1、Designation: D6775 13Standard Test Method forBreaking Strength and Elongation of Textile Webbing, Tapeand Braided Material1This standard is issued under the fixed designation D6775; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, t
2、he year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the break-ing strength and elongation of textile webbing, tape
3、 andbraided materials using a split-drum type specimen clamp.1.2 This test method is limited to materials with a maximumwidth of 90 mm (3.5 in.) and a maximum breaking strength ofno more than 89000 N (20000 lb).1.3 The values stated in either SI units or U.S. Customaryunits are to be regarded separa
4、tely as standard. Within the text,the U.S. Customary units are given in parentheses. The valuesstated in each system are not exact equivalents; therefore, eachsystem shall be used independently of the other.1.4 This standard does not purport to address all of thesafety concerns, if any, associated w
5、ith its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D76 Specification for Tensile Testing Machines for TextilesD123 T
6、erminology Relating to TextilesD1776 Practice for Conditioning and Testing TextilesD4848 Terminology Related to Force, Deformation andRelated Properties of TextilesD4850 Terminology Relating to Fabrics and Fabric TestMethods3. Terminology3.1 For definitions of terms related to force and deformationu
7、sed in this test method, refer to Terminology D4848. Fordefinitions of other terms related to textiles used in thisstandard, refer to Terminology D123, and D4850.4. Summary of Test Method4.1 A specimen is clamped in a tensile testing machine andextended to rupture. The breaking force is determined f
8、rom aforce-elongation curve or with an interfaced computer. Elon-gation is determined by calculating the difference betweenbench marks before the application of a force and at a specifiedforce.5. Significance and Use5.1 This test method can be used for acceptance testing ofcommercial shipments but c
9、omparisons should be made withcaution because estimates of between-laboratory precision areincomplete.5.1.1 If there are differences of practical significance be-tween reported test results for two laboratories (or more),comparative tests should be performed to determine if there isa statistical bia
10、s between them, using competent statisticalassistance. As a minimum, use samples for such comparativetests that are as homogeneous as possible, drawn from the samelot of material as the samples that resulted in disparate resultsduring initial testing, and randomly assigned in equal numbersto each la
11、boratory. The test results from the laboratoriesinvolved should be compared using a statistical test forunpaired data, at a probability level chosen prior to the testingseries. If bias is found, either its cause must be found andcorrected, or future test results for that material must beadjusted in
12、consideration of the known bias.5.2 Elongation is an indication of the ability of a fiber toabsorb energy. The elongation of textile materials must be greatenough to withstand strains experienced in processing and enduse, and to absorb the energies of applied forces repeatedly.6. Apparatus36.1 Tensi
13、le Testing Machine, CRE-type, conforming toSpecification D76 with respect to force indication, working1This test method is under the jurisdiction of ASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.60 on Fabric Test Methods,Specific.Current edition approved July 1,
14、2013. Published August 2013. Originallyapproved in 2002. Last previous edition approved in 2011 as D6775 02(2011).DOI: 10.1520/D6775-13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume in
15、formation, refer to the standards Document Summary page onthe ASTM website.3Apparatus and clamps are commercially available.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1FIG. 1 Side View of Clamping AssemblyFIG. 2 Example of Clampin
16、g AssemblyD6775 132range, capacity and verification of recorded elongation, anddesigned for operation at a pulling speed of 75 6 25 mm/min(3 6 1 in./min).6.2 Clamping Assembly, consisting of an upper and lowerclamp, each a split-drum type, as shown in Fig. 1 and Fig. 2.6.3 Computer or Microprocessor
17、, interfaced, with automaticdata gathering system, including photo or electronic instru-ments to measure elongation. (Optional.)7. Sampling, Test Specimens, and Test Units7.1 Lot SampleTake a lot sample as directed in theapplicable material specification. In absence of such a specifi-cation randomly
18、 select five rolls or pieces to constitute the lotsample.7.2 Laboratory Sampling Unit, as produced materialAs alaboratory sampling unit take one piece of full-width webbing,tape or braid that is at least 1.4 m (1.5 yd) in length from eachroll or piece in the lot sample.7.2.1 For thick specimens, lon
