Lamb Wave Propagation Modeling Using Cellular Automata

نویسندگان

  • P. KLUSKA
  • W. J. STASZEWSKI
  • M. J. LEAMY
چکیده

Theory of Lamb Wave propagation in plate-like structures have found many practical applications in Structural Health Monitoring. However for better understanding of complex physical phenomena associated with wave propagation and wave interaction with damage numerical simulations are as important as laboratory experiments. The paper shows the application of Cellular Automata technique for modeling of elastic wave propagation. After a brief introduction to Lamb waves, 2-D triangular Cellular Automata approach for wave propagation is presented. Numerical simulations are performed for undamaged and damaged aluminium plates. The results are compared with the Local Interaction Simulation Approach (LISA). INTRODUCTION Monitoring for structural damage is important in maintenance of many engineering structures. Various damage detection techniques have been developed for Structural Health Monitoring (SHM) applications. Methods based on guided waves are particularly attractive in plate-like structures. It appears that Lamb waves are the most widely used guided ultrasonic waves for damage detection in metals and composites, as reviewed in [1-3]. Despite numerous laboratory implementation SHM application of Lamb waves in real engineering systems remain limited. The complexity of physical mechanism associated with these waves is an important factor when implementation of Lamb waves techniques is considered for damage detection. _____________ P. Kluska, W.J. Staszewski and T. Uhl Department of Robotics and Mechatronics, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Krakow, Poland; M.J. Leamy George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332-04505, USA 6th European Workshop on Structural Health Monitoring We.3.E.2 Licence: http://creativecommons.org/licenses/by-nd/3.0 1 M or e in fo a bo ut th is a rt ic le : ht tp :// w w w .n dt .n et /? id = 14 17 1 Also, signal features produced by defects tend to be embedded in the background noise associated with material, structural and environmental variability and thus are difficult to detect reliably. It is widely acknowledged that numerical simulations can help with the entire damage detection implementation process and interpretation analysis, leading to accurate SHM diagnosis and prognosis. Various methods have been developed for modelling and numerical simulations of elastic wave propagation, including semi-analytic techniques (e.g. methods based on the theory of diffraction, boundary element methods) and numerical algorithms such as methods based finite differences, finite elements, spectral elements, elastodynamic finite integration techniques (EFIT) or local interaction simulation approach (LISA), as reviewed in [4] . The LISA is particularly attractive for very fast parallel computation of large models of wave propagation in complex media with sharp interfaces [5]. More recently the Cellular Automata (CA) approach based on rectangular [6] and triangular [7] . The latter offers arbitrary meshing geometries and is an attractive alternative finite difference based methods. The major objective of the paper is to explore the CA approach for Lamb wave propagation in metallic structures. A 2-D case study of wave propagation in undamaged and damaged aluminium plates is investigated. Numerical results are compared with simulations based on the LISA technique.

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تاریخ انتشار 2012