Comparison of vibration measurements of elastic and mechanically lossy (visco-elastic) materials, using fibre grating sensors

The paper compares results when measuring oscillatory strain in elastic (Al alloy) and visco-elastic materials using infibre Bragg gratings. These show the effects of self-heating in the latter, when mechanical losses arise, and also show the effects of materials creeping at high strain levels. Results are also taken for highly-elastic metallic substrate materials when a visco-elastic damping medium is in close contact. The results show that care must be taken, not only when monitoring fast oscillatory perturbations in visco-elastic materials, but also when choosing fibre bonding cements or protective coatings for use with fibre gratings.