1 Scope
1.1 This test method specifies the test method for the tensile properties of plastic sheets and films (thickness less than 1.0 mm).
Note 1-The film is mandatory defined as a sheet with a rated thickness not greater than 0.25 mm (0.01 in).
Note 2—Plastics with a thickness greater than 1 mm (0.04 in) should be tested for tensile properties in accordance with the D 638 test method.
1.2 This test method can test all plastics that meet the above thickness and load range of the testing machine.
1.2.1 Static weighing of fixtures, and constant rate separation test-This test method uses a fixture that separates at a constant rate to clamp both ends of the test sample.
1.3 This test method obtains the tensile degree of the test sample by the displacement of the separation clamp, the tensile indicator or the gauge line.
1.4 The measurement procedure of the elastic tensile coefficient, including a certain strain rate.
NOTE 3—The stretch factor is obtained by measuring the degree of stretch using a separate clip. The provisions for measuring with an extensometer as described in 5.2 are also included in this step.
1.5 The data obtained from this test method can be used in engineering design.
1.6 All values ​​are in the International System of Units. The values ​​in parentheses are for reference only.
1.7 This standard does not contain any safety issues related to the use of the standard (if any). Before using this standard, it is the user's responsibility to establish appropriate safety and health regulations and to establish restrictions on the use of the standard.
Note 4—This test method is similar to ISO 527-3, but technically the two cannot be equal. ISO 527-3 can use other types of samples with different test speeds and requires the use of extensometers or gauge wires.
2. Related documents
2.1 ASTM standard: [2]
D 618 Standard Practice for Conditioning of Test Plastics
D 638 Standard Test Method for Tensile Properties of Plastics
D 4000 Standard classification system for specified plastic materials
D 5947 Test method for physical dimensions of solid plastic samples
D 6287 Standard Operating Procedures for Slicing and Compression Test Samples
E 4 test mechanical qualification rules
E 691 Standard Practice for Determination of Precision of Test Methods for Inter-laboratory Research
2.2 ISO standard
ISO 527-3 Determination of tensile properties of plastics-Part 3: Test conditions for films and sheets [3]
3. Terminology
3.1 Definitions—For definitions of terms and symbols related to plastic tensile testing, see the Appendix of Test Method D 638.
3.1.1 Linear fixture—The fixture should be designed so that all clamping force is distributed along a line perpendicular to the test sample. Such a fixture usually consists of a standard horizontal clamping surface and a semicircular opposite surface.
3.1.2 Tear failure—a tensile fracture that begins at the edge of the specimen and ruptures through the entire specimen at a slow rate sufficient to produce a load-deformation curve.
4. Significance and application
4.1 The tensile properties measured by this test method are very valuable for the definition and description of materials, quality control and specification division. The tensile properties will vary with the thickness of the sample, the preparation method, the test speed, the type of fixture, and the method of measuring the stretch. Therefore, when accurate comparison results are required, these factors must be strictly controlled. Except for other special materials that have clear specifications, this test method should be used for arbitration. Many material specifications may require the use of this test method, but in order to comply with the specifications, some procedural adjustments must be made. It is therefore recommended to consult the relevant material specifications before using this test method. Table 1 in the D4000 classification system lists the existing ASTM material standards.
4.2 Tensile properties can provide relevant data for scientific research, engineering design, quality control and specification division. However, when judging the situation that the material is stressed for a long time in actual use, you cannot refer to the data obtained in this test alone.
4.3 The elastic stretch coefficient is the hardness index of thin plastic sheets. If the test environment is accurately controlled, the test results will have very good reproducibility. If comparing the hardness of different materials, samples of the same size should be used.
4.4 Tensile fracture energy (TEB) refers to the total energy contained per unit volume when the sample is at the critical point of rupture. This characteristic is called toughness in some documents and is used to evaluate the performance of materials that are often subjected to large loads. However, strain rate, sample parameters, and especially sample flaws may cause severe fluctuations in results. Therefore, extra care should be taken when using TEB test results in the design of end-use products.
