APPROXIMATE TRANSMISSION EQUIVALENCE OF ELASTIC BAR TRANSITIONS UNDER 3-D CONDITIONS

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 1-D analytical results for transmitted waves. It is found that two smooth and significantly U001different elastic bar transitions which are transmission-equivalent in a 1-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.