《GMW-14736-2007.pdf》由会员分享，可在线阅读，更多相关《GMW-14736-2007.pdf（4页珍藏版）》请在三一文库上搜索。
1、Test Method Materials GMW14736 Determination of the Torsional Force-Deflection Characteristics of Elastomeric Components under uni-axial Stress 1 Scope Note: Nothing inthisstandard supersedes applicable laws and regulations. Note: In the event of a conflict between the Eng- lish and the domestic lan
2、guage, the English language shall take precedence. 1.1 Theobjectofthis test method isthe determination of the torsional characteristics shown by elastomeric components used in vehicles under a constant angu- lar rate of strain at a temperature of (+23 5) C. 1.2 Objectives. 1.2.1 The determination of
3、 the torsional force-deflec- tion characteristics of elastomeric components. This test method supplies data on the viscoelastic properties of the elastomer, and also on the cohesive strength of interference fits between rubber and metal of the elastomeric components. The determination of the torsion
4、al force acting on the elastomeric component when strained to the vehicle installation conditions. 1.3 Definitions. 1.3.1 Uni-axial Stress. Uni-axial stress defines the case, inwhich the onlyforce acting on the elastomeric component is the torque M acting about the axis of rotation of the elastomeri
5、c component. 1.3.2 Torque M. The torque M is the moment acting on the elastomeric component to produce a stress. Its magnitude, direction and axis are defined by the vehicle installation conditions. 1.3.3 Torque max M. The torque max M is the maxi- mum torque M,with which the elastomeric component i
6、s stressed in addition to the initial torque Mv. 1.3.4 Torque Mv. The torque Mvis the initial torque, which is applied to the elastomeric component in order to establish a datum point for measure- ments. Its direction is the same as that of torque M, and its magnitude normally not more than 1 % of t
7、orque max M. 1.3.5 Angle .The angle is the angle, through which the clamping devices on the elastomeric com- ponent rotate relative to each other under the effect of torque M, in the direction of application of torque M. 1.3.6 Angle v. The angle vis the angle, through which the clamping devices on t
8、he elastomeric com- ponent rotate relative to each other under the effect of torque Mv, in the direction of application of torque Mv. 1.3.7 Angular Velocity . The angular velocity is the constant angular velocity, at which the clamping devices onthe elastomeric component are rotated rel- ative to ea
9、ch other by the torque M. 1.3.8 Torsional Force-deflection Curve M = f (). The torsional force-deflection curve M = f () is the mapping of the relationship between torque M and the angle when the applied torque moves from M = Mv to M = Mv+ max M at an angular velocity . 1.3.9 Stress Cycle.One stress
10、 cycle is the sequence whereby the elastomeric component is stressed by a torque steadily increasing from M = Mv to M = Mv+ max M, and then steadily reducing back to M = Mv. 1.3.10 Initial Curve. The initial curve is the torsional force-deflection curve obtained during the first stress cycle, in whi
11、ch the elastomeric component is stressed from M = Mvto M = Mv+ max M. 1.3.11 Angle f. The angle fis the angular change between the clamping devices on the elastomeric component relative to one another, which is mea- sured from the commencement of the first stress cycle until the end of the third str
12、ess cycle. The stress cycles have to be performed continuously. The angle fmay be due to creep properties of the elastomer, or slipping between interference fits on the component. 1.3.12 Subscripts. Alphabetical and numerical sub- scripts shall be used to identify measurement values and stress direc
13、tions. 1.3.12.1 Alphabetical subscripts indicate the type of measurement value e.g. Mv- Initial torque. Copyright 2007 General Motors Corporation All Rights Reserved Publication Department: GME Specification Center December 2007Page 1 of 4 PRD045 - VPRE ST 1 10/03 GMW14736GM WORLDWIDE ENGINEERING ST
14、ANDARDS 1.3.12.2 Numerical subscripts identify the direction of application of a stress, generally denoted by i. i shall take a value 1, 2, 3,n. The numerical subscript shall follow any alphabetic subscript, which may be used e.g. Mv1, 1. If there is only one direction in which a torque is applied,
15、the numerical subscript 1 may be excluded, e.g. Mv. 2 References Note: Only the latest approved standards are appli- cable unless otherwise specified. 2.1 External Standards/Specifications. DIN 51220 2.2 GM Group Standards/Specifications. None. 2.3 Additional References. None. 3 Test Equipment 3.1 A
16、 torsion testing machine, capable of stressing elastomeric components up to a maximum torque M = 350 Nm max. at a constant angular velocity (maximum deviation 10 %). The machine shall comply with DIN 51220, and also comply with the following requirements: Total accuracy of the torque measuring equip
17、- ment: 2 % of the measured value Torsional displacement measuring equipment: 1.75 m rad Note: A torsion testing machine, which meets these conditions were built e.g.in Product Engineering, Material Development, Physical Section, according to the following design drawings: Testing machine for dampen
