How to Improve the Test Accuracy of Elmendorf Tear Test?

Fabric tears occur when a sharp object catches on it. A small puncture can quickly turn into a long trip with just a little extra force. The relevant test is called Elmendorf Tearing Test and today we will share with you how to improve the test accuracy of the Elmendorf Tear Test.

The Elmendorf tear tester, or Elmendorf tearing tester, uses a pendulum method for testing. The pendulum starts from a certain height. As it lowers, potential energy turns into kinetic energy.

The ballistic pendulum test measures the force needed to create a tear in the fabric. This happens when a sudden force of a specific length is applied.

It is the most common type of fabric strength failure. This matters a lot for fabrics that get rough treatment. This includes industrial textiles, bulletproof jackets, tents, jeans, and stylish clothing.

Types of Tear Test

Two main types of tearing strength tests are commonly used in textile industries.

Tongue or Single-Rip Tear Test

Number one, the tongue or single-rip tear test, involves making two cuts in a sample to form a tongue shape and then pulling the sample in a tensile testing machine to measure the force required to continue the tear.

Elmendorf Tear Test

Number two, the Elmendorf tear testing, is a standard method for determining the force required to propagate a tear through a fabric. A pendulum device tears the fabric, and the energy absorbed in tearing it is measured.

Today, we will learn how to improve the Test Accuracy of the Elmendorf Tear Tester.

 

This is an important test that determines how resistant a fabric is to tearing once it starts. This test can be applied to both woven and non-woven fabrics but not to knitted fabrics and woven flexible fabrics.

Steps to Improve the Test Accuracy of Elmendorf Tear Tester

Following the steps below will help you perform the test efficiently and improve the test accuracy of the Elmendorf tear tester.

Elmendorf Tear Test Sample Preparation

Thorough sample preparation is essential to ensure the success of your test. We need five specimens cut lengthwise or along the warp direction. And five cut widthwise, or along the weft direction for this test.

The technician cuts the samples at the weft and warp lengths from the sample laid on a flat surface. The artist completes a sample drawing using the standard template.

We place the tear template on the fabric and mark the size to do this. Each piece should be 100 x 75 mm. Then, cut out a small piece 15 x 12 mm from the top center of each sample. We will do the same for both warp and weft specimens.

 

In the sample drawing, the specimen’s short edge runs parallel to the warp. It points toward the weft, following the template.

We draw five test samples in this way. Draw test samples with various warp and weft yarns to represent the entire fabric. When draw the samples, you must draw the selvages as straight as possible.

Also, do not take specimens from wrinkled areas or places with folds. You should align the specimen cutting along a straight line with the template.

Improper cutting can distract from the tearing behavior, which may cause false values. When taking specimens, do not take them from places that are too close to the edges.

Specimen Conditioning

We will condition the specimen in atmospheric conditions. To do so, keep the sample in a controlled room at 20° C and 65% relative humidity for a specific time, up to 04 hours.

Specimen conditioning is part of the standard operating procedure. Proper conditioning ensures that the specimen is in rest condition. If it experiences too hot or too cold conditions, the temperature variation can affect the threads’ strength.

Threads tend to elongate at temperatures higher than room temperature and undergo minor contraction at temperatures below room temperature. Too low temperatures also cause threads to become brittle.

So, placing the specimen in the standard atmospheric area is very important to avoid faulty results. The conditioned samples are laid on a flat surface.

Balancing the Instrument

Now that we’re ready to test, we place the tear-strength tester on a sturdy table and set it to zero. This device has two bubble scales.

Before starting the test it should be checked whether the bubble scales are in balance. The bubble scales should be brought into balance if they are not.

 

 

There is a ballistic pendulum and a blade sample holder. The device is placed on a table and there are start buttons on either side of the table.

Calibration of Apparatus

The device’s calibration is done by measuring test weights and calibration weights.

There are four calibration weights and four test weights. For the calibration process, we begin with the most negligible weight. We attach the calibration weight to the testing weight and then choose the test weight on the device.

Pressing the start button on either side of the table under the device releases the pendulum. The value read this way is compared with the table values to see whether it is in the correct range.

If the device’s calibration is in the correct range, it is in good condition. We will repeat the same process for weight B and adjust it on the device’s screen.

We will compare the value read on the screen with the table value. Now, we will select C and check D on the screen. When testing, weights go up from A to D. This means strength will rise too.

