ASTM International Standard Test Method for Stiffness of Fabrics ASTM D1388-23

1.1 This test method covers the measurement of stiffness properties of fabrics. Bending length is measured and flexural rigidity is calculated. Two procedures are provided. 1.1.1 Option A\u2014Cantilever Test, employing the principle of cantilever bending of the fabric under its own mass. 1.1.2 Option B\u2014Heart Loop Test, employing the principle of a loop formed in a fabric strip and hung vertically. 1.2 This test method applies to most fabrics including woven fabrics, air bag fabrics, blankets, napped fabrics, knitted fabrics, layered fabrics, pile fabrics. The fabrics may be untreated, heavily sized, coated, resin-treated, or otherwise treated. 1.2.1 This method may be used to determine the stiffness of nonwoven materials (for example, hydroentangled, dry laid, needlepunch, resin bonded, thermal, and wet laid) or refer to Test Method D5732. To determine the stiffness of medical textiles (for example, surgical mesh, films, and membranes), refer to Test Method F3260. Note 1: The formula to calculate flexural rigidity in D5732-95 (2001) is incorrect and should not be used. Utilize the formula presented in 11.5 of Test Method D1388. 1.3 Units\u2014The values stated in SI units are to be regarded as the standard. The values given in parentheses after SI units are provided for information only and are not considered standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.