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

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 COSMOS/M(TM) 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 and/or 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.

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Document Details

Document Type
Technical Report
Publication Date
Nov 01, 1999
Accession Number
ADA383217

Entities

People

  • Daniel J. Biezad

Organizations

  • California Polytechnic State University

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Aerodynamic Configurations
  • Air Force
  • Aircraft Models
  • Aircrafts
  • Airframes
  • Center Of Gravity
  • Control Systems
  • Dynamic Response
  • Equations
  • Frequency
  • Geometry
  • Resonant Frequency
  • Simulations
  • Swept Wings
  • Test Methods
  • Two Dimensional
  • Vibration

Readers

  • Computational Modeling and Simulation
  • Structural Dynamics.