1、 WORLDWIDE ENGINEERING STANDARDS Test Procedure GMW14736 The Determination of the Torsional Force-Deflection Characteristics of Elastomeric Components under Uni-axial Stress Copyright 2013 General Motors Company All Rights Reserved February 2013 Page 1 of 5 1 Scope Note: Nothing in this standard sup
2、ercedes 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 torsional characteristics shown by elastomeric components used in
3、vehicles under a constant angular rate of strain at a temperature of +23 C 5 C. 1.1.1 Objectives. The determination of the torsional force-deflection characteristics of elastomeric components. This test procedure supplies data on the viscoelastic properties of the elastomer, and also on the cohesive
4、 strength of interference fits between rubber and metal of the elastomeric components. 1.1.1.2 The determination of the torsional force acting on the elastomeric component when strained to the vehicle installation conditions. 1.2 Foreword. Not applicable. 1.3 Applicability. Not applicable. 2 Referen
5、ces Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Specifications. DIN 51220 2.2 GM Standards/Specifications. None 3 Resources 3.1 Facilities. Not applicable. 3.1.1 Calibration. The test facilities and equipment shall be in good working ord
6、er and shall have a valid calibration label. 3.1.2 Alternatives. Alternative test facilities and equipment may also be used. However, all measuring variables as specified in this standard shall be determined correctly with respect to their physical definition. 3.2 Equipment. A torsion testing machin
7、e, capable of stressing elastomeric components up to a maximum torque M = 350 Nm maximum 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 equipment: 2% of the measu
8、red value Torsional displacement measuring equipment: 1.75 mrad (milliradians) 3.2.1. Suitable clamping devices for fixing the test sample to the torsion testing machine. 3.2.2 Work bench with machine vice. 3.2.3 Suitable press for forces up to 7 kN for press-fitting bushings into metal parts. 3.2.4
9、 Inspection of Test Equipment. The test equipment shall be calibrated at intervals not exceeding one (1) year and certification retained. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license fr
10、om IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14736 Copyright 2013 General Motors Company All Rights Reserved February 2013 Page 2 of 5 3.3 Test Vehicle/Test Piece. 3.3.1 Test Material. 3.3.1.1 Test Sample Form. The test samples shall be elastomeric components, which are as assembled into the veh
11、icle. 3.3.1.2 Test Sample Quantity. Three (3) test samples minimum shall be tested. 3.4 Test Time. Not applicable. 3.5 Test Required Information. Not applicable. 3.6 Personnel/Skills. Not applicable. 4 Procedure 4.1 Preparation. 4.1.1 Test Sample Preparation. For initial sample approval and arbitrat
12、ion purposes, the time period between vulcanization and testing shall be seven (7) days minimum. For quality control purposes the period shall be 72 h minimum. 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
13、. 4.2 Conditions. 4.2.1 Environmental 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 Test Procedure. 4.3.1.1 General
14、. The test samples shall be tested according to the data given on the test specifications and the relevant engineering drawing of the elastomeric component regarding method of assembly, direction of stressing, degrees of clearance, etc., in addition to compliance with this test procedure. A time of
15、24 h minimum should elapse before successive tests on the same sample are performed. 4.3.1.2 Test Method. Mount the test sample onto the torsion testing machine. Apply a torque until Mi = Mvi, stop torsion testing machine and adjust torque measuring equipment so that Mi = 0, adjust torsional displac
16、ement measuring equipment so that i = 0. Then proceed as follows in compliance with diagram as shown in Appendix A. Stress test sample additionally with Mi = max Mi at an angular velocity i and subsequently reduce this torque at the same angular speed by the value max Mi. Repeat this stress cycle th
17、ree (3) times. 5 Data 5.1 Calculations. Not applicable. 5.2 Interpretation of Results. Not applicable. 5.3 Test Documentation. 5.3.1 Evaluation and Rating. 5.3.1.1 Record the initial curve Mi = f (i) in the diagram of torque. 5.3.1.2 Record the fourth curve Mi = f (i) in the same diagram over the ra
18、nge of values Mi = Mvi to Mi = Mvi + max Mi and also determine fi. Note: For tolerance checking, the curve Mi = f (i) and the angle i determined in 5.3.1.2 shall be used. The zero point of the tolerance band for the curve Mi = f (i) is variable along the abscissa of the diagram up to the angle maxim
19、um fi. 5.3.2 Report. In addition to reference being made to this test procedure, the test report shall also include the following data: Part name. Part number or drawing number. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or
