ワイヤロープの非破壊評価手法確立のために，累積的高調波を含む非線形ガイド波に着目し，長距離伝播時の動力学的な挙動の解明を目指した．まず，累積的高調波について，非線形連成と減衰の効果を考慮し，伝播モードの直交性と多重尺度法を用いた理論解析によりその挙動を解明し，数値解析および実験によりこれを検証した．つぎに，材質や厚さの異なる領域に入射するガイド波のモード変換の理論解析と実験により，振動形態や伝播速度の変化を確認した．さらに電磁超音波探触子EMATについて，ガイド波入力モードの選択的励振を解析で明らかにし，その結果を有限要素解析と実験により検証した．
In order to establish a non-destructive evaluation method for wire ropes, we focused on nonlinear guided waves including cumulative harmonics and aimed to clarify the dynamic behavior during long-distance propagation. First, considering the effects of nonlinear coupling and damping, the behavior of cumulative harmonics was clarified by theoretical analysis using orthogonality of propagation modes and multiscale method, and verified by numerical analysis and experiments. Next, changes in the vibration mode and propagation velocity were confirmed by theoretical analysis and experiments of mode conversion of guided waves incident on regions of different materials and thickness. Furthermore, for the electromagnetic acoustic transducer EMAT, selective excitation of guided wave input modes was clarified by analysis, and the results were verified by finite element analysis and experiments.

研究種目 : 基盤研究 (C) (一般)
研究期間 : 2017～2019
課題番号 : 17K06237
研究分野 : 振動・波動, 超音波応用