So, the harder a fabric is to tear, the more resistance it has and the heavier the testing weight. Lastly, we will choose weight B on the device and reread the value. After completing the calibration process, you can begin to test your samples.

Preliminary Study of Weights Before Testing

The preliminary study of weight is helpful for successful test performance. This way, we can determine which weight can tear the fabric specimen without causing slippage and uneven thread breakage.

We are heading towards the testing device to test our prepared samples before starting the test, we must check whether the bubble scales on the device are balanced. Before testing the samples, we need to do a preliminary study to determine the testing weight.

Doing this initial work with the D weight is more advantageous because weight D can tear even those fabrics that weight A, B, and C cannot tear. We are doing the preliminary study with a weft sample.

 

Mark the Exact Notch of 2 cm

We will place the sample in the sample holder. Then, using the knife, we will open a 2 cm Notch, as weight D has already been selected on the screen.

The two cm notch on the Elmendorf tear testing specimen propagates the tear. Without this notch, the specimen may face slippage or uneven thread breakage.

The point to be noticed is that the notch should be no more or less than 2 cm. If it is not equal to two cm, you must adjust the knife position to meet the 2 cm requirement.

Use Weight according to Fabric Strength

Different fabrics have different tear values due to the variation in strength of the threads and fabric. So you must know the idea and range of weight before testing.

For that purpose, you may try weights individually, and then you will know the best weight to tear that fabric smoothly.

We will release the Pendulum by pressing the tray’s start button on two sides. This will give us a tear value. The value you will read on the device will give you an idea about which weight you must use.

We use weight as if the value is between 0 and 8 Newton. We will use weight B if it is between 8 and 16 Newton. We used weight C if it is between 16 and 32 Newton. Weight D will be used if it is between 32 and 64 Newton.

If the obtained value is 15.07, we can test weft length using weight B. Before removing weight, we can study a warped sample and determine its weight.

Clamp Firmly to Avoid the Specimen’s Slippage

The fabric specimen should be clamped in the clamping jaws tightly. Otherwise, the sample may slip, leading to faulted results.

The yarn shift in the jaw or the slipping of the sample itself shows that the test has failed. On the other hand, the sample must be completely torn, or no threads must remain un-torn before the rest comes to a complete conclusion.

Successful Test Symptom

How will we know that our test has been successfully performed? To ensure the answer to this question, we must see that the rupture is within the 1.5 CM width on the template. When we examine the sample, if it is clear that the rupture is within the 1.5 CM width, we will confirm the test is successful. We repeat the same process for five warp samples and five weft samples.

Adopting Latest Technology 

That’s how we test the tearing strength of fabrics. This test ensures that Fabrics used in high-performance and Industrial applications are strong and reliable.

We can improve the test accuracy of the Elmendorf tear testing by adopting the latest technology.

For example, the ChiuVention Elmendorf instrument can connect seamlessly to the SmarTex lab application, set parameters, monitor tests, and receive essential alerts from your smartphone.

Innovative balance pendulum plate design ensures the highest testing accuracy with the center of gravity perfectly aligned to achieve reliable Elmendorf tier strength tests every time.

This tearing strength tester automatically recognizes attached weights and effortlessly adjusts to the correct Force range for optimal testing.

Intending to innovate and automate Excel, ChiuVention supports you at every stage of your textile testing Journey.

Test Results

Read the test results from the scale or digital display. It’s essential to check that the tear occurred in the central area of the specimen. If it did not, we will discard that result. We repeat this process for all the remaining samples.

Finally, we calculate the mean strength in the warp and weft directions. If some specimens didn’t tear, we report their strength as more significant than the maximum capacity of the pendulum used.

The arithmetic mean of these five values is the test result. If three of the results obtained fail, we accept that the test has failed.

This is the procedure for getting an accurate result using an Elmendorf tear tester. Now, let’s see the technician’s common mistakes during this test.

Common Mistakes to Avoid in the Elmendorf Tear Test

The technical training for the lab staff is crucial for performing all lab tests correctly. A technician may make some mistakes during testing that can cause faulty results.

Improper Calibration

Calibration is an important factor for the smooth and efficient working of the instrument. The negligence in doing calibration on time leads to improper results.

So for the calibration, it is necessary to follow the machine’s standard operating procedure or it can be done by following the manufacturer’s guidelines. In Elmendorf tear tester calibrated weights also help the technician to check the performance of the machine.

