1、GM DAEWOO Auto & Technology EDS Engineering, GM DAEWOO Auto & Technology Standards DETERMINATION OF DYNAMIC STIFFNESS LOSS ANGLE OF ELASTOMERS Do Not Use on New Programs. Being Replaced by GMW14473&GMW14738 EDS-T-7130 ISSUED DATE: 1990. 08. 10 REVISED DATE: 2008. 10. 15 VERSION: 5 (Superceded) EDS-T
2、-7130DETERMINATION OF DYNAMIC STIFFNESS LOSS ANGLE OF ELASTOMERS PAGE: 1/7 ISSUED DATE: 1990. 08. 10 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 It is Superceded for all future projects and replace
3、d by GMW14473 & GMW14738. 1. PURPOSE This purpose of this standard is the determination of the dynamic stiffness and loss angle of elastomeric under dynamic strain conditions. 2. SCOPE This standard determines the viscoelastic properties of elastomeric components used in vehicles when subjected to f
4、orced sinusoidal oscillations. 3. DEFINITIONS 3.1. Static force Fm To be the constant force exerted in a certain direction causing the mean stress to which the elastomeric component is subjected. The direction and size of force shall be applied to the test condition of respective part drawing (unit
5、: N, KN) 3.2. Static deflection Im To be the deflection of the elastomeric component resulting from and on the same axis as the static force Fm (unit : mm, cm). 3.3. Dynamic deflection Io To be the deflection resulting from the sinusoidal oscillation after applying static force Fm 3.4. Frequency f T
6、o be of the sinusoidal oscillation (unit : HZ) 3.5. Loss angle To be the damping capacity of the elastomeric component (unit : Deg.) 3.6. Dynamic stiffness K To be the dynamic stiffness of the elastomeric component (unit : N/mm, KN/mm) 3.7. Suffixes 3.7.1. Alphabetical suffixes of a small letter. To
7、 indicate a force and a deflection. e.g) Fm : Static force, Io : Dynamic deflection. 3.7.2. Alphabetical suffixes of a big letter. EDS-T-7130DETERMINATION OF DYNAMIC STIFFNESS LOSS ANGLE OF ELASTOMERS PAGE: 2/7 ISSUED DATE: 1990. 08. 10 REVISED DATE: 2008. 10. 15 VERSION: 5 GM DAEWOO Auto & Technolo
8、gy To indicate the test temperature. e.g) FGm : Indicates a force Fm under test temperatures given by test type G (See clause 5.3). 3.7.3. Numerical subscripts To indicate the direction of a force and a deflection and follow the alphabetical suffixes. If there is only one direction of force applicat
9、ion, numerical subscripts can be excluded. e.g) Fm2: static force Fm in 2 directions on the drawings. Io2: dynamic deflection Fm moving in 2 directions on the drawings. 4. CONDITIONS AND NUMBER OF TEST PIECES 4.1. The test pieces shall be complete elastomeric components, as assembled into the vehicl
10、e and at least three test pieces shall be tested. 4.2. For initial sample approval and arbitration purposes, the minimum time period between vulcanization and testing shall be 7 days and for routine quality control the period, shall be 3 days. 4.3. The test pieces shall be remain at a temperature of
11、 235 for at least 8 hours before testing, and shall be free from strain during this period. 5. APPRATUS 5.1. Tester The tester shall be capable of applying the static load and sinusoidal dynamic displacement to the rubber parts and easily adjusting dynamic displacement, static load, test frequency a
12、nd test temperature applied to the rubber parts. 5.1.1. Load measuring and control device The load measuring and control device shall be composed of the load cell attached to the test equipment, amplifier and voltmeter to be able to measure the static load Fm and oscillation load Fa applied to the r
13、ubber parts. The measuring device shall be capable of measuring the load of at least 10KN. 5.1.2. Displacement measuring and control device The displacement measuring and control device to which the vibrator is connected shall be capable of measuring frequency between 1Hz and 300 Hz and adjustable d
14、own to the unit of 1Hz. The frequency applied to the test sample shall be kept constant and not deviate from the test frequency by more than 5%. 5.2. Test chamber The chamber shall have a sufficient space to accommodate not only the rubber parts but also the test jig during test. Also, the chamber s
