1、GM DAEWOO Auto & Technology EDS Engineering, GM DAEWOO Auto & Technology Standards FORCE-DEFLECTION CHARACTERISTICS OF ELASTOMERIC COMPONENTS UNDER BI-AXIAL STRESS Do Not Use on New Programs. Being Replaced by GMW14683 EDS-T-7412 ISSUED DATE: 1991. 12. 16 REVISED DATE: 2008. 10. 15 VERSION: 5 (Super
2、ceded) FORCE-DEFLECTION CHARACTERISTICS OF ELASTOMERIC COMPONENTS UNDER BI-AXIAL STRESS EDS-T-7412PAGE: 1/6 ISSUED DATE: 1991. 12. 16 REVISED DATE: 2008. 10. 15 VERSION: 5 GM DAEWOO Auto & Technology Note: This standard may be applied only for current project (incl. CKD Program). It is Superceded fo
3、r all future projects and replaced by GMW14683. 1. PURPOSE This standard is test method that determines the deformation characteristics under a bi-axial stress of elastomeric components used in vehicles in the temperature range -30 to +150 under a constant velocity. 2. SCOPE 2.1. The determination o
4、f the force-deflection curve of elastomeric components. This test will also give some indication of the creep properties of the elastomer. 2.2. The determination of the force required to act on the elastomeric component in order to strain it to the vehicle installation conditions. 3. DEFINITION 3.1.
5、 Bi-axial stress The biaxial load refers to a continuous loading to a rubber part using two axes. 3.2. Force F The force F shall be the force applied to the elastomeric component. Its magnitude and direction shall correspond with the installation conditions of the component. 3.3. Initial force FvThe
6、 initial force Fvshall be the force applied to the elastomeric component point in order to establish the test results. Its magnitude shall be in normally 1 to 2% of force max F, and it shall act in the same direction as force max F. 3.4. Force max F The force max F is the maximum force F with which
7、the elastomeric component is stressed in addition to the initial force Fv. 3.5. Height hoThe height hoshall be the height of the component measured in the direction of the force F, determined on the unstressed elastomeric component prior to the application of any force. 3.6. Force-application point
8、The force-application point is the position on the moving head of the universal testing machine to which the elastomeric component or test fixture is attached. The force-application point is located along the direction of application of the force F. FORCE-DEFLECTION CHARACTERISTICS OF ELASTOMERIC CO
9、MPONENTS UNDER BI-AXIAL STRESS EDS-T-7412PAGE: 2/6 ISSUED DATE: 1991. 12. 16 REVISED DATE: 2008. 10. 15 VERSION: 5 GM DAEWOO Auto & Technology 3.7. Velocity v The velocity v is the constant velocity with which the force-application point moves in the direction of application of the force F. 3.8. Def
10、lection s The deflection s is the distance through which the force-application point moves under the force F during deformation of the elastomeric component. It is measured in the direction of application of the force F. 3.9. Deflection svThe deflection svis the distance through which the force-appl
11、ication point moves when the initial force Fvis applied to the elastomeric component. It is measured in the direction of application of the initial force Fv. 3.10. Force-deflection curve F=f(s) The force-deflection curve F=f(s) is the mapping of the relationship between the applied force F and the d
12、eflection s when the applied force is increased from F = Fvto F = Fv+ max F. 3.11. Spring rate c The spring rate c is the slope of the tangent at a point P(e.g. specified on drawings) on the force-deflection curve. The spring rate c is determined by the relationship sFC=, and the point P by one of t
13、he two values F or s, with reference to the force-deflection curve. 3.12. Stress cycle A stress cycle shall consists of a constant increase of the load acting on the rubber part from F = FV to F = FV+ max F and subsequent constant decrease to F = FV. 3.13. Initial curve The initial curve is the Forc
14、e-deflection curve obtained during the first stress cycle of stress cycle. 3.14. Displacement sfThe displacement sfis the distance by which the force-application point is moved, and measured from the commencement of the first stress cycle to the end of the third stress cycle. The stress cycles shall
