幅值谱在斜声束回波法多界面粘接质量检测中的应用

APPLICATION OF AMPLITUDE SPECTRUM IN THE ULTRASONIC INSPECTION OF ADHESIVE QUALITY IN MULTI-LAYERED STRUCTURES BY THE OBLIQUE ECHO METHOD

在采用斜声束水浸回波法对机载固体火箭发动机的钢、绝热层、衬层多层结构的粘接质量进行超声图像诊断时 ,为了消除信号混叠影响 ,本文利用检测回波之间的幅值谱极值提取信号特征值 ,并针对在实际检测中出现的极值点分布不均匀现象 ,提出了若干提高特征值提取精度的措施 ,有效地提高了检测信噪比 。

When the adhesive quality in multi-layered structures (steel shell, insulation layer and under lying layer) in airbourne solid rocket motors is inspected through oblique ultrasonic pulse echo in immersion, the amplitude spectrum extrema between echoes are used to get signal characters, in order to eliminate signal overlapping in the time field. The phenomenon of unevenly distributed extrema in practical testing, some measures were introduced to improve precision in the extraction of characters. As a result the signal-to-noise ratio is increased and the image quality is much improved.