Abstract
Conventional tools for aerospace structure design for static and dynamic aeroelastic analysis are based on invariant stiffness and damping characteristics. That is, these design tools assume that the structural stiffness and modal damping matrices remain constant as the structure is subjected to large elastic deformation. However in reality, the modal characteristics of a given structure may vary with large oscillatory motion. The aim of this paper is to explore a methodology to quantify the nonlinear damping and damped natural frequencies as a function of elastic deflection using a dynamic testing technique with step-sine excitation. The frequency response function is constructed over an interval containing each modal frequency of interest. The fundamental equations for extraction of the modal parameters are derived and reveal an error in the expression for damping that propagated through published literature. The corrected forms of the equations are presented herein. The analysis technique is applied to a synthesized modal data set with specified nonlinear damping for validation of the nonlinearity detection methodology and is deemed satisfactory for application to dynamic test data on an aircraft structure.
| Original language | English |
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| Title of host publication | AIAA Scitech 2019 Forum |
| Publisher | American Institute of Aeronautics and Astronautics Inc, AIAA |
| ISBN (Print) | 9781624105784 |
| DOIs | |
| State | Published - 2019 |
| Event | AIAA Scitech Forum, 2019 - San Diego, United States Duration: Jan 7 2019 → Jan 11 2019 |
Publication series
| Name | AIAA Scitech 2019 Forum |
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Conference
| Conference | AIAA Scitech Forum, 2019 |
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| Country/Territory | United States |
| City | San Diego |
| Period | 01/7/19 → 01/11/19 |
Funding
This research work is a combined effort of the Air Force Research Laboratory Munitions Directorate and the Air Force SEEK EAGLE Office, Eglin AFB, FL. The funding source is AFOSR LRIR# 16RWCOR359. Encouragement and support from Dr. Michael J. Kendra, Dr. Brett J. Pokines, and Dr. Crystal L. Pasiliao is sincerely appreciated. A special acknowledgement is owed to Mr. Gary Foss of The Boeing Company for introducing Carrella’s work on nonlinearity detection, at the Aerospace Flutter and Dynamics Council meeting in the Fall of 2016.