Free-cylinder, strain-gauge, pressure transducers up to 2 GPa

A review of the main metrological characteristics obtained with a large family of free-cylinder and free-rod pressure transducers using different materials (hard tool steels, tungsten carbide and ceramics), different shapes of active elements and different pressure ranges up to 2 GPa is presented. In general, they have a resolution better than 1 x 10(4). Repeatability of measurements depends on pressure and typically it is of the order of few parts in 10(4) up to 0.5 GPa, approaching 1 x 10(3) for pressure range up to 2 GPa. Their pressure sensitivity is always of the order of few parts in 10(5) up to 0.5 GPa and of the order of few parts in 10(4) for higher pressures up to 2 GPa. Linearity of the calibration factor is of the order of some percent, so it is always necessary to use appropriate polynomial fitting to express the output signal of the pressure transducers versus the measuring pressure. The main limiting factor is hysteresis that can be of the order of few parts in 10(4) for some of the pressure transducers (for pressures not generally exceeding 0.5 GPa) but it can reach values of some parts in 10(3) for pressures from 0.5 to 1 GPa and of some percent from 1 to 2 GPa. (C) 1999 Elsevier Science B.V. All rights reserved.