Uneven Sample Cutting

The uneven sample cutting is not suitable for getting accurate results. It will disturb the alignment position of the specimen in the clamping holder which may cause the uneven force applied on the specimen when the pendulum is released.

Proper cutting is essential according to the standard conditions of 100 x 75 mm. Then, cut out a small piece 15 x 12 mm from the top center of each sample.

Specimen Placement Disorder

The specimen should be placed in the clamping jaws equally by marking the center of the jaw. The fabric sample’s center should align with the clamping jaws’ center.

Secondly, place the specimen firmly in the clamp holder. Loose holding will lead to slippage or uneven breakage of the specimen.

The tear should be straight and in line with the notch.

Environmental Factors

The controlled environmental conditions are crucial for getting accurate results. Temperature and humidity can affect the fabric tear resistance values.

Increasing humidity will cause to add moisture to the surface of the fabric, which may lead to variations during the test. So, it is essential to place the specimen in controlled environmental conditions and perform the test.

Operator Error

Operator error may lead to inconsistent results. First, the lab staff must be educated with technical knowledge and professional training.

Improper and hurried handling of the instrument can cause variations in results.

For example, suppose the operator does not carefully place and handle the specimen and releases the pendulum at different speeds, repeating the same test. In that case, it will cause different tear values.

The operator should be trained with all the standard operating procedures to avoid this issue and get accurate results.

Ignoring Tester Limitations

The operator must understand the limitations of the Elmendorf tear tester. This tester is designed to determine the tar resistance of thin and moderate materials.

If the operator forcefully checks the thick and rigid materials on it, it will not give accurate results and can even damage the instrument alignment or any part. So, ignoring the tester’s limitation can also lead to faulty results.

Avoiding these mistakes will improve the accuracy of the Elmendorf Tear Tester.

Conclusion

Proper sample conditioning, specimen preparation according to the standard, and firmly mounting the specimen in the Elmendorf clamping jaws can improve the tear test’s accuracy.

The preliminary study of weights is advantageous in finding the right weight for successfully performing the test. The exact 2 cm notch is necessary for performing according to the standard operating procedure.

The rupture within the 1.5 cm width on the template indicates that the test has been performed successfully. The trained technicians, regular instrument calibration, and adoption of the latest technology also play essential roles in the test accuracy of the Elmendorf tear test.

FAQs

What is the purpose of Elmendorf tear testing?

The ballistic pendulum test measures the force needed to cause a tear in the fabric. A sudden force of a specific length applies, causing this to happen.

How many types of tear tests do professionals use in the textile industry?

Two main types of tearing strength tests are widely utilized in textile industries.

Tongue or Single-Rip Tear Test

Elmendorf Tear Test

How should we prepare a specimen for the Elmendorf tear testing?

To prepare the Elmendorf tear test specimen, we lay the tear template on the fabric and mark its size. Each piece should be 100 x 75 mm.

Then, cut out a small piece 15 x 12 mm from the top center of each sample. We will do the same for both warp and weft specimens.

What precautions should we take during specimen preparation?

Do not take specimens from wrinkled areas or places with folding traces. The specimen cutting should be aligned with the template.

Improper cutting can distract from the tearing behavior, which may cause false values. When taking specimens, do not take them from places too close to the edges.

Why is a preliminary study of weight helpful?

The preliminary study of weight is helpful for successful test performance. This way, we can see which weight tears the fabric. We will check for slippage and uneven thread breakage.

Why is a 2 cm notch done on the Elmendorf tear testing specimen?

The 2 cm notch on the Elmendorf tear testing specimen propagates the tear. Without this notch, the specimen may face slippage or uneven thread breakage.

Is it necessary to use the weight according to the fabric?

Yes, it is necessary to achieve a successful outcome on the test.

How can we know the best weight for a successful Elmendorf tear test?

To find the best weight, we can test each one on its own. This way, we’ll know which weight tears the fabric without snagging.

How a specimen be clamped in the Elmendorf jaws?

Clamp the fabric specimen with a firm grip in the clamping jaws. Otherwise, the sample may slip, leading to faulted results.

How will we know that we successfully performed our test?

To ensure the answer to this question, we must see that the rupture is within the 1.5 cm width on the template. We will check the sample. If the rupture is within the specified width, the test is successful.

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