Strain gauge pick

Laboratory rotors have been used to evaluate the drag resistance of immersed surfaces as well. The rotational frequency of the innermost cylinder is adjusted to the relevant speed (monitored by a tachometer) and after about 30 minutes of flow stabilisation a 50 Nm strain gauge transducer picks up the torque, M,. All measurements are based on the average of three replicate tests. A sketch of the set-up is shown in Figure 13 details on the set-up and calculations are described in Weinell et al. (2003). 

Electrical output transducers exist in many forms and consist simply of elastic elements coupled with suitable displacement transducers such as capacitance, inductance and reluctance pick-ups, certain types of strain gauge, piezoelectric elements, potentiometers and eddy current probes. A selection of these is described in the following paragraphs. 

The determination of the thrust of a rocket motor involves recording the time diagram of the force (tons, kp, or newtons) during combustion. The force is allowed to act on a support, with a pick-up element thrust cell interposed between them. The measurement is carried out by the aid of a strain gauge element (variation of resistance with pressure) or of a piezo-quartz element, and the results are recorded on an oscillograph connected in a compensation circuit. Modern measuring and computation techniques yield the total thrust time (impulse) immediately. 

Frost thickness data would be improvedwith the use of a cathetometer capable of movements in two planes. With such an instrument, periodic maps of a vertical section of the frost surface could be obtained. The mass of frost formed on a container might be determined directly with the use of strain gauges, inductive pick-offs or load cells. Such methods of measurements would warrant investigation. 

The strains indicated by gauges 3 and 5 on the conductor were lower than the corresponding gauges, 4 and 6, on the steel. The steel pins were not forced into the ring with an interference fit, and thus some relative motion between the conductor and the steel near the joint was allowed, accompanied by elastic deformation of the epoxy and a reduced strain level in the copper. This effect was not observed at gauge 1, far from the copper joint, because enough load was picked up by the... 

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