1、WORLDWIDEENGINEERINGSTANDARDSTest Procedure GMW16856Moisture Absorption of Coverings and Insulation,Corrosion Behaviour of Catches Copyright 2012 General Motors Company All Rights ReservedOctober 2012 Originating Department: GME Specification Center Page 1 of 41 ScopeNote: Nothing in this standard s
2、upercedes applicable laws and regulations.Note: In the event of conflict between the English and domestic language, the English language shall takeprecedence.1.1 Purpose. Determination of1. Stability of shape of the absorbing parts (Example: bonnet insulation)2. Absorption of moisture by insulation
3、and coverings3. Corrosion behavior (resistance) of catches1.2 Foreword. Insulation, coverings or sound-absorbing components frequently absorb water temporarily,especially in the edge areas, depending on the environmental conditions and the material characteristics.The components can be evaluated rel
4、iably with regard to their moisture characteristics in a climatic chamber indefined test conditions.It is important for the evaluation how the quantity of water absorbed is released again. A distinction is madehere between short term behaviour ( 8 h) and long term behaviour ( 24 h).The proneness to
5、corrosion shall be assessed for metal catches.1.3 Applicability.1.3.1 Absorbent parts outside and inside the passenger cells which are exposed to the weather/moisture (e.g.foot mats/floor coverings).1.3.2 Insulation as applied in “Horizontal Position” (e.g. insulation of engine compartment).1.3.3 La
6、tches (luggage compartment, hood etc.).2 ReferencesNote: Only the latest approved standards are applicable unless otherwise specified.2.1 External Standards/Specifications.None2.2 GM Standards/Specifications.None3 Resources3.1 Facilities.3.1.1 Climatic chamber.3.2 Equipment.3.2.1 Balance with an acc
7、uracy of 1 g.3.2.2 Device/supports to simulate the original installed position (see Figure 1).3.2.3 Caliper gauge, measuring tape.Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,
8、GM WORLDWIDE ENGINEERING STANDARDS GMW16856 Copyright 2012 General Motors Company All Rights ReservedOctober 2012 Page 2 of 4Figure 1: Test Set-Up1. Engine hood2. Insulation3. Clip fastening4. Retaining device (supports)3.3 Test Vehicle/Test Piece. Insulation in original installed position (Appli
9、es to Horizontal Components).3.4 Test Time. See paragraph 4.3.2. The test period can vary depending on the component.3.5 Test Required Information. Not applicable.3.6 Personnel/Skills. Technical personnel.4 Procedure4.1 Preparation.4.1.1 The weight of the test piece shall be established when determi
10、ning the moisture absorbed.4.1.2 It shall be checked that the test piece is fitted correctly when testing the dimensional stability.4.1.3 Before the test, the test piece shall be stored in the installed position in normal environmental conditionsfor 2 h.4.1.4 The climatic chamber shall be set to the
11、 conditions required for the measurement. It is necessary toensure that the conditions are constant (temperature stable).4.2 Conditions.4.2.1 Environmental Conditions. Storage temperature, relative humidity and dwell time, see paragraph 4.3.2.4.2.2 Test Conditions. Deviations from the requirements o
12、f this standard shall have been agreed upon. Suchrequirements shall be specified on component drawings, test certificates, reports, etc.4.2.2.1 The test can be performed both installed within the vehicle and on the individual component.4.2.2.2 The test piece (insulation) shall be tested in its origi
13、nal installed position, e.g. in a suitable retainingdevice or on supports (see Figure 1).4.3 Instructions.4.3.1 The test piece shall be attached in the device in accordance with its installed position.4.3.2 Followed by storage in the climatic chamber.1 cycle consists of:8 h storage at (+50 3) C and
14、95 3) % relative humidity, followed by 4 h minimum and 15 h maximumstorage at (+23 5) C.A total of 5 cycles shall be performed.4.3.3 After the test cycles have been completed, deformation shall be measured first when determiningdimensional stability. The measurement shall be performed with a calipe
15、r gauge.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 STANDARDS GMW16856 Copyright 2012 General Motors Company All Rights ReservedOctober 2012 Page
16、3 of 4Note: If the material has risen away from the base, it can be useful to pierce the test piece with a scriber todetermine the distance as the difference from the original position.4.3.4 The test piece shall be weighed again to determine the moisture absorbed.The weight shall be determined:x 15
17、minutes after removing the test piece from the climatic chamberx 24 h after removing the test piece from the climatic chamber5 Data5.1 Calculations.5.1.1 Absorption of Moisture. Calculation of the percentage change in weight between the initial weight andthe weight after storage.5.2 Interpretation o
18、f Results. Deviations are specified on the relevant drawing.After the 5th test cycle:5.2.1 Absorption of Moisture.1. Weight increase 15 minutes after removing the test piece from the climatic chamber: 20 % maximum.2. Weight increase 24 h after removing the test piece from the climatic chamber: 5 % m
19、aximum.5.2.2 Deformation. The measuring points shall be established after inspecting the component visually. Asketch shall be produced if necessary. The deformations are measured at the critical points and entered in thedata sheet (Appendix A).The permissible deformation/sag shall be 10 mm maximum.5
20、2.3 Corrosion Behaviour. The corrosion is evaluated visually immediately after removing and drying thetest piece. No corrosion shall be visible.5.3 Test Documentation. The results shall be entered in the data sheet (Appendix A) with reference to thisTest Procedure and enclosed with the test report.
21、6 SafetyThis standard may involve hazardous materials, operations, and equipment. This standard does not propose toaddress all the safety problems associated with its use. It is the responsibility of the user of this standard toestablish appropriate safety and health practices and determine the appl
22、icability of regulatory limitations priorto use.7 Notes7.1 Glossary. Not applicable.7.2 Acronyms, Abbreviations, and Symbols. Not applicable.8 Coding SystemThis standard shall be referenced in other documents, drawings, etc., as follows:Test to GMW168569 Release and RevisionsThis standard was origin
23、ated in August 2012. It was first approved by Global Cargo/Carpet/Acoustics CCAGSSLT in October 2012. It was first published in October 2012.Issue Publication Date Description (Organization)1 OCT 2012 Initial publication.Copyright General Motors Company Provided by IHS under license with General Mot
24、ors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16856 Copyright 2012 General Motors Company All Rights ReservedOctober 2012 Page 4 of 4Appendix AProject: Temperature:Object: Relative humidity:Design status: Date:Inst
25、alled condition: Tester:Water AbsorptionWeight before test Weight 15 minutes after test Weight 24 h after testSag (visual evaluation)Measuring point Deformation in mmCopyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
