Tensile Test Grips for Single Fiber Filaments

Carbon fiber is widely used in composite materials to make light-weight high-strength materials. Theory of fiber-reinforced matrix composites uses the idea that the entire surface area of each fiber is wetted by matrix material, when considering load transfer interactions. Load transfer within the composite is then achieved through each individual fiber-matrix interaction, instead of through the interaction between a group of fibers and the matrix. In a well manufactured fiber-matrix composite, fiber-matrix interactions and stress transfer can closely approximate composite theory. Single-fiber tests provide results for material strengths closest to the theoretical value for fiber materials. This information is useful for the development of new fiber based materials, such as yarns, fiber reinforced composites, and fiber reinforced ceramics. Single-fiber tests are also used in the fiber selection process when developing new composite materials. Although carbon fibers have high strength, individual fibers must be handled carefully and can also present fixturing difficulties. Typical test methods for single-filament testing of carbon fiber use cutout paper, or thin plastic tabs for mounting the fibers. An individual fiber is laid across the cutout of the tab and attached using an adhesive. The tabs are mounted into a set of grips and then the tabs are cut at mid-gage. The tabs facilitate consistent and proper mounting of fiber specimens, while not interfering with test data since they are cut after mounting and before load application. For help with testing your single fiber filaments, call an applications engineer today. ASTM and ISO have developed standard test methods for testing the tensile strength of single-filament carbon fiber specimens. These test methods ensure consistent test procedures and conditions that can be replicated and verified between different laboratories and manufacturers. Popular single-fiber carbon standards are ASTM C1557 for tensile strength and Young's modulus of fibers and ISO 11566 for tensile properties of single-filament carbon-fibre specimens. The load requirements to break single-fiber carbon specimens can be met using table top tensile machines. Simple vice grips are typically used to clamp the fiber mounting tabs.

Applicable Testing Standards

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