15、 be consecutive. The displacement sfmay be influenced by the creep properties of the elastomer. 3.15. Suffixes To identify the forces or dimension being applied or determined, and their directions, alphabetical and numerical suffixes shall be used. 3.15.1. Alphabetical subscripts shall be used to id
16、entify the type of force or dimension. e.g. ho- a dimension of the unstressed elastomeric component. Fv- the force initially applied. 3.15.2. Numerical subscripts shall be used to identify the direction in which a force is applied, and generally FORCE-DEFLECTION CHARACTERISTICS OF ELASTOMERIC COMPON
17、ENTS UNDER BI-AXIAL STRESS EDS-T-7412PAGE: 3/6 ISSUED DATE: 1991. 12. 16 REVISED DATE: 2008. 10. 15 VERSION: 5 GM DAEWOO Auto & Technology designated by i and j. i and j may take the form 1, 2, 3 -n. The numerical subscripts shall follow the alphabetical subscript e.g. ho1, FCv3, FA1. 4. TEST SAMPLE
18、S 4.1. Test sample form The test sample shall be a piece of elastomeric components assembled into the vehicle. 4.2. Test sample quantity At least three test samples shall be tested. 4.3. Test sample conditioning For initial sample approval and arbitration purposes, the minimum time period between vu
19、lcanization and testing shall be 7 days. For quality control purposes, the period shall be 3 days. The test sample shall remain at temperature of +235K for at least 8 hours before testing, and shall be free from strain during this period. 5. APPARATUS 5.1. Universal testing machine The universal tes
20、ting machine (hereafter referred to as “the testing machine“) shall be capable of stressing elastomeric components to a maximum force of 50kN at a constant velocity(max deviation 10%). The testing machine shall comply with DIN 51220, 51221 sheet 1 to 3, DIN 51223, 51227, or BS 1610, and also meet th
21、e following requirements: accuracy The force measuring equipment : 1.5% of the measured value. Displacement measuring equipment : 0.05mm 5.2. A test device for applying an additional constant force Fj to the elastomeric component (hereafter referred to as the “test device“). A test device shall be e
22、nable a stress to be gradually applied to the elastomeric component, up to a force Fj = Fvj + max Fj at a constant velocity of (1.25 0.1) 10-3 m/s, and subsequently maintains this force at a constant value. The moment at which the force reaches its maximum value shall be indicated by the test device
23、. The test device shall span a range of force from 50N to 4000N with a precision within 10N. Test devices which apply the force by means of suitable masses, such as lever systems, are preferred. 5.3. Suitable fixtures for locating and attaching the test samples to the testing machine and to the test
24、 device. 5.4. Dimensional measuring equipment: The displacement transducer shall be a linear dial gauge having an accuracy of 0.01mm in a 10mm measuring section and capable of a constant loading of 2N or less throughout the measuring range. FORCE-DEFLECTION CHARACTERISTICS OF ELASTOMERIC COMPONENTS
25、UNDER BI-AXIAL STRESS EDS-T-7412PAGE: 4/6 ISSUED DATE: 1991. 12. 16 REVISED DATE: 2008. 10. 15 VERSION: 5 GM DAEWOO Auto & Technology 5.5. Surface plate of cast iron, approximately 400 mm2. 6. PROCEDURE 6.1. General 6.1.1. The test sample shall be tested according to the data shown on the test speci
26、fications and the relevant component drawings for the elastomeric component regarding method of assembly, direction of stressing, etc., in addition to this test method. The test shall normally carried out at +235. A period of at least 24 hours shall elapse between successive tests on the same test s
27、ample. 6.1.2. If the force, on the force indicating device on the testing machine, is indicated owing to influenced by the weight of the test sample and/or its fixtures, compensation shall be made prior to the commencement of the test. The dimensional change measuring equipment shall be attached to
28、the testing machine such that the dimensional change of the test sample may be determined in the direction of application of the force Fj. 6.2. Test Procedure 6.2.1. Measure the height according to EDS-T-7134(force change and permanent change test method), if required. 6.2.2. The test sample shall b
