Vibration Characteristics of a Beam with a Gap at the Support in Terms of the Equivalent Linearized Transfer Function

An experimental and analytical investigation to identify the frequency response characteristics of a beam system with a minute gap at the support was conducted. A L shape beam was adopted for the system, which made it possible to compare the results of both investigations easily by restricting the direction of the vibration at the gap. The frequency response characteristics of the system was evaluated in terms of the equivalent linearization method using the describing function. This is a fundamental method which can be extended by the nonlinear building block approach to the general beam system with multinonlinearities. The length of the gap was accurately controlled by adjusting the position of the stopper attached to the micrometer head. Jump phenomena around the natural frequencies, which are specific to the nonlinear system, were obtained by analysis. However, the frequency range obtained by analysis of the jump phenomena, which are not affected by the disturbance of the higher harmonics, was wider than that by the experiment