Abstract: “Presence of nonlinearity in the structure can affect the global dynamic behavior. Hence detection of nonlinearity has a greater significance in the context of structural health monitoring. In this paper we present a technique based on principal component analysis for detecting the presence of nonlinearity in the structure. The angle between response subspaces is taken as a feature to detect nonlinearity. The major advantages of the proposed technique is that it uses only acceleration time history data and can be used with ambient vibration data, which is ideally suited for civil structures. Numerical simulation studies have been carried out using a cantilever beam with nonlinear cubic stiffness attachment. Studies presented in this paper clearly indicate that the proposed technique is robust.”

Keywords: principal components, subspace angle