- PURPOSE AND SCOPE:
To determine the breaking strength of a woven, non-woven or coated
fabric using the grab Method. Strength of a fabric is generally considered the most
obvious indicator of the service life of a fabric. Also the strength of fabric indicates
its ability to resist mechanical damage due to stress of normal wear and refurbishing.
- PRINCIPLE:
A continually increasing load is applied lengthwise or widthwise to the
specimen, and the test is carried to fabric rupture. Values for the breaking load of the
test specimen are obtained from machine scales, dials or charts.
- REFERENCE:
3.1 ASTM D 5034-95(2001), Standard Test Method for Breaking Strength and
Elongation of Textile Fabrics (Grab Test).
- APPARATUS:
4.1 Tensile testing machine, constant rate of traverse (CRT) such as
Instron Model #4206
- PROCEDURE:
5.1 Prepare 3 specimens each 100 +/- 1 mm (4+/- 0.05 in.) wide by at least
150 mm (6 in.) long in both warp (length) and filling (width) directions.
5.2 Condition the specimens for a minimum of 2 hours with 21° +/- 1C (70°
+/- 2F) and 65%
+/-2% RH.
5.3 Set the crosshead speed at 30.5 cm (12 in.) per minute.
5.4 Set the gauge (distance between the jaws) at 76 mm (3 in.), and clamp the specimen
lengthwise in both jaws. If the fabric being tested has too much stretch, the gauge length
25 mm (1 in.) may be used. Use a tension load cell with a capacity that exceeds the
expected breaking strength.
5.5 To start the test, press "up" key on crosshead control panel.
5.6 Note the reading on the instrument panel when the fabric breaks, this is breaking
strength.
5.7 Return the jaws to the original gauge length.
5.8 Remove the ruptured specimen from the jaws.
5.9 Repeat Steps 5.4 through 5.8 on the remaining test specimens.
- EVALUATION:
Calculate the average of 3 readings of breaking strength in each
direction, i.e., length and Width or warp and filling, to the nearest 0.1 of the unit
chosen, i.e., pounds or grams.
- REPORT:
Report the values calculated in Step 6 as the breaking force of the fabric
tested in respective directions.