15、hall be an air circulation type and meet the following conditions: Test temperature range : -30 +150 EDS-T-7130DETERMINATION OF DYNAMIC STIFFNESS LOSS ANGLE OF ELASTOMERS PAGE: 3/7 ISSUED DATE: 1990. 08. 10 REVISED DATE: 2008. 10. 15 VERSION: 5 GM DAEWOO Auto & Technology Temperature change : 2K Tem
16、perature change rate : 1.5 K/min Min (empty state) 5.3. Test jig The test jig shall be so designed as to securely fasten the test sample and permit no play. It shall also has the specific oscillation frequency that is not smaller than the test frequency. Especially the jig connected to the load cell
17、 shall be designed as light as possible to minimize the test error 6. PROCEDURE 6.1. Cautions 6.1.1. The test piece shall be tested according to the data defined on the drawings. If the test piece is required to be pressed into a fixture, suitable lubricant shall be used and sufficient time allowed
18、for the lubricant to have dried before any tests. 6.1.2. If various test temperature are to be used then the testing at the lower temperature shall commence first. 6.1.3. If various dynamic deflections or frequencies are to be used then to minimize the heating up effects the smaller deflection or lo
19、wer frequency tests shall be conducted first. 6.1.4. If various frequencies are to be used then the testing at the lower frequency shall commence first. 6.2. Procedure 6.2.1. Attach the load cell at the test machine and set the force displacement indicator to 0 (Force : 0, Deflection : 0) 6.2.2. 2.
20、Mount the test sample to the jig. The test sample, once mounted to the jig, shall not be subject to any type of load. 6.2.3. Input the requirements on the drawing (load, displacement, frequency, etc.) into the computer. 6.2.4. Proceed with the test by pressing the start key. The test shall proceed i
21、n the following sequence: (1) After applying a static load to the test piece within 2 seconds, keep this state for 6 seconds. (2) Apply a certain displacement and sinusoidal oscillation with a regular frequency to the test piece. During this test duration, the static load shall be kept constant. 6.2
22、.5. Calculate the loss angle and dynamic stiffness with a computer at a point where the load change according to the dynamic displacement is kept constant (approximately after 5 10 seconds) and arrange the test result. EDS-T-7130DETERMINATION OF DYNAMIC STIFFNESS LOSS ANGLE OF ELASTOMERS PAGE: 4/7 I
23、SSUED DATE: 1990. 08. 10 REVISED DATE: 2008. 10. 15 VERSION: 5 GM DAEWOO Auto & Technology 6.3. Coding for test condition The test condition shall be indicated on the relevant drawing according to Table 1. Table 1. Coding for test condition Conditioning Code Letter Conditioning (H) Test Temperature
24、(2) NONE A B C D E F G H I K L M N O P Q MIN 8 168 72 3 168 72 3 168 72 3 3 3 3 3 3 3 3 23 -30 -30 -30 -20 -20 -20 -10 -10 -10 23 50 70 80 100 125 150 7. EVALUATION 7.1. Theory and evaluation method 7.1.1. In case of complete elasticity In case of complete elasticity, the dynamic displacement applie
25、d to the test piece and the resulting load change take place at the same time to result in a curve with the same frequency and phase difference. 7.1.2. In case of complete viscosity In case of complete viscosity, the load change different from that for the elastic body results in a curve that has a
26、phase difference of 90with respect to the dynamic displacement applied to the test piece. 7.1.3. Dynamic characteristics of various materials Dynamic characteristics of various materials are shown in Fig 1. Materials that are generally used do not have the 0 - 2 0 - 2 0 - 2 0 - 2 0 - 2 0 - 2 + 1 0 +
27、 1 0 + 1 0 + 1 0 + 1 0 + 1 0 + 1 0 + 1 0 + 1 0 + 1 0 EDS-T-7130DETERMINATION OF DYNAMIC STIFFNESS LOSS ANGLE OF ELASTOMERS PAGE: 5/7 ISSUED DATE: 1990. 08. 10 REVISED DATE: 2008. 10. 15 VERSION: 5 GM DAEWOO Auto & Technology properties of complete elasticity or complete viscosity but have mixed char
