单点面约束悬臂梁自由振动实验研究

Experimental Studies on Free Vibration of Cantilever Beam with Additional-Single-Side-Point-Constraint

本文应用实验方法，对具有附加单面点约束的悬臂梁，在给定初始条件下的自由振 动进行探索性的研究．由于梁的非线性边界条件，使其表现出异乎寻常的动力行为、在实验 中发现了许多十分罕见的奇异现象．除了梁与附加支座的碰触周期是无序之外。附加支撑反 力的幅值并不是单调地衰减，而是随时间呈多次起伏，颇似“拍频”，仿佛受到某种调 制，此外，还发现梁的动力行为敏感地依赖于附加支撑点的位置．

This paper aims at exploring experimentally the free vibration of cantilever beam with additional -single-side-point-constraint induced by the initial conditoins given. The motion of the beam exhabits some stranget behaviours, as a result of the nonlinear boundary condition of the beam. In the experiment we have observed varieties of singular phenomena. Besides the impact periods of the beam and the additional support being in disorder, the amplitude of reaction at the additional support did not weaken monotonously but more than once fluctuated with time morc than once, rather like 'beats' as if they were the modulated by something else. In addition, we have also found that the dynamical behaviours of the beam depend sensitivily on the position of the additional support.