Non-collinear interaction of guided elastic waves in plates

2018 Fiscal Year Final Research Report

• Project/Area Number: 17K14557
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Materials/Mechanics of materials
• Research Institution: Toyohashi University of Technology
• Principal Investigator: Yosuke Ishii 豊橋技術科学大学, 工学(系)研究科(研究院), 助教 (70781706)
• Project Period (FY): 2017-04-01 – 2019-03-31
• Keywords: 三波相互作用 / 板波 / 材料非線形性 / 摂動解析 / 動的有限要素解析 / 超音波非破壊評価

Outline of Final Research Achievements

Non-collinear interaction of elastic guided waves in plates due to material nonlinearity has been investigated theoretically, numerically, and experimentally.
Using a perturbation analysis, it has been theoretically shown that the interaction of two monochromatic plane guided waves significantly produces a third wave when the resonance condition is met, i.e., when the wavevector and frequency of third wave coincide with the sum/difference of those of the primary waves. This feature has been found to be valid even when the primary waves have finite beam widths and time durations by numerical simulations with a three-dimensional dynamic finite-element method. Furthermore, these results obtained by the theoretical and numerical studies have been validated experimentally for the interaction in an aluminum alloy plate.

Free Research Field

超音波による非破壊評価

Academic Significance and Societal Importance of the Research Achievements

近年，発電所といった薄板構造からなる大型構造物の高経年化，特に金属疲労が問題視されており，国民の安全性を保障するための超音波非破壊評価の重要性が増している．特に，疲労の早期段階（主き裂発生前の塑性ひずみの蓄積段階）などのように明示的な波動散乱を伴わない場合には従来法による損傷評価が困難であることが指摘されており，それらを検出可能な評価手法の確立が喫緊の課題となっている．本研究で着目した板波の非線形三波相互作用は疲労の早期段階を高感度で捉えられる可能性を秘めており，本研究で得られた知見は今後薄板構造の新しい非破壊評価法を構築する際の理論的基盤になると期待される．