1、Designation: D5822 08D5822 13Standard Test Method forDetermining Seam Strength in Inflatable RestraintCushions1This standard is issued under the fixed designation D5822; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of l
2、ast 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 measurement of seam efficiency and the maximum seam strength in inflatable restraint cushio
3、nscomposed of woven fabrics when a force is applied perpendicular to the seam, using a grab test. For evaluating sewing thread, referto Test Method D204.1.2 This test method is restricted to seams that are either obtained from an inflatable restraint cushion. cushion or preparedoff-line, specificall
4、y for testing, using fabric blanks, not obtained from a previously sewn cushion assembly. Seams may includebut are not limited to sewn, OPW, glued, sealed and sewn, or fused (chemically or thermally). This test method can be used foreither lot testing of production cushions, or for research and deve
5、lopment purposes.1.3 This test method is used when the measurement of a resistance to a specified force, a breaking force, a minimum elongation,or a combination thereof are required to determine the seam strength, or seam integrity of a particular fabric for inflatable restraintuse.1.4 Procedures an
6、d apparatus other than those stated in this standard may be used by agreement between purchaser and supplierwith the specific deviations from the standard acknowledged in the report.1.5 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values sta
7、ted in eachsystem are not exact equivalents; therefore, each system must be used independently of the other.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety
8、and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D123 Terminology Relating to TextilesD204 Test Methods for Sewing ThreadsD1776 Practice for Conditioning and Testing TextilesD6799 Terminology Relating to Inflatable
9、Restraints3. Terminology3.1 For all terminology relating to D13.20, Inflatable restraints, refer to Terminology D6799.3.1.1 The following terms are relevant to this standard: seam efficiency, seam failure, seam strength.3.2 For all other terms related to textiles, see Terminology D123.4. Summary of
10、Test Method4.1 Specimens with and without seam assemblies either taken from inflatable restraint cushions or made off-line using fabricblanks, specifically for testing, are destructively tested in a tensile testing machine under laboratory conditions to determine seamstrength and seam efficiency. ef
11、ficiency and nature of the failure mode.1 This test method is under the jurisdiction of ASTM Committee D13 on Textiles and is the direct responsibility of Subcommittee D13.20 on Inflatable Restraints.Current edition approved July 1, 2008Jan. 1, 2013. Published July 2008February 2013. Originally appr
12、oved in 1995. Last previous edition approved in 20072008 asD5822 03D5822 08.(2007). DOI: 10.1520/D5822-08.10.1520/D5822-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, ref
13、er to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all ch
14、anges accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959.
15、United States15. Significance and Use5.1 Seam strength testing is used for design validation and for lot acceptance.5.2 This test method constitutes the conditions, procedures, and equipment by which inflatable restraints either seams takenfrom inflatable restraint cushions, or seam types that can p
16、otentially be used for inflatable restraint cushions are tested for seamstrength and seam efficiency.strength, seam efficiency, and failure mode. It is intended to be used as a guideline in establishing awritten part specification or print. The specification or agreement of purchaser and supplier ma
17、y deviate from the proceduresdescribed herein when (based on experience) considerations of equipment, cushion design, or other factors dictate otherwise.5.3 In cases of dispute arising from differences in reported test results when using this test method for acceptance testing ofcommercial shipments
18、, the purchaser and the supplier should perform comparative tests to determine if there is a statistical biasbetween their laboratories. Competent statistical assistance is recommended for the investigation of bias. As a minimum, the twoparties should take a group of test specimens from the same lot
19、 of fabric to be evaluated, which utilize a like seam assembly (orstandard seam assembly) to achieve seam interaction. The test specimens should then be randomly assigned in equal numbers toeach laboratory for testing. If a bias is found, either its cause must be determined and corrected, or the pur
20、chaser and supplier mustagree to interpret future test results in light of the known bias.5.4 Test Method D5822 is a reliable test method but procedures which may require special attention are identified in theprecision and bias section of this test method.6. Apparatus6.1 Tensile Testing Machine, of
21、 the CRE, CRL or CRT type conforming to Specification D76, with respect to force indication,working range, capacity, and elongation indicator, and designed for operation at a speed of 300 6 10 mm/min (12 6 0.5 in./min);or, a variable speed drive, change gears, or interchangeable weights as required
22、to obtain a 20 6 3-s time-to-break (see 12.4). Theconstant-rate-of-extension type of tensile testing machine is preferred in this test method.6.2 Clamp and Jaw Faces, adjustable clamps compatible with tensile testing machine, the jaws of which have smooth, flat,metallic gripping surfaces parallel to
23、 each other.6.2.1 Each clamp shall have a front (or top) jaw face measuring 25 6 1 mm (1.0 6 0.02 in.) perpendicular to the direction ofthe application of the force, and not less than 25 nor more than 50 mm (1.0 nor more than 2.0 in.) parallel to the direction of theapplication of the force. The bac
24、k, or bottom, jaw face of each clamp shall be at least as large as its mate. Use of a larger facefor the second jaw reduces the problem of front and 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
25、 1.0-in.) faces.For many materials, the former are preferable because of the larger gripping area which tends to reduce slippage. While both sizes of gripping surfaceare permitted, the face sizes used must be the same for all samples in the test and must be recorded in the report.6.2.2 At least one
26、clamp should be supported by a free swivel or universal joint to allow the clamp to rotate in the plane of thefabric.6.3 For inflatable restraints, all test equipment used in accordance with this test method shall be certified for calibration annuallyby an independent agency or equipment manufacture
