| 摘要 |
PURPOSE:To accurately measure changes in strain in the early stage of a displacement and reduce a measuring time by providing distance sensors for detecting the displacements of the upper and lower portions of a specimen and obtaining a stress applied to the specimen from a difference between the displacements detected by the sensors. CONSTITUTION:A measuring instrument is provided with first and second shafts 9 and 15, respectively, on the common axial line of the instrument. A load sensor 10 is arranged on the upper portion of the shaft 9 and upper and lower chucks 5 and 6 as engaging means for a specimen 7 are provided on the lower portion of the shaft 9 and the upper portion of the shaft 15, respectively. A first distance sensor 26 is provided close to a metal plate 25 mounted to the shaft 9, a stopper 27 that moves integrally with the shaft 15 is mounted and a second distance sensor 28 is provided near the stopper 27. The displacement positions of the shafts 9 and 15 detected by the sensors 26 and 28, respectively, are applied to a differential amplifier 29. A stress is applied to the specimen 7 by solenoids 23 and 24 provided on the lower portion of the instrument and the stress is sensed from a difference between displacements detected by the sensors 26 and 28 to accurately measure changes in the strain in the initial stage of the displacement.
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