Damage Detection with Symplectic Geometry Spectrum Analysis in Changing Environment

Abstract

Time-varying environmental and operational conditions such as temperature and external loading may often mask subtle structural changes caused by damage and have to be removed for successful structural damage identification. In the paper, a symplectic geometry spectrum analysis method is employed to decompose a time series into the sum of a small number of independent and interpretable components, in which one can determine which components are caused by external influences. The symplectic geometry spectrum analysis method is performed in four steps: embedding, symplectic QR decomposition, grouping and diagonal averaging. One excellent advantage of the method is that it can deal with nonlinear time series which is inherently rooted in structural damage due to crack opening and closing. Numerical simulation shows that the method is promising to detect structural damage in the presence of environmental and operational variations.