ASDAH: An automated structural change detection algorithm based on the Hilbert–Huang transform

• An automated online algorithm for structural change detection proposed.
• Developed algorithm uses EMD-HHT to track frequencies.
• Energy based frequency weights used for detecting change.
• An automated alarm system proposed based on training.
• Algorithm demonstrated to identify structural change on experimental set-up.

A novel automated structural change detection algorithm is presented in this paper. The algorithm is principally based on a windowed Hilbert–Huang transform of online data, and incorporates a combination of energy based averaging and moving window averaging. The expected system behaviour is characterised during a dynamic parameterisation and training phase. A hierarchical alarm mechanism is employed to account for short and long term changes in the structural properties. The algorithm has been validated in an experimental setting with two different structures: a single degree of freedom (SDOF) discrete dynamical system and a 2.5 kW wind turbine blade. The system has been shown to reliably and promptly detect structural changes in both structures, one with a stiffness variation and the other with mass variation.