Tensile Testing Hair
Tensile testing human hair is a common practice among manufacturers of various hair products, such as shampoos, dyes, and gels. It is important to be able to characterize the strength of hair to determine whether these products weaken or strengthen it. Similar to single strand textiles, there are many challenges associated with tensile testing of hair. Hair is normally very fine and often not long enough to be used in a cord and yarn style grip. In addition, hair is typically inconsistent, so it is important to test large sample sizes.
We were asked to provide a system that could test various hair samples. In this particular case, the manufacturer wanted to conduct tests on untreated human hair. The equipment would later be used to test hair before, as well as after being subjected to the company's various hair products to determine if there were any changes in strength.
Hair may be tested in single strands or multi-strands. When testing multi-strands, we recommend to prepare the specimens in such a way that the individual hairs are bonded together. Adhesives, waxes, and other materials can be used to prepare specimens.
We evaluated single strands of hair and were successful in determining a suitable test configuration. 250 N capacity pneumatic side acting grips were used along with 25x25 mm rubber coated jaw faces, which were necessary to avoid specimen failures at the jaw faces. Pieces of masking tape, approximately 50 mm long, were folded and adhered to each end of the specimens to serve as tabs (these tabs make it easier to manipulate the specimens and insert them into the grips). The tape also helped to reduce specimen failures at the jaw faces by providing additional cushion. Specimens were tested at 25 mm/min and the data capture rate was 100 Hz.
5900 Universal Testing Systems are engineered for precision, built for durability, and offer the flexibility for changing requirements. They are designed with standard and optional features that increase testing efficiency and improve the testing experience for the operator. A wide range of models are available for testing capacities from < 100N up to 600kN.
- 2.8 MB
Instron 3300 Series Universal Testing Systems for Tensile, Compression, Bend, and other material property tests.
- 12.0 MB
Bluehill® 3 is the newest version of Instron’s widely popular Bluehill Software, designed to meet the demands of any level of user from educators and test technicians to, quality engineers and laboratory managers. Compatible with 5900, 3300 and 5500 systems.
- 2.0 MB