Accession Number:

ADA383217

Title:

Investigation of Dynamic Structural Models Suitable for the Simulation of Large Aircraft

Descriptive Note:

Final rept. 1 Nov 1997-30 Sep 1999

Corporate Author:

CALIFORNIA POLYTECHNIC STATE UNIV SAN LUIS OBISPO

Personal Author(s):

Report Date:

1999-11-01

Pagination or Media Count:

125.0

Abstract:

The simulation of modern aircraft with lightweight structures and high bandwidth control systems requires more sophisticated modeling than the standard six degree-of-freedom representation. The objective of this work was to investigate and test methods for incorporating longitudinal structural mode vibration data into the simulation equations which would allow for variation in frequency and shape functions relative to an established baseline. Using a two-dimensional COSMOSMTM finite element model, the thickness and the length of the aircraft model were varied to match the resonant frequency of the baseline model. The addition of forces then matched the mode shape of the computer model to the actual shape of the baseline. The results, confirmed by experimental tests, indicated that it is possible to effectively model the natural frequency and mode shape at any longitudinal location as center of gravity andor weight is varied about a nominal condition. Moreover, the methodology allows new configuration baselines to be established by the matching of modal frequencies and shapes to external data from ground or flight tests.

Subject Categories:

  • Military Aircraft Operations
  • Computer Programming and Software
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE