THE HARMONIC RESPONSE OF UNIFORM BEAMS ON MULTIPLE LINEAR SUPPORTS - A FLEXURAL WAVE ANALYSIS

A wave approach is developed for the exact analysis of the harmonic response of uniform finite beams on multiple supports. The beam may be excited by single or multi-point harmonic forces or moments; its supports may have general linear characteristics which may include displacement-rotation coupling. Use is made of the harmonic response function for an infinite beam subjected to a single-point harmonic force or moment. The unknowns of the finite beam problem are the support reaction forces/moments and the magnitudes of four waves reflected from the ends of the beam. Equations are presented for the response of a single-bay beam with various support conditions and subjected to single-point harmonic excitation. The same equations, but with the simple addition of further straightforward terms on the right-hand side, are used for multi-point excitation. The effects of damping are easily incorporated. Equations for multi-supported beams are also presented together with illustrative computed frequency-response curves. Natural frequencies have been calculated by finding resonance frequencies of very lightly damped beams. These compare impeccably with the results of other investigators