Approximate transmission equivalence of elastic bar transitions under 3-D conditions

摘要

Transmission of quasi-longitudinal elastic waves through elastic bar transitions between uniform and collinear bar segments is studied by means of three-dimensional (3-D) finite element analysis. The aim is to examine, through an example, to what extent two geometrically different transitions which are transmission-equivalent in a one-dimensional (1-D) context may retain this property under 3-D conditions. The difference between the two transitions is assessed from the difference between 3-D results for reflected waves, while the presence of 3-D effects is judged from the difference between 3-D finite element and I-D analytical results for transmitted waves. It is found that two smooth and significantly different elastic bar transitions which are transmission-equivalent in a I-D context may retain this property with good approximation under significantly 3-D conditions, well beyond those under which 1-D theory can be used for prediction of wave shapes. This extends the domain of potential applications in areas such as percussive drilling correspondingly. (C) 2002 Elsevier Science Ltd. All rights reserved. [References: 17]