PVDF gauge

PA PCP PCR PFA PGB PHA PID PLC PMACWA PMD POTW ppm PRH PRR psi psig PTFE PVDF PWS picric acid pentachlorophenol propellant collection reactor perfluoroalkoxy product gas burner preliminary hazards analysis proportional integral differential controller programmable logic control Program Manager for Assembled Chemical Weapons Assessment projectile mortar demilitarization (machine) publicly owned treatment works parts per million projectile rotary hydrolyzer propellant removal room pounds per square inch pounds per square inch gauge polytetrafluoroethylene (Teflon) polyvinylidene fluoride projectile washout system... 

Hyndman, D. A. and Gaffney, E. S, "Development of PVDF Water Shock Gauges," Ktech Corp., Albuquerque, NM, Rept. TR-89-19, July 1989. 

Certain polymers, such as polyvinylidene fluoride (PVDF) and polyvinyl fluoride (PVF), possess special properties in the film form, caileApiezoelectricity and pyroelectricity. Piezoelectricity is electric polarization of a film produced by mechanical strain in some crystals. The polarization is proportional to the amount of strain and changes sign with it. The reverse is true and an electrical polarization induces a mechanical strain in piezoelectric sensors. Pyroelectricity is electric polarization of a film induced by thermal absorption in some polymer crystals. The induced polarization is proportional to the level of thermal change. These properties can be used in the manufacture of transducers, microphones, loudspeakers, pressure gauges, pickup heads, hydrophones, motion sensors, and other devices from biaxially oriented PVDF films. Table 13.37 gives the properties of a piezoelectric film of polyvinylidene fluoride. 

Takasc et al. (63] have found that rctiumcni polarizatkms of 0.1 Cfm can be achieved in deulcratcd PVDF, and Bauer [64] reported the same for biaxially oriented films. Bauer and co-workers have developed a standard stress gauge using PVDF and in the process have demonstrated [6S] that they can achieve a remanent polarizalioo of 0.092 0.002 C/m using a patented poling process. 

I. M. Lee. E A. Graham. F. Bauer, and E P. Reed, Standardize Bauer PVDF piezoelectric polymer shock gauge, /. fhyj. CoUoq. 49(C J) 6S1 (1988). 

PVDF is useful for a variety of measurement instruments iitcluding acceletometers, stress gauges, strain gauges, shock gauges, turbulence sensors, fiber optic phase modulators. 

PVDF has recently found application as a dynamic strain gauge (35). The distinct advantage of using a piezoelectric polymer, as opposed to the traditional wire and semiconductor resbtance gauges, b that PVDF-based gauges arc nonparametric transducen because their output b directly propoitiooal to strain. Thb means that the electronic... 

Figure 24 Cross-icctiooal view of two-layer PVDF strain gauge (1) PVDF (2) inner eketmde (3) outer electrode (4) cable (S) center coaductar, (6) shield. (Adapted from Ref. 35.)...

FIgurn 25 Cross-sectional view of the impact toading configuration showing the Bauer PVDF stress gauge. (Adapted froni Ref. 38.)... 

R. A. Oraham. L. M. Lee. and F. Bauer, Reapanac piezoelectric polymer stress gauges (PVDF) lo shock loading, Shack Waves in Condensed Matter (S. C Schmidl and... 

In spile of the case of construction, robustness, and high sensitivity, the lack of a truly static response of a ferroelectric polymer pressure transducer represents a serious limitation to widespread use of this type of device. Several techniques can be conceived in order to overcome this drawback [21] (such as the parallel use of a strain gauge sensor and the use of this transducer to calibrate at intervals the signal detected by the PVDF sensor), but excessive complexity and costs are usually added to the originally simple and cheap design of the piezoelectric polymer catheter-tip sensor. 

Assume the same configuration as Example 16.1, but now assume that the bottom electrode layer is perfectly bonded to a structure under tension. Also, assume in this case that there is perfect bonding between the PVDF and electrode layers in order to transfer the tensile strain in the structure to the gauge. Assume that a potential difference of E = 12.5 V is detected across the gauge in the normal direction. What is the magnitude of strain detected in the structure ... 

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