19、ger specimens may be re-quired to maintain the specified gage length and to ensure thespecimen is completely in the clamps.7.2.2 When testing after abrasion is required, as a laboratorysampling unit, take one piece of full-width webbing, tape orbraid that is at least 2.8 m (3.0 yd) in length from ea
20、ch roll orpiece in the lot sample (see 7.2.1).7.3 Test Specimens, as produced materialFrom each labo-ratory sampling unit, cut 1 test specimen full-width and at least1.4 m (1.5 yd) in length (see 7.2.1).7.3.1 When testing after abrasion is required, from eachlaboratory sampling unit, cut 2 test spec
21、imens full width and atleast 1.4 m (1.5 yd) in length (see 7.2.1). Mark one specimen“A” for abraded and the other “U” for unabraded.7.4 When the lot or shipment consist of less than 5 rolls orpieces, randomly select 5 test specimens for each condition oftest, that represent all rolls or pieces in th
22、e lot or shipment.7.5 Ensure specimens are free of folds, creases, or wrinkles.Avoid getting oil, water, grease, etc. on the specimens whenhandling.NOTE 1An adequate specification or other agreement between thepurchaser and the supplier requires taking into account the variabilitybetween shipping un
23、its, between packages or ends within a shipping unit,and between specimens from a single package to provide a sampling witha meaningful producers risk, consumers risk, acceptable quality leveland limiting quality level.8. Preparation of Apparatus8.1 Prepare and verify the calibration of the tensile
24、testingmachine as directed in the manufacturers instructions andSpecification D76.8.2 Set up and adjust the CRE-type tensile testing machineas follows:8.2.1 Ensure that the clamps are positioned such that theyare facing opposite of each other with the upper clamp facingfront and the lower clamp faci
25、ng back. Set the distancebetween clamps, (gage length) to 250 6 10 mm (10 6 0.5 in.),center to center of the drums at the split.8.2.2 Use a force measuring system such that the breakingforce will fall between 15 and 85 percent of its full-scalecapacity.8.2.3 Set the crosshead speed to 75 6 25 mm/min
26、 (3 6 1in./min).8.2.4 When using an interfaced computer ormicroprocessor, set parameters to obtain selected propertiesusing suppliers directions and Specification D76.9. Conditioning9.1 Condition the test specimens to moisture equilibrium fortesting in the standard atmosphere for testing textiles in
27、accordance with Practice D1776 or, if applicable, in thespecified atmosphere in which the testing is to be performed.9.2 In the event of dispute concerning the results of teststhat may be affected by the moisture content, test specimen(s)shall be preconditioned by bringing them to approximatemoistur
28、e equilibrium in the standard atmosphere for precondi-tioning textiles in accordance with Practice D1776.10. Procedure10.1 Test the relaxed specimens in the standard atmospherefor testing textiles.NOTE 2The force measuring system should be zeroed prior to runningany specimens and periodically during
29、 the course of the test, particularlyif drift is observed in the zero value of the force measuring system.10.2 Insert one end of the specimen centrally and com-pletely between the two halves of the split drum in the upperclamp. From the front of the drum, wrap the specimen downand around the back of
30、 the lower half of the drum and uparound the upper half, such that the specimen comes over theupper clamp front.10.3 Take the opposite end of the specimen and starting atthe back, loosely wrap around both halves of the lower clamp.From the back of the lower clamp, lift the upper half of the splitdru
31、m and insert the specimen end centrally and completelybetween the two halves of the split drum. Remove as muchslack from the specimen as possible.10.3.1 When elongation is required and a slight tension isspecified in a material specification, apply the tension bymoving the lower crosshead (pulling m
32、echanism) down untilthe specified tension is shown on the recording device.10.4 When elongation is required, set the photo or elec-tronic instruments as directed in the manufacturers directions,if used, or place two fine ink bench marks such that thedistance between them is 125 6 1mm(56 0.05 in.) ap
33、art.Ensure neither bench mark is closer than 40 mm (1.5 in.) toeither clamp.10.5 Start the tester.10.6 When elongation is required, determine on the samespecimen as used for breaking strength. Stop the tester at thespecified force, determine the percent elongation from thephoto or electronic instrum
34、ents, if used, or measure and recordthe distance between bench marks to the nearest 1 mm (0.05in.). Restart the tester and immediately stop and record thebreaking force when the specimen ruptures.D6775 13310.7 If the specimen breaks within 6 mm (0.25 in.) of thenip of either clamp edge, or slippage