4.5 Irregular data obtained by the material being torn and destroyed cannot be compared with the data obtained by ordinary destruction.
5. Instruments
5.1 Testing machine—The testing machine should have a constant cross motion rate, and it must have the following devices:
5.1.1 Fixed parts-fixed or basically fixed, with a clamp.
5.1.2 Moving parts-movable, with a second fixture.
5.1.3 Fixtures-On the testing machine, a series of clamps used to clamp the test sample between the fixed and moving parts can be fixed or automatically aligned. Regardless of the fixture system, the relative sliding and uneven stress distribution should be minimized.
5.1.3.1 The fixed fixture is firmly installed on the fixed or movable parts of the testing machine. When using this type of clamp, the sample must be carefully clamped in the clamp so that the long axis of the sample coincides with the direction of the pulling force through the center line of the clamp.
5.1.3.2 The auto-alignment fixture is installed on the component, and once it reaches a certain load, it will be automatically arranged in a row so that the long axis of the sample coincides with the direction of the pulling force through the center line of the fixture. The clamps should be aligned as much as possible in the direction of the pulling force to avoid the sample rotating and sliding. Automatic alignment fixtures can only be adjusted automatically within certain limits.
5.1.3.3 The sample should be prevented from sliding relative to the fixture as much as possible. Use thin rubber, abrasive cloth, pressure sensitive tape, flat mouth or serrated clamps to prevent the sample from sliding. The surface of the fixture should be selected according to the test material and its thickness. Use 1.0mm (40mil) blotting paper or filter paper pad on the round surface of the fixture, the effect is better. For materials that are easy to "shrink" in the fixture, pneumatic clamps that can always maintain a constant pressure are more advantageous. For materials that often tear at the edge of the clamp, the radius of curvature where the clamp contacts the sample can be increased slightly.
5.1.4 Driving device-The driving device can apply a relatively stable and controllable speed to the moving parts. The speed should be set according to section 9.
5.1.5 Load indicator—A suitable load indicating device that can indicate the total tensile load on the test specimen on the fixture. This device basically has no inertial hysteresis at a specific test rate (Note 5). Unless a suitable extensometer is used, the movement of the weighing system should not exceed 2% of the sample elongation within the measurement range. The load indicator is accurate to 1% of the tensile load on the sample. The accuracy of the testing machine should be corrected according to the E4 specification.
5.1.6 Cross elongation indicator—A suitable elongation indicator device can indicate the distance of the clamps when they move in a cross motion. This device basically has no inertial hysteresis at a specific test rate. This indicator is accurate to 1% of the cross movement distance of the fixture.
5.2 Extensometer (optional)-if necessary, use this instrument to measure the distance between two defined points on the stretched sample. When using this instrument, the pressure at the point of contact between the instrument and the sample should be minimized (see 8.3). The instrument should automatically record any changes in distance or samples, such as a function of sample load and a function of time taken. If only the function of time used is recorded, the value of load time should also be recorded. The instrument must be substantially free of inertial hysteresis at a specific test rate (see Note 5).
5.2.1 Measurement of modulus of elasticity and low elongation-use an extensometer to measure the modulus of elasticity and low elongation (less than 20% of elongation), which should be at least 1% accurate Required operation of the instrument.
5.2.2 Measurement of high elongation—When measuring high elongation (more than 20% of elongation), the instrument and related technical index should be accurate to 1%.
Note 5—In the process of marking and recording load and tensile data, it must respond quickly. The required reaction speed of the system depends on the material tested (high or low tensile strength) and strain rate.
5.3 Thickness measuring instrument—The net weight dial micrometer described in Test Method D5947 Method C, or an equivalent measuring device, shall be accurate to 0.0025 mm (0.0001 in) or less.
5.4 Width measuring instrument-a suitable measuring instrument or other instrument that can be accurate to 0.25mm (0.010in).
5.5 Sample cutter—Select the technology and equipment suitable for cutting film and sheet according to D6287 specification.
5.5.1 It has been proved that the device using the blade is particularly suitable for cutting materials with elongation at break of 10-20% or more.
