Fabric tear strength is a fabric’s resistance to get rapture when a force is applied to it under tension. It is measured by ISO 1974/ASTM D1424 Elmendorf fabric tearing strength tester. Tear strength depends upon the fabric weight GSM (fabric GSM Definition), yarn strength, fabric type, and weave structure.
What is Tear Strength?
Tear strength is known as the fabric’s strength against tearing or when a force is applied on the fabric to propagate the tear once it is initiated. We can also say that tear strength is a cloth’s resistance when subjected to a sudden tension or force.
Why is Tear Strength Important for Fabrics?
Why is Tear Strength Important for Fabrics?Tear strength (TS) is a very important parameter for high-performance textiles and even conventional textiles that are used in industrial applications. The fabric should have higher TS in the case of bulletproof jackets, tents, workers’ jeans, sacks, aesthetic apparel, and many more applications.
This physical parameter gets more weightage in the case of industrial textiles, where heavy-duty work is performed. As the tear strength increases, the fabric will not propagate to rapture easily under tension.
Which Factors Affect the Tear Strength?
Which Factors Affect the Tear Strength?It depends upon various factors which can directly affect the tearing results for a fabric. Here are the following main parameters that influence TS.
Fabric GSM Definition
Fabric GSM affects the tearing results. Fabrics with higher GSM are thicker and have more weight than lower GSM fabrics, which are thin and have less weight. Thick fabrics have higher TS than thin fabrics, which can rip easily.
Yarn Strength
Yarn strength is directly proportional to TS. If a fabric has good yarn strength, it will be difficult to puncture the fabric. If a fabric is made of low-grade or recycled yarn, its strength will be poor, its TS will definitely be lower, and it can rip easily.
Weaving Structure
Weaving structure can change the tear results. For example, a fabric with a plain weave has lower TS than a fabric with a complex weave structure.
If the weaving design gives space between the yarns, its TS will be lower, compared to a weaving design with a compact structure, and yarns do not have free space between them. A compact structure enhances the tear strength due to the compound effect.
Fabric Type
Woven fabrics have more TS than knitted fabrics, which are weak in strength.
Understanding of Terms Used In Tear Test
Before performing the test, we should be aware of the terms that are used in the fabric tear strength test. Let’s see the terms that are important to know.
Tear Strength
Tear strength is the amount of strength at which a fabric starts tearing or propagates to tear under specific conditions.
Tearing Force
Tearing force is the amount of force that is required to propagate the tearing of fabric. It is the average force of initiation and propagation of fabric tear.
Tearing Resistance
Tearing resistance is the property of a fabric or material that resists puncturing.
Fabric Tear Strength Test
In this test, we know at what amount of force (N) our fabric starts to burst or propagate to bursting. Tear strength depends upon the type of fabric. Different types of fabric will have different tear strength values.
Fabric tear strength is measured in the textile lab. How is it measured? Let’s look at the testing method.
The tear strength (TS) test defines the force required to propagate the tear of fabric that already has a cut on the fabric surface. So, the force is applied to the fabric to propagate the initial cut, and the tearing force is measured.
Two halves of the sample is gripped with a cutter standard tear tester to perform the test. Similarly, 05 samples for warp and 05 for weft are taken to perform the whole test.
Fabric Tear Strength Testing Methods
These are the common methods used to measure the tear strength of a fabric.
- Elmendorf
- Wing
- Trapezoidal
- Pendulum
- Tongue
- Single Tongue
- Double tongue
In this article, we will discuss Elmendorf and Wing tear testing methods.
Elmendorf Method ASTM D1424
The ASTM D1424 is also called the Pendulum method to measure the tear strength of a fabric. In this method, the Elmendorf Tearing Tester is used to perform the test.
Elmendorf Tearing TesterApparatus
Elmendorf tester, weights, scale, scissors, and fabric sample
Test Principle
The test specimen is placed in an Elmendorf tester fixture with a small cut. The pendulum is released at its maximum potential energy and applies force on the specimen held in the fixture. Specimen tears from the notch and tear strength is measured in Newton through the weights.
Sample Preparation
The specimen is cut from the fabric that has to be tested with the help of a template supplied with the equipment. Using the sampling ruler, the specimen is taken with 100 × 75 mm of warp and weft directions.
The warp sample should be cut parallel to the warp yarn, and similarly, the weft sample should be cut parallel to the weft yarn.
Three to five samples should be cut in a stair-like pattern from left, middle, and right positions. There should be two sets of samples, 01 for warp and 01 for weft direction.
Testing Procedure
- Place the Elmendorf Tearing Tester on a rigid horizontal table or shelf area. Set the zero point.
- Check the weights and perform calibration before testing.
- Take the pendulum to its starting position.
- The manual Elmendorf tearing tester has a scale on the pendulum, which indicates the tearing strength, while the digital tester shows the numeric value on the screen in Newton.
- Set and secure the pendulum release mechanism.
- Apply different weights to find the correct weight according to the fabric thickness.
- Fix the specimen into the instrument fixture with a concave face upward.
