DYNAMIC CHARACTERISTICS OF STEPPED CANTILEVER BEAMS CONNECTED WITH A RIGID BODY

The object of this work is to analyze the dynamic characteristics of the portal frame which consists of two stepped beams including a thin plate and a torsional spring at the discontinuous point and a rigid body connecting each beam tip. This structure is available in a lot of cases that need higher stiffness and linear motion of the tip mass. For example, it might be used for an optical pick-up actuator, using piezoelectric materials, for the high area density CD, DVD or the next generation of optical memory devices, which require superrigidity and linear motion in focusing. The mathematical modelling and the derivation of the equation of motion are given for the cantilevers with identically paralleled and stepped beams. The equation of motion and the associated boundary and the continuous conditions are analytically obtained by using Hamiltonʹs variational principle. The exact solutions are presented and compared with the results obtained by FEM Tool (IDEAS).