5.5.2 Since the edges of the sample may be uneven or cracked, it is recommended not to use a punch or press to cut the sample.
6. Sampling
6.1 The test sample shall be a strip of uniform width and thickness, and the length shall be at least 50 mm (2 in) longer than the distance between the fixtures.
6.2 The rated width of the sample should be no less than 5.0mm (0.20in) and no more than 25.4mm (1in).
6.3 The ratio of width to thickness is at least 8. A sample that is too narrow will magnify the strain and cracks at the edge of the sample.
6.4 When cutting samples, try to avoid defects that may cause premature fractures such as notches or tears (Note 6). The two sides of the sample should be parallel, and the width of the edge part should be less than 5% of the length of the sample between the two fixtures.
Note 6—When preparing samples, the samples should be checked with a microscope for defects.
6.5 The thickness of the test sample should be constant. When the thickness of the material is less than 0.25mm (0.010in), the thickness of the sample should be less than 10% of the length of the sample between the fixtures; when the thickness of the material is greater than 0.25mm (0.010in) and less than 1.00mm (0.040in) At this time, the thickness of the sample should be less than 5% of the length of the sample between the fixtures.
Note 7—When the thickness of the sample exceeds the recommended value of 6.5, the data obtained from the test may not represent the characteristics of the material.
6.6 If the material is suspected to be anisotropic, two sets of samples should be prepared separately, the long axis of which should be parallel and perpendicular to the anisotropic direction.
6.7 When measuring the elastic tensile coefficient, the standard length of the sample shall be 250 mm (10 in). This length is used to minimize the impact of fixture slip on the test results. When this length is not feasible, the length of the test area can be 100 mm (4 in) without affecting the test results. However, the length of 250mm should still be used in arbitration. When testing shorter samples, the test rate should be adjusted so that the strain rate is the same as the standard sample.
Note 8—A series of cyclic tests [4] indicate that for materials with a thickness of less than 0.25 mm (10 mil), the results obtained by measuring 1.0 mm (40 mil) blotting paper on the round pad of the fixture with a sample of 100 mm in the test area, It is the same as the result obtained by using a flat-mouthed jig to measure a sample with a test area of ​​250 mm.
Note 9—For some materials with high elastic coefficients thicker than 0.25 mm (0.010 in), it is difficult to avoid slipping of the fixture.
7. Experimental environment
7.1 Environment-Unless otherwise specified in the contract or relevant ASTM standards, the environment of the sample shall be adjusted to a temperature of 23 ± 2 ° C (73.4 ± 3.6 ° F), relative to the requirements of D618 Method A, at least 40 hours before the test Humidity 50 ± 10%. The allowable error range for resolving disputes is temperature ± 1 ° C (± 1.8 ° F) and relative humidity ± 5%.
7.2 Experimental environment-Unless otherwise specified in the contract or relevant ASTM standards, the test shall be conducted at a temperature of 23 ± 2 ° C (73.4 ± 3.6 ° F) and a relative humidity of 50 ± 10%. The allowable error range for resolving disputes is temperature ± 1 ° C (± 1.8 ° F) and relative humidity ± 5%.
8. Number of test samples
8.1 For isotropic materials, at least 5 samples shall be prepared for each specimen.
8.2 For anisotropic materials, at least 10 samples must be prepared for each specimen. The five long axes are parallel to the anisotropic direction of the sample, and the five long axes are perpendicular to the anisotropic direction of the sample.
8.3 If the sample ruptures at an apparent defect, or ruptures beyond the standard length, the sample should also be discarded and re-tested unless such defect or environment is the object of the study. However, when pinch cracks (cracks where the fixture contacts the sample) occur, if the values ​​obtained by the test have been proven to be substantially the same as those obtained during the standard length, pinch cracks are acceptable.
Note 10—For some materials, the optical cross-polarizer can be used to detect defects in the sample that may or have caused early fractures before and after the test.
9. Test speed
9.1 Test speed refers to the speed at which the two parts (or fixtures) separate when the test machine is operating without load. The difference between this separation speed and the full-load separation speed cannot exceed 5% of the no-load separation speed.