- The clamp should be tightly closed to avoid the specimen slipping during the test.
- Mark a cut on the specimen using the instrument’s knife.
- The cut length should be 20 mm. If the cut length is more than 20 mm, then you should adjust the cutter position to ensure the standard cut length.
- The specimen should be equally distributed in the holding clamps and must be firmly held by tightening the screws.
- Both grips should hold the specimen with the same force.
- Release the pendulum; it will go down and tear the fabric.
- Note the position of the needle on the manual tearing scale. It will be a tear result value. The digital tear tester will show the result numerically on the screen.
- Similarly, you can repeat the testing procedure for other specimens.
Precaution
During the tear test, if the specimen is released from the clamps, when the pendulum strikes the specimen, or the tearing deviation is more than 6 mm, this test result will be considered a faulted result.
In such cases, you must repeat the test to get precise results. To avoid this issue, you must ensure the specimen is firmly held in the clamps.
Wing Shape Tear Method ISO 13937-3
The wing shape tear testing method evaluates the tear strength of lightweight fabrics that are used in clothing and upholstery.
Wing Shape Tear Method ISO 13937-3Apparatus
Wing tear tester, scale, scissor, and fabric sample
Test Principle
A wing template is used to cut the specimen in that shape. The specimen’s two halves are put in clamping jaws. One end is on the upper end, and the second end is in the lower clamping holder. The upper clamping holder moves upward and tears the fabric by applying force.
Sample Preparation
The fabric is conditioned for up to 04 hours before taking the specimen for testing. A wing shape template is used to cut the specimen in that way. According to the standard, we will take the specimen by leaving 150 mm space from the selvage.
The yarn cutting will happen on the weft side when we take the sample from the warp side. Similarly, when we take samples from the weft side, the yarn cutting will happen to the warp side.
So, mention warp and weft names on the specimens according to the yarn cutting side. Make a set of warp and waft specimens.
The length of a wing tear specimen from the center is 200 mm, and the width is 100 mm. The center cutting line is 100 mm. Similarly, we will take 05 samples for each side warp and weft. These samples are taken diagonally from the fabric.
Testing Procedure
- Turn on the software-operated wing tear tester instrument.
- Open the program in software ISO 1737-3
- Set the machine setting, jaws T 20 7, speed 100 mm/min, select the number of specimens, then click the start button, and the machine will start.
- The machine’s upper clamp will move to 100 mm jaw separation as we click on the start button.
- Firstly, we will perform warp specimens.
- The specimen’s ends are clamped in the clamping jaws. It should be clamped and equally distributed in the clamping holders.
- After clamping it in the jaws, the specimen’s shape will become like that of a flying bird.
- The machine starts moving constantly after clicking on the start button with a speed of 100 mm/min.
- The fabric will start tearing. We will stop the machine when the tearing position comes to the margin line of 75 mm.
- We will note the tearing behavior and position.
- Similarly, you can perform the remaining specimens.
- As all the tests are performed, we will click on the save results, and all results will be shown in the computerized report.
- Wing tear tester instrument’s software can give you the individual specimen report, all results report graphs and even average results report.
Precaution
Make sure the specimen is clamped through the clamping jaws with equal force. If the specimen is loosely held, it can slip during the test, which will cause the wrong tear values. So, it should be ensured that the specimen is equally distributed in both upper and lower clamping jaws and firmly held.
Conclusion
Fabric tear strength is the physical property of fabric which resists getting ripped. Tear strength can be measured through Elmendorf, Trapezoidal, Tongue, and Wing tear testing methods.
This is an important parameter of the fabric that is used in high-performance textiles like bulletproof jackets, tents, workers’ jeans, sacks, aesthetic apparel, and many more applications.
FAQs
What is Tear Strength?
Tear strength is known as the fabric’s strength against tearing or when a force is applied on the fabric to propagate the tear once it is initiated.
Why is Tear Strength Important for Fabrics?
Tear strength (TS) is a very important parameter for high-performance textiles and even conventional textiles that are used in industrial applications. The fabric should have higher TS in the case of bulletproof jackets, tents, workers’ jeans, sacks, aesthetic apparel, and many more applications.
Which Factors Affect the Tear Strength?
Tear strength depends upon the fabric weight, GSM, yarn strength, fabric type, and weave structure.
What is the difference between tearing force and tearing resistance?
Tearing force is the amount of force that is required to propagate the tearing of fabric. It is the average force of initiation and propagation of fabric tear. Tearing resistance is the property of a fabric or material that resists puncturing.
How many ways is tear strength measured?
Tear strength is measured through Elmendorf, Trapezoidal, Tongue, and Wing tear testing methods.
What is the test principle of the Elmendorf tear testing method?
The test specimen is placed in an Elmendorf tester fixture with a small cut. The pendulum is released at its maximum potential energy and applies force on the specimen held in the fixture. Specimen tears from the notch and tear strength are measured in Newton through the weights.
Why is the wing tear testing method used?
The wing shape tear testing method evaluates the fabric tear strength of lightweight textiles used in clothing and upholstery.