1、Designation: D 5822 08Standard 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, the year of last re
2、vision. 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 measurement of seamefficiency and the maximum seam strength in inflatable re-straint cushions com
3、posed 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 limited to sewn, OPW, gl
4、ued, 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 forinflatable restraint us
5、e.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 separately as standa
6、rd. 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 standard to establish app
7、ro-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 TextilesD 6799 Terminology
8、Relating to Inflatable Restraints3. Terminology3.1 For all terminology relating to D13.20, Inflatable re-straints, refer to Terminology D 6799.3.1.1 The following terms are relevant to this standard:seam efficiency, seam failure, seam strength.3.2 For all other terms related to textiles, see Termino
9、logyD 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 efficiency.5. Significance and Use5.1 Seam strength testing
10、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 guideline in establishing a written part specification or print.
11、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 arising from differences in reportedtest results when using this t
12、est 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 for the investigation of bias. As aminimum, the two parties s
13、hould 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 achieveseam interaction. The test specimens should then be randomlyassigned in equal numbers to each laboratory for testing. If abias is found, either i
14、ts cause must be determined and cor-rected, or the purchaser and supplier must agree to interpretfuture test results in light of the known bias.1This test method is under the jurisdiction of ASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.20 on Inflatable Restraint
15、s.Current edition approved July 1, 2008. Published July 2008. Originally approvedin 1995. Last previous edition approved in 2007 as D 5822 03(2007).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandar
16、ds 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.5.4 Test Method D 5822 is a reliable test method butprocedures which may require special attention
17、 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 elongation indicator, anddesigned for operation at a speed of 300
18、 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 test method.6.2 Clamp and Jaw Faces, adjustable clamps comp
19、atiblewith 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 the application of the force, and not less than 25nor m
20、ore 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 of frontand back jaw misalignment.NOTE 1Front (or top) fa
21、ces 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 sizes of grippingsurface are permitted, the face sizes
22、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 restraints, all test equipment used inaccordance with this tes
23、t 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 parameters of the equipment shall be testedwithin the operat
24、ing 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 testing, the lot size is the quantity ofcushions produced in o
25、ne 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 SpecimensSelect portions of sampled cushionscontaining
26、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 specimen was taken. Wherever possible, such speci-mens shoul
27、d 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 greatest stresses areanticipated. In seams involving wo
28、ven 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 radius turns. During seam strength testing,these areas will e
29、xhibit 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 warp direction of the fabric inthe front panel.7.4.1 Cut
30、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 application of force.NOTE 5The length of the specimen de
31、pends 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)Specimen length, in. 5 K 1 2W (2)where:C = 95 mm (constant b
32、ased 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 the specimens in the clamps of thetensile testing machi
33、ne, 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 direction of test are gripped in both clamps.8. Conditioni
34、ng8.1 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 withSections 7 and 8 of this test method.9.2 For seam assem
35、bly 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 direction of test. For seam efficiency, placethe unseamed
36、 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 specimen at the front inner edgeof each jaw to check for specimen slippage. W
37、hen slippageD5822082occurs, 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 failure is yarn slippage or rupture, and its location.9.6 Record t
38、he 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 seamslippage should occur during the test.9.8 Discard test data if the meas
39、ured 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 rupture at the edge of orwithin the jaws, and (3) faulty operation of
40、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 results shall beretained.NOTE 7When a specimen is observed to sl
41、ip 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 face may bemodified. If any of these modifications are used, state
42、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, however, the break is due merely to randomly distributed weak place
43、s,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 break near the edge of the jaw is inevitable and should beaccept
44、ed 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= maximum seam strength, N (lbf),k = a constant equal to 1000 for
45、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 Determine percent seam efficiency using Eq 4:E 5 100 Ss/F (4)where:FIG. 1 Specimen Placement in Clamps(Clamp Gage Area and Vertical Alignment Guides)D5822083E = seam
46、 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 inflatable restraints cushions.11.1.1 If deviation from Test Method D 5822 occ
47、urred, 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 otherwise specified, the reportshall provide the following information:11.2
48、.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.
49、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,11.2.12 Number of specimens used in each test,11.2.13 Type of test specimen,11.2.14 The average breaking force for specimens givingacceptable breaks,11.2.15 Results of the seam strength tests for each location,11.2.16 Tests performed and data obtained,11.2.17 Laboratory conditions if other than standard, and11.2.18 Deviations from standard procedures and apparatus.12. Precision and
