Start Date

2016 12:00 AM

Description

Non-destructive testing (NDT) and structural health monitoring (SHM) are engineering techniques for investigating defects without breaking structures. Guided wave ultrasonic modes propagating over long distances can be applied to NDT for long structures such as plates, rods and pipes. Guided waves have a dispersion property, which represents dependence of propagation velocities on frequencies. Therefore, for effective use of guided waves, we need to know this property, which is usually expressed as dispersion curves [1]~[3].

The goal of this paper is to numerically investigate effects of curvatures on the dispersion property of guided waves propagating in a helical structure and a curved plate by a semi-analytical finite element method (SAFE) [4]~[6]. A helical structure is regarded as cylinder with curvatures and torsions, and a curved plate is regarded as a flat plate with curvatures. Thus, the authors investigated how dispersion properties of fundamental modes change as the curvature increases.

Numerical results show that the cut-off frequency of some propagation modes increases as the curvature increases.

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Curvature-dependence of Cut-off Frequencies of Guided Waves Propagating through Curved Structures Obtained by a Semi-Analytical Finite Element Method

Non-destructive testing (NDT) and structural health monitoring (SHM) are engineering techniques for investigating defects without breaking structures. Guided wave ultrasonic modes propagating over long distances can be applied to NDT for long structures such as plates, rods and pipes. Guided waves have a dispersion property, which represents dependence of propagation velocities on frequencies. Therefore, for effective use of guided waves, we need to know this property, which is usually expressed as dispersion curves [1]~[3].

The goal of this paper is to numerically investigate effects of curvatures on the dispersion property of guided waves propagating in a helical structure and a curved plate by a semi-analytical finite element method (SAFE) [4]~[6]. A helical structure is regarded as cylinder with curvatures and torsions, and a curved plate is regarded as a flat plate with curvatures. Thus, the authors investigated how dispersion properties of fundamental modes change as the curvature increases.

Numerical results show that the cut-off frequency of some propagation modes increases as the curvature increases.