Modeling wave propagation in damped waveguides of arbitrary cross-section

A semi-analytical finite element formulation for modeling stress wave propagation in axisymmetric damped waveguides

This article deals with the monitoring of the composite wing skin-to-spar joint in unmanned aerial vehicles using ultrasonic guided waves The study investigates simulated wing skin-to-spar joints with two different types of bond defects, namely poorly cured adhesive and disbonded interfaces The bond-sensitive feature considered is the ultrasonic strength of transmission through the joints The dispersive wave propagation problem is studied numerically by a semi-analytical finite element method that accounts for viscoelastic damping, and experimentally by ultrasonic testing that uses highly durable, flexible macro fiber composite transducers The discrete wavelet transform is also employed to de-noise and compress the ultrasonic measurements Both numerical and experimental tests confirm that the ultrasonic strength of transmission increases across the defected bonds

Health Monitoring of UAV Wing Skin-to-spar Joints using Guided Waves and Macro Fiber Composite Transducers:

The monitoring of adhesively bonded joints by ultrasonic guided waves is the general topic of this paper. Specifically, composite-to-composite joints representative of the wing skin-to-spar bonds of unmanned aerial vehicles (UAVs) are examined. This research is the first step towards the development of an on-board structural health monitoring system for UAV wings based on integrated ultrasonic sensors. The study investigates two different lay-ups for the wing skin and two different types of bond defects, namely poorly cured adhesive and disbonded interfaces. The assessment of bond state is based on monitoring the strength of transmission through the joints of selected guided modes. The wave propagation problem is studied numerically by a semi-analytical finite element method that accounts for viscoelastic damping, and experimentally by ultrasonic testing that uses small PZT disks preferably exciting and detecting the single-plate s0 mode. Both the models and the experiments confirm that the ultrasonic ene...

Ultrasonic guided wave monitoring of composite wing skin-to-spar bonded joints in aerospace structures

The computation of dispersion relations for three-dimensional elastic waveguides using the Scaled Boundary Finite Element Method

Guided waves in a layered elastic plate of rectangular cross section (finite width and thickness) has been studied in this paper A semianalytical finite element method in which the deformation of the cross section is modeled by two-dimensional finite elements and analytical representation of propagating waves along the length of the plate has been used The method is applicable to arbitrary number of layers and general anisotropic material properties of each layer, and is similar to the stiffness method used earlier to study guided waves in a laminated composite plate of infinite width Numerical results showing the effect of varying the width of the plate on the dispersion of guided waves are presented and are compared with those for an infinite plate In addition, effect of thin anisotropic coating or interface layers on the guided waves is investigated

A. J. Niklasson

Papers

Elastic guided waves in a layered plate with rectangular cross section.