| 摘要 |
PURPOSE:To perform the test of life and the like by cutting the plastic pipe in a short length, holding it at two points separated by about 180 deg. in the circumferential direction, and repeatedly reciprocating at least one holding point. CONSTITUTION:A fixed frame 3 and a moving frame 4 are fabricated in a stand 2 provided in a constant temperature tank 1. Between holders 9 of both frames, is held the cylindrical plastic pipe 10 which is cut in a relatively short configuration. An output shaft 6a of a speed shifting device 6, which is linked to the motor 5, is linked to the moving frame 4 via a crank 7 and a crank arm 8. The moving frame 4 is repeatedly reciprocated. In this way, the plastic pipe 10 is subjected to repeated plastic deformation, and the correlation between a distortion coefficient and the crack generating time is obtained. In this constitution, the crack generation time is greatly reduced in comparison with a conventional reliable method, and the correlation of both methods are similar with each other. |
