Imaging and identification of anomalies in metal by nonlinear ultrasonics

2014 Fiscal Year Final Research Report

• Project/Area Number: 24560119
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Materials/Mechanics of materials
• Research Institution: Nagoya Industrial Science Research Institute
• Principal Investigator: KAWASHIMA Koichiro 公益財団法人名古屋産業科学研究所, その他部局等, 研究員 (50023239)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 非線形超音波 / 超音波試験 / 非破壊検査 / 非破壊材料評価 / 高調波 / 画像化 / 劣化・損傷 / 局部塑性域

Outline of Final Research Achievements

This project aims to visualize nondestructively material degradation, small nonmetallic inclusions, weak diffusion bond and local plastic region. To visualize these anomalies, we have applied an immersion harmonic imaging technique in which large amplitude sinusoidal burst wave forces the anomalies to vibrate and thus excited higher harmonics are extracted by a pertinent analogue high-pass filter. By mapping the higher harmonic amplitude of interest, we can image the anomalies. Plastically deformed region is imaged by a local resonance harmonic method, in which sinusoidal burst wave of a through-thickness resonant frequency of a flat plate forces dislocation loops to vibrate and higher harmonic amplitude thus generated are imaged. Thermal fatigue cracks of tens nanometer gap in a glass plate is imaged by through-transmission local resonance method. By comparing C- and B-scan images, we identify anomalies with narrow gaps from those without gap.

Free Research Field

工学，機械工学，材料力学・機械材料