Application of operating data scaling techniques

Operating deflection shapes are extremely useful in trouble shooting vibration problems. However, operating data is not scaled so it has limited usefulness for further analytical predictions. Scaled modal data is required for further analytical studies such as Structural Dynamic Modification and Forced Response Simulation. Thus, development of scaled shapes from operating data is desired. Several techniques have been developed over recent years to scale operating data to modal data.; The focus of this paper is to identify and evaluate some of these scaling techniques. Their strengths and weaknesses will be identified and compared, as well as the robustness of each to good and poor choices in parameters necessary for each technique. To determine their validity, these shapes will be compared to actual Frequency Response Function data of the structure, and the scaled shapes will also be used in structural dynamic modification to demonstrate their usefulness as replacements for modal data when needed.