Dynamic properties of slender solid waveguides (beams, rods), described by dispersion curves, are usually evaluated by using one of the beam theories (Euler-Bernoulli, Timoshenko, etc.). The most important hypothesis of all the beam theories is that the cross-section remains undeformed while undergoing vibrational movement. This hypothesis is valid only at low frequencies. The experimental results obtained for a rail show significant deformation of the cross-section above about 1500 Hz (D.J. Thompson 1993 Journal of Sound and Vibration 161 (3), 421-446). Since the frequency range important for noise generation extends here up to 5000 Hz, an improved computational technique which can take into account deformations of cross-section is needed for an accurate evaluation of the dispersion properties in the frequency range of interest. A method is presented for the numerical computation of the wave numbers and associated modes of the cross-section of solid waveguides. The method, based on the finite element technique, is well suited to the computation of both the propagative and the evanescent waves in a straight waveguide with an arbitrary cross-section. The solution is obtained by factorization, with the cross-section of the waveguide being modelled by numerical discretization. The dispersion curves of propagative waves in a free rail are computed by using triangular and quadrilateral 'finite elements of the cross-section'. The evolution of cross-section modes as the frequency increases is evaluated and discussed.
Computation of propagative waves in free rail using a finite element technique
Berechnung der Wellenausbreitung in Eisenbahnschienen mit Hilfe der finiten Elemente-Methode
Journal of Sound and Vibration ; 185 , 3 ; 531-543
1995
13 Seiten, 12 Bilder, 9 Quellen
Article (Journal)
English
Computation of propagative waves in free rail using a finite element technique
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