9.1 The test speed shall be calculated according to the requirements shown in Table 1 for the initial strain rate. In these test methods, the calculation formula of the fixture separation speed and the initial strain rate is as follows: A = BC
among them:
A = separation speed of the fixture, mm (or in) / min;
B = initial distance between fixtures, mm (or in);
C = initial strain rate, mm / mm · min (or in / in · min).
9.3 Unless otherwise specified in the material specifications, the initial strain rate shall be as specified in Table 1.
NOTE 11—The results obtained at different initial strain rates are not comparable; therefore, when materials of different tensile grades need to be compared directly, they should be compared at the same strain rate. For some materials, it is recommended to select the strain rate based on the yield elongation of the material.
9.4 In special cases, for example, the value obtained by measuring the tensile rupture rate is inconsistent with the classification of the material, so that the strain rate must be selected, and the lower strain rate should be selected.
9.5 When measuring the coefficient, once the strain rate and sample size are different from other tensile properties, additional samples should be used.
10. Test procedure
10.1 Select a load range so that the sample ruptures at two thirds of the load range. In order to select the appropriate load-sample width combination, several tests are required.
10.2 Measure the cross-sectional area at several different points along the length of the sample. The measuring width should be accurate to 0.25mm (0.010in). When measuring the thickness, it should be accurate to 0.0025mm (0.0001in) for the film with thickness less than 0.25mm (0.010in); it should be accurate to 1% for the film with thickness greater than 0.25mm (0.010in) and less than 1.0mm (0.040in) .
10.3 Set the initial distance of the fixture according to Table 1.
10.4 According to Table 1 and the initial distance of the fixture, set the separation speed of the fixture to make the required strain rate. Zero the load metering system, tension indicator and recording system.
Note 12: Using an extensometer to measure the elastic stretch coefficient is more accurate than using a separate fixture. Care should be taken to prevent the extensometer from slipping and to avoid undue stress on the sample. Also refer to 6.7.
10.5 If it is necessary to measure the length of the test area, rather than the length between the fixtures, use soft colored crayons or water pens to mark the two ends of the test area on the sample. Do not use hard objects to mark the surface of the sample, because these scratches may increase the pressure and cause the sample to break prematurely. If an extensometer is used, the test area shall be the distance between the extensometer and the sample contact point. Note 13: For some samples with high tensile strength, it is necessary to measure the length of the test area. As the sample stretches, the area of ​​the fixture liner and the material release will decrease, causing the material to relax. As a result, this problem is similar to the sliding of the fixture, that is, the measured amount of stretch is exaggerated.
10.6 Place the sample in the fixture of the testing machine, carefully align the main axis of the sample with the center line of the contact point of the fixture, and clamp the fixture firmly to minimize the possibility of sample sliding.
10.7 Start the machine and record the load-stretch amount.
10.7.1 When the full length of the sample between the fixtures is used as the test area, record the value of the load-fixture spacing.
10.7.2 When the test area has been marked on the sample, use a suitable instrument to record the displacement of the edge boundary line. If necessary, the load-tension curve can be made based on the reading of the load indicator.
10.7.3 When using the stretch timer, record the load-stretch amount of the test zone displayed by the stretch gauge.
10.8 If a coefficient value is required, select a load range and drawing rate, and make a load-tension curve within the range of 30-60 ° on the X axis. To achieve the highest accuracy, the load should be measured with the most sensitive instrument under the test conditions. If the load-elongation curve deviates from the linear direction, the test shall be stopped.
10.9 In the test for measuring the secant coefficient of a material, the test shall be stopped when the material reaches the specified elongation.
10.10 If the tensile fracture energy of the material is measured, it should be prepared to integrate the stress-stress curve. It can be the electronic integral during the test, or the area under the curve after the test (see Appendix A2).
11. Calculation
11.1 Unless the initial area of ​​the curve is not caused by the tension of the sample, installation or other human factors, but the true reflection of the material, the initial compensation should be made according to Appendix A1.
