Friday, March 27, 2020

FABRIC STIFFNESS AND FLEXURAL RIGIDITY TESTING AND CALCULATION


FABRIC STIFFNESS AND FLEXURAL RIGIDITY TESTING:

FABRIC STIFFNESS:

The ability to resist the bending of fabric is called fabric stiffness.

FLEXURAL RIGIDITY OF THE FABRIC:

It is a measure of the resistance of a fabric to bending by external forces.

APPARATUS USED:

1 - Fabric stiffness tester ( cantilever type)

2 - Scissor

3 - Measuring scale ( made of steel)

4 -  fabric 

5 - weighing scale ( three decimal digits)

SPECIMEN PREPARATION:

4 testing specimens are prepared from each direction ( warp and weft).  The specimen size is kept 6" length & 1" width. The specimens are prepared by cutting the fabric with the help of a scissor.  Please see the below picture to learn about specimen preparation:




TESTING PROCEDURE:

The full testing procedure gets completed in the below steps:

Each specimen is placed on a smooth platform. This platform has a low frictional coefficient. The edge of the specimen to getting bend during the test is placed just over the edge of the platform where the sliding plate gets started. You can refer to the below figure of cantilever type stiffness tester:



The red colour is showing the test specimen:

Now, the weighting plate is placed just over the test specimen. The front edge of the weighting plate is placed just over the specimen's front edge. We have shown weighting plate as aqua colour.

The angle of the sliding plate is checked and adjusted accurately.  The bending angle of the sliding plate is kept at 41.5°.

Now, the technician starts to push the weighting plate toward the sliding plate. The test specimen also slides with the weighting plate. The pushing of the specimen is carried out steadily and carefully. The technician also keeps a regular watch over the front edge of the specimen.

As the specimen comes out, it starts to hang. The pushing process gets continued. The specimen begins to bend due to its own weight. As the front edge of the specimen gets touched with a sliding plate, the pushing of the specimen is stopped immediately.

Now travel the length of the specimen is recorded. This process is repeated for all remaining specimens. Now we calculate the bending length and flexural rigidity as below:


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