An experimental sample about tear strength testing of a fabric by Elmendorf's Tear Tester. This will helpful for the Textile Engineering student to know the measuring process of tear strength of a fabric.
1. Experiment No: 02
Experiment Name: Determination of Tear Strength of a Fabric By Elmendorf’s Tear Tester.
Theory:
Tear strength is the resistance of the fabric against tearing or force required to propagate the tear once it is
initiated. The tear strength is required in high performance applications as well as in the conventional textiles
i.e. 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 make sure that the punctures in the fabrics doesn't propagates easily.
A fabric tears when it is snagged by a sharp object and the immediate small puncher is converted into long
rip by what may be a very small extra effort. It is probably the most common type of strength failure of
fabrics in use. It is particularly important in industrial fabrics that are exposed to rough handling. (E.g. Tents,
Sacks, Parachutes, etc.) In some applications low tear strength is require, e.g. Adhesive tape, bandages, etc.
Tear strength is the strength required to start or continue the tear in a fabric under specific condition &
tearing force is the required to continue a tear previously started in a fabric. The tear resistance test on fabrics
or tear strength is measured to check how the material can withstand the effects of tearing or cuts when in
tension.
Objectives:
1. To know about tear tester and its parts.
2. To determine the tear strength of fabric.
Materials Requires:
Template
Scissor
Fabric
Elmendorf Tear Tester
mm/cm Scale
Machine Parts & Diagram:
Tear tester machine is completely made of stainless steel. It consists of a sector of pendulum pivoted on anti-
friction ball bearings on a vertical bracket fixed on a rigid metallic bare. The test specimen in shape of
2. rectangular pieces is held between two jaws, one of which is mounted on the pendulum & other is mounted
on the vertical arm. The jaw clamps are mounted in such a manner that their holding forces are aligned with a
each other when the pendulum is locked in its raised position. An adjustable knife is also mounted on the
vertical arm. It is centered between the two brake release lever. This action causes the test specimen to tear
right through. The Testing strength is indicated on calibrated scale fettle on the pendulum by a fine point.
A set of calibrated check weights are supplied with the tester for verification calibration of the scale at 3200,
6400 & 12800gms capacities. In order to increase the capacity of the tester from the 3200Gms augmenting
weights of 6400gms & 12800gms are supplied as standard Accessories.
Working Principle:
1. Cotton fabric was taken.
2. Warp and weft direction of the fabric was identified.
3. Two strips were cut from the fabric in both directions having dimensions of 100 x 64 mm.
4. The sample was then fixed in the jaws of the tearing tester.
5. A cut of 20mm was made along the width of the fabric using the cutter in the tearing tester.
6. By using falling pendulum of the tearing tester the fabric was tear and the readings were noted from the
Elmendorf's tester's scale.
Fig: Elmendorf Tear Tester
3. Table:
SL. No. Warp-wise strength % of 3200/6400
and 12800gm. Capacity
Weft-wise strength % of 3200/6400 and
12800gm. Capacity
1. 2112 1792
2. 1920 1728
3. 2048 1664
4. 1856 1728
5. 2112 1856
Mean Value 2009.5 1753.6
Results & Discussion:
Warp-wise tear strength = 2009.5 Kg
Weft-wise tear strength = 1753.6 Kg
The results shows that the warp-wise tear strength of the fabric is more than that of the weft-wise tear
strength of the fabric. This shows that the warp yarns are much more than that of the weft yarns, that's why
the warp yarn strength is much more than that of the weft yarn.
Conclusion:
This experiment showed that the warp-wise tear strength of fabric is greater; hence the fabric is more stable
along the warp-wise direction.
Prepared by
Md. Asiqul Alam
B.Sc in Textile Engineering
Port City International University