عنوان مقاله [English]
These days, Maintenance and health monitoring of structures and infrastructures of the country are the top priority of engineers. Therefore, it is used attached acceleration sensor to measure and extract the bridge's modal response, and the last studies showed that sensors that have attached to the car's chassis can record the bridge's response to vibration. It is important to use an accurate method based on output only to measure frequency, damping ratio, and mode shapes. For that reason, modal analysis is used for that purpose. In this paper, a new method of blind source separation, complexity pursuit, purposed which is able to extract and measure modal parts in the time domain. Complexity pursuit is known as a highly recommended method that is able to recover hidden sources and it can calculate the mixing matrix from only output data. Some various conditions are considered in this paper to verify complexity pursuit (3 degrees of freedom mass-spring with various damping ratios, in white Gaussian Noise condition, in non-diagonal damping matrix, close modes, and for 12 DOF mass-spring system). In all that condition the comparison between results of cp and modal analysis showed that the proposed method is able that to extract frequency and damping ratio with high accuracy.