Showing papers on "Gauge factor published in 1969"
TL;DR: Gold films of 80 to 500 A thickness were deposited onto 6-milthick glass substrates, and continuous measurement of electrical and mechanical properties pertinent to the use of a film as a strain gauge element were made in situ as mentioned in this paper.
Abstract: Gold films of 80 to 500 A thickness were deposited onto 6-mil-thick glass substrates, and continuous measurement of electrical and mechanical properties pertinent to the use of a film as a strain gauge element were made in situ. Gauge factors of greater than 100 for films that are less than 100 A thick have been observed. These are over a factor of 20 greater than reported foil bulk values. The temperature coefficients of resistance for these high-gauge factor films were negative and their microstructure consisted of isolated islands. Increasing the island size and joining of islands, such as occurs in annealing, caused the gauge factor to decrease for films having the same surface resistivity. Straining and relaxing films up to 16 000 times resulted in drift in most specimens although there was no observable microstructure change. Films having high initial surface resistivities and gauge factors drifted to higher values upon cycling, while those with relatively low initial values dropped upon cycling. Surface passivation by silicon monoxide films did not change the film structure, but did increase the resistivity and decrease the gauge factor.
26 citations
TL;DR: In this article, a p-n heterojunction diode is used to measure the surface strain of a flexible substrate, which can be used as a low-output-impedance voltage source.
Abstract: A new type of strain sensor has been demonstrated in the laboratory. The basic device is a p-n heterojunction diode that is fabricated by vacuum evaporation techniques directly onto a flexible substrate. Its two important properties are 1) its mechanical input characteristics are determined by the flexible substrate used in fabricating the heterojunction and 2) it functions as a low-output-impedance voltage source modulated by the substrate surface strain. The heterojunction combination that has been most commonly used is CdSe on Se. Typical devices exhibit a voltage/strain sensitivity of 500 volts per unit strain, with a differential resistance of 100 ohms, when biased at 5 mA. This corresponds to a "gauge factor" of 1000 for the diode strain sensor. Thus far, the substrates used have ranged in mechanical properties from 2-mil-thick plastic to 40 mil microscope slides but the most useful substrate appears to be anodized Al. This device is still under active experimental study. Thus the characteristics cited in this paper are preliminary in nature, and represent the current research status of this strain sensor.
14 citations
TL;DR: In this paper, a range of strain gauges with a sensitive element made of annealed or unannealed constantan on a Viniflex base are used for low-temperature measurements of deformations.
Abstract: 1.
Strain gauges with a sensitive element made of annealed or unannealed constantan on a Viniflex base are suitable for low-temperature measurements of deformations e up to 0.4%. Strain gauges made of unannealed constantan can be used without temperature compensation within a definite interval of low temperatures.
2.
In the investigated range of strains, the strain gauge factor of Viniflex based gauges cemented with VL-931 and “Terebek” varnishes is practically constant and equal to 2 within the temperature interval from +20 to −120°C; the gauge factor varies between 2.01 and 2.15 in the temperature interval from −120 and −180°C, and amounts to 2.15 from −180 to −196°C. The strain gauge factor is independent of the strain level (up to e=0.4%).
3 citations