Nonlinear identification of structures using ambient vibration data

Most of the practical engineering structures exhibit a certain degree of nonlinearity due to nonlinear dynamic characteristics of structural joints, nonlinear boundary conditions and nonlinear material properties. In this paper, we present a new technique based on null subspace analysis to detect the presence of nonlinearity and estimate the degree of nonlinearity in structures using ambient vibration data. Effectiveness of the proposed approach is demonstrated using carefully designed numerical examples and also using the experimental data. Extended version of the technique is presented to detect the nonlinearity using a single sensor data. (C) 2015 Elsevier Ltd. All rights reserved.