1、GM DAEWOO Auto & Technology EDS Engineering, GM DAEWOO Auto & Technology Standards THE TEST METHOD FOR TENSILE PROPERTY OF PLASTICS EDS-T-7511 ISSUED DATE: 1993. 09. 27 REVISED DATE: 2006. 06. 19 VERSION: 5 EDS-T-7511THE TEST METHOD FOR TENSILE PROPERTY OF PLASTICS PAGE: 1/10 ISSUED DATE: 1993. 09.
2、27 REVISED DATE: 2006. 06. 19 VERSION: 5 GM DAEWOO Auto & Technology 1. PURPOSE This standard is used to determine the tensile characteristics of plastics by applying the specified load on the plastic test piece. 2. SCOPE 2.1. This test method applies to determining tensile characteristics of plasti
3、cs by applying a load on the specified test piece under the constant conditions (conditioning, temperature/humidity, test speed). 2.2. Characteristics of plastics measured by this test method are as follows. 2.2.1. Tensile strength 2.2.2. Tensile stress at break 2.2.3. Yield stress or off-set yield
4、stress 2.2.4. Tensile stress at given elongation 2.2.5. Strain at maximum load 2.2.6. Strain at break 2.2.7. Strain at yield stress 3. DEFINITION 3.1. Strain : The length which is momentary extended during the test at the extended length ( L) on the basis of the initial length (LO) of the marking li
5、ne of the test piece. B : Strain at maximum load R : Strain at break S : Strain at yield stress SX : Strain at off set yield stress 3.2. Tensile stress : A momentary tensile strength based on the minimum sectional area of the test piece during the test. 3.2.1. Tensile strength (B): Tensile stress at
6、 maximum load 3.2.2. Stress at break (R): Tensile stress at break 3.2.3. Yield stress(or yield point) (S): In case of such material that has not tensile and yield stress when the inclination of the stress-elongation curve reaches zero point for the first time, offset yield stress can be replaced wit
7、h yield stress. EDS-T-7511THE TEST METHOD FOR TENSILE PROPERTY OF PLASTICS PAGE: 2/10 ISSUED DATE: 1993. 09. 27 REVISED DATE: 2006. 06. 19 VERSION: 5 GM DAEWOO Auto & Technology 3.2.4. Offset yield stress(SX): The tensile stress at the cross point of the stress-strain curve and the line which is dra
8、wn parallel to the initial straight line. 3.2.5. Tensile stress at given elongation(1): The tensile stress when strain reaches 1%. Fig. 1. Stress - strain curve EDS-T-7511THE TEST METHOD FOR TENSILE PROPERTY OF PLASTICS PAGE: 3/10 ISSUED DATE: 1993. 09. 27 REVISED DATE: 2006. 06. 19 VERSION: 5 GM DA
9、EWOO Auto & Technology 4. APPARATUS 4.1. Tensile test machine The one which can apply a speed and force freely and has a measuring device capable of expressing them. In this case, the test value shall meet the expressed value in the measuring device if possible. 4.2. Extension indicator (extensomete
10、r) Low-Extension Measurements : For making measurements at elongations nominally 20% or less, measuring techniques with error no greater than 1% of the measured value are acceptable. High-Extension Measurements : For making measurements at elongations greater than 20%, measuring techniques with erro
11、r no greater than 10% of the measured value are acceptable. 4.3. Clamp When tightening a test piece, the following shall be fulfilled. 4.3.1. It shall be capable of adjusting the longitudinal axle(vertical direction) of the test piece not to get load in the direction of extension. 4.3.2. Free from f
12、ailures caused by grips. 4.3.3. Care shall be taken that the test piece does not slide in the grips. 4.4. Micrometer The one which can measure the thickness of a test piece to the nearest 0.025 mm. Note : A micrometer and a width measuring device shall apply a pressure of 252.5 KPa on the test piece
13、. 5. TEST PIECES 5.1. Preparation of test pieces Preparation of test pieces varies depending on the products to be tested and is specified on the relevant standard. Test pieces shall be prepared by compression or injection molding, or machining. All surfaces and edges shall be free from damage and f
14、ailure in order that notch effects are avoided. In case that flash marks appear during preparation of test pieces, they shall be removed without damage on the surface. This machining process shall be conducted in longitudinal direction of the test sample. If aeolotropic material is to be expected, t
15、est pieces shall be prepared respectively parallel and vertical to the expectant direction. 5.2. Shape and dimensions of test pieces 5.2.1. Shape and dimensions of possible test pieces shall be shown in Table 1 and Fig. 2. Selection of test pieces is dependent on the products to be tested. As far as
16、 the shape of test pieces is not specified in the respective EDS-T-7511THE TEST METHOD FOR TENSILE PROPERTY OF PLASTICS PAGE: 4/10 ISSUED DATE: 1993. 09. 27 REVISED DATE: 2006. 06. 19 VERSION: 5 GM DAEWOO Auto & Technology material standard, it shall be agreed upon between those concerned. Table 1.
