Name of the Experiment:
Heavy fabric strength testing by horizontal strength tester.
Introduction:
The strength of a fabric gives us an idea how much load we can apply on it and it is very important for fabric. The strength of the fabric is very necessary for it because if the fabric strength is not good then it will break with excessive tensile force and thus the dresses produced may tear with the outside force. The strength of a fabric varies with EPI, PPI, and Count Variation. The strength of the fabric also varies if the length and width of the fabric to be tested is changed. The strength of the fabric also depends on the construction of the fabric. A plain fabric is stronger than a twill fabric if made from yarn of same count. The machine used here is a horizontal strength tester. In this experiment I will discuss complete method of heavy fabric strength testing.
Objectives:
The experiment of fabric strength testing has below objects:
- To find out the strength of the fabric.
- To be precise in testing.
- To compare among the different fabric with standard value.
- To measure the deviation of the result with the standard value and to produce the required fabric as per buyer specification.
- To know the fabric quality.
- To know about the Horizontal Strength Tester.
- To know the mechanism of the machine used.
Theory:
Strength is a measure of the steady force necessary to break a material and is measured in pound. The machine works in constant rate of extension principle. When the tension is high on the fabric then the fabric breaks.
Basically, two methods are used to observed the effect of tensile forces on textile specimens, ‘constant rate of loading’ (C.R.L.) and ‘constant rate of extension’ (C.R.L.).
Consider two identical specimens A and B in below figure. Specimen A is gripped in a jaw J1 and in a fixed-top jaw J2 which is movable. A force F, initially zero but increasing at a constant rate, is applied to the specimen in a direction shown. The effect of applying this force is to extend the specimen until it eventually breaks. The loading has thus caused the elongation. Here we have C.R.L. conditions.
Specimen B is gripped in the fixed-top jaw J3 and in the bottom jaw J4 which can be moved downwards at a constant velocity by means of a screw mechanism. Initially the tension in B is zero but when the bottom jaw J4 which can be moved downwards the specimen is extended and an increasing tension is developed until the specimen finally breaks. In this case the effect is the other way round, extension causes loading. Here we have C.R.E. condition.
Apparatus:
- Heavy fabric.
- Fabric strength tester.
- Scissors.
Machine specification:
- Name: The Fabric Strength Tester
- Brand: Goodbrand & Co. Ltd.
- Capacity: 2000lb
Testing atmosphere:
- Temperature: 29oC and relative humidity 76%
- Standard atmosphere: Temperature 20oC and relative humidity 65%.
Sample:
- Size – 6inch × 2inch.
- No. of sample – 20 (For warp way-10, for weft way-10).
Working procedure:
- At first 10inch × 2inch fabric was cut out from a big piece of fabric. The excess amount of fabric was cut because the two jaws will require at least 2inch each to grip the fabric. Thus 10 samples were cut down for testing warp way strength and 10 samples for weft way strength.
- Now, the first sample is fixed with the upper jaw J1 and the lower jaw J2.
- The machine is started and observed the dial until the sample is torn out.
- When the sample is torn out the machine is stopped and the reading is taken.
- By this way the others’ reading are taken.
- At last average and CV% are calculated.
Experimental Data:
Warp way:
Reading | Fabric strength (Lbs) | Avg strength (Lbs) | SD% | CV% |
1 | 290 | 300.5 | 3.06 | 4.32 |
2 | 320 | |||
3 | 290 | |||
4 | 290 | |||
5 | 295 |
Weft way:
Reading | Fabric strength (lbs) | Avg strength (lbs) | SD% | CV% |
1 | 190 | 189 | 3.08 | 4.92 |
2 | 180 | |||
3 | 200 | |||
4 | 190 | |||
5 | 200 |
Calculation:
……………………………………..290 + 320 + 290 + 290 + 295 + 310 + 320 + 290 + 310 + 290
The average warp way strength = ————————————————————————————
…………………………………………………………………………………..10
= 300.5 lbs
………………………………………..190 + 180 + 200 + 190 + 200 + 160 + 195 + 205 + 180 + 190
The average weft way strength = ————————————————————————————–
…………………………………………………………………………………….10
= 189 lbs
Results:
- The warp way fabric strength = 300.5 lbs
- The weft way fabric strength = 189 lbs
- The CV% for warp way fabric strength = 4.32%
- The CV% for weft way fabric strength = 4.92%
Remark:
The strength of a fabric varies with (1) EPI variation, (2) PPI variation & (3) Count variation. The strength of the fabric also varies if the length and width of the fabric to be tested is changed. If we take a sample which size is 3inch × 6inch and another sample size 2inch × 6inch then the strength of the first sample will be greater than the second one. Thus if we increase the length of the second sample then the strength of the second sample will be decreased. The strength of the fabric also depends on the construction of the fabric. A plain fabric is stronger than a twill fabric if made from yarn of same count. The CV% for warp = 4.62% & for weft = 4.92%. it means there is a lot of variation in strength of the fabric.
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Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. He is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.
Pregunta.
Equivalencia de resistencia de los hilos
cN/tex a libras?
gracias