Fabric Stiffness by Circular Bend Testing
ASTM 4032 covers a test for measuring the fabric stiffness of woven textiles. A circular plunger is pushed through a double ply square of fabric using a special puncture fixture.
The orifice of the puncture fixture is 1.5 inches in diameter. The diameter of the plunger is 1 inch and is mounted concentrically with the lower puncture jig, leaving .25 in. of clearance on all sides. The sample is an 8x4 inch rectangular swatch which is folded in order to creat a two ply sample which is then a 4x4 inch square.
The ASTM D4032 puncture fixture can be used with a universal testing machine such as the Galdabini in order to test the fabric stiffness. The circular bend testing fixture have a standard female clevis coupling size of 5/8" and use a 5/16" locking pin. With simple adapters this fixture cancan attach onto any universal testing machine.
The maximum or peak load measurement is taken during the test. This is given as the fabric stiffness. This peak value is averaged over 5 different sample specimens for a specific sample lot. The Galdabini testing machine can organize samples into separate lots to create detailed reports for printing or analysis.