Fabric Loop Grips are used for tension and elongation testing of wide or narrow elastic fabrics. This test is performed with various types or combination of materials, and tested at a constant-rate-of-extension.
Loop Tension at specified Elongation and Elongation at Specified Loop Tension are test procedures that require 3 cycles to bring the specimen under test to a specified point and returned to a zero value as described in ASTM D 4964.
Principle Of Operation
These grips have a U-shaped body style, and are also referred to as Band Clamps. One edge of the U is attached to a connector that mounts to the moving crosshead and to the base of the testing machine. The other edge of the U has a 6.5 mm (0.25 in) diameter which makes contact with the specimen. The specimen is wrapped onto itself and sewn at the end with two rows using a single needle stitch, forming a loop. This loop is then inserted around both the upper and lower grip and made ready for testing.