【国外标准】 Standard Test Method for Determining the Flexural Stiffness of Medical Textiles

5.1 Consideration of the flexural stiffness of medical textiles is important, as these devices often need to possess properties that allow them to conform readily to the anatomic structures they are designed to support or protect. This test method outlines the materials and methods for the determination of flexural properties along the different textile directions (that is, machine and cross-machine) and for the effects of textile surface orientation (that is, face and back orientations).5.2 This test method can be used for quality control purposes.5.3 This test method can be used for non-absorbable, absorbable, and partially absorbable medical textiles including films and membranes. Testing should be performed on both dry and appropriately conditioned specimens. If the specimen is fabricated from a hydrolytically degradable absorbable material or contains an absorbable component, testing after hydrolytic conditioning at appropriate time intervals should be undertaken using Test Method F1635. For partially absorbable textiles, testing should be performed through at least two time intervals that exceed the point where the absorbable component no longer contributes to the specimen’s measurable mechanical properties.5.4 If flexural rigidity values are found to show effects related to planar and surface orientation, results from this test method could potentially help in determining if devices should be implanted or used only at specific textile directions and surface orientations. Considerations for determining device planar and surface orientations for use would include, but are not limited to, primary direction of bending once implanted or during use, anatomic structures that will interact with the device, and physiologic loads (normal, pathological, and worst-case) the device would experience during use.5.5 No evidence has been found showing that bending length is dependent on the width. However, the tendency for specimens to curl or twist can affect the result through the rigidity provided at the edge. Consequently, use of test specimens with greater width can help to reduce this edge effect.5.6 This test method differs from Test Method D1388 in that it requires tracking of sample surface orientation and includes absorbable and partially absorbable medical textiles. Medical textiles with stiffness higher than is measureable using this cantilever bending method should consider evaluation using the cantilever beam method described in Test Method D747.1.1 This test method covers the measurement of flexural stiffness properties of medical textiles (for example, surgical mesh, films, and membranes). Bending length is measured and flexural rigidity is calculated.1.2 This test method may be used for absorbable or non-absorbable medical textiles.1.3 This test method measures the flexural stiffness at room temperature in air and, if used directly, may not provide an accurate measure of in-vivo behavior for implantable medical textiles.1.4 This test method is not suitable for testing tubular samples.1.5 The values stated in SI units are to be regarded as standard. Values in parentheses are for information only.1.6 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.1.7 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.