17、Test piece dimensions for thickness (mm) 7mm or less 7 to 14mm 4mm or less Dimensions Type Type Type Type Type ToleranceW 13 6 19 6 3.18 0.5 L 57 57 57 33 9.53 0.5 WO 19 19 29 19 - 6.4 WO - - - - 9.53 3.18 LO 165 183 246 115 63.5 no max G 50 50 50 - 7.62 0.25 G - - - 25 - 0.13 D 115 135 115 64 25.4
18、5 R 76 76 76 14 12.7 1 RO - - - 25 - 1 Fig. 2. Test pieces for tensile test EDS-T-7511THE TEST METHOD FOR TENSILE PROPERTY OF PLASTICS PAGE: 5/10 ISSUED DATE: 1993. 09. 27 REVISED DATE: 2006. 06. 19 VERSION: 5 GM DAEWOO Auto & Technology 5.2.2. Rigid and Semirigid Plastics : The test piece shall con
19、firm to the dimensions shown in Table 1 and Fig. 2. The Type test piece is the preferred test piece and shall be used where sufficient material having a thickness of 7mm or less is available. The Type test piece may be used when a material dose not break in the narrow section with the preferred Type
20、 test piece. The Type test piece shall be used where only limited material having a thickness of 4mm or less is available for evaluation, or where a large number of test pieces are to be exposed in a limited space (thermal and environmental stability tests etc.). The Type test piece should be used w
21、hen direct comparisons are required between materials in different rigidity cases (that is, nonrigid and semirigid). The Type test piece must be used for all materials with a thickness of greater than 7mm but not more than 14mm. 5.2.3. Nonrigid Plastics : The test piece shall confirm to the dimensio
22、ns shown in Table 1 and Fig. 2. The Type test piece shall be used for testing nonrigid plastics with a thickness of 4mm or less. The Type test piece must be used for all materials with a thickness greater than 7mm but more than 14mm. 5.2.4. Reinforced Composites : The test piece for reinforced compo
23、sites including highly orthotropic laminates, shall confirm to the dimensions of the Type test piece shown in Table 1 and Fig. 2. 5.2.5. In case of Film, the nominal width of the test pieces shall be 5.0 to 25.4mm range and a width-thickness ratio of at least 8 shall be used. A test piece gage lengt
24、h of 250mm shall be considered as standard. When this length is not feasible, test sections as short as 100mm may be used, if it has been shown that results are not appreciably affected. 5.3. Indication of marking lines To determine strain, marking lines shall be on the test piece in a suitable mann
25、er. Here, the marking lines shall not be applied by scratching, punching or pressing. And when using the recording instrument or adhesive, it shall be guaranteed that the substance does not affect the test piece. 5.4. Number of test pieces 5.4.1. If the product to be tested is composed of isotropic
26、material, at least 5 test pieces shall be tested. 5.4.2. If the product to be tested is composed of aeolotropic material, at least 5 test pieces shall be tested respectively in the horizontal and vertical direction. 6. CONDITIONING 6.1. All test pieces shall be conditioned as required by the appropr
27、iate drawings or material specifications. Unless otherwise specified, test pieces shall be stored at (232) and (505)% relative humidity for not less than 40hours prior to test. 6.2. Some hygroscopic materials, such as nylons, shall be stored free from humidity until ready for testing. EDS-T-7511THE
28、TEST METHOD FOR TENSILE PROPERTY OF PLASTICS PAGE: 6/10 ISSUED DATE: 1993. 09. 27 REVISED DATE: 2006. 06. 19 VERSION: 5 GM DAEWOO Auto & Technology 7. TEST METHOD 7.1. Measure the width and thickness of the test pieces at minimum 5 points along the length of the marking line. If a test piece shows a
29、 difference not less than 0.1 mm between the maximum and minimum measured values in thickness or width, it shall be excluded from the test. 7.2. Unless otherwise specified, conduct the test under the standard temperature and humidity condition. 7.3. Align the clamp to tighten the test piece in such
30、way that the long axis of the clamp coincides with the extension direction of the test piece. Tighten the grips evenly and firmly to the degree necessary to prevent slippage of the test piece during the test. 7.4. Attach the extension indicator to the testing machine. 7.5. Speed of testing shall be
31、the relative rate of motion of grips. Determine chosen speed of testing by the specification for the material being tested, or by agreement between those. Apply the stress to the test piece at a speed specified in Table 2. 7.5.1. In case of Film, the speed of testing shall be calculated as follows.