20、 networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14736 Copyright 2013 General Motors Company All Rights Reserved February 2013 Page 3 of 5 Test specification number. Additional identifications. Grade of elastomer. Manufacturer, date of manufacture. Date of tes
21、t, test sample number. The values of the following: Torque Mvi (Nm). Torque maximum Mi (Nm). Angular velocity i radians(rad/s) Initial curve Mi = f (i) according to 5.3.1.1. Fourth curve Mi = f (i) according to 5.3.1.2. Angle fi rounded to one decimal place radian (rad). Any specific observations on
22、 the test sample, e.g., creases, cracks, other changes on the surface 6 Safety This standard 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
23、 establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 7 Notes 7.1 Glossary. Angle . The angle is the angle, through which the clamping devices on the elastomeric component rotate relative to each other under the effect of torque M,
24、 in the direction of application of torque M. Angle f. The angle f is the angular change between the clamping devices on the elastomeric component relative to one another, which is measured from the commencement of the first stress cycle until the end of the third stress cycle. The stress cycles hav
25、e to be performed continuously. The angle f may be due to creep properties of the elastomer, or slipping between interference fits on the component. Angle v. The angle v is the angle, through which the clamping devices on the elastomeric component rotate relative to each other under the effect of to
26、rque Mv, in the direction of application of torque Mv Angular Velocity . The angular velocity is the constant angular velocity, at which the clamping devices on the elastomeric component are rotated relative to each other by the torque M. Initial Curve. The initial curve is the torsional force-defle
27、ction curve obtained during the first stress cycle, in which the elastomeric component is stressed from M = Mv to M = Mv + max M. Stress Cycle. One stress 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 stead
28、ily reducing back to M = Mv. 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. Torque max M. The torque maximum M is the maximum torque M, with which the elastomeric comp
29、onent is stressed in addition to the initial torque Mv. Torque Mv. The torque Mv is the initial torque, which is applied to the elastomeric component in order to establish a datum point for measurements. Its direction is the same as that of torque M, and its magnitude normally not more than 1% of to
30、rque max M. 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 . Uni-axial Stress. Uni-axial stress defines the c
31、ase, in which the only force acting on the elastomeric component is the torque M acting about the axis of rotation of the elastomeric component. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without lic
32、ense from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14736 Copyright 2013 General Motors Company All Rights Reserved February 2013 Page 4 of 5 Subscripts. Alphabetical and numerical subscripts shall be used to identify measurement values and stress directions. Alphabetical subscripts indicate the
33、 type of measurement value e.g., Mv - Initial torque. Numerical subscripts identify the direction of application of a stress, generally denoted by i, i may take a value 1, 2, 3 to n. The numerical subscript shall follow any alphabetic subscript, which may be used e.g., Mv1, 1. If there is only one (
34、1) direction in which a torque is applied, the numerical subscript one (1) can be excluded, e.g., Mv. 7.2 Acronyms, Abbreviations, and Symbols. max Maximum mrad milliradians rad radians 8 Coding System This standard shall be referenced in other documents, drawings, etc., as follows: Test to GMW14736
35、 The requirements for the torsional force-deflection characteristics of elastomeric components shall be specified on drawings, test specifications, material specifications, reports, etc. For example: Torsional Test to GMW14736 Mv = 0.2 Nm max Mv = 20 Nm Initial curve M = f () etc. Where: Torsional T
36、est = Designation GMW14736 = Test Procedure Mv = 0.2 Nm; max Mv = 20 Nm; initial = Test Condition and Requirements 9 Release and Revisions This standard was originated in October 2005. It was first approved by Global Elastomer Components and Engine Mounts Team in December 2006. It was first publishe
37、d in December 2007. Issue Publication Date Description (Organization) 1 DEC 2007 Initial publication. 2 FEB 2013 2012 Refresh. (Elastomers Global Subsystem Leadership Team) Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or netw
38、orking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14736 Copyright 2013 General Motors Company All Rights Reserved February 2013 Page 5 of 5 Appendix A Note 1: A in above diagram is t Note 2: Upper Curve . Refer to Section 4 and Section 5 of this procedure. Note 3: L
39、ower Curve: Example of method of specifying the torsional force deflection characteristics and tolerance on drawings. Refer to Section 5 of this procedure. Figure A1: Test Procedure Typical Diagrams Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
