Numerical Investigation on Guided Waves Dispersion and Scattering Phenomena in Stiffened Panels

Abstract

The aim of this work is to propose a numerical methodology based on the finite element (FE) method to investigate the dispersive behavior of guided waves transmitted, converted, and reflected by reinforced aluminum and composite structures, highlighting their differences. The dispersion curves of such modes can help designers in improving the damage detection sensitivity of Lamb wave based structural health monitoring (SHM) systems. A preliminary phase has been carried out to assess the reliability of the modelling technique. The accuracy of the results has been demonstrated for aluminum and composite flat panels by comparing them against experimental tests and semi-analytical data, respectively. Since the good agreement, the FE method has been used to analyze the phenomena of dispersion, scattering, and mode conversion in aluminum and composite panels characterized by a structural discontinuity, as a stiffener. The research activity allowed emphasizing modes conversion at the stiffener, offering new observations with respect to state of the art. Converted modes propagate with a slightly slower speed than the incident ones. Reflected waves, instead, have been found to travel with the same velocity of the incident ones. Moreover, waves reflected in the composite stiffened plate appeared different from those that occurred in the aluminum one for the aspects herein discussed.

Development and validation of a probabilistic multistage algorithm for damage localization in piezo-monitored structures

“…Sensors number and configuration could depend on the shape of the monitored part. However, authors demonstrated that the same number and configuration of sensors can be used to inspect and monitor rectangular/squared flat/curved fibre-reinforced composite panels [27], whilst in presence of stiffeners a different setup is needed to capture converted/reflected wave modes [28]. Moreover, the distance between the sensors can be changed according to the size of the demonstrator.…”

Application of Supervised and Unsupervised Machine Learning to the Classification of Damaged Rotor‐Bearing Systems

“…[8][9][10][11][12] Crack onset and propagation must be properly identified, and Structural Health Monitoring systems can be implemented on the to be monitored part. [13][14][15][16][17][18][19] However, the extraction of the main crack-related features is a tricky task. Moreover, nonlinear features can complicate the identification and analysis stages because a crack can breathe throughout a full rotation, i.e., opening and closing its edges.…”

Numerical Study of Ultrasonic Guided Wave in Composite Reinforced Panels with Different Stiffener Shapes

“…[21] This approach is particularly useful when studying complex phenomena like reflected, transmitted, and converted wave behavior in stiffened plates. [14,22] In this work, two numerical models were developed to investigate the behavior of ultrasonic guided waves in stiffened fiberreinforced polymeric (FRP) plates, specifically with two different stiffening shapes: Form C and Form Omega. The two models represent sub-components of structures used in an industrial environment, e.g., the fuselage of an aircraft (Figure 1).…”

“…[ 21 ] This approach is particularly useful when studying complex phenomena like reflected, transmitted, and converted wave behavior in stiffened plates. [ 14,22 ]…”