Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
J Acoust Soc Am. 2013 Jan;133(1):127-35. doi: 10.1121/1.4770238.
Transducer arrays can be utilized in ultrasonic guided wave applications to achieve preferential excitation of particular points on a dispersion curve. These arrays are designed according to the principles of wave interference and the influence of the wavelength excitation spectrum. This paper develops the relationships between the peak wavelength in the excitation spectra and the element spacing of linear comb and annular arrays. The excitation spectra are developed by applying Fourier and Hankel transforms to the spatial loading distribution functions of the comb and annular arrays, respectively. Although the peak wavelength of excitation of a comb array is typically assumed to be equal to the element spacing, it is shown that this can be an inaccurate assumption for annular arrays. The ratio of element spacing to the peak wavelength in the excitation spectrum is termed the spacing compensation factor, and is dependent on the number of array elements and the inner radius. It is determined that the compensation factor is negligible for comb arrays but is crucial for annular arrays in order to achieve optimal mode selection. Finite element analyses and experimental data are used to verify the calculations and demonstrate the significance of the compensation factor.
换能器阵列可用于超声导波应用中，以实现对频散曲线上特定点的优先激励。这些阵列是根据波干涉原理和波长激励谱的影响设计的。本文研究了线性梳状和环形阵列的激励谱中峰值波长与单元间距之间的关系。通过分别对梳状和环形阵列的空间加载分布函数进行傅里叶变换和汉克尔变换，得到了激励谱。虽然通常假设梳状阵列的激励峰值波长等于单元间距，但对于环形阵列来说，这可能是一个不准确的假设。激励谱中单元间距与峰值波长的比值称为间距补偿因子，它取决于阵列单元的数量和内半径。结果表明，对于梳状阵列，补偿因子可以忽略不计，但对于环形阵列，为了实现最佳的模式选择，补偿因子是至关重要的。有限元分析和实验数据验证了计算结果，并证明了补偿因子的重要性。
