How to Measure the Tensile Strength of Fabric

03.04.24

Fabric tensile strength plays a crucial role in the quality and performance of fabric. Materials with higher tensile strength are more durable, as they can withstand greater stress and strain without failing. They're less likely to tear or develop holes, therefore increasing their life span.

Tensile strength is particularly important where fabric is used for structural purposes, such as for architectural membranes or in asset protection, like covered parking structures. Fabrics with sufficient tensile strength can provide stability and support to different kinds of structures, ensuring they can withstand external forces. Knowing how to accurately measure fabric tensile strength helps you choose suitable options for your applications.

What Causes Problems in Fabric Tensile Strength?

High tensile strength indicates that fabric will be less likely to suffer wear and tear while in use. Fabric with higher tensile strength and performance are more suitable for products and applications in industries that require durability, versatility, and low maintenance.

Manufacturers and researchers can make informed decisions about a material's suitability for different applications when they know of the factors affecting the tensile strength of fabrics. These elements can lead to issues with fabric tensile strength:

• Fine material composition: Different types of fabric have varying levels of strength, density, and elasticity. Coarse materials generally are stronger than fine materials.
• Weak weave patterns: The weave pattern used can influence fabric tensile strength. Plain weave patterns are stronger than twill since the density of warp and weft strengths are higher.
• Environmental factors: Long and regular exposure to heat can lower the tensile strength of fabrics. Moisture can also negatively affect tensile strength depending on the type of fabric.
• Fabric treatments: Some treatments can reduce a fabric's tensile strength, while polyvinyl chloride (PVC) and polytetrafluoroethylene (PTFE) add to its strength and life span. Consider the impact of the fabric's treatment and how specific treatments may create a stronger fabric.

How to Test the Tensile Strength of Fabric

In a tensile test, a sample of the fabric is placed in a tensile testing machine. The machine pulls the fabric in different directions until it snaps. While the fabric is being stretched, the machine measures the force being applied and the amount of stretch the fabric undergoes. The tensile strength of the fabric is then calculated by dividing the maximum force applied to the fabric by the cross-sectional area of the sample.

Here's how to test the tensile strength of fabric.

1. Equipment and Setup 

Prepare and measure your fabric specimen according to the requirements of the test standard. Specimens are usually shaped like long dumbbells, featuring a small cross-section or gauge length with two large ends called shoulders. The tensile testing machine grips the shoulders while the test focuses on the gauge length.

The typical components of a tensile testing machine include:

• Load cells: The tensile force is converted into a measurable electrical signal.
• Extensometers: This device measures the strain of a specimen.
• Specimen grips: Grips hold onto the specimen during a test and transfer the test force to the load cells.
• Moving crosshead: One specimen grip is attached to the moving crosshead, which moves during the test while the other grip remains stationary.
• Drive system: This system supplies the motor of the machine with different levels of power and frequencies.

2. Conducting the Test

Once the specimen is positioned properly between the grips and the other components in the correct positions, set the appropriate test speed on the machine. The tensile tester machine takes a few minutes to complete a test, depending on the size and shape of the material.

1. The specimen slowly elongates at a constant speed.
2. The software captures the material's test parameters, such as the force and changes in the gauge length.
3. The specimen eventually deforms in the middle of the length.
4. The test ends once the specimen breaks.

3. Analyzing Test Results

Tensile strength tests generate a graph known as the stress-strain curve, which is used to analyze several mechanical properties of materials while subjected to stresses. This curve represents the material's relationship between stress and strain.

• The y-axis represents stress, which is the force per unit area applied to the material.
• The x-axis represents strain, which is the amount of deformation the material undergoes in response to the applied stress.

The curve typically starts with a linear region called the elastic region, as the material can return to its original shape once the stress is removed. As stress increases, the curve enters the plastic region, where the material experiences permanent deformation. Finally, the curve reaches the ultimate strength point where the material can no longer withstand the applied stress, beyond which point it breaks. Analyzing this curve provides information on any material's strength, stiffness, and ability to resist deformation.

5 Proven Methods for Measuring Tensile Strength in Fabrics

There are different methods of testing the tensile strength of fabrics, including:

1. Strip method: This is the traditional approach to testing by separating the specimen at a certain speed until the material breaks.
2. Grab method: For more focused fabric testing, the grab method is used to test the central part of a specimen's width to establish its effective strength.
3. Ball burst method: This method determines the multi-directional bursting strength of textiles by placing stress on the material with a spherical plunger.
4. Elmendorf tear test: To measure the quantifying tear strength of the fabric, this method can be used to test the pendulum impact force required to tear the fabric.
5. Pneumatic bursting strength test: For real-world stress simulations, pneumatic testers can test the bursting strength of materials.

No matter which approach you choose, keep in mind that some challenges in measuring tensile strength might arise. One common example is an unexpected reading on the load indicator — make sure the specimen is placed and aligned properly and the machine is calibrated. Otherwise, so long as you follow the recommended steps for your preferred testing method, you should be able to achieve accurate, informative results.

Find High-Quality Tensile Strength Fabric Shade Structures From VPS

Rigorous testing in product development is crucial to ensure superior fabric performance and customer satisfaction. At VPS, we create and build tensile fabric shade structures that are among the most durable, innovative, and economical in the industry. Our tensile fabrics are coated with PVC or PTFE that add extra protection and resistance to protect valuable assets from hail, heat, and UV light.

VPS is committed to consistently delivering products with tensile strength of the highest quality. Have questions? Get in touch with our team today for expert solutions in fabric protection and quality assurance.