11.2 The calculation of the rupture factor (nominal value) should be the maximum load value divided by the initial minimum width of the sample. The result should be expressed as force per unit width, generally Newtons per meter (pounds per inch); accurate to 3 significant digits in the report. The thickness of the film should be close to 0.0025 mm (0.0001 inch).
Example: 0.1300mm (0.0051in) thick film, burst factor = 1.75kN / m (10.0 lbf / in)
Note 14-This method is very effective for extremely thin plastic films (thickness less than 0.13 mm (0.005 in)). The breaking load of this kind of film may not be proportional to the cross-sectional area, and the thickness is difficult to measure accurately. Moreover, due to the influence of factors such as stretching effect, skin effect, crystallinity, etc., the tensile properties are not proportional to the cross-sectional area.
11.3 The tensile strength (nominal value) is calculated as the maximum load value divided by the initial minimum cross-sectional area of ​​the sample. The result is expressed as force per unit area, usually megapascals (pounds per square inch). In the report, the value is accurate to 3 significant digits.
Note 15: When tearing and rupture occurs, the calculation result should be based on the load-stretch amount when the rupture occurs.
11.4 The tensile strength at break (nominal value) is calculated in the same way as the tensile strength, except that the maximum tensile load is replaced by the rupture load (refer to Note 15 and Note 16).
NOTE 16—In many cases, the calculation of tensile strength at break and tensile strength are the same.
11.5 The elongation at break is calculated by dividing the sample's elongation at break by the initial gauge length of the sample and multiplying by 100. When using a gauge line or an extensometer to indicate the test area, the value is used for calculation; otherwise, the distance between fixtures is used. The result is expressed as a percentage, accurate to 2 significant digits.
11.6 The yield strength is calculated as the load at the yield point divided by the initial cross-sectional area of ​​the sample. The result is expressed as force per unit area, usually megapascals (pounds per square inch). Accurate to 3 significant digits. For materials exhibiting Hooke's elastic behavior in the initial section of the curve, the compensation yield strength should be supplemented as described in the Appendix of Test Method D638. In this case, the result should be expressed as "yield strength-compensation%".
11.7 The yield elongation is calculated by dividing the tensile strength at the yield point of the sample by the initial gauge length of the sample and multiplying by 100. When using a gauge line or an extensometer to mark the sample test area, use this value for the calculation. Before calculation, the sample must be initially compensated for as described in Appendix A1. The result is expressed as a percentage, accurate to 2 significant digits. When using compensated yield strength, the elongation at compensated yield strength should be calculated.
11.8 The calculation of the elastic coefficient is to draw a tangent line in the initial part of the stress-stretch curve, select a point on the tangent line, and then divide the tensile strain by the corresponding stress. Before calculation, perform initial compensation for the amount of stretching as described in Appendix A1. For this, the tensile stress should be the load value divided by the initial cross-sectional area of ​​the sample. The result is expressed as force per unit area, usually megapascals (pounds per square inch). Accurate to 3 significant digits.
11.9 The secant coefficient is calculated by dividing the nominal pressure by the stress under a certain stress. The elastic coefficient should be selected and calculated first. However, for materials whose correlation properties are not proportional, the secant modulus should be used and calculated. Make a tangent as shown in Appendix A1.3 and Figure A1.2 in Appendix A1, and mark the stress at the yield point. The tangent at this time passes through the zero pressure point. The pressure used in the calculation is the load under a certain stress divided by the initial cross-sectional area of ​​the sample.
11.10 The calculation of tensile energy at break should be the energy integral value per unit volume under the pressure stress curve. Or calculate the total energy absorbed by the material divided by the volume between the sample lines. As described in Annex A2, this calculation can be obtained directly by an electronic integrator, or it can be used to calculate the area under the curve. The results are expressed as energy per unit volume, megajoules per cubic meter (part-pound force per cubic inch). The value is accurate to 2 significant digits.
