Extraction of the structural mode shapes utilizing image processing method and data fusion

Abstract

Dynamic properties of structures, such as natural frequency, mode shapes, and damping ratios, play a decisive role in the structural behavior against dynamic loads such as earthquakes. One of the utilizations of these properties is the determination of the earthquake forces imposed on structures based on the design spectra. Other applications of these features could be utilized to update the finite element model, detect damage in structures, and long-term health-monitoring of the structures. So, accuracy and reducing the cost of evaluating these properties would have a significant role in increasing the efficiency and the consequences of the useful life of the structures. Image processing is one of the methods for determination of dynamic properties of structures. The aim of this article is presenting a data fusion method to improve the accuracy of extraction of the mode shapes by image processing. For this purpose, a cantilever aluminum beam and a Three-story frame with additional mass have been considered, then their vibration was recorded utilizing the image processing method. To extract dynamic properties of structure, peak survey method was used. The proposed average method in signal level and Improved Distance Evaluation (IDE) in feature level were utilized to improve the accuracy of obtained mode shapes. The accuracy of the novel technique was investigated by comparing the seismic properties to the results from the accelerometer sensors and the finite element method. The results show that this method could enhance the accuracy of the image processing method for remote sensing.