Response-based stiffness identification of beam elements with rotation rate sensors

An accurate damage detection is one of the main problems of structural health monitoring (SHM). It can be solved on various levels – from simple information on the existence of damage to the localisation and quantification of damage. Numerous methods were proposed. One of them is damage detection, which is done by monitoring the stiffness change of structural elements. The response-based stiffness identification that is used for this study utilises a familiar relation (EI=M/κ) between flexural stiffness EI, modal bending moment M, and curvature mode κ. The curvature modes are usually obtained through double differentiation of translational acceleration response. Due to inherent measurement errors, a smoothing procedure needs to be applied. Recently, rotation rate sensors appeared as a potential measurement equipment for the SHM. The main advantage of rotation measurement is that it reduces curvature calculation to a single derivative, which simplifies the smoothing procedure. The main aim of this presentation is to compare response-based stiffness identification methods that utilise translational or rotational responses of the beam structure. In the study, stiffness identified on damaged r/c beam using a model-updating procedure will serve as a baseline for comparison.