11.11 In this test, all calculations shall be accurate to the required significant figures.
11.12 The standard deviation (estimated value) is calculated as follows, accurate to 2 significant digits.
among them,
s = standard deviation (estimated value)
X = single record value
n = number of recorded values
X = Average of recorded values ​​Table 1 Cross movement speed of initial fixture separation Elongation rate of rupture Initial strain rate Initial fixture separation furniture separation rate
Mm / mm · min
mm In Mm / min In / min
Measuring the elastic coefficient
0.1 250 10 25 1.0
Measure less than 20 0.1 125 5 12.5 0.5 except the elastic coefficient
20 to 100 0.5 100 4 50 2.0
Greater than 100 10.0 50 2 500 20.0
Table 2 Accurate data of coefficients Tangent coefficient wipe thickness
mils
average
103 psi
Sr,
103 psi
SR,
103 psi
Ir,
103 psi
IR,
103 psi
LDPE 1.4 53.9 1.81 8.81 5.12 24.9
HEPE 1.6 191 5.47 16.2 15.5 45.9
PP 1.1 425 10.3 34.5 29.0 89.1
PET 0.9 672 13.8 55.5 39.1 157.1
Secant coefficient
LDPE 1.4 45.0 2.11 3.43 5.98 9.70
HAPE 1.6 150 3.29 9.58 9.30 27.1
PP 1.1 372 4.66 26.5 13.2 74.9
PET 0.9 640 10.0 27.5 28.4 77.8
12. Test report
12.1 The report should include the following:
12.1.1 Complete information of test sample: type, source, production code, format, size, processing history. If it is an anisotropic material, the direction of stretching of the material is also required.
12.1.2 Preparation method of test samples.
12.1.3 The thickness, width and length of the sample.
12.1.4 The test code of the sample.
12.1.5 The strain rate used.
12.1.6 The initial fixture distance used.
12.1.7 The separation speed of the fixture.
12.1.8 The distance between the marking lines (if the distance between the initial fixtures is not used).
12.1.9 Type of fixture used (including the inner surface type of fixture)
12.1.10 Sample environment (test environment, temperature and relative humidity).
12.1.11 Abnormal behavior, such as premature fracture, fracture occurs at the edge of the fixture.
12.1.12 Average breaking factor and standard deviation.
12.1.13 Average tensile strength (nominal value) and standard deviation.
12.1.14 Average tensile strength at break (nominal value) and standard deviation.
12.1.15 Average elongation at break and standard deviation.
12.1.16 If necessary, the average elongation at break and standard deviation are required.
12.1.17 For materials with yield phenomena, there must be average yield tensile strength and standard deviation; average yield tensile rate and standard deviation.
12.1.18 For materials without yield phenomenon, the yield strength and standard deviation of the average percent compensation value; the average percent elongation and standard deviation are required.
12.1.19 Average elastic coefficient and standard deviation (if using secant coefficient, the stress value for calculation should be indicated)
12.1.20 If an extensometer is used, explain.
13. Accuracy and error
13.1 These tensile properties have been tested twice in-house. The first test was conducted in 1977. The coefficient was only measured, using four randomly selected thin materials. Each laboratory tested 5 samples. The elastic coefficient is measured by 6 laboratories, and the orthogonal coefficient is measured by 5 laboratories. See Table 2 for the accuracy of laboratory internal tests.
13.1.1 Table 2 complies with the E691 specification, and deviation data is not deleted. [5]
13.1.2 The internal standard error of the laboratory, S x¯, is derived from the average value of the standard errors of 5 independent samples. S x¯ is a summary of standard errors in the laboratory for the same top material. See 13.3-13.3.2.
13.2 Another laboratory internal test was conducted in 1981 and tested other than the coefficient of tensile properties. Six randomly selected materials (one of which has three thicknesses) were used, with thicknesses ranging from 0.019mm to 0.178mm (0.00075-0.007in). The test results are derived from the average of 5 samples. Each laboratory tested 8 samples, however, S x¯ was calculated as above S x¯ = Sx / (5) 1â„2. This is done to keep the data consistent with the five sample trials while improving the data quality as much as possible. Tables 3 and 7 specify the materials and their thicknesses, and each table specifies one of the following characteristics: tensile yield strength, yield yield, tensile stress, tensile strength at break, and tensile strength at break (see Note 17) . [6]
Note 17—In order to fill in the experimental report, the detection of low-density polyethylene (LDPE) in this study, using a cross polarizer to measure the linearity of the length and the width change of the molecular orientation, may not fully represent the data difference between the laboratories.
