates a permanent set found under the conditions given by Test Type B. Force F: The force F is the force, which shall be applied to the elastomeric component. Its magnitude
27、 and direction shall correspond with the installed condition. Height h0: The height h0 shall be a dimension in the direction of the force F. It shall be determined upon the unstressed elastomeric component prior to the application of any force. Height hs: The height hs shall be a dimension in the di
28、rection of the force F, measured in the unstressed condition on the elastomeric component at the conclusion of the test. Installed Height H: The installed height H shall be a dimension in the direction of the force F, measured on the elastomeric component according to GMW14734 or a dimension specifi
29、ed at constant deformation of an elastomeric component in the vehicle under installed condition. Numerical Subscripts: Shall identify the direction, in which a force is applied, and shall be generally designated i:i may take the form 1, 2, 3.n. The numerical subscript shall follow the alphabetical s
30、ubscript, e.g., XA1, H1, h01 and hs1. If there is only one direction, in which a force is applied, the numerical subscript 1 can be excluded, e.g., XA. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted with
31、out license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARD GMW14735 Copyright 2012 General Motors Company All Rights Reserved September 2012 Page 5 of 5 Permanent Set X: The permanent set X due to a constant deflection is the proportionate residual contraction expressed as a percentage, remaining at
32、 a given time after the removal of strain from the elastomeric component. Suffixes: To identify the force or dimension being applied or determined and their directions, alphabetical and numerical suffixes shall be used. 7.2 Acronyms, Abbreviations, and Symbols. Not applicable. 8 Coding System This s
33、tandard shall be referenced in other documents, drawings, etc., as follows: Test to GMW14735 Example: Permanent Set to GMW14735 - XB1 20% maximum Permanent Set = Designation GMW14735 = Test Procedure XB1 = Identification letter and condition code letter with numerical subscript for direction of forc
34、e 20% Maximum = Specified Requirements 9 Release and Revisions This standard was originated in October 2005. It was first approved by the Global Elastomer Components and Engine Mounts Team in December 2006. It was first published in December 2007. Issue Publication Date Description (Organization) 1 DEC 2007 Initial publication. 2 SEP 2012 5 Year Refresh. (Elastomers Global Subsystem Leadership Team) Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
