Identification of the nonlinear function in a vibrating nonlinear beam

The Constant Level Identification (CLI) method for nonlinear dynamical systems has
been shown to identify accurately a wide variety of systems with discrete degrees of
freedom. In this paper, the method is applied to a continuous nonlinear system, namely
a simulated model of a vibrating beam attached to a nonlinear spring. A Rayleigh-Ritz
series representation of the beam is assumed in order to extract the desired number of
modal responses. Then, a combination of modal and physical coordinates are used in
the identification process. It is shown that the CLI method can accurately capture the
shape of the nonlinearity in the system.