Abstract
Experimental studies have been conducted to clarify the influence of horizontal harmonic excitation on the dynamic stability of a slender beam under vertical harmonic excitation. Three kinds of aluminum test beams with rectangular cross section have been used. The test beam was vertically stood clamping at one end and free at the other end. And it was harmonically excited to both vertical and horizontal directions simultaneously. The direction of the horizontal excitation was taken parallel to one of beam side faces. By varying the horizontal excitation amplitude, keeping the excitation amplitude in the vertical direction, the influence of the horizontal excitation has been investigated on the principal instability regions in which unstable vibrations occur..
