| 摘要 |
PURPOSE:To obtain stress and elongation at many points regardless of the material of a test-piece by drawing the test-piece following up a strain quantity so that a stress increasing speed is held constant at a raised part. CONSTITUTION:The stress increasing speed of the raised part and the strain increasing speed of a part which changes from a linear part to a horizontal part are roughly known in advance from the material of the test-piece 2, so they are stored in a memory 7. Then, hydraulic pressure is supplied to a servo valve 14 to drive an actuator 13 and a chuck 11 is drawn up to draw the test- piece 2. In this drawing, the outputs of an elongation quantity detector 4 and a load cell 12 are inputted to an arithmetic circuit 74 through amplifiers 5 and 6 and A/D converters 71 and 72 and the strain increasing speed is made to follow so as to equal the value in a memory 75. Then when the strain increasing speed becomes larger than the previously supplied value, the speed is fixed at the value and the drawing is finished.
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