| 摘要 |
PURPOSE:To correct an penetration length of a pre-crack of the surface and the reverse side of the width direction of a test piece by a simple operation, by connecting a block which is provided so as to be movable between a base and a receiving seat, so as to be freely turnable to the receiving seat, and providing its moving extent adjusting mechanism. CONSTITUTION:A test piece 1 is set so that its notch 1c is positioned right under a pressure roller 6, an actuator 7 is operated, and a precrack is generated gradually from the notch 1c by operating a repeated load. In this case, in case a crack progress of a surface side 1a of the test piece 1 is quick, a block 12 which is provided on a recesses groove of a base 11 is moved to a side where a crack speed is high, by operating an adjusting knob 27. The test piece 1 remains contacting to the pressure roller 6, and at the same time as a horizontal movement of a shaft 13, a bracket 16 turns around the shaft 13 through a bearing 15, and a receiving seat 3 and the test piece 1 are inclined. In this way, in the test piece 1, a large stress works on an A-B line, and a progress of a crack of a reverse side 1b is quickened. When the crack progress degrees of the surface and the reverse side becomes the same, the test piece 1, the receiving seat 3, etc. are returned to each normal position by operating the knob 27.
|