35、is indicated by a levelingin the force direction with abnormally high elongation, or forany reason attributable to faulty technique an individualmeasurement falls 20 % below the average test result for thelot, discard the result and test another specimen from the samepackage.10.8 Remove the specimen
36、 from the tester and continuetesting until all specimens have been tested for each laboratorysampling unit and for the lot.11. Calculation or Interpretation of Results11.1 Breaking ForceCalculate the breaking force for in-dividual specimens as read directly from the testing machineforce indicator to
37、 the nearest 1 %.11.1.1 Calculate the average breaking strength to the nearest1 % for the lot using the individual breaking force determina-tions.11.2 When specified, calculate the percent elongation atspecified force (EASF) for each specimen to the nearest 1.0 %using Eq 1.EASF 5 100!B2AA(1)where:EA
38、SF = elongation at specified force, %,A = initial length between bench marks, nominally 125mm (5 in.), andB = length between bench marks at a specified force,mm (in.).11.2.1 Calculate the average percent elongation at specifiedforce (EASF) for the lot using individual elongation determi-nations at s
39、pecified force determinations.11.3 Computer-Processed DataWhen data is automati-cally computer processed, calculations are generally containedin the associated software and the results displayed or printed,or both. In any event, it is recommended that the computer-processed data be verified against
40、known property values andthat the software be described in the report.12. Report12.1 State that the tests were made as directed in TestMethod D6775. Describe the material or product tested and themethod of sampling used.12.2 Report the following information for each laboratorysampling unit and for t
41、he lot:12.2.1 Individual breaking force,12.2.2 Average breaking strength,12.2.3 When required, individual elongation at specifiedforce,12.2.4 When required, average elongation at specified force,and12.2.5 For computer-processed data, identify the program(software) used.13. Precision and Bias13.1 Sum
42、maryBased upon limited information from onelaboratory, the single-operator and within-laboratory compo-nents of variation and critical differences shown in Tables 1and 2 are approximate. These tables are constructed to illustratewhat one laboratory found when all the observations are takenby well-tr
43、ained operators using the same piece of equipmentand specimens randomly drawn from the sample of material.For this laboratory, in comparing two averages , the differencesshould not exceed the single-operator precision values shownin Table 2 for the respective number of tests in 95 out of 100cases. D
44、ifferences for other laboratories may be larger orsmaller.13.2 Single-laboratory Test DataA single-laboratory testwas run in 2000 in which randomly-drawn samples of onematerial was tested. Six operators performed breaking strengthtests in the laboratory. Each operator tested five sets ofspecimens, e
45、ach set consisted of five specimens for a total of25 determinations. The tests were conducted over a two-weekperiod using the breaking strength procedure outlined in thistest method. Analysis of the data was conducted using theadjunct “Tex-Pac.” The components of variance for breakingstrength expres
46、sed as standard deviations were calculated to bethe values listed in Table 1. The material was MIL-W-4088Class 1, Type VIII, BRM Lot 946616 Webbing.13.3 PrecisionBecause tests were conducted in only onelaboratory, estimates of between laboratory precision have notbeen determined. Before a meaningful
47、 statement can be madeabout two specific laboratories, the amount of statistical bias, ifany, between them must be established, with each comparisonbeing based on recent data obtained on specimens taken froma lot of material of the type being evaluated so as to be asnearly homogeneous as possible an
48、d then randomly assigned inequal numbers to each of the laboratories. However whenagreed upon between the contractual parties, for the approxi-mate components of variance reported in Table 1, two averagesof observed values may be considered significantly different atthe 95 % probability level if the
49、 difference equals or exceedsthe critical differences listed in Table 2, for breaking strength ofwebbing material.NOTE 3Because the intralaboratory test included less than therecommended five laboratories, estimates of precision data in Tables 1 and2 may be either underestimated or overestimated to a considerable extentand should be used with special caution.13.4 BiasThe procedure of this test method produces atest value that can be defined only in terms of a test method.There is no independent, referee method by which bias may bedetermined. This test method has