29、e stressed by Fj= Fvjat a velocity of (1.25 0.1) 10-3m/s, the dimensional change measuring equipment zeroed(sj=0). Reduce the stress with an equal speed to Fj=0. This cycle is repeated until the deflection change under stress(Fj=Fvj) is less than 0.01 mm(Normally three cycles will be sufficient). Th
30、e zero point of the dimensional change measuring equipment is then fixed. 6.2.3. Increase the force at a velocity of (1.250.1)10-3m/s to be Fj= Fvj+ max Fj. This time is t = to, and shall be indicated by the test device. The measuring period shall commence at this time. The force Fjshall be maintain
31、ed at a constant value during the test. 6.2.4. If required, stress test sample during (60010) seconds from time to, with Fi= Fvi and measure svi.Reset the force and the displacement respectively to Fi=0, si=0, and test as indicated with diagram in clause 12. 6.2.5. Gradually increase the force by Fi
32、= max Fi, at a velocity vi, subsequently release it at the same speed. In addition, at specified values of Fithe relevant values of sjshall be determined. 6.2.6. Repeat this stress cycle 3 times as detailed in sub-clause 6.2.5. 7. EVALUATION 7.1. Record the initial curve Fi= f(si, Fvj+ max Fj) of th
33、e force-deflection curve. 7.2. Record the fourth curve Fi= f(si, Fvj+ max Fj) of the force-deflection curve in the range from Fi= Fvito Fi= Fvi+ max Fi, and also record displacement sfi. 7.3. Determine the spring rate ciat the point P of the force-deflection curve recorded in clause 7.2. FORCE-DEFLE
34、CTION CHARACTERISTICS OF ELASTOMERIC COMPONENTS UNDER BI-AXIAL STRESS EDS-T-7412PAGE: 5/6 ISSUED DATE: 1991. 12. 16 REVISED DATE: 2008. 10. 15 VERSION: 5 GM DAEWOO Auto & Technology 7.4. For checking that the test sample is within the tolerance allowed, the force-deflection Fji= f(sji) and the displ
35、acement sjias determined in clause 7.2, the spring rate cjias determined in clause 7.3 and the height hjoishall normally be used. The initial point of the tolerance band for the force-deflection curve may be moved along the force-axis of the mapping up to a maximum displacement point. 8. TEST REPORT
36、 This test method is made with a reference appended, and the test report shall also include the following data. Record the following values in addition to part name, part number drawing number, test spec. number, grade of elastomer, manufacturer, date of manufacture, test sample number, date of test
37、. Initial force - Fjvi (N) Force - max Fji (N) Velocity - vi (m/s) Point P Fourth curve - Fji = f(si, Fvj + max Fj) Record relevant values of sjto initial and fourth stress cycles, if required. And, the individual values of the following, rounded to one decimal place. Height - hjoi (mm) Height - hjv
38、i (mm) Displacement - sjfi (mm) Spring rate - cji (N/mm) Record any specific observations on the test sample, e.g. folds, cracks, splits, other visible defects. 9. CODING SYSTEM The requirements for the force-deflection characteristics of elastomeric component shall be specified on component drawing
39、s, test and material specifications, reports, etc. Force-Deflection Curve to EDS-T-7412 Fv1= N, Fv2= N, max F1= N, max F2 = N, v1= m/s Initial curve F1= f(s1. Fv2+max F2) Designation Test method Test conditions and requirements 10. DEVIATIONS Deviations from the requirements of this test method (e.g
40、. test sample preparation, technical details of the testing machine, etc) shall have been agreed upon. These requirements shall be specified on component drawings, shall be defined in test reports etc. 11. REFERENCE GME 60233 Force-deflection characteristics of elastomeric components under bi-axial
41、stress FORCE-DEFLECTION CHARACTERISTICS OF ELASTOMERIC COMPONENTS UNDER BI-AXIAL STRESS EDS-T-7412PAGE: 6/6 ISSUED DATE: 1991. 12. 16 REVISED DATE: 2008. 10. 15 VERSION: 5 GM DAEWOO Auto & Technology EDS-T-7134 Determination of the force-deflection characteristics and permanent set of elastomeric components 12. TYPICAL FORCE-DEFLECTION CURVE OBTAINED DURING TEST PROCEDURE FOR DETERMINATION OF Fji = f(sji)(refer also to clauses 6 and 7 of this test method). 13. TOLERANCES RANGE OF FORCE-DEFLECTION CHARACTERISTICS ON DRAWING
