| 摘要 |
Apparatus for applying an optimal tension exceeding alternating forces to a specimen being measured by automatically detecting saturation of a relaxation phenomenon that has occurred in the specimen when the dynamic viscoelasticity of the specimen is measured by a tension method. The apparatus includes a strain detector for detecting changes in length of the specimen, an electromagnetic force generator for applying a force to the specimen, a moving mechanism for moving the electromagnetic force generator, a movement control unit for controlling the amount of movement of the drive mechanism, a strain differentiation circuit for differentiating the output of the strain detector, and a comparator for comparing the output of the strain differentiation circuit with a target differential value and producing a tension control timing signal. When the drive mechanism is moved or the force produced by the electromagnetic force generator is changed, a relaxation phenomenon occurs in the specimen, with the result that the effective tension and length of the specimen will continue to change for a relaxation time while keeping their proportional relationship. When the output of the strain differentiation circuit becomes less than the target differential value, it can be concluded that the relaxation phenomenon has been saturated so that the comparator can produce the tension control timing signal, making it possible to control the drive mechanism to apply an appropriate tension to the specimen.
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