Mode shape identification using mobile sensors

Abstract

The accurate identification of mode shapes is a k ey issue for vibration analysis and model updating. The standard identification procedure is to place sensors at fixed locations in the structure, and i dentify modal coordinates at those points. Economic and practical constraints for in situ identification prevent the use of high number of sensors available for dynamic measurements, limiting the spatial resolution of the identified modes. Mode shape expansion methods are used to estimate the unmeasured modal coordinates. However, these approaches could introduce errors on the identification. This paper presents an original methodology for the identification of mode shapes with high spatial resolution using few stationary and mobile sensors. Numerical simulations and validation tests are performed using uniform simply supported beams under sinusoidal, impact and random excitation. High correlation is obtained between the mode shapes identified using a traditional modal identification approach and the ones using the proposed methodology. ©2010 Society for Experimental Mechanics Inc.