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1、Test Method Materials GMW14734 Determination of the Force-Deflection Characteristics and Creep Properties of Elastomeric Components 1 Scope Note: Nothing inthisstandard supersedes applicable laws and regulations. Note: In the event of a conflict between the Eng- lish and the domestic language, the E
2、nglish language shall take precedence. 1.1 The object of this test method is the determina- tion of the deflection and creep shown by elastomeric components used in vehicles under a constant force at a temperature of (+ 23 5) C. 1.2 Objectives. 1.2.1 The determination of the force-deflection and cre
3、ep characteristics shown by elastomeric compo- nents. The data given by this test method will also enable an indication of the state of cure of the elastomer to be obtained. 1.2.2 The determination of the installed dimensions of the elastomeric components in the “as assembled” condition. 1.3 Definit
4、ions. 1.3.1 Force F. The force F is the force, which shall be applied to the elastomeric component. Its magnitude and direction shall correspond with the installed con- ditions of the component. 1.3.2 Initial Force Fv. The initial force Fvshall be the force, which is initially applied to the elastom
5、eric com- ponent in order to establish a datum point for mea- surements.Its magnitude is normally (12) % of force Fkand it acts in the direction of the force F. 1.3.3 Force Fk. The force Fkshall be the major force applied to the elastomeric component in order to determine its force-deflection and cr
6、eep properties. It acts in the direction of the force F. 1.3.4 Height h0. The height h0shall 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. 1.3.5 Height hv. The height hvshall be a dimension in t
7、he direction of the force F, determined under the initial force Fvacting on the elastomeric component. 1.3.6 Installed Height H. The installed height H shall be a dimension in the direction of the force F, and is measured in the 6000ths after application of the force F = Fv+ Fkon the elastomeric com
8、ponent. 1.3.7 Force-deflection s6(s60, s600, s6000, ). Commencing from the height hvthe force-deflection s6(s60, s600, s6000, ) shall be the change in this dimension which occurs after the 6ths (60th, 600th, 6000th, s) following the application of the force F = Fv+ Fk, in the direction of this force
9、. 1.3.8 Creeps6000. The creeps6000shall be the change in dimension of the elastomeric component which occurs between the 6thand 6000ths following application of the force F = Fv+ Fk, measured in the direction of that force. 1.3.9 Subscripts.To identify the force or dimen- sion being applied or deter
10、mined and their directions, alphabetical and numerical subscripts shall be used. 1.3.9.1 Alphabetical subscripts shall normally indi- cate the type of force or dimension, e.g. H0A dimension of the unstressed elastomeric component FvInitial force applied FkMajor force applied In specific instances nu
11、merical subscripts are used to define certain values, e.g. s6(s60, s600, s6000, ) which indicates the deflection of the elastomeric component after the 6ths (60th, 600th, 6000th, s). 1.3.9.2 Numerical subscripts are generally used to identify the direction, in which a force is applied, and shall be
12、generally designated i. i may take the form 1, 2, 3n. They shall be placed behind any other subscript used e.g. Fkl. Where two numerical sub- scripts occur, they shall be separated by a comma, e.g. s6000,1. If there is only one direction, in which Copyright 2007 General Motors Corporation All Rights
13、 Reserved Publication Department: GME Specification Center December 2007Page 1 of 5 PRD045 - VPRE ST 1 10/03 GMW14734GM WORLDWIDE ENGINEERING STANDARDS a force is applied, the numerical subscript l can be excluded, e.g. s6000. 2 References Note: Only the latest approved standards are appli- cable un
14、less otherwise specified. 2.1 External Standards/Specifications. DIN 862 DIN 876 DIN 878 2.2 GM Group Standards/Specifications. None. 2.3 Additional References. None. 3 Test Equipment 3.1 The test machine for applying a constant force to elastomeric components (hereafter referred to as “test machine
