| 摘要 |
PURPOSE: To evaluate damage on a metallic sample, e.g. the blade off gas turbine, owing to creep and fatigue and the residual service life with high accuracy. CONSTITUTION: The distance between a metallic sample 1 and an acoustic lens 3 is determined by detecting the period ΔZ of interferential variation in the amplitude of reflected wave in the direction of relative movement detected through an oscillator 2 oscillating relatively in the approaching or separating direction. Sound velocity Vr of surface acoustic wave corresponding to the period ΔZ is then operated for the sample 1. It is then normalized using the sound velocity Vr0 at the initial stage of creep and fatigue thus evaluating the damage and service life based on the value Vr/Vr0. |
