Favimat+ fibre testing machine

The Favimat+ fibre testing machine combines measurements on individual material fibres, including a single-fibre tensile test and vibroscopic estimation of linear mass density. Its useful feature is the association of the force-extension record with a measurement of the same strand, rather than with a batch-average geometry.

In the reported glass- and carbon-fibre study, a magazine held the prepared strands and a robotic device transferred each to the grips. The built-in vibroscope used acoustic excitation and a frequency sweep to identify resonance; a load cell measured tension and grip separation supplied the suspended length. Tensile measurements followed vibroscope measurements on the same still-gripped fibre.^[ref]

An original pairing example shows why strand identity matters. Suppose two strands have independently established material areas $50$ and $100\mu {\mathrm{m}}^2$, and each carries $0.050\mathrm{N}$. Their engineering stresses areUsing the common mean area $75\mu {\mathrm{m}}^2$ would assign both $0.667\mathrm{GPa}$, concealing the difference. These are chosen values, not measured instrument data.

Frequency first supports a mass-per-length estimate under the vibration model; converting it into area also needs compatible mass density and deformation conventions. The vibroscope area estimator explains that inference and its limitations. Force and displacement readout resolution are likewise not complete statements of measurement uncertainty or specimen extension: machine compliance and grip motion must be assessed when extracting a modulus.