1、 WORLDWIDE ENGINEERING STANDARDS Test Procedure GMW14357 Procedures of Test for Cellular and Related Materials Determination of Resistance to Humidity Aging Copyright 2012 General Motors Company All Rights Reserved December 2012 Originating Department: North American Engineering Standards Page 1 of
2、3 1 Scope Note: Nothing 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. This test method shall be used to determine the effects of humidity aging on cellula
3、r materials. The test attempts, by the use of water vapor at elevated temperature, to simulate the naturally occurring effects of oxidation and hydrolysis. Deterioration of the material is observed by measurements of physical properties prior to and after aging. 1.2 Foreword. Not applicable. 1.3 App
4、licability. Cellular materials. 2 References Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Specifications. ISO 1856 ISO 3386-1 2.2 GM Standards/Specifications. None 2.3 Additional References. None 3 Resources 3.1 Facilities. Not applicable
5、. 3.2 Equipment. 3.2.1 A steam autoclave or similar vessel capable of maintaining the required temperature to within 1 C and of withstanding pressures up to 1.5 bar (150 kPa) above atmospheric pressure (i.e., 2.5 bar absolute). The test vessel shall be equipped with means of venting at completion of
6、 the test so as to prevent undue frothing of water when the vessel is opened. 3.2.2 Alternatively, for aging at temperatures below +100 C: 3.2.2.1 A glass vessel with a suitable closure. 3.2.2.2 A water bath or drying oven for heating the vessel, capable of maintaining the required tem-perature to w
7、ithin 1 C, may be used. 3.2.3 During the test, sample supports shall be used that prevent test pieces from coming into contact with one another, the sides of the vessel or the water. Minimal contact with the supports shall also be ensured. No additional pressure on the test pieces is permissible. 3.
8、2.4 Test equipment for performance of the appropriate physical property. 3.3 Test Vehicle/Test Piece. Test pieces shall comply with the appropriate requirements for the test procedure to which physical property tests are to be conducted (i.e., tensile strength, compression set, etc.) 3.4 Test Time.
9、Not applicable. 3.5 Test Required Information. Not applicable. 3.6 Personnel/Skills. Not applicable. 4 Procedure 4.1 Preparation. Not applicable. 4.2 Conditions. 4.2.1 Environmental Conditions. Not applicable. 4.2.2 Test Conditions. Deviations from the requirements of this standard shall have been a
10、greed upon. Such requirements shall be specified on component drawings, test certificates, reports, etc. 4.3 Instructions. 4.3.1 Test Temperature and Test Period. See Table 1. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or n
11、etworking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14357 Copyright 2012 General Motors Company All Rights Reserved December 2012 Page 2 of 3 Table 1: Test Conditions Coding Test Temperature in 3 C Test Period in 5% h Typical Materials Tested A Specially Defined B
12、70 20 Cellular Polyethylene C 85 20 Cellular Polyester Polyurethane D 105 3 Cellular Polyester Polyurethane E 120 5 Cellular Polyether Polyurethane 4.3.2 Procedure. 4.3.2.1 The initial property A0 (i.e., tensile strength) is to be determined on the required number of test pieces. 4.3.2.2 Sufficient
13、water shall be added to the test vessel dependent upon its volume, the support rack inserted and test pieces placed on the rack (Paragraph 3.2.3). 4.3.2.3 The vessel shall be tightly closed and subjected to the test conditions specified (see Section 4.3.2). Timing shall commence when the air in the
14、vessel has been replaced by water vapor or steam (i.e., when steam is issuing from the autoclave and the valve is closed). 4.3.2.4 After the appropriate test period (see Table 1), the test vessel shall be vented and opened and the test pieces removed within 1 minute. At that time, determine the appr
15、opriate physical properties after humidity aging (A1), including conditioning, according to the appropriate test procedure. 5 Data 5.1 Calculations. The percentage change in property after humidity aging (exception, see Paragraph 5.3.1) is calculated as follows: 100A AAC h a n g e 0 01 in percent (%
16、) Where: A0 = Value (arithmetic average) of property prior to humidity aging (units dependent on test) A1 = Value (individual values and arithmetic average) of property after humidity aging (units the same as A0) Note: Except values for compression, load deflection to ISO 3386-1 CV40 +23 C, 50% rela
17、tive humidity since test prior to and after humidity aging shall be performed on the same test piece. 5.2 Interpretation of Results. Not applicable. 5.3 Test Documentation. 5.3.1 For compression, set tests to ISO 1856 - A after humidity aging. Results shall be recorded only as individual and arithme
18、tic average values and, deviating from Paragraph 5.1, not as percentage change. 5.3.2 Only results on test pieces of the same dimension can be compared to each other. 5.3.3 Testing results as described in Section 5 shall be presented in a test report to the involved GM Engineer. 6 Safety This standa
19、rd may involve 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 regu
20、latory limitations prior to use. 7 Notes 7.1 Glossary. Not applicable. 7.2 Acronyms, Abbreviations, and Symbols. GSSLT Global Subsystem Leadership Team Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted with
21、out license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14357 Copyright 2012 General Motors Company All Rights Reserved December 2012 Page 3 of 3 8 Coding System This standard shall be referenced in other documents, drawings, etc., as follows: Test to GMW14357 E Requirement Where: GMW14357 =
22、Test Procedure E = Test conditions to Paragraph 4.3.1 Note: Test to ISO 1856 A: (50%, 22 h, +70 C) - 10% maximum. Where: ISO 1856 = Test Standard A - (50%, 22 h, +70 C) = Compression to ISO 1856, Method A (compression 50%, for 22 h at +70 C) 10% maximum = Requirement 9 Release and Revisions This sta
23、ndard was originated in September 2005. It was first approved by the Global Foam Team in December 2006. It was first published in February 2007. Issue Publication Date Description (Organization) 1 FEB 2007 Initial publication. 2 DEC 2012 Five-year refresh to update template and references. (Trim Materials/Textiles/ Leather/Foam GSSLT) Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