Note 18—Warning: The following explanations of IR and Ir (13.3-13.3.3) are only one way to deal with the accuracy of this test method. The data in Table 2 may be slightly different from the material properties, and only represents the results of a series of related tests, not other environments, materials, or laboratories. Users of this real method should accept the principles described in the E 691 specification and acknowledge that these are specific data generated by specific laboratories for specific materials. The principles in 13.3-13.3.3 are only valid for these data. ) Table 3 Accurate data for yield force Material thickness, mils average, 103 psi (Sr) A 103 psi (SR) B 103 psi I (r) C 103 psi I (R) D 103 psi
LDPE 1.0 1.49 0.051 0.13 0.14 0.37
HDPE 1.0 4.33 0.084 0.16 0.24 0.44
PP 0.75 6.40 0.13 0.52 0.37 1.46
PC 4.0 8.59 0.072 0.29 0.20 0.82
CTA 5.3 11.4 0.12 0.50 0.34 1.43
PET 4.0 14.3 0.12 0.23 0.34 0.66
PET 2.5 14.4 0.14 0.54 0.40 1.52
PET 7.0 14.4 0.13 0.36 0.37 1.03
(Sr) A
It is the average of standard errors in the laboratory.
(SR) B is the average of standard errors between laboratories.
I (r) C = 2.83 Sr
I (R) D = 2.83SR
Table 4 Accurate data of yield yield Material thickness, mils average,% (Sr) A,% i (SR) B,% I (r) C,% I (R) D,%
PP 0.75 3.5 0.15 0.41 0.42 1.2
PET 2.5 5.2 0.26 0.92 0.74 2.6
PET 4.0 5.3 0.25 0.62 0.71 1.7
PET 7.0 5.4 0.14 1.05 0.40 3.0
CTA 5.3 5.4 0.19 0.99 0.54 2.8
PC 4.0 6.9 0.24 0.98 0.68 2.8
HDPE 1.0 8.8 0.32 1.82 0.91 5.2
LDPE 1.0 10.0 0.55 3.41 1.56 9.6
Note 1-See the explanation of the footnotes in Table 3.
Table 5 Accurate data of tensile strength Material thickness, mils average, 103 psi (Sr) A 103 psi (SR) B 103 psi I (r) C 103 psi I (R) D 103 psi
LDPE 1.0 2.43 0.14 0.53 0.40 1.5
HDPE 1.0 6.87 0.27 0.81 0.76 2.3
PP 4.0 12.0 0.34 0.93 0.96 2.6
CTA 5.3 14.6 0.20 1.37 0.57 3.9
PP 0.75 28.4 1.57 4.56 4.4 12.9
PET 4.0 28.9 0.65 1.27 1.8 3.6
PET 7.0 30.3 0.83 1.32 2.3 3.7
PET 2.5 30.6 1.22 2.64 3.4 7.5
Note 1-See the explanation of the footnotes in Table 3.
Table 6 Accurate data of tensile strength at break Material thickness, mils average,% (Sr) A,% i (SR) B,% I (r) C,% I (R) D,%
CTA 5.3 26.4 1.0 4.3 3 12
PP 0.75 57.8 4.4 12.7 12 36
PET 2.5 120 8.0 14.6 23 41
PET 7.0 132 5.8 10.6 16 30
PET 4.0 134 4.4 12.2 12 35
PC 4.0 155 5.4 17.1 15 48
LDPE 1.0 205 24.4 73.3 69 210
HDPE 1.0 570 26.0 91.7 74 260
Note 1-See the explanation of the footnotes in Table 3.
