ASTM D5822-2003(2007) Standard Test Method for Determining Seam Strength in Inflatable Restraint Cushions《测定充气缓冲垫接缝强度的标准试验方法》.pdf

1、Designation: D 5822 03 (Reapproved 2007)Standard Test Method forDetermining Seam Strength in Inflatable RestraintCushions1This standard is issued under the fixed designation D 5822; 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the measurement of seamefficiency and the maximum seam strength in inflatable re-s

3、traint cushions composed of woven fabrics when a force isapplied perpendicular to the seam, using a grab test. Forevaluating sewing thread, refer to Test Method D 204.1.2 This test method is restricted to seams that are obtainedfrom an inflatable restraint cushion. Seams may include but arenot limit

4、ed to sewn, OPW, glued, fused (chemically or ther-mally).1.3 This test method is used when the measurement of aresistance to a specified force, a breaking force, a minimumelongation, or a combination thereof are required to determinethe seam strength, or seam integrity of a particular fabric forinfl

5、atable restraint use.1.4 Procedures and apparatus other than those stated in thisstandard may be used by agreement between purchaser andsupplier with the specific deviations from the standard ac-knowledged in the report.1.5 The values stated in either SI units or inch-pound unitsare to be regarded s

6、eparately as standard. The values stated ineach system are not exact equivalents; therefore, each systemmust be used independently of the other.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standa

7、rd 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:2D 123 Terminology Relating to TextilesD 204 Test Methods for Sewing ThreadsD 1776 Practice for Conditioning and Testing Textiles

8、D 3990 Terminology Relating to Fabric Defects3. Terminology3.1 Definitions:3.1.1 seam effciency, nin inflatable restraints, the ratio ofseam strength to fabric strength.3.1.2 seam failure, nin inflatable restraints, the point atwhich an external force ruptures a seam assembly or the fabric,or causes

9、 excessive yarn slippage adjacent to the seam assem-bly.3.1.3 seam strength, nin inflatable restraints, the maxi-mum force required to create a seam failure.3.2 For definitions of textile terms relating to inflatablerestraints used in this standard, refer to Terminology D 3990.3.3 For definitions of

10、 other textile terms used in thisstandard, refer to Terminology D 123.4. Summary of Test Method4.1 Specimens with and without seam assemblies takenfrom inflatable restraint cushions are destructively tested in atensile testing machine under laboratory conditions to deter-mine seam strength and seam

11、efficiency.5. Significance and Use5.1 Seam strength testing is used for design validation andfor lot acceptance.5.2 This test method constitutes the conditions, procedures,and equipment by which inflatable restraints are tested forseam strength and seam efficiency. It is intended to be used asa guid

12、eline in establishing a written part specification or print.The specification or agreement of purchaser and supplier maydeviate from the procedures described herein when (based onexperience) considerations of equipment, cushion design, orother factors dictate otherwise.5.3 In cases of dispute arisin

13、g from differences in reportedtest results when using this test method for acceptance testingof commercial shipments, the purchaser and the suppliershould perform comparative tests to determine if there is astatistical bias between their laboratories. Competent statisticalassistance is recommended f

14、or the investigation of bias. As aminimum, the two parties should take a group of test speci-mens from the same lot of fabric to be evaluated, which utilizea like seam assembly (or standard seam assembly) to achieve1This test method is under the jurisdiction of ASTM Committee D13 on Textilesand is t

15、he direct responsibility of Subcommittee D13.20 on Inflatable Restraints.Current edition approved July 1, 2007. Published August 2007. Originallyapproved in 1995. Last previous edition approved in 2003 as D 5822 03.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM

16、Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.seam interaction. The test spec

17、imens should then be randomlyassigned in equal numbers to each laboratory for testing. If abias is found, either its cause must be determined and cor-rected, or the purchaser and supplier must agree to interpretfuture test results in light of the known bias.5.4 Test Method D 5822 is a reliable test

18、method butprocedures which may require special attention are identified inthe precision and bias section of this test method.6. Apparatus6.1 Tensile Testing Machine, of the CRE, CRL or CRT typeconforming to Specification D 76, with respect to force indi-cation, working range, capacity, and elongatio

19、n indicator, anddesigned for operation at a speed of 300 6 10 mm/min (12 60.5 in./min); or, a variable speed drive, change gears, orinterchangeable weights as required to obtain a 20 6 3-stime-to-break (see 12.4). The constant-rate-of-extension typeof tensile testing machine is preferred in this tes

