1、Designation: D 6775 02 (Reapproved 2007)Standard Test Method forBreaking Strength and Elongation of Textile Webbing, Tapeand Braided Material1This standard is issued under the fixed designation D 6775; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、 case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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
3、textile webbing, tape 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 89000N (20000 lb).1.3 The values stated in either SI units or U.S. Customaryunits are t
4、o be regarded separately 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,
5、if any, associated with 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 Machine
6、s for TextilesD 123 Terminology Relating to TextilesD 1776 Practice for Conditioning and Testing TextilesD 4848 Terminology of Force, Deformation and RelatedProperties of TextilesD 4850 Terminology Relating to Fabric3. Terminology3.1 For definitions of terms related to force and deformationused in t
7、his test method, refer to Terminology D 4848. Fordefinitions of other terms related to textiles used in thisstandard, refer to Terminology D 123, and D 4850.4. Summary of Test Method4.1 A specimen is clamped in a tensile testing machine andextended to rupture. The breaking force is determined from a
8、force-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 compar
9、isons 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 bias bet
10、ween 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 laborat
11、ory. 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 consi
12、deration 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 Tensile Te
13、sting Machine, CRE-type, conforming toSpecification D76with respect to force indication, workingrange, capacity and verification of recorded elongation, anddesigned for operation at a pulling speed of 75 6 25 mm/min(3 6 1 in./min).1This test method is under the jurisdiction of ASTM Committee D13 on
14、Textilesand is the direct responsibility of Subcommittee D13.60 on Fabric Test Methods,Specific.Current edition approved Jan. 1, 2007. Published January 2007. Originallyapproved in 2002. Last previous edition approved in 2002 as D 6775 02e1.2For referenced ASTM standards, visit the ASTM website, www
15、.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Apparatus and clamps are commercially available.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West
16、 Conshohocken, PA 19428-2959, United States.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, interfaced, with auto-matic data gathering system, including photo or electronicinstruments to measure elong
17、ation. (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 select five rolls or pieces to constitute the lotsample.7.2 Laboratory Sampling Unit, as produced materialAs
18、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, longer specimens may be re-quired to maintain the specified gage length and to ensure thespecimen is completely i
19、n 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 each roll orpiece in the lot sample (see 7.2.1).7.3 Test Specimens, as produced materialFrom each labo-ratory sa
20、mpling 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 specimens full width and atleast 1.4 m (1.5 yd) in length (see 7.2.1). Mark one specimen“A” for abraded and the ot
21、her “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 the lot or shipment.7.5 Ensure specimens are free of folds, creases, or wrinkles.Avoid getting oil, water, greas
22、e, etc. on the specimens whenhandling.NOTE 1An adequate specification or other agreement between thepurchaser and the supplier requires taking into account the variabilitybetween shipping units, between packages or ends within a shipping unit,and between specimens from a single package to provide a
23、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 testingmachine as directed in the manufacturers instructions andSpecification D76.8.2 Set up and adjust the CR
24、E-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 facing back. Set the distancebetween clamps, (gage length) to 250 6 10 mm (10 6 0.5 in.),center to center of the d
25、rums 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 (3 6 1in./min).FIG. 1 Side View of Clamping AssemblyD 6775 02 (2007)28.2.4 When using an interfaced computer
26、or microproces-sor, set parameters to obtain selected properties using suppli-ers directions and Specification D76.9. Conditioning9.1 Condition the test specimens to moisture equilibrium fortesting in the standard atmosphere for testing textiles inaccordance with Practice D 1776 or, if applicable, i
27、n 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 approximatemoisture equilibrium in the standard atmosphere for precon
28、di-tioning textiles in accordance with Practice D 1776.10. 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 the course of the test, particularlyif drift is o
29、bserved 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 the lower half of the drum and uparound the upper
30、 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 splitdrum and insert the specimen end centrally and comple
31、telybetween 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 mechanism) down untilthe specified tension is shown
32、 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.) apart.Ensure neither bench mark is closer than 40 mm
33、 (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 instruments, if used, or measure and recordthe distance b
34、etween bench marks to the nearest 1 mm (0.05in.). Restart the tester and immediately stop and record thebreaking force when the specimen ruptures.10.7 If the specimen breaks within 6 mm (0.25 in.) of thenip of either clamp edge, or slippage is indicated by a levelingin the force direction with abnor
35、mally 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.FIG. 2 Example of Clamping AssemblyD 6775 02 (2007)310.8 Remove the specimen from t
36、he 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 the ne
37、arest 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!AB(1)where:EASF = elon
38、gation at specified force, %,A = initial nominal length between bench marks, 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 specified fo
39、rce 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 known prope
40、rty values andthat the software be described in the report.12. Report12.1 State that the tests were made as directed in TestMethod D 6775. Describe the material or product tested andthe method of sampling used.12.2 Report the following information for each laboratorysampling unit and for the lot:12.
41、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 SummaryBased
42、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-trained oper
43、ators 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. Differences
44、 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, each set co
45、nsisted 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 expressed as sta
46、ndard 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 statement
47、 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 and then ran
48、domly 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 differenc
49、e equals or exceedsthe critical differences listed in Table 2, for breaking strength ofwebbing material.NOTE 3Because the intralaboratory test included less than the recom-mended five laboratories, estimates of precision data in Tables 1 and 2may 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 no known