28、acteristics of both. The modulus of elasticity of a material when subject to dynamic oscillation can be divided into two vectors: the storage modulus, k, which is a elastic portion, and the loss modulus, k”, which is a viscous portion. The loss angle can be obtained from the ratio of the magnitude o
29、f the two vectors. General metals, in which the storage modulus is significantly larger than loss modulus before reaching the yield point, exhibit characteristics of the elastic body and a low loss angle. Oil and other liquids show characteristics of the viscous materials, which have a larger loss m
30、odulus than the storage modulus and a very large loss angle. Rubber products belong to viscous-elastic body, which has characteristics of both the elastic body and viscous materials, and thus show the characteristics somewhere between the metals and oil & other liquids. Figure 1. Dynamic characteris
31、tic of various materials 7.2. Loss angle 7.2.1. When the stiffness characteristic is linear, as in the rubber parts, the test result as shown in Fig 2 is obtained. (1) The graph of dynamic displacement shown in Fig 1 is the result of measurement with a displacement transducer and shows the same sinu
32、soidal curve having the same frequency as the test frequency. Here, the maximum value of the sinusoidal curve is identical to the displacement specified in the drawing. (2) As a result of dynamic displacement with a certain amplitude, the test sample exhibits change in the load as shown in Fig 2. Th
33、e resulting sinusoidal curve has the same frequency as the test frequency with the static load (Fm) as the origin but shows some delay when compared to the dynamic displacement curve. (3) The loss angle means the degree of delay of the dynamic load change curve as compared to the dynamic displacemen
34、t change curve as shown above and is obtained by calculating the phase difference between the two. 7.2.2. If the dynamic load change curve does not show a perfect sinusoidal curve but a complicated deformed curve as shown in Fig 3, divide the obtained load curve into the fundamental wave, which has
35、the same frequency EDS-T-7130DETERMINATION OF DYNAMIC STIFFNESS LOSS ANGLE OF ELASTOMERS PAGE: 6/7 ISSUED DATE: 1990. 08. 10 REVISED DATE: 2008. 10. 15 VERSION: 5 GM DAEWOO Auto & Technology as the dynamic displacement, and other waves and then obtain the loss angle using the fundamental wave. Note
36、1)Fig 2. General dynamic displacement curve Fig 3. Deformed dynamic load change curve Note 1)The above phenomenon takes place when testing dynamic characteristics of high frequency above 100 Hz. Accordingly, special care is required in test. 7.3. DYNAMIC STIFFNESS 7.3.1. The dynamic stiffness is cal
37、culated by the following formula with characteristic values shown in Fig1: Fjai (dynamic load) Kji (dynamic stiffness) = - ljoi (dynamic displacement) 7.3.2. If the load change curve is not sinusoidal as shown in Fig 2 but deformed, calculate the dynamic load using the separated fundamental wave and
38、 use it to calculate the stiffness. 8. CODING SYSTEM Dynamic Stiffness and Loss Angle to EDS-T-7130 Fkm2= N Iko2= mm f = Hz k = N = Deg. Designation Test Method Test conditions and Requirement EDS-T-7130DETERMINATION OF DYNAMIC STIFFNESS LOSS ANGLE OF ELASTOMERS PAGE: 7/7 ISSUED DATE: 1990. 08. 10 R
39、EVISED DATE: 2008. 10. 15 VERSION: 5 GM DAEWOO Auto & Technology 9. DEVIATION Deviations from the requirements of this standard or other additional requirements shall have been agreed upon and shall be specified on the individual component drawings, material standards, etc. and shall be noted on all test certificates, reports, etc. 10. REFERENCE DIN 53 513 Determination of the viscoelastic properties of elastomers on exposure to forced vibration at non-resonant frequencies GME 60 237 Determination of dynamic stiffness and loss angle of elastomeric components
