An on-site modal testing method for the detection of structural non-linearities Part II: Application

The work presented in this paper discusses the practical implementation of an experimental testing/analysis method to detect non-linear structural behaviour in an effective on-site fashion. The testing/evaluation method is based on the linear analysis of non-linear systems with increasing amplitude random excitation signals and is presented in Part I of this work. In the second part of this work, the method is applied to two distinctly different types of structures; (1) a simple beam structure and; (2) an industrial robot. The analysis shows that the beam structure behaves in a linear fashion throughout the operating range. The robot structure exhibited non-linear characteristics over the frequency range of interest. The analysis of the robot data provided a means to classify the types of non-linearities present in the structure. These actual testing applications indicate the feasibility and capability of the proposed method.