(1．中南大學CAD/CAM研究所，長沙410075；
2．中國兵器科學研究院寧波分院，寧波315103)
摘 要: 利用基爾霍夫近似法建立鎂合金殼體內(nèi)部缺陷的超聲測量模型，并利用該測量模型對缺陷回波幅值進行數(shù)值計算，獲得缺陷波/底波幅值比曲線。在此基礎上，建立基于幅值比曲線的缺陷檢測理論模型，并對缺陷進行定量檢測分析。采用搭建的超聲檢測實驗系統(tǒng)，對含有人工缺陷的鎂合金殼體進行缺陷檢測試驗。結果表明：相比于傳統(tǒng)距離增益尺寸曲線定量方法，本實驗方法在缺陷定量檢測精度和有效檢測深度范圍上均有較大提高，從而為提升鎂合金殼體內(nèi)部缺陷的定量檢測水平提供新的方法和技術途徑。
關鍵字: 鎂合金殼體；缺陷定量；超聲測量模型；距離增益尺寸
（1. Computer Aided Design and Computer Aided Manufacture Institute, Central South University,
Changsha 410075, China;
2. Ningbo Branch, Ordnance Science Institute of China, Ningbo 315103, China）
Abstract:The model of ultrasonic measurement for defects in magnesium alloy shell was established by using Kirchhoff approximation, and then the numerical calculation on the echo amplitude of defects was conducted by the measurement model, and the defect wave/bottom wave amplitude ratio curve was drawn. On this basis, the defects quantitative evaluation model was presented according to the amplitude ratio curve for defects quantitative evaluation. The magnesium alloy shell containing artificial defects was analyzed by using the ultrasonic quantitative evaluation model. The result shows that, compared with the traditional distance gain size (DGS) curve of quantitative methods, the effective range and accuracy of defects quantitative evaluation are improved by this method. This method provides a new and effective tool to improve the performance of quantitative evaluation on the defects in magnesium alloy shells.
Key words: magnesium alloy shell; flaw-sizing; ultrasonic measurement model; distance gain size
