Modal Analysis and Testing of Missile Systems
Abstract
This study was performed to establish the effectiveness of using modal tests to verify the accuracy of NASTRAN Finite Element Models (FEMs) of missiles. The structure used in this study was a mock-up of the FOG-M (Fiber Optics Guided Missile) system. While the missile was not a flight version, the structural characteristics and internal subcomponents were sufficiently close to the FOG-M to allow meaningful conclusions concerning the testing and analysis techniques. The study also permitted a comparison between two different methods of testing, i.e., normal mode and random response. Also, sensitivity analyses were conducted on the NASTRAN mathematical model to identify peculiarities associated with a subroutine used to compute eigenvectors and eigenvalues and to study the requirement for additional nodes when modeling the wings and fins. Eight modes of vibration were measured and correlated with the FEM models. Excellent to good correlation was obtained for the critical first bending modes of the airframe, wings, and fins. Excellent to good correlation was obtained for the wings and fins higher mode shapes, but differences in most frequencies were noted for the higher modes of vibration. A Lessons Learned Chapter is provided that documents all difficulties experienced, and suggestions were provided for future test and analysis efforts. Finally, recommendations are offered on how this effort can most effectively be extended to a flight model of the FOG-M.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1988
- Accession Number
- ADA204051
Entities
People
- John A. Schaeffel Jr.
- Larry C. Mixon
- Peter L. Green
- Roque L. Salas
- Russell Garner
Organizations
- United States Army