ASTM_D_3940_-_83_scan.pdf

ASTM D3=lqO 83 B?J 0759530 0032767 B m/j-36-a5 Designation:D 3940-83 AMERICAN SOCIETY FOR TESTING AND MATERIALS 1916 Race St.,Philadelphia,Pa.19103 Reprinted from the Annual Book of ASTM Standards,Copyright ASTM If not listed in the current combined index,will appear in the next edition.Standard Test Method for BURSTING STRENGTH(LOAD)AND ELONGATION OF SEWN SEAMS OF KNIT OR WOVEN STRETCH TEXTILE FABRICS This standard is issued under the fared designation D 3940;the number immediately following the designation indicates the year of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon(e)indicates an editorial change since the last revision or reapproval.1.Scope 1.1 This test method covers the determination of the bursting strength and elongation of sewn seams in knit or stretch fabrics.The sewn seams may be obtained from previously fabricated ar-ticles such as garments or may be prepared from fabric samples.1.2 This test method requires a straight seam line,and is not applicable if the seam line is curved.1.3 Preparation of test specimens from fabric samples requires prior specification of sewing details as agreed upon by the purchaser and seller.NOTE l-If the breaking force of the fabric alone is also required,test as directed in Method D 3787.2.Applicable Documents 2.1 ASTM Standards:D76 Specification for Tensile Testing Ma-chines for Textiles2 D 123 Definitions of Terms Relating to Tex-tiles2 D 204 Testing Sewing Threads3 D 1683 Test for Breaking Strength(Load)and Slippage of Yams of Sewn Seams in Woven Textile Fab.ric?D 1776 Practice for Conditioning Textiles for Testing2 D3787 Test for Bursting Strength of Knit-ted Goods:Constant-Rate-of-Traverse(CRT),Ball Burst Test3 D3823 Practice for Determining Ticket Numbers for Sewing Threads3 2.2 Federal Standards:Fed.Std.No.751a Standard for Stitches,Seams,and Stitching4 3.Definitions 3.I failure,n.-in sewn fabric seams,fabric or sewing thread rupture or seam-yarn SliPPage.3.1.1 Djscussion-A seam in knit or stretch fabric is considered to have failed when the sew-ing thread ruptures due to low longitudinal elan-gation of the seam.3.2 seam allowance,n.-in sewn fabrics,the distance from the edge of a fabric to the parallel stitch line furthest from that edge.3.3 seam assembly,n.-the composite struc-ture obtained.when fabric(s)are joined by means of a seam.3.3.1 Discussion-A seam assembly may be described in terms of the fabric orientation,seam direction,seam type,stitch type,seam allowance,sewing thread tex ticket number(s)and type(s),stitch density,and stitch gage.3.4 seam type,n.-in sewn fabrics,an alpha-numeric designation relating to the essential characteristics of fabric positioning and rows of stitching in a specified sewn fabric seam.3.4.1 Discussion-seam types are described in Fed.Std.No.75 la.3.5 sewn seam,n.-in sewn fabrics,a juncture of which two or more planar structures such as textile fabrics,are joined by sewing,usually near the edge.This test method is under the jurisdiction of ASTM Com-mittee D-13 on Textiles and is the direct responsibility of Subcommittee D13.54 on Consumer Product Performance.Current edition approved July 29,1983.Published Septem-ber 1983.Originally published as D 3940-80.Last previous edition D 3940-82.1983 Annrtal Book of ASTM Standards,Vols 07.01 and 07.02.1983 Annual Book of ASTM Standards,VolO7.0 1.Available from.Naval Publications and Forms Center,580 I Tahor Ave.,Philadelphia,Pa.19120.1 NOTICE:This standard has either been superseded and replaced by a new version or discontinued.Contact ASTM International(www.astm.org)for the latest information.3.6 stitch,n-in sewn seams,the repeated unit formed by the sewing thread(s)in the pro-duction of seams.3.1 stitch density,n.-in sewn seams,the number of stitches per unit length in one row of stitching in the seam.3.7.1 Determine stitch density as directed in Part II Section 4,Stitches Per Unit Length,of Federal Standard No,75 la.3.8 stitch gage,n.-in sewn fabrics,the per-pendicular distance between adjacent parallel rows of stitching.3.9 stitch type,n.-in sebvn seams,a numeri-cal designation relating to the essential character-istics of the interlacing of sewing thread(s)in a specified stitch.3.9.1 Discttssion-Stitch types are described in Fed.Std.No.75 la.3.10 strength,bursting,n-the force or pres-sure required to rupture a textile by distending it with a force,applied at right angles to the plane of the fabric,under specified conditions.3.11 For definitions of other textile terms used in this method,refer to Definitions D 123.4.Summary of Method 4.1 Prescribed sewn seams taken from an al-ready sewn item or prepared in accordance with a specification are tested for force to rupture and for extensibility using the ball burst procedure.5.Significance and Uses 5.1 This test method is useful for determining the rupture force and extensibility of seams in knit or woven stretch fabrics