| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for deciding a deterioration of a high polymer sheet which can decide a deterioration of the high polymer sheet for a short period of time, readily, and with high precision in a job site by measuring a propagation speed of SH ultrasonic waves propagating inside the high polymer sheet, does not require repair due to complete non-breakdown, does not reduce quality of this high polymer sheet at a plurality of measurement points, and is not influenced by conditions of an underlayer, etc. SOLUTION: In this method, calibration curve l indicating a correlative relation between a propagation speed of SH ultrasonic waves propagating inside a high polymer sheet receiving processings or exposures under a plurality of different conditions and a tensile breakage extension of the high polymer sheet has beforehand been acquired. The propagation speed of the SH ultrasonic waves propagating inside the high polymer sheet which is an object of deterioration decision is measured and the tensile breakage extension of the calibration curve l corresponding to this measurement value, so that a deterioration of the high. |
