Detection of Flaws and Evaluation of Deterioration by Use of Multi-Frequency Ultrasonic

利用多频超声波进行缺陷检测及劣化评价

基本信息

批准号：
12650463
负责人：
KOBAYASHI Shoichi
金额：
$ 2.3万
依托单位：
Fukui University of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

The followings are obtained :1) UItrasonic System : An ultrasonic measuring system was constructed by use of a square-wave pulser, receivers, a gate, an oscilloscope together a sing-around unit and filters. In addition an acoustic system using a microphone and amplifier was set up for impact tests.2) Detection of Surface cracks : Depth of a surface crack was measured by TOFD method. The shape was estimated by scanning over the surface.3) Detection of interior Flaws : Interior flaws were detected by the impact method. Inspection by human ears was useful for the detection. Using the scanning technique, the size can be estimated. Using a microphone and amplifier together with a recorder, size and depth of flaws can be estimated by comparing the amplitudes and spectra with the standard ones.4) Evaluation of deterioration : As a model, the deterioration due to the uniaxial compression (homogeneous deterioration) was studied. a)Phase velocities of longitudinal and shear waves, respectively, propagating in the perpendicular direction to the compression axis decrease according to the increase of stress (progress of deterioration) and abruptly change at the ever-experienced stresses when re-loaded. b)The amplitude of the received waves accordingly decreases, and the reduction is more dominant in high-frequency waves. c)The spectra did not change so much.5) How to evaluate deterioration : a)Detection and estimate the size and the depth of flaws can be simply done by hearing the impact sound by human ears. Using a microphone system they can be done more accurately provided that standard data are at hand. b)The homogeneous deterioration can be evaluated using the data of phase-velocity change or data of amplitude reduction of received waves.

获得以下内容：1）uitrasonic系统：通过使用方波脉冲器，接收器，门，示波器，一个单圈单元和过滤器来构建超声测量系统。另外，设置了使用麦克风和放大器的声学系统进行冲击测试。2）检测表面裂纹：通过TOFD方法测量表面裂纹的深度。通过在表面上进行扫描来估计形状。3）检测内部缺陷：通过冲击方法检测到内部缺陷。人耳的检查对于检测很有用。使用扫描技术，可以估算大小。使用麦克风和放大器以及录音机，可以通过比较幅度和光谱与标准的幅度和光谱来估计缺陷的大小和深度。4）评估劣化：作为模型，由于单轴压缩（同质性降低）而导致的降低。 a）纵向和剪切波的相位速度分别在垂直方向向压缩轴的垂直方向传播，根据应力的增加（恶化的进展），并在重新加载后不断经验的应力下突然改变。 b）接收波的幅度相应降低，并且在高频波中的还原更为主导。 c）光谱没有太大变化。5）如何评估恶化：a）可以简单地通过听到人耳的冲击声来进行检测和估计缺陷的大小和深度。使用麦克风系统，只要标准数据即将到来，它们就可以更准确地完成。 b）可以使用相位速度变化的数据或接收波的振幅减少数据来评估均质恶化。