Fabric Stiffness Tester Test Method and Procedures
Fabric stiffness is one of the basic styles of fabrics and one of the key indicators that determine the beauty of fabrics and consumer preferences, such as the stiffness of suits, the softness of knitted underwear, and the stiffness of nonwovens.
What is the stiffness of fabric
The stiffness of clothing materials refers to the flexural stiffness and softness of the fabric. The ability of a fabric to resist shape changes in its bending direction is called bending stiffness. Bending stiffness is often used to evaluate its opposite characteristic – softness. The bending stiffness of clothing materials is determined by the bending stiffness and structure of the fibers and yarns that make up the fabric, and increases significantly as the thickness of the fabric increases.
Knitted fabrics have greater softness; compared with knitted fabrics, woven fabrics of the same thickness have greater bending stiffness. Under other conditions being equal, plain weave fabric is stiffer. As the yarn floating length in the fabric increases, the interweaving points between warp and weft yarns decrease, the bending stiffness of the fabric decreases, and the fabric body becomes soft. Under the condition that the tightness in the warp direction (or latitude direction) is constant, it is proportional to the tightness in the latitudinal direction (or warp direction). The results of changes in fabric stiffness caused by warp tightness and weft tightness are approximate. When the tightness is close, the bending stiffness of fabrics with fine yarns is smaller, and the fabrics with large bending stiffness feel stiff.
Fabrics and underwear materials for general clothing need to have good softness to meet the body’s fit and fit needs. Materials used for outerwear should maintain the necessary shape and have certain styling capabilities when worn. At the same time, the fabric should have a certain degree of rigidity and flexibility.
Knitted fabrics have greater softness; compared with knitted fabrics, woven fabrics of the same thickness have greater bending stiffness. Under other conditions being equal, plain weave fabric is stiffer. As the yarn floating length in the fabric increases, the interweaving points between warp and weft yarns decrease, the bending stiffness of the fabric decreases, and the fabric body becomes soft. Under the condition that the tightness in the warp direction (or latitude direction) is constant, it is proportional to the tightness in the latitudinal direction (or warp direction). The results of changes in fabric stiffness caused by warp tightness and weft tightness are approximate. When the tightness is close, the bending stiffness of fabrics with fine yarns is smaller, and the fabrics with large bending stiffness feel stiff.
Fabrics and underwear materials for general clothing need to have good softness to meet the body’s fit and fit needs. Materials used for outerwear should maintain the necessary shape and have certain styling capabilities when worn. At the same time, the fabric should have a certain degree of rigidity and flexibility.
Fabric stiffness tester
FY207 Automatic Fabric Stiffness Tester is designed to determine the bending height, flexural rigidity and bending modulus of fabrics by simple procedures and calculation, and suitable for stiffness testing of cotton, wool, silk, ramie and chemical fabrics. Read more details about fabric stiffness tester
On the fabric stiffness tester, the specimen is suspended as a uniformly distributed load, flat on the workbench. The driving mechanism makes it move at a constant speed along the length direction. When it bends and sag due to its own weight and touches the slope detection line, measure the extended length L. The calculated bending length is also known as suspension stiffness and bending stiffness (also known as bending stiffness). Based on the principle that the greater the bending stiffness, the more difficult it is to bend, it is used as a test index to evaluate the rigidity and flexibility of the material being tested. There are three measuring angles: 41.5°, 43° and 45°. The calculation formulas for bending length and bending stiffness are as follows:
When the test angle is 41.5°:
Bending length C≈L/2 (mm)
Bending stiffness B=G×C3/10 (g/m2)
In the formula: G—mass per unit area of the sample (g/m2), L—protrusion length (mm)
When the measurement angle is 45°:
Bending length C=0.487L (mm)
Bending stiffness B=G×0.1155L3/10 (g/m2)
When the measurement angle is 43°:
Bending length C=0.5L (mm)
Bending stiffness B=G×0.125L3/10 (g/m2)
When the test angle is 41.5°:
Bending length C≈L/2 (mm)
Bending stiffness B=G×C3/10 (g/m2)
In the formula: G—mass per unit area of the sample (g/m2), L—protrusion length (mm)
When the measurement angle is 45°:
Bending length C=0.487L (mm)
Bending stiffness B=G×0.1155L3/10 (g/m2)
When the measurement angle is 43°:
Bending length C=0.5L (mm)
Bending stiffness B=G×0.125L3/10 (g/m2)
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