20、t method.6.2 Clamp and Jaw Faces, adjustable clamps compatiblewith tensile testing machine, the jaws of which have smooth,flat, metallic gripping surfaces parallel to each other.6.2.1 Each clamp shall have a front (or top) jaw facemeasuring 25 6 1 mm (1.0 6 0.02 in.) perpendicular to thedirection of

21、 the application of the force, and not less than 25nor more than 50 mm (1.0 nor more than 2.0 in.) parallel to thedirection of the application of the force. The back, or bottom,jaw face of each clamp shall be at least as large as its mate. Useof a larger face for the second jaw reduces the problem o

22、f frontand back jaw misalignment.NOTE 1Front (or top) faces measuring 25 by 50-mm (1.0 by 2.0-in.)will not necessarily give the same value as 25 by 25-mm (1.0 by 1.0-in.)faces. For many materials, the former are preferable because of the largergripping area which tends to reduce slippage. While both

23、 sizes of grippingsurface are permitted, the face sizes used must be the same for all samplesin the test and must be recorded in the report.6.2.2 At least one clamp should be supported by a freeswivel or universal joint to allow the clamp to rotate in theplane of the fabric.6.3 For inflatable restra

24、ints, all test equipment used inaccordance with this test method shall be certified for calibra-tion annually by an independent agency or equipment manu-facturer whose results are traceable to the National Institute ofScience and Technology (NIST) or other national standardslaboratory. The test para

25、meters of the equipment shall be testedwithin the operating ranges covered in the cushion specifica-tion or equivalent document.7. Sampling7.1 Seam strength testing is a destructive test and thereforenecessitates sampling procedures if used in conjunction withlot acceptance.7.2 For acceptance testin

26、g, the lot size is the quantity ofcushions produced in one day.7.3 Lot SampleFor acceptance testing, take at random thenumber of cushions directed in an applicable cushion specifi-cation or other agreement between purchaser and supplier.Consider the cushions to be the primary sampling units.7.4 Test

27、 SpecimensSelect portions of sampled cushionscontaining seam assemblies as directed in an applicable cush-ion specification or as agreed upon by purchaser and supplier.If seam efficiency testing is to be done, select a portion ofunseamed fabric adjacent to the sampled area, from which theseamed spec

28、imen was taken. Wherever possible, such speci-mens should contain the same yarns as the seam assembliesthat are to be placed in the clamps oriented parallel to thetraverse direction of test.NOTE 2Specimens are usually specified to be taken from a cushion ata location on the cushion seam(s) where the

29、 greatest stresses areanticipated. In seams involving woven fabric, this is usually where thewarp or filling yarns are parallel to the seam. Cushion design may indicateother stress points of concern.NOTE 3Use caution in selecting specimens from areas of the cushionwhere the seams exhibit sharp radiu

30、s turns. During seam strength testing,these areas will exhibit uneven point loading at the edges of the testspecimen.NOTE 4Unless otherwise specified for driver-side cushions, selectspecimens taken from the perimeter seam at the 0 rad (0), 0.79 rad (45),and 1.57 rad (90) positions, relative to the w

31、arp direction of the fabric inthe front panel.7.4.1 Cut each specimen 100 6 1mm(46 0.05 in.) wideby at least 150 mm (6 in.) long (Note 5) with the longdimension parallel to the direction of testing and force appli-cation. For seamed specimens, the seam shall be centrallylocated perpendicular to the

32、application of force.NOTE 5The length of the specimen depends on the type of clampsbeing used. The specimen should be long enough to extend through theclamps and project at least 10 mm (0.5 in.) at each end. The specimenlength may be calculated using Eq 1 or Eq 2:Specimen length, mm 5 C 1 2W (1)Spec

33、imen length, in. 5 K 1 2W (2)where:C = 95 mm (constant based on a gage length of 75 plus 20mm for projections beyond the clamp),K = 4 in. (constant based on a gage length of 3 plus 1 in.for projections beyond the clamps), andW = jaw face width in direction of force, mm (in.).7.4.2 To aid in aligning

34、 the specimens in the clamps of thetensile testing machine, draw vertical lines parallel to the longdirection (and along a yarn of woven fabric) located 37 6 1mm (1.5 6 0.02 in.) in from the edge of both sides of thespecimen. The parallel lines serve as a guide to ensure that thesame yarns in the di

