抄録
In recent years, nonlinear ultrasonic methods, owing to contact acoustic nonlinearity (CAN) and material nonlinearity, are counted on more sensitive non-destructive testing (NDT). Also, ultrasonic guided wave propagating over long distances can be applied to NDT for long structures. Therefore, nonlinear guided wave methods attract attention and are researched. In particular, the cumulative nonlinear guided waves caused by internal resonance are expected as possessing merits of nonlinear ultrasonics and guided waves. However, in previous researches, the area inspected by the cumulative nonlinear guided wave method are as large as that inspected by the conventional guided wave method. Therefore, we propose the method of using autoparametrically excited guided waves in order to expand the inspective area. In this study, nonlinearity and excitation are given only to one of the boundaries for simplicity. We theoretically investigated autoparametrically excited guided waves using the method of multiple scales (MMS).
