Title: A Frequency Domain Approach to Model Validation in the Presence of High Modal Density (UQ/V&V Seminar Announcement) Speaker: Aaron Nimityongskul, Air Force Research Laboratory Date/Time: Monday, June 29, 2:00-3:00(NM), 1:00-2:00(CA) Location: CSRI Building, Room 90 (Sandia NM), 915/S145 (CA) Brief Abstract: High-performance space vehicles with extremely low levels of on-orbit vibration are required for many Air Force mission areas. Finite element models of these high-performance vehicles must be valid to a higher frequency range than what is required for most other spacecraft. In the low-frequency range, the aerospace community has traditionally relied on modal-based methods for tasks such as sensor placement, model reduction, model correlation, and model updating. At higher frequencies, noise and errors in the test modes, combined with high modal density, produces coupling sensitivity between test and analysis mode shapes. This leads to the breakdown of modal-based correlation and updating techniques. This work proposes new techniques for the model validation process that are based directly on the structure’s frequency response. Principal component analysis of the analytical frequency response is used to aide in sensor placement and model reduction. Correlation metrics that compare experimental frequency response directly to the reduced impedance matrix are used as validation criteria, as well as in the model updating cost functions. Use of the frequency response avoids the difficult tasks of selecting target modes, mode pairing, and mode extraction, all of which become more difficult in the presence of high modal density. The goal of this work is to provide an alternative to modal analysis for model validation that can be used beyond the low-frequency range. Bio: Mr. Nimityongskul is currently a Space Scholar studying the effects of test and model uncertainty on the validation process at the Air Force Research Laboratory, Space Vehicles Directorate. He earned the BS in 2004 and the MS in 2005, both in Engineering Mechanics and Astronautics from the University of Wisconsin-Madison. He is pursuing his PhD “A Frequency Domain Approach to Model Validation in the Presence of High Modal Density” at the University of Wisconsin-Madison under the advice of Professor Daniel Kammer.CSRI POC: Laura Painton Swiler, (505) 844-8093 |