Textile Adviser: TESTING OF FABRIC BURSTING STRENGTH TEST BY DIAPHRAGM HYDRAULIC BURSTING STRENGTH TESTER

TESTING OF BURSTING STRENGTH OF THE FABRIC BY DIAPHRAGM HYDRAULIC BURSTING STRENGTH TESTER:

Bursting strength:

When the fabric is subjected to pressure, the fabric begins to expand in all the possible directions at the same time. When the applied pressure increases gradually, the fabric begins to burst after crossing a pressure limit. This pressure limit is called bursting strength. Thus we can say that “the pressure required to burst the fabric surface is termed as bursting strength of the fabric”. It is measured in pounds (lbs.) per inch²or kilograms per Centimeter². The bursting strength of the fabric is a very important property for parachute fabric. Type of yarn and material used in the fabric, the count and construction of the fabric greatly affect the bursting strength of the fabric.

Apparatus used:

1 - Diaphragm bursting strength tester.

2 - Fabric.

3 - Scissor.

4 - Measuring scale

Testing procedure:

Fabric is spread over a table with having a flat surface. The template is placed over the spread fabric. The outlines are marked with the help of a marking pen. Now the specimen is cut by a scissor. The diameter of the specimen disc is kept equal to or more than the outer diameter of the rubber diaphragm. Please see the below diagram:

Now the specimen is placed over the diaphragm properly and the specimen clamp is tightened by turning round clamp clockwise direction by using the special tool supplied by the instrument manufacturer.

Now the electric supply of the hydraulic pump switches on. The fluid pressure begins to increase constantly. After a certain interval of time, the test specimen gets ruptured. The distance between the clamped diaphragm and the top surface of the inflate diaphragm is measured precisely. The reading of the pressure gauge is also recorded at the same time. This pressure gauge reading is called pressure required to rupture a specimen( P)

The developed hydraulic pressure inside the pressure cylinder is released immediately and the specimen clamp is loosened at the same time.

Now we find the pressure required to inflate the diaphragm. The diaphragm is tightened again by a circular clamp without a test specimen. The electrical supply is switched on. The diaphragm starts to expand. When the top surface of the diaphragm reaches the height equal to the height reached during rupture of the specimen, the pressure gauge reading is recorded again immediately. This pressure is called inflate pressure ( P ' ).

Calculation of bursting strength:

Precautions:

Below precautions should be taken during testing of the bursting strength of the fabric.

1 - The specimen should be prepared precisely.

2 - The height of the inflate diaphragm should be measured correctly during the rupture of the specimen.

3 - The pressure must be released immediately after rupture of the specimen.

4 - The diaphragm should be replaced after the recommended time.

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