Table 7 Exact data of tensile fracture energy Material thickness, mils average, 103
in./lbâ„in.3
(Sr) A103
in./lbâ„in.3
(SR) B103
in./lbâ„in.3
I (r) C103
in./lbâ„in.3
I (R) D103
in./lbâ„in.3
CTA 5.0 3.14 0.14 0.70 0.4 2.0
LDPE 1.0 5.55 0.84 2.47 2.4 7.0
PP 0.75 11.3 1.19 3.11 3.4 8.8
PC 4.0 12.9 0.59 1.55 1.7 4.4
HDPE 1.0 26.0 1.87 5.02 5.3 14.2
PET 2.5 26.1 2.13 4.20 6.0 11.9
PET 4.0 27.1 1.42 2.75 4.0 7.8
PET 7.0 28.4 1.71 2.72 4.8 7.7
Note 1-See the explanation of the footnotes in Table 3.
Appendix (informative appendix)
A1. Initial compensation
A1.1 In the typical pressure stress curve (Figure A1.1), the initial area AC does not show the material properties. This is artificially caused during the tightening, fixing and installation of the sample. In order to correct the values ​​of parameters, such as coefficients, stresses, and yield point compensation, such human factors must be compensated so that the axis of stress or tension returns to zero.
A1.2 For materials that exhibit Hooke's behavior in a certain area (Figure A1.1), the continuation of the linear area of ​​the curve (CD) is along the zero pressure axis. There is a zone (B) inside which is the zero stress point, and all stresses and stretches from this point must be measured, including yield compensation (BE). The elastic coefficient can be measured by dividing the pressure at any point on the CD by the stress at the same point (point B is defined as the zero stress point).
A1.3 For materials that do not exhibit any linear region (Figure A1.2), the same zero stress point correction can be achieved by making a tangent at the maximum radian of the deformation point (H ′). This line extends and compares with the stress axis to B ′, which is the zero stress correction point. Taking B ′ as the zero stress point, the secant coefficient (B′G ′) is the pressure at any point (G ′) on the curve divided by the stress at this point. For materials in the wireless area, if the tangent at the reaction point is used as the basis for measuring strain compensation, it will cause unacceptable errors.
A2. Determination of tensile fracture energy
A2.1 Tensile fracture energy (TEB) is the area under the pressure stress curve, or where S is the pressure on any stress, and εT is the stress at break. The unit of the value is the unit volume of energy per sample initial area. Using a tensile tester with an indicator can easily and accurately measure TEB. The calculation is as follows:
(I / K) (full load) (drawing speed) (cross movement speed / drawing speed)
TEB = ------------------------------------------------ ---
(Average vernier caliper) (sample width) (calibrated length)
(A2.2)
Where I is the indicator reading and K is the maximum value per unit time under full load. The entire calculation formula is completed by electronic calculation. The results are usually expressed in megajoules per cubic meter (pound-force per cubic inch).
A2.2 Except for the indicator, the area under the pressure stress curve can be measured by the surface measuring device to measure the area or cut the curve. Because the load values ​​are not recorded as integers on some drawings, the accuracy of these techniques will decrease with time. If the force and tension are expressed instead of pressure and stress, the energy should be calculated by dividing the measured area by the sample calibration length, sample width, and average vernier caliper:
(Curve area) (force per unit on the graph) (stretching amount per unit on the graph)
TEB = ---------------------------------------------
(Average vernier caliper) (sample width) (calibrated length)
A2.3 For example, if the area of ​​the force-stretch curve is 60000mm2, the load is 2.0N / mm, the sample size is 0.1mm vernier caliper, the width is 15mm, and the calibration length is 100mm, then the calculation of the tensile strength at break is the revision summary The revisions that may affect the use of this standard are included in the latest version of this standard (D 882-02).
(January 1, 2009)
(1) Section 7 has been revised.
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[1] This test method is under the jurisdiction of the ASTM D20-Plastics Committee and is directly responsible for the D20.19-Film and Sheet Subcommittee. The current version was approved on January 1, 2009. Published in January 2009. The year of first approval was 1946. The most recent revision (D882-02) was approved in 2002.
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