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EVALUATION OF SURFACE DAMAGE,DEGRADATION AND STRESS WITH BROADBAND SURFACE ELASTIC WAVES

利用宽带表面弹性波评估表面损伤、退化和应力

基本信息

批准号：
08455056
负责人：
KAWASHIMA Koichiro
金额：
$ 1.09万
依托单位：
NAGOYA INSTITUTE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08455056/
关键词：
SURFACE WAVE ULTRASONIC LEAKY RAYLEIGH WAVE WAVE PROPAGATION FEM SURFACE DAMAGE ACOUSTELASTICITY STRESS MEASUREMENT 音弾性応力測定

项目摘要

(1) A digital ultrasonic measurement system of the surface waves has been established to measure their velocities of the leaky Rayleigh, creeping and surface SV waves as well as attenuation of the leaky Rayleigh wave with line-focused broadband PVDF ultrasonic transducers of 10-50MHz. The relative precision of their velocities measured on fused quartz and 2017 aluminum alloy with a 10MHz transducer are 0.015,0.03 and 0.018%, respectively.(2) The densities of the surface layr of fused quartz and 2017 aluminum alloy were measure nondestructively by using the velocities of those surface waves and attenuation of the leaky Rayleigh wave. The measured values are agreed with those measured by Archimedes'method within 10%.(3) The acoustoelastic coefficients of Rayleigh wave on 2017 aluminum alloy are found to be-2.3 and 0.9x10^<-5>/MP_a for the loading and transverse direction.(4) Young's modulus of TiN coating of 4mum thickness on WC-Co substrate is estimated to be 400GP_a by using the dispersion of the leaky Rayleigh wave and a wave equations of layred structures. The value is consistent with the reported so far.Wave propagation excited by a line-focused transducer has been analyzed by FEM for an aluminum plate which is immersed in water. The calculated and measured velocities of the leaky Rayleigh and creeping waves agree within 2%. The attenuation of the leaky Rayleigh wave due to energy leak into water also agree well with the measured.The minute cracks generated in fatigue tests on stainless steel have been detected as a drop of amplitude spectra of the leaky Rayleigh wave in high frequency range.

(1)建立了一套数字式表面波超声测量系统，采用10- 50 MHz的线聚焦宽带PVDF超声换能器，测量了泄漏瑞利波、爬行波和表面SV波的速度以及泄漏瑞利波的衰减。用10 MHz的换能器在熔融石英和2017铝合金上测得的速度相对精度分别为0.015，0.03和0.018%。(2)利用表面波的传播速度和泄漏瑞利波的衰减，对熔融石英和2017铝合金表面层的密度进行了无损测量。测量值与阿基米德法测量值在10%以内符合。(3)2017铝合金的瑞利波声弹性系数在加载方向和横向分别为-2.3和0.9 × 10 ~（10）^<-5>/MP_a。(4)利用泄漏瑞利波的频散和层状结构的波动方程，估算了WC-Co基体上4 μ m厚TiN涂层的杨氏模量为400GP_a。用有限元法分析了线聚焦换能器激发的波在水中铝板上的传播。泄漏瑞利波和爬行波的速度计算值与实测值吻合在2%以内。由于能量泄漏到水中而引起的泄漏瑞利波的衰减也与实测值吻合得很好，不锈钢疲劳试验中产生的微小裂纹被检测为泄漏瑞利波在高频范围内的幅值谱的下降。