Continuous Control of Modes of Vibration

点击翻译按钮获取中文摘要

A method was devised to shift the position of a node of the structural vibration along a designated path on the structure by applying controlled multiple exciting forces.This method is based on the following idea. Assume that we take three points 1, 2 and 3 on the structure, apply two exciting forces at point 1 and 2 and observe the vibration at point 3. If the vibration of point 3 caused by the force applied at point 1 and the vibration of the point 3 caused by forceapplied at point 2 are the same in amplitude and opposite in phase, the vibration at point 3 will be stopped as a result of superposition. Then, if we can shift the position of point 3 continually by controlling exciting forces, a node will move along a path on the structure. If we need to stop the vibration of a particular point on the structure, we can simply allocate point 3 there.First, a theory was derived to stop the vibration of a designated point on the structure. Experiments were made to test the theory using a beam simply supported at both ends by two exciters. Then, a theory was derived to shift the position of a node by controlling amplitude ratio, frequency and phase of exciting forces. Experiments were made to test the theory under two control conditions.