27、r whose results are traceable to the National Institute of Science andTechnology (NIST) or other national standards laboratory. The test parameters of the equipment shall be tested within the operatingranges covered in the cushion specification or equivalent document.7. Sampling7.1 Seam strength tes
28、ting is a destructive test and therefore necessitates sampling procedures if used in conjunction with lotacceptance.7.2 For acceptance testing, the lot size is the quantity of cushions produced in one day.7.3 Lot SampleFor acceptance testing, take at random the number of cushions directed in an appl
29、icable cushion specificationor other agreement between purchaser and supplier. Consider the cushions to be the primary sampling units.7.4 Test SpecimensSelect portions of sampled cushions containing seam assemblies as directed in an applicable cushionspecification or as agreed upon by purchaser and
30、supplier. If seam efficiency testing is to be done, select a portion of unseamedfabric adjacent to the sampled area, from which the seamed specimen was taken. Wherever possible, such specimens shouldcontain the same yarns as the seam assemblies that are to be placed in the clamps oriented parallel t
31、o the traverse direction of test.NOTE 2Specimens are usually specified to be taken from a cushion at a location on the cushion seam(s) where the greatest stresses are anticipated.In seams involving woven fabric, this is usually where the warp or filling yarns are parallel to the seam. Cushion design
32、 may indicate other stress pointsof concern.NOTE 3Use caution in selecting specimens from areas of the cushion where the seams exhibit sharp radius turns. During seam strength testing, theseareas will exhibit uneven point loading at the edges of the test specimen.NOTE 4Unless otherwise specified for
33、 driver-side cushions, select specimens taken from the perimeter seam at the 0 rad (0), 0.79 rad (45), and 1.57rad (90) positions, relative to the warp direction of the fabric in the front panel.D5822 1327.4.1 Cut each specimen 100 6 1 mm (4 6 0.05 in.) wide by at least 150 mm (6 in.) long (Note 5)
34、with the long dimensionparallel to the direction of testing and force application. For seamed specimens, the seam shall be centrally located perpendicularto the application of force.NOTE 5The length of the specimen depends on the type of clamps being used. The specimen should be long enough to exten
35、d through the clampsand project at least 10 mm (0.5 in.) at each end. The specimen length may be calculated using Eq 1 or Eq 2:Specimen length,mm5C12W (1)Specimen length,in.5K12W (2)where:C = 95 mm (constant based on a gage length of 75 plus 20 mm for projections beyond the clamp),K = 4 in. (constan
36、t 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 the tensile testing machine, draw vertical lines parallel to the longdirection (and along a yarn of woven fabric)
37、 located 37 6 1 mm (1.5 6 0.02 in.) in from the edge of both sides of the specimen.The parallel lines serve as a guide to ensure that the same yarns in the direction of test are gripped in both clamps.8. Conditioning8.1 Conditioning of specimens for seam strength testing shall be at the standard atm
38、osphere for testing textiles for at least 4 hprior to test, in accordance with Practice D1776.9. Procedure9.1 Select and condition specimens in accordance with Sections 7 and 8 of this test method.FIG. 1 Specimen Placement in Clamps(Clamp Gage Area and Vertical Alignment Guides)D5822 1339.2 For seam
39、 assembly testing, place the specimen containing the seam assembly in the clamps with the seam towards the rearof the machine (as shown in Fig. 1) using the vertical alignment guides, and center the seam line in the clamp faces, perpendicularto the direction of test. For seam efficiency, place the u
40、nseamed fabric specimen in the clamps using the vertical alignment guidesin the clamp faces, parallel to the direction of test.9.3 Ensure that the tension on the specimen is uniform across the clamp width.9.4 Draw a mark across the specimen at the front inner edge of each jaw to check for specimen s
41、lippage. When slippage occurs,the mark will move away from the jaw edge and such movement can be observed.9.5 Operate the tensile tester until partial rupture or severe yarn slippage of the specimen is observed. Record whether the modeof failure is yarn slippage or rupture, and its location.9.6 Reco
42、rd the maximum seam strength or maximum fabric strength of the test specimen depending upon the type of specimentested.9.7 Inspect the mark previously drawn on each specimen across the jaw to check for seam slippage. No noticeable seam slippageshould occur during the test.9.8 Discard test data if th
43、e measured breaking force values are significantly below specified value or below the average valueof the other specimens.NOTE 6The causes of such outlying data include, but are not limited to, (1) specimen slippage in jaws, (2) specimen rupture at the edge of or withinthe jaws, and (3) faulty opera
44、tion of the tensile tester. The criteria for deciding to discard outlying test data and the method of reporting such rejectionof test data should be established by purchaser and supplier. In the absence of any such agreement, these specimens and results shall be retained.NOTE 7When a specimen is obs
45、erved to slip in the jaws, or if more than 25 % of the specimens break at a point within 5 mm (0.020 in.) of the edgeof the jaw, then (1) the jaws may be padded, (2) the fabric may be coated under the jaw face area, or (3) the surface of the jaw face may be modified.If any of these modifications are
46、 used, state so in the report.NOTE 8It is difficult to determine the precise reason for certain specimens to break near the edge of the jaws. If such a break is caused by damageto the specimen by the jaws, then the results should be discarded. If, however, the break is due merely to randomly distrib
47、uted weak places, it is alegitimate test result. In some cases, it may also be caused by a concentration of stress in the area adjacent to the jaws because the jaws prevent thespecimen from contracting in width as the force is applied. In such cases, a break near the edge of the jaw is inevitable an
48、d should be accepted as acharacteristic of the particular test method. This is often the case when testing fabrics using the grab procedure.10. Calculations10.1 Calculate the maximum seam strength of individual specimens using Eq 3:Ss 5kSb/W (3)where:Ss = maximum seam strength, N (lbf),k = a constan
49、t equal to 1000 for SI units and 1 for inch-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:E5100 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 with Test Method D5822 for determining the maximum seam strengthin inflatable restraints cushions.11.1.1 If deviation from Test Method D5822 occurred, any reference to this test method
