How to Test the Tensile Strength of Fabric
To test tensile strength, a testing machine stretches a fabric sample until it tears while recording the maximum force applied. Tensile strength is then calculated by dividing the maximum force by the fabric’s cross-sectional area.
Tensile Strength = Maximum Force / Cross-Sectional Area
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.
- The specimen slowly elongates at a constant speed.
- The software captures the material’s test parameters, such as the force and changes in the gauge length.
- The specimen eventually deforms in the middle of the length.
- 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:
- Strip method: This is the traditional approach to testing by separating the specimen at a certain speed until the material breaks.
- 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.
- Ball burst method: This method determines the multi-directional bursting strength of textiles by placing stress on the material with a spherical plunger.
- 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.
- 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.
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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.