15、”), shall consist of a device which will allow a force to be gradually applied to the component up to a value of, at a velocity v = (1.25 0.10) x 10-3m/s, and shall also be capable of maintaining a constant force.The time of application of the full load shall be indicated. The force range of the tes
16、t machine shall normally be from (5010000) N, and the accuracy of force indication shall be at least 0.2 N up to 500 N force, and 10 N above this. Test machines, which apply the force by means of suitable masses, with the use of lever systems if required, shall be preferred. 3.1.1 Note. Testing mach
17、ines which meet these con- ditions were built e.g. in Product Engineering, Mate- rial Development, Physical Section, according to the following design drawings: Testing machine, power range (502000) N, see drawing no. 500001, of Product Engineering, Mate- rial Development, Physical Section. Testing
18、machine, power range (5010000) N, see drawingno. 500008, of Product Engineering, Material Development, Physical Section. 3.2 Dimensional Measuring Equipment. 3.2.1 Dimensional change measuring equipment, e.g.linear dial gauge to DIN 878, with a range of (010) mm, an accuracy of 0.01 mm and exerting
19、a substantially constant force of s6000,i(e.g. s60000,i, s600000,i) shall be noted. The creep will normally be found to be a linear function of log time, and this may be plotted as a check. The change of the ambient temperature during the test period shall be measured and recorded. 5.3.2.7 Shortened
20、 Test.If, at 600 s it is found, that the creep is a linear function of log time, when checked from the values obtained at s6, s60and s600, a shortened test may be performed as specified in paragraph . 6 Evaluation and Rating If the shortened test method described in paragraph 5.3.2.7 isperformed, th
21、e values of s6000,iandinstalled height Hishallbe obtained byextrapolation as follows: 6.1 Creeps6000,i 6.2 Force-deflection s6000,i 6.3 Installed height Hi 7 Report In addition to reference being made to this test method, the test report shall also include the follow- ing data: Part name, part no.,
22、test specification no., additional identifications, manufacturer, grade of elastomer, date of manufacture, date of test, test sample no. Copyright 2007 General Motors Corporation All Rights Reserved December 2007Page 3 of 5 PRD045 - VPRE ST U 10/03 GMW14734GM WORLDWIDE ENGINEERING STANDARDS The valu
23、es of the following: Initial force Fvi(N) Force Fki(N) The individual values, the means of the individual val- ues, and the range of the extreme values from the mean of the following, rounded to one decimal place: Heighth0i(mm) Heighthvi(mm)(if required) Installed heightHi(mm) and alsothe following,
24、 roundedto two decimalplaces: Force-deflection s6,i(mm) Creeps6000,i(mm) Any specific observations on the test sample e.g.: folds, cracks, other surface defects. 8 Safety This standard may involve hazardous materials, oper- ations and equipment. This standard does not pro- pose to adress all the saf
25、ety problems associatedwith its use. It is the responsibility of the user of this stan- dard to establish appropriate safety and health prac- tices and determine the applicability of regulatory lim- itations prior to use. 9 Coding System This standard shall be referencedin other documents, drawings,
26、 etc. as follows: Example: “GMW14734” 10 Release and Revisions 10.1 Release. Thisstandard originated inOCT2005, replacing GME 60230. It was first approved by Global Elastomer Components & Engine Mounts Team in DEC 2006 and published in DEC 2007. Copyright 2007 General Motors Corporation All Rights R
27、eserved Page 4 of 5December 2007 PRD045 - VPRE ST G 10/03 -,-,- GM WORLDWIDE ENGINEERING STANDARDSGMW14734 Appendix A Figure 1: Sequence of the Force-Deflection Test Schematic sketch (only in principle, not to scale) Curve A: Force-Time Diagram (Fi= f (t) Curve B: Displacement-Time Diagram (si= f (t) Curve C: Velocity-Time Diagram (v = f (t) (also refer to paragraph 5.3.2 of this test method) Copyright 2007 General Motors Corporation All Rights Reserved December 2007Page 5 of 5 PRD045 - VPRE ST U 10/03 -,-,-
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