The ambient and forced vibration techniques for testing full-scale structures are critically compared. Both methods, based on small level excitation, may be used to determine many mode shapes and frequencies of vibration and the corresponding damping values, with adequate accuracy for most purposes. The two techniques give mutually consistent results. The mode amplitudes determined by ambient a...

In this paper, topology optimization is utilized for damage detection in three dimensional elasticity problems. In addition, two mode expansion techniques are used to derive unknown modal data from measured data identified by installed sensors. Damages in the model are assumed as reduction of mass and stiffness in the discretized finite elements. The Solid Isotropic Material with Penalization (...

it has been pointed out the static lateral response procedure for a base-isolated structure proposed in international building code (ibc) somewhat overestimates the seismic story force. that is why in the current paper, vertical distribution of base shear over the height of isolated structures considering higher mode effects under near field earthquakes is investigated. nonlinear behavior of is...

Functionalities of wireless sensors to measure bridge dynamic behavior are maturing; dense measurements of large structures are expected to reveal details of the behavior of existing structures. Traffic-induced vibrations at an arch bridge, instrumented by 48 wireless smart sensors, were measured before and after seismic retrofit of the structure. The differences between the measured dynamic ch...

Studying the dynamic response of Francis turbine runners is of paramount importance in order to avoid resonance problems during operating conditions. For this purpose, the natural frequencies as well as their associated mode-shapes and damping ratios of the runner have to be determined. In this paper, an Experimental Modal Analysis (EMA) of the runner of a Francis turbine prototype has been per...

The Modal Phase Collinearity (MPC) is a modal indicator designed to decide whether the mode shape used in its computation real or complex-valued vector. Its estimate inherits statistical properties of corresponding estimate. While framework for uncertainty quantification parameters well-known and developed context subspace-based system identification methods, MPC has not been carried out yet. I...