FEM Modeling of Guided Wave Behavior in Integrally Stiffened Plate Structures
FEM Modeling of Guided Wave Behavior in Integrally Stiffened Plate Structures

Author:

Publisher:

Published: 2007

Total Pages: 12

ISBN-13:

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Structural health monitoring (SHM) technologies, which use integrated sensing for damage detection, are expected to improve system reliability, availability, and operational cost. Guided waves can propagate great distances while experiencing low attenuation. They have been successfully used for damage detection in structures of relatively low geometric complexity such as plates and cylindrical pipes. The use of guided waves for this purpose becomes increasingly difficult as the geometric complexity of the structure increases. Aerospace structural components such as fuel tanks, wings, etc. often are comprised of substructures that consist of plates with integral stiffeners. This work reports on finite element simulations of guided waves in integrally stiffened plate structures. In these studies, the guided waves are generated by PZT wafer-type transducers mounted on the structure. Transient dynamic finite element simulations using PZFlex, in 2D and in 3D, were used to model both the structure and transducers. The interaction of the guided waves with cracks, simulated by notches of varying dimensions, is also modeled. This allows appraisal of the sensitivity of various modes for crack detection by providing insight into mode conversion and scattering resulting from the guided wave and crack interaction.

Guided Waves in Structures for SHM
Guided Waves in Structures for SHM

Author: Wieslaw Ostachowicz

Publisher: John Wiley & Sons

Published: 2011-12-30

Total Pages: 267

ISBN-13: 1119966744

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Understanding and analysing the complex phenomena related to elastic wave propagation has been the subject of intense research for many years and has enabled application in numerous fields of technology, including structural health monitoring (SHM). In the course of the rapid advancement of diagnostic methods utilising elastic wave propagation, it has become clear that existing methods of elastic wave modeling and analysis are not always very useful; developing numerical methods aimed at modeling and analysing these phenomena has become a necessity. Furthermore, any methods developed need to be verified experimentally, which has become achievable with the advancement of measurement methods utilising laser vibrometry. Guided Waves in Structures for SHM reports on the simulation, analysis and experimental investigation related propagation of elastic waves in isotropic or laminated structures. The full spectrum of theoretical and practical issues associated with propagation of elastic waves is presented and discussed in this one study. Key features: Covers both numerical and experimental aspects of modeling, analysis and measurement of elastic wave propagation in structural elements formed from isotropic or composite materials Comprehensively discusses the application of the Spectral Finite Element Method for modelling and analysing elastic wave propagation in diverse structural elements Presents results of experimental measurements employing advanced laser technologies, validating the quality and correctness of the developed numerical models Accompanying website (www.wiley.com/go/ostachowicz) contains demonstration versions of commercial software developed by the authors for modelling and analyzing elastic wave propagation using the Spectral Finite Element Method Guided Waves in Structures for SHM provides a state of the art resource for researchers and graduate students in structural health monitoring, signal processing and structural dynamics. This book should also provide a useful reference for practising engineers within structural health monitoring and non-destructive testing.

ICCS21
ICCS21

Author: Antonio J.M. Ferreira

Publisher: Società Editrice Esculapio

Published: 2018-07-23

Total Pages: 160

ISBN-13: 8893850796

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It is well-known that the topic of composite mate- rials affects many engineering fields, such as civil, mechanical, aerospace, automotive and chemical. In the last decades, in fact, a huge number of scientific papers concerning these peculiar constituents has been published. Analogously, the industrial progress has been extremely noticeable. The study of composite materials, in general, is a challenging activity since the advancements both in the academia and in the industry provide continually new sparks to develop innovative ideas and applications. The communication, the sharing and the exchange of views can surely help the works of many researchers. This aspect represents the main purpose of this Conference, which aims to collect high-level contributions on the development and the application of composite materials. The establishment of this 21st edition of International Conference on Composite Structures has appeared appropriate to continue what has been begun during the previous editions. ICCS wants to be an occasion for many researchers from each part of the globe to meet and discuss about the recent advancements regarding the use of composite structures, sandwich panels, nanotechnology, bio-composites, delamination and fracture, experimental methods, manufacturing and other countless topics that have filled many sessions during this conference. As a proof of this event, which has taken place in Bologna (Italy), selected plenary and key-note lectures have been collected in the present book.

Guided Waves in Thin-walled Structural Members
Guided Waves in Thin-walled Structural Members

Author:

Publisher:

Published: 1904

Total Pages:

ISBN-13:

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Many common structural members can be thought of as an assemblage of thin plates. For example, an I shaped cross-section can be made from three or five thin plates and an angle can be thought of as two thin: plates whose sides are rigidly attached at an angle, and so on. In this study a multi-purpose computer program was developed, based on a Rayleigh-Ritz (RR) type stiffness approximation, to investigate the wave propagation in infinitely long thin-walled members and the free vibration of thin-walled members that are simply sup orted at their ends. Also, wave propagation characteristics of these members where studied. To model the behaviour of these types of structural members, using a finite element methodology, an element that closely models the behaviour of a thin plate was created. There are two uncoupled motions of a homogeneous thin plate having material symmetry about its middle surface; one corresponds to inplane motion and the other to bending. Previous studies used a three node parabolic element to model the inplane motion of the plate. In the present work, the three node inplane element and a two node beam element were used to generate an element which models both the inplane and bending motions of a thin plate. The program was checked for accuracy against another approximate solutions as well as analytical solutions. The Rayleigh-Ritz approximation proved to be effective in calculating the wave dispersion characteristics (wavenumber and modeshapes for a given frequency) of thin-walled, infinitely long members as well as the characteristic frequencies of vibration of simply supported thin-walled structural members.