The Prediction of Mass Loaded Natural Frequencies and Forced Response of Complex, Rib-Stiffened Structures.
Abstract
An experimental investigation was conducted to determine the validity of an algorithm developed by Whaley (Ref 14) to approximate the natural frequencies of a complex structure under arbitrary mass loading conditions, when only the unloaded natural frequency and mode shape data is known. The chosen test specimen was a curved, rib-stiffened panel from a C-141 Starlifter, aircraft. The panel was suspended from the ceiling by bungy cords and tested in an unloaded configuration and nine separate mass loaded configurations. Then using only unloaded data the generalized mass and generalized stiffness for each mass loaded configuration were computed, and the natural frequencies for each configuration were computationally predicted using the aforementioned algorithm. The theoretical and experimental results were then compared to detemine the amount of error incurred in the approximation technique. The theory of how to ultimately determine the overall forced response of the specimen was discussed and an error model was developed to enable an examination of the reliability of the algorithm in predicting forced response. Recommendations concerning future test procedures, areas requiring further study, and the use of the algorithm were made. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1979
- Accession Number
- ADA079856
Entities
People
- Larry Blake Glenesk
Organizations
- Air Force Institute of Technology