18、ing bushings, drawing no. 600007, of Product Engineering, Material Devel- opment, Physical Section. 3.2 Suitable clamping devices for fixing the test sam- ple to the torsion testing machine. 3.3 Work bench with machine vice. 3.4 Suitable press for forces 7 kN for press-fitting bushings into metal pa
19、rts. 3.5 Inspection of Test Equipment. The test equip- ment shall be calibrated at intervals not exceeding one year and certification retained. 4 Test Material 4.1 Test Sample Form. The test samples shall be elastomeric components, which are as assembled into the vehicle. 4.2 Test Sample Quantity. A
20、t least 3 test samples shall be tested. 5 Test Method Deviations from the requirements of this standard (e.g. number of test pieces, testing time, etc.) shall have been agreed upon. These requirements shall be specified on component drawings, and shall be indicated on test certificates, test reports
21、 etc. 5.1 Summary of Test Method. Not applicable. 5.2 Test Sample Preparation.For initial sample approval and arbitration purposes, the time period between vulcanization and testing shall be seven days minimum. For quality control purposes the period shall be 72 h minimum. The test samples shall rem
22、ain at a temperature of (+23 5) C for at least 8 h before testing, and shall be free from strain during this period. 5.3 Test Procedure. 5.3.1 General.The test samples shall be tested according to the data given on the test specifications and the relevant engineering drawing of the elas- tomeric com
23、ponent regarding method of assembly, direction of stressing, degrees of clearance, etc., in addition to compliance with this test method. A time of at least 24 h shall elapse before successive tests on the same sample are performed. 5.3.2 Test Method. Mount the test sample onto the torsion testing m
24、achine. Apply a torque until Mi= Mvi, stop torsion testing machine and adjust torque mea- suring equipment so that Mi= 0, adjust torsional dis- placement measuring equipment so that i= 0. Then proceed as follows in compliance with diagram as shown in Appendix A: Stress test sample additionally with
25、Mi= max Mi at an angular velocity iand subsequently reduce this torque at the same angular speed by the value max Mi. Repeat this stress cycle three times. 6 Evaluation and Rating 6.1 Record the initial curve Mi= f (i) in the diagram of torque. Copyright 2007 General Motors Corporation All Rights Re
26、served Page 2 of 4December 2007 PRD045 - VPRE ST G 10/03 GM WORLDWIDE ENGINEERING STANDARDSGMW14736 6.2 Record the fourth curve Mi= f (i) in the same diagram over the range of values Mi= Mvito Mi= Mvi+ max Miand also determine fi. Note: For tolerance checking, the curve Mi= f (i) and the angle idete
27、rmined in paragraph 6.2 shall be used. The zero point of the tolerance band for the curve Mi= f (i) isvariablealong the abscissaof the diagram up to the angle max fi. 7 Report In addition to reference being made to this test method, the test report shall also include the follow- ing data: Part name,
28、 part no. or drawing no., test specifica- tion no., additional identifications, grade of elastomer, manufacturer, date of manufacture, date of test, test sample no. The values of the following: Torque Mvi(Nm) Torque max Mi(Nm) Angular velocity i(rad/s) Initial curve Mi= f (i) according to paragraph
29、6.1 Fourth curve Mi= f (i) according to paragraph 6.2 Angle firounded to one decimal place (rad) Any specific observations on the test sample, e.g. creases, cracks, other changes on the surface. 8 Safety Thisstandard may involvehazardous materials, oper- ations and equipment. This standard does not
30、pro- pose to adress all the safety problems associated with 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 Thisstandard shall bereference
31、d inother documents, drawings, etc. as follows: The requirements for the torsional force-deflection characteristics of elastomeric components shall be specified on drawings, test specifications, material specifications, reports, etc. as follows e.g. Example: Torsional Test to GMW14736Mv= 0.2 Nm max
32、Mv= 20 Nm initial curve M = f () etc. Torsional Test =Designation GMW14736 =Test Method Mv= 0.2 Nm; max Mv= 20 Nm; initial.= Test condition and requirements 10 Release and Revisions 10.1 Release. Thisstandard originatedinOCT 2005, replacing GME 60235. It was first approved by Global Elastomer Compon
33、ents & Engine Mounts Team in DEC 2006 and published in DEC 2007. Copyright 2007 General Motors Corporation All Rights Reserved December 2007Page 3 of 4 PRD045 - VPRE ST U 10/03 GMW14736GM WORLDWIDE ENGINEERING STANDARDS Appendix A Figure 1: Upper Curve: Typical diagram (not to scale) obtained during
34、 the test procedure for the deter- mination of Mi(i) (see also paragraph and paragraph of this test method) Lower Curve: Example of method of specifying the torsional force deflection characteristics and tol- erance on drawings (see also paragraph of this test method) ATolerance range for Mi(i) Copyright 2007 General Motors Corporation All Rights Reserved Page 4 of 4December 2007 PRD045 - VPRE ST G 10/03 -,-,-