title: Shear horizontal feature guided ultrasonic waves in plate structures with 90° transverse bends.
abstract: Antisymmetric and symmetric Lamb-type feature guided waves (FGW) have recently been shown to exist in small angle plate bends. This paper reports Semi-Analytical Finite Element (SAFE) method simulations revealing the existence of a new family of Shear Horizontal (SHB) type of FGW mode in 90° bends in plate structures. Mode shapes and velocity dispersion curves are extracted, demonstrating the SH-like nature of a bend-confined mode identified in studies of power flow across the bend. The SHB mode is shown to have reduced attenuation in the higher frequency range, making it an ideal choice for high-resolution inspection of such bends. Further modal studies examine the physical basis for mode confinement, and argue that this is strongly related to FGW phenomena reported earlier, and also linked to the curvature at the bend region. Wedge acoustic waves discussed widely in literature are shown as arising from surface-limiting of the SHB mode at higher frequencies. The results are validated by experiments and supported by 3D Finite Element (FE) simulations.
authors.affiliation: School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
authors.forename: Xudong
authors.initials: X
authors.lastname: Yu
authors.affiliation: Centre for Nondestructive Evaluation and Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India.
authors.forename: Prabhakaran
authors.initials: P
authors.lastname: Manogharan
authors.affiliation: School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore. Electronic address: ZFAN@ntu.edu.sg.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Fan
authors.affiliation: Centre for Nondestructive Evaluation and Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India. Electronic address: prajagopal@iitm.ac.in.
authors.forename: Prabhu
authors.initials: P
authors.lastname: Rajagopal
keywords: Feature guided wave; Little-dispersive and low-attenuative; Shear horizontal