Integration of locating baseline-free nonlinear elements and identifying model-free nonlinear restoring forces in structures

Structural local nonlinearity often occurs when a structure is subject to strong excitation. Therefore, the identification of structural localizations and characteristics nonlinear restoring forces great significance in ensuring safety reliability. Among existing methods, locating elements under seismic excitations still challenging problem identifying model-free requires prior knowledge position. To overcome these limitations, novel two-step localization algorithm proposed this paper. First, by considering wavelet energy distribution element become different from those other linear elements, relative entropy which able quantify difference or similarity between two distributions employed localize based on sparsity nonlinearity. In process, response data baseline are not required. Then, regarded as ‘unknown virtual forces’ underlying structure. The generalized Kalman filter with unknown input, was recently authors, used identify reconstruct without models forces. method verified numerical simulations types structures. Furthermore, it tested MR damper its laboratory four-story shear-type frame.