Title: Guided waves in elastic rectangular bars: A solution using partial plate mode decomposition

Author(s): FENG Feilong; SHEN Zhuangzhi; SHEN Jianzhong; LU Chao

Affiliation(s): Shaanxi Key Lab of Ultrasonics, Shaanxi Normal University; Institute of Acoustics, Chinese Academy of Sciences; Key Labotary of Nondestructive Testing, Nanchang Hangkong University

Abstract: Similar to Auld's solution for Lamb waves, the wave modes in elastic rectangular bar are solved by partial wave decomposition method. The partial waves are composed of plate modes with the same wavenumber component in waveguide longitudinal direction, thus free boundary conditions on one pair of opposite surfaces are automatically satisfied. Based on completeness assumption and orthogonality of the plate modes, four independent eigenequations are eventually derived for dispersion curve and mode shape investigation. Numerical evaluation shows the calculated results are in consistent with the FEM results. It is then verified that the plate modes which obliquely bounced back and forth between the two opposite surfaces compose the guided modes traveling in the rectangular waveguides with certain wave numbers in transversely resonant cases.