32、A = B C Where, A : rate of grip separation (mm/min.) , B : initial distance between grips (mm) C : initial strain rate (mm/mmmin) The initial strain rate shall be as in table 3 unless otherwise indicated by the specification for the material being tested. Table 2. Speed of Testing Classification Tes
33、t piece Type Speed of Testing (mm/min) , 525% 5010% 50010% 525% 5010% 50010% Rigid and Semirigid 1.325% 12.525% 12525% 5010% 50010% Nonrigid 5010% 50010% * Select the lowest speed that produces rupture in 1/2 to 5 minutes for the test piece geometry being used EDS-T-7511THE TEST METHOD FOR TENSILE P
34、ROPERTY OF PLASTICS PAGE: 7/10 ISSUED DATE: 1993. 09. 27 REVISED DATE: 2006. 06. 19 VERSION: 5 GM DAEWOO Auto & Technology Table 3. Speed of Testing for Film Elongation at Break(%) Initial Strain Rate (mm/mmmin) Initial Grip Separation(mm) Rate of Grip Separation (mm/min) Less than 20 0.1 125 12.5 2
35、0 to 100 0.5 100 50 Greater than 100 10.5 50 500 7.6. Record the change in the length of the marking line appeared during the test and the maximum force (or tensile strength) as well as the force at break. 7.7. If the test piece is not broken along the length of the marking line, tensile stress at b
36、reak cannot be measured. Yield stress and strain can be measured as the sectional area along the length of the marking line begins to decrease. Strain at maximum load and strain at break can be measured when the range of strain exists within the length of the marking line. 7.8. To measure offset yie
37、ld stress, a stress-strain curve shall be drawn without exception. 8. EVALUATION 8.1. Measure the initial sectional area AOof each test piece. * The symbols used in 8.28.10 are as follows. Fmax: Maximum force (N) FR : Force at break (N) FS : Force corresponding to yield stress (N) FSX : Force corres
38、ponding to offset yield stress (N) AO : Initial sectional area (mm2) LFmax: Extension at maximum force (mm) LR : Extension at break (mm) LS : Extension at yield stress (mm) LSX : Extension at offset yield stress (mm) LO: Initial length of the mark (mm) Fi: Force at the strain of X% (N) 8.2. Tensile
39、strength (N/m2) Fmax B= - AOEDS-T-7511THE TEST METHOD FOR TENSILE PROPERTY OF PLASTICS PAGE: 8/10 ISSUED DATE: 1993. 09. 27 REVISED DATE: 2006. 06. 19 VERSION: 5 GM DAEWOO Auto & Technology 8.3. Tensile stress at break (N/m2) FRR= - AO8.4. Yield stress (N/m2) FSS= - AO8.5. Offset yield stress SX sha
40、ll be measured by making a line parallel to the initial straight line of the stress-strain curve by removing the Lx which corresponds to the strain of X% onto the horizontal axis. The force at the cross point of the parallel line and the stress-strain curve (Fsx) is offset yield stress. FSS= - (N/m2
41、) AO8.6. Tensile stress at given extension (N/m2) FiS= - AO8.7. Strain at maximum load (%) LFmax B = - X 100 LO8.8. Strain at break (%) LRR = - X 100 LO8.9. Strain at yield stress (%) LRS = - X 100 LO8.10. Strain at offset yield stress (%) LSXSX = - X 100 LO 8.11. Get the arithmetic mean of the valu
42、es obtained for each test and enter it. 9. REPORT Test report shall include the following. EDS-T-7511THE TEST METHOD FOR TENSILE PROPERTY OF PLASTICS PAGE: 9/10 ISSUED DATE: 1993. 09. 27 REVISED DATE: 2006. 06. 19 VERSION: 5 GM DAEWOO Auto & Technology 9.1. Designation and shape of the applied produ
43、cts 9.2. Measured date and measuring method of test pieces 9.3. Location of test piece from products 9.4. Type of test pieces 9.5. Thickness of test pieces 9.6. Width of test pieces 9.7. Number of test pieces 9.8. Conditioning of test pieces 9.9. Test temperature and humidity condition 9.10. Speed o
44、f testing 9.11. Tensile strength 9.12. Tensile stress at break 9.13. Yield stress 9.14. Offset yield stress and tensile stress at given strain if necessary 9.15. Strain at yield 9.16. Strain at offset yield stress if necessary 9.17. Strain at maximum load 9.18. Appearance of test pieces after test 9
45、.19. Conditions deviated from this standard 9.20. Test date EDS-T-7511THE TEST METHOD FOR TENSILE PROPERTY OF PLASTICS PAGE: 10/10 ISSUED DATE: 1993. 09. 27 REVISED DATE: 2006. 06. 19 VERSION: 5 GM DAEWOO Auto & Technology 10. CODING SYSTEM Tensile test EDS - T - 7511 - 5 - Type of test pieces Speed
46、 of testing (mm/min) Test method Designation 11. DEVIATIONS Deviations from the requirements of this specification or other additional requirements shall have been agreed upon and shall be specified on the relevant component drawings, test specifications material specifications, etc., and shall be indicated on all test certificates, reports, etc. 12. REFERRENCES ASTM D 638 Standard test method for tensile properties of plastics ASTM D 882 Standard test method for tensile properties of thin plastic sheeting
