A Novel Approach for Local Smoothing With the Weighted Residual Penalty‐Based Technique for Direct Stiffness Identification Using Measured Rotational Modes

ABSTRACT Accurate stiffness and damage identification are the most important parts of structural health monitoring (SHM) for civil engineering structures. Reinforced concrete (r/c) structures are especially challenging due to the numerous cracks dispersed along the length of concrete elements. These cracks can originate from, for example, regular load of a structure, shrinkage or overloading. The usual way to tackle stiffness identification of r/c structures is to obtain the averaged linear stiffness of selected element areas through finite element model‐based or response‐based methods. In this paper, a variation of a weighted residual penalty‐based local smoothing technique for direct stiffness identification was developed and compared to the state‐of‐the‐art methods. The method is based on direct measurement of the axis rotations and rotational natural modes using novel MEMS rotation rate sensors. The rotational modes can be later smoothed without additional traditional translational acceleration measurements to calculate the curvature and stiffness of the beam. However, as shown in the paper, rotational modes can also be used directly for stiffness identification. The experimental analysis shows that the application of rotational measurements facilitates response‐based stiffness identification of the r/c elements, providing more accurate damage identification.