Thickness reduction arising due to corrosion or in any other ways can cause severe damages to structures. Hence regular inspection of structures is vital in many industries. One of the factors deciding the replacement of a structure is the minimum thickness remaining in the structure. A novel ultrasonic method is introduced in this paper to precisely evaluate the minimum remnant thickness of structures. This method utilized the cut-off property of SH1 guided wave mode. A continuous broadband SH1 wave mode was required for establishing this method. This was achieved by exciting a range of wavelength and a range of frequency corresponding to the desired SH1 generation region. The range of wavelength generation was achieved by appropriately selecting the magnet spacings in a Lorentz force EMAT. The range of frequency input was achieved using a linear frequency modulated chirp signal. Finite Element models and experiments were conducted to demonstrate the method. These results are in close agreement.

由于腐蚀或以任何其他方式引起的厚度减小会导致结构严重损坏。因此，在许多行业中，定期检查结构至关重要。决定更换结构的因素之一是结构中剩余的最小厚度。本文介绍了一种新颖的超声方法，以精确评估结构的最小剩余厚度。该方法利用了SH1导波模式的截止特性。建立此方法需要连续的宽带SH1波模式。这是通过激发与所需SH1生成区域相对应的波长范围和频率范围来实现的。波长代的范围内通过在洛伦兹力EMAT适当地选择磁铁的间距来实现。频率输入范围是使用线性调频线性调频信号实现的。进行了有限元模型和实验以证明该方法。这些结果非常吻合。