STANDARD TEST METHOD FOR TEARING RESISTANCE OF PENDULUM DROP FABRICS (ELMENDORF TYPE)
This test method covers the determination of the force required to propagate a tear from a cut in a fabric and using a downward pendulum apparatus (Elmendorf Type).
This test method applies to most fabrics, including woven fabrics, layered blankets, plush fabrics, blankets, and air bags, as long as the fabric does not tear in the direction transverse to the direction of travel. application of force during the test.
For warp direction tests of warp knitted fabrics only. It is not suitable for the course direction of warp knitted fabrics or for any direction of most other knitted fabrics.
-Elmendorf type equipment
-Calibration weights
-Cutting die
-Pressurized air regulator
-Cutting blade gauge
-Jaws
-Vacuum Booth
PROCEDURE:
-Equipment calibration: Select the range of the equipment force so that the tear occurs between 20 – 80% of the full scale range or between 20 – 60% when using a large capacity pendulum. Check that the blades are aligned and that all accessories are working properly.
-Sample conditioning according to D1776/D1776M
-Wet sample conditioning: follow the procedure described in the standard.
-Samples: randomly select the number of rolls or pieces of fabric indicated in the material specification or according to agreement with the manufacturer.
-Laboratory sample: take 1 m along each roll or piece sampled.
-From each laboratory sample, cut 5 test specimens in the direction of the machine and 5 test specimens in the transverse direction of the machine.
-When cutting woven fabric samples, be careful to line up the threads running in the short direction parallel to the die in such a way that when the indentation is cut, the subsequent tear occurs between these threads and not through them.
-Cut specimens that represent a wide distribution across the width and length, and preferably along the diagonal of the laboratory specimen, and no closer to the edge than one-tenth of its width.
-For slit specimens (groove cut):
-Place the long sides of the sample in the center of the clamps
-Close the clamps, securing the sample with approximately the same tension on both clamps
-Using the built-in blade, cut a 20 mm (0.787 in.) slit (slot) in the specimen extending from the bottom edge and leaving a remaining 43.0 ± 0.2 mm (1.69 ± 0.01 in.) fabric to tear.
-For die-cut or manually cut samples:
-If a non-slit die is used, manually cut a 20 mm (0.787 in.) long slit (slot) in the center of an edge in the longitudinal direction of the specimen. Ensure that the excess sample is 43.0 ± 0.2 mm (1.69 ± 0.01 in.).
-Place the parallel sides without slits of the specimen on the clamps with the bottom edge carefully positioned against the stops, the top edge parallel to the top of the clamp, and the slot located in the center between the clamps.
-Close the clamps, securing the sample with approximately equal tension on both clamps.
-For wet sample testing:
-Remove a sample from the water and immediately mount it on the test machine in the normal setting. Perform the test within 2 minutes of removing the specimen from the water.
-Remove the torn specimen and continue until five tears have been recorded for each test direction and test condition.
-Discard those specimens with a cut not parallel to the tear.
-Discard readings where the specimen slips from the jaws.
-Discard readings where the tear deviates more than 6 mm from the original slip projection.
RESULTS
-Determine the tear force for each specimen according to the equation of the standard, in cN
-Calculate the average tear force for each direction and test condition for each batch, at the nearest 1% to the full scale range, in cN.
-For equipment with automatic calculations, ensure that the reading scale is correct so that the calculations are carried out correctly.
