Ballistic strength or impact strength of yarn is measured on ballistic strength tester to determine the ability of yarn to sustain the sudden shocks.
During weaving yarn is undergoing in many sudden shocks such as beat-up. So that to know the behaviour of yarn when sudden shocks are imposed, yarn impact strength with ballistic principle has to be carried out.
Work of rupture.
Instrument Used For Testing
Ballistic Or Impact Tester
Working Principle Of Instrument (Ballistic)
It operates on the ballistic (sudden impact) principle. The loading is done by means of a pendulum. It measures the work of rupture i.e. energy required to break the sample.
Specifications Of The Instrument
- Make: Good Brand Company, England.
- Mass of pendulum: 2 kg.
- The range of measurement: 0 to 150-inch pounds.
A heavy pendulum is fixed at A. The specimen is anchored at a fixed point J1 and also connected to a grip J2 on the bob of the pendulum. Let G be the centre of gravity and W be its weight.
Initially, the pendulum is in position 1, with the centre of gravity G at when the pendulum is released, it swings downwards and rises to position 3 when the sample breaks.
The work required to break the specimen can be calculated by considering the height to which the centre of gravity rises after the break.
Without mounting the sample, the pointer is set in the vertical position and the pendulum is released. If the pointer reaches o the scale, the instrument is functioning properly.
The yarn is prepared in the form of leas (120 yards) using an electronic wrap reel.
- The pendulum is kept at height h1.
- The sample is mounted to the jaws j1 and j2.
- When the pendulum is released, it swings downwards when the nearly vertical begins to pull the sample.
- Continuing to swing, the specimen gets stretched and breaks.
- The pointer gets pushed to the corresponding value by the pendulum.
- The reading from the scale gives the work of rupture directly in inch pounds.
- The procedure is repeated for the remaining samples.
|S.NO||Weight(g)||Count(Ne)||Work Of Rupture (inch*lbs)|
Work of rupture = w(h1- h2) in lbs
w- the weight of the pendulum.
h1 – maximum height of pendulum above its lowest point.
h2 – maximum height to which pendulum rises.
Statistical Tools/Parameters Used
Mean, C, t-test, f-test.
Test Results With Unit
|Yarn||Count(Ne)||Work of rupture (inch*pound)|