35、rection of test are gripped in both clamps.8. Conditioning8.1 Conditioning of specimens for seam strength testingshall be at the standard atmosphere for testing textiles for atleast 4 h prior to test, in accordance with Practice D 1776.9. Procedure9.1 Select and condition specimens in accordance wit

36、hSections 7 and 8 of this test method.9.2 For seam assembly testing, place the specimen contain-ing the seam assembly in the clamps with the seam towards therear of the machine (as shown in Fig. 1) using the verticalalignment guides, and center the seam line in the clamp faces,perpendicular to the d

37、irection of test. For seam efficiency, placeD 5822 03 (2007)2the unseamed fabric specimen in the clamps using the verticalalignment guides in the clamp faces, parallel to the direction oftest.9.3 Ensure that the tension on the specimen is uniformacross the clamp width.9.4 Draw a mark across the spec

38、imen at the front inner edgeof each jaw to check for specimen slippage. When slippageoccurs, the mark will move away from the jaw edge and suchmovement can be observed.9.5 Operate the tensile tester until partial rupture or severeyarn slippage of the specimen is observed. Record whether themode of f

39、ailure is yarn slippage or rupture, and its location.9.6 Record the maximum seam strength or maximum fabricstrength of the test specimen depending upon the type ofspecimen tested.9.7 Inspect the mark previously drawn on each specimenacross the jaw to check for seam slippage. No noticeable seamslippa

40、ge should occur during the test.9.8 Discard test data if the measured breaking force valuesare significantly below specified value or below the averagevalue of the other specimens.NOTE 6The causes of such outlying data include, but are not limitedto, (1) specimen slippage in jaws, (2) specimen ruptu

41、re at the edge of orwithin the jaws, and (3) faulty operation of the tensile tester. The criteriafor deciding to discard outlying test data and the method of reporting suchrejection of test data should be established by purchaser and supplier. Inthe absence of any such agreement, these specimens and

42、 results shall beretained.NOTE 7When a specimen is observed to slip in the jaws, or if morethan 25 % of the specimens break at a point within 5 mm (0.020 in.) of theedge of the jaw, then (1) the jaws may be padded, (2) the fabric may becoated under the jaw face area, or (3) the surface of the jaw fa

43、ce may bemodified. If any of these modifications are used, state so in the report.NOTE 8It is difficult to determine the precise reason for certainspecimens to break near the edge of the jaws. If such a break is caused bydamage to the specimen by the jaws, then the results should be discarded.If, ho

44、wever, the break is due merely to randomly distributed weak places,it is a legitimate test result. In some cases, it may also be caused by aconcentration of stress in the area adjacent to the jaws because the jawsprevent the specimen from contracting in width as the force is applied. Insuch cases, a

45、 break near the edge of the jaw is inevitable and should beaccepted as a characteristic of the particular test method. This is often thecase when testing fabrics using the grab procedure.10. Calculations10.1 Calculate the maximum seam strength of individualspecimens using Eq 3:Ss5 kSb/W (3)where:Ss=

46、 maximum seam strength, N (lbf),FIG. 1 Specimen Placement in Clamps(Clamp Gage Area and Vertical Alignment Guides)D 5822 03 (2007)3k = a constant equal to 1000 for SI units and 1 forinch-pound units,Sb= recorded seam assembly breaking force, N (lbf), andW = width of specimen in jaws, mm (in.).10.2 D

47、etermine percent seam efficiency using Eq 4:E 5 100 Ss/F (4)where:E = seam efficiency, %,Ss= recorded seam strength, N (lbf), andF = fabric breaking force, N (lbf).11. Report11.1 State that the tests were conducted in accordance withTest Method D 5822 for determining the maximum seamstrength in infl

48、atable restraints cushions.11.1.1 If deviation from Test Method D 5822 occurred, anyreference to this test method shall state: “Testing was per-formed in accordance with ASTM D 5822, with the followingchanges:”11.2 The purchaser and supplier shall determine the exactform of the test report. Unless o

49、therwise specified, the reportshall provide the following information:11.2.1 Cushion designation(s),11.2.2 Lot identification,11.2.3 Date of report,11.2.4 Name of person certifying report,11.2.5 Relevant specification,11.2.6 Type of testing machine used,11.2.7 Maximum force obtainable in the range used fortesting,11.2.8 Pretension if used,11.2.9 Size of jaw faces used,11.2.10 Type of padding used in the jaws, modification ofspecimen gripped in the jaws, or modification of jaw faces, ifany,11.2.11 Cushion location of the specimens used in the seamstrength test,11.2.