Different Types of Fabric Tearing Strength Test Method

Last Updated on 25/05/2021

Tearing Strength Test of Fabric by Elmendorf Tear Strength Tester

Md. Rubel Miah
Department of Textile engineering
World University of Bangladesh
Email: rubel099@gmail.com

 

Tearing Strength:
Tearing strength is the resistance of the fabric against tearing or force required to propagate the tear once it is initiated. Generally, the resistance offered by a textile material when it is subjected to sudden force is generally termed as tearing strength. The tear strength is required in high performance applications as well as in the conventional textiles, that is, in the industrial applications, bullet proof jackets, tents, worker jeans, sacks, aesthetic apparel and many more applications. This is also important in the industrial textiles where heavy duty work is performed. High tear strength of textiles makes sure that the punctures in the fabrics do not propagates easily.

Fabric Tearing Strength Test:
Force required to propagate an existing tear is measured. As a part of the preparation of fabric specimen, a cut is in them and the force is required to extend the cut is measured.

This is conventionally carried out by gripping the two halves of the cut a standard tensile tester. 5 warp and 5 weft samples should be taken to carry out this test.

Types of Tearing Strength Test of Fabric:

  1. Single rip tear test / Trouser tear test
  2. Wing rip tear test

1. Single Rip Tear test: According to SSEN ISO 13937(2) – 2000, a fabric sample of 200mm length and 50mm width is prepared with a single tear in it.

Mounting the sample:

Tearing strength test
Fig: Tearing strength test

Result:
The overall mean tear force across weft, in newton (N) or centinewton (cN).

2. Wing Rip Tear Test: The Wing rip tear test overcomes some problems which are found with the single rip test as it is capable of testing most types of fabrics without causing a transfer of tear. During the test the point of tearing remains substantially in line with center of the grip.

Sample preparation:  (According to British Standard)

Sample preparation for tear strength test
Fig: Sample preparation for tear strength test

Mounting in the tensile test:

Mounting sample for tear test
Fig: Mounting sample

Five specimen across the warp and five specimen across the weft are tested.

Result: Mean tear force N or cN

Tearing Strength Test of Fabric by Elmendorf Tear Strength Tester

Sample preparation

  • Mark the specimen with the help of the template supplied with the equipment.
  • Cut the warp set with short dimension parallel to warp yarns.
  • While cutting test specimens take care to align the yarns running in short direction parallel to template.
  • Each specimen of warp set should have different warp yarns, and each specimen of weft set should have different weft yarns.
  • Prepare at least five specimens of each type.
Elmendorf Tear Strength Tester
Fig: Elmendorf Tear Strength Tester

Formula of tear strength test:

Mean tearing strength (gf) = K × mean value of scale reading / n

Where,
n = number of test specimens tested together.
k = 16 without any augmenting weight for 1600 gf range.
k = 32 with any augmenting weight for 3200 gf range.
k = 64 with both augmenting weight for 6400 gf range.

Working procedure:

  1. Place the tear strength tester on a rigid horizontal table, set the zero point. Next, check the calibrated weights.
  2. Raise the pendulum sector on the starting position. Secure it by the pendulum sector release mechanism and set the pointer against its stop.
  3. Clamp a specimen securely in the clamps, so that it is centered with the bottom edge, set against the stop and the upper edge parallel to the top of the clamps; close the clamps by tightening the setting screws.
  4. Where applicable operate the knife to make the initial slit in lower edge of the specimen. The specimen should lie free with its upper edge directed towards the pendulum sector so as to ensure a shearing action with the pendulum raised and locked against the release lever; fix a dummy test specimen in the grips such that its lower edge is in contact with the fabric, raising it till the knife goes up to maximum extent possible.
  5. Measure the cut position of the test specimen. If this size is not 20 mm then adjust the blade movement stopper till the cut length is 20 mm.
  6. Tighten the grips in this position. When waded, the specimen should have its longer edges parallel to top of the grips and the width-wise yarns should be exactly perpendicular to the top edge of the grips. The two grips should hold the specimen under approximately the same force.
  7. Depress the pendulum sector release mechanism as far as it goes and hold it down until tearing is completed. Catch the pendulum sector by the handle on the return swing, disturbing the position of the pointer.
  8. Note the position of the needle as indicated by the nearest whole scale division for the capacity used.
  9. Repeat the operation on the remaining test specimens.
  10. If the specimen slips through the gaps or if the tear strength deviates by more than 6 mm away from the projection of the original slit, reject the reading and repeat the test with fresh specimen.

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