Fabric Strength Testing with a Universal Testing Machine
Textiles, yarn, thread, fabrics, wool, cotton, and other animal and plant-derived fibers are commonly tested to ensure product quality by assessing the performance of materials and making sure they are acceptable towards proper end-use. This blog post will cover certain mechanical testing methods to test fabric and go over the testing standards as well as the recommended equipment.
Measurement Methods of the Mechanical Properties of Fabrics
Tensile testing is the most commonly applied test method for analyzing the mechanical properties of fabric materials. Although the direction of applied force is always in tension, there are a variety of tensile test methods available for capturing the most relevant data for final product usage.
The strip test is a tensile test in which the full width of the test specimen is gripped in the tensile grip jaws of a universal testing machine. During this test, tensile force is applied on the fabric specimen until it ruptures. Mechanical properties to analyze include the force at rupture and the elongation (expressed as percentage) at maximum force and/or at rupture.
Trapezoidal tear is another tear strength test that uses a specimen prepared as an isosceles trapezoid with a small cut on one side. When testing starts and force is applied, the trapezoid tear produces tension along a reasonably defined course such that the tear propagates across the width of the specimen. This test method applies to most fabrics such as woven fabrics, air bag fabrics, blankets, napped, knitted, layered, and pile fabrics.
Adhesion Coating Testing
Adhesion coating testing is applicable to fabrics with an adhesive coating compound applied, forming a chemical bond between the adhesive and the fabric material. The bond strength that is created between the coating compound and the fabric material can be measured running adhesion coating tests. If the adhesion is not strong enough, seam strength will decrease. If adhesion is too strong, problems may arise as tear strength will be affected. Standards outlining the minimum required criteria for specific fabric constructions can be used to ensure both the seam and tear strength are acceptable.
Puncture testing of fabric specimens determines the strength of a material by measuring the force required to penetrate the specimen. Contact with sharp edged objects in a real-world scenario is simulated by the use of puncture fixtures. Puncture fixtures are often used in the tensile direction but may also be used in the compressive direction. In order to calculate the specimen puncture resistance, the specimen is first stretched and placed on the ring clamp mechanism of the puncture fixture. Load is then applied by the puncture probe until specimen rupture.