What’s a tear strength?
Fabric tear strength shows how much local yarns can handle a concentrated load. This leads to the fabric tearing. In fabrics, clothing can get caught on objects. This pulls on the local yarn, causing the fabric to tear in strips or triangles. This leads to yarn breakage.
What is the scope of the application of tear strength?
Tear strength can change based on the fabric’s catalyzing after finishing. Check the tear strength of combed cotton and wool-like chemical fiber fabrics. This applies to both pure and resin-blended types. Knitted fabrics are generally not tested for tearing strength, except in cases where special requirements dictate otherwise.
What is the significance of studying tear strength?
Clothing wears out over time. Friction weakens the yarn, causing it to thin. This leads to breaks in the fabric and the formation of cracks. Military uniforms, sails, parachutes, and hammocks often face concentrated loads. This can lead to localized damage and tears. If the fabric gets caught on something or gripped in one spot, external forces can tear it apart. Tearing, or ripping, occurs when fabrics are torn apart due to heavy loads. Tearing happens when one or more yarns in a fabric break along a seam. This is a common way for fabrics to fail or become unusable.
The tearing of fabrics is a common form of damage that happens with little resistance. The force at the split is very specific. Because of this, the tear strength of the fabric is much less than its tensile breaking strength. The tear strength index is the main quality measure for fabrics. It shows how well fabrics resist damage from localized force during use. Other types of mechanical damage to the fabric, such as top break and wear and tear, can cause tears. These tears often mark the final stage of destruction. To extend the fabric’s life, it is important to study fabric tearing.
Methodology and Criteria
| Test Method | Standard | Title (Translated) |
|---|---|---|
| Pendulum Method | GB/T 3917.1 | Textiles — Tear properties of fabrics — Part 1: Determination of tear strength by the pendulum method |
| ISO 13937-1 | Textiles — Tear properties of fabrics — Part 1: Determination of tear force using the pendulum method | |
| ASTM D1424 | Standard Test Method for Tearing Strength of Fabrics by Falling-Pendulum (ElmenGuide) Apparatus | |
| Trouser Method – Single Tongue | GB/T 3917.2 | Textiles — Tear properties of fabrics — Part 2: Determination of tear force of trouser-shaped (single seam) specimens |
| ISO 13937-2 | Textiles — Tear properties of fabrics — Part 2: Determination of tear force of trouser-shaped (single seam) specimens | |
| ASTM D2261 | Standard Test Method for Tearing Strength of Fabrics by the Tongue (Single Rip) Procedure (CRE-Type Testing Machine) | |
| Trouser Method – Double Tongue | GB/T 3917.4 | Textiles — Tear properties of fabrics — Part 4: Determination of tear force of tongue-shaped (double seam) specimens |
| ISO 13937-4 | Textiles — Tear properties of fabrics — Part 4: Determination of tear force of tongue-shaped (double seam) specimens | |
| Trapezoid Method | GB/T 3917.3 | Textiles — Tear properties of fabrics — Part 3: Determination of tear force of trapezoid-shaped specimens |
| ISO 9073-4 | Textiles — Test method for nonwovens — Part 4: Determination of tear resistance by the trapezoid method | |
| ASTM D5587 | Standard Test Method for Tearing Strength of Fabrics by the Trapezoid Procedure | |
| ASTM D5733 | Standard Test Method for Tearing Strength of Nonwoven Fabrics by the Trapezoid Procedure | |
| Wing Method | GB/T 3917.5 | Textiles — Tear properties of fabrics — Part 5: Determination of tear force of wing-shaped (single seam) specimens |
| ISO 13937-3 | Textiles — Tear properties of fabrics — Part 3: Determination of tear force of wing-shaped specimens (single tongue method) |
Sampling diagram
A: The pendulum method
The Elmendorf Tear Tester measures how strong a fabric is against tearing. Elmendorf tear testing is used to find out how much force is needed to continue a tear in different sheet materials. These materials can be paper, plastic film, textiles, or non-woven fabrics. It uses a pendulum tearing method. It meets the standards of ASTM D1424, BS ISO 13937-1, GB/T 3917.1, and ISO 4674-2. This helps improve fabric quality.
B: Pants Method – Single Tongue
C: Pants Method – Double Tongue
D: Trapezoidal method
E: Wing method
Testing Principle
The pendulum method
The sample has a cut. When the hammer drops, it breaks the first yarn in the tearing triangle. Then, the sample tears completely. The system records the tearing force when this happens.
Pants Method
The pendulum method performs a rapid assessment of tearing strength. The trouser-type method is slower, but it yields more consistent results. In this test, both sides of the trouser-type or tongue sample go into the strength machine fixture. The surgeon applies the force in the direction of the incision. We record the tear until it reaches the specified length of tearing strength.
Trapezoidal method
Clap the trapezoidal specimen by its two non-parallel sides in the force machine. Apply force to tear along the width of the specimen. Then, record the average largest tearing force. Trapezoidal tearing kicks off at the first marked yarn and goes up to the nth unstretched yarn. This group of yarns resists vertical tension. Thus, the yarn’s tensile strength links to the trapezoidal tearing method.
Wing method
The wing method keeps the specimen steady. Both wings tilt in the tensile strength machine. It measures the average tearing force until it reaches the set length. The wing method and trapezoidal method for measuring tearing strength are similar. They differ only in angle. This angle represents the number of yarns resisting tension. Researchers are unable to directly compare the final results of the two methods.
Tips
The size of the fabric tear triangle is a primary factor affecting the tear strength. Different methods for testing have unique principles. So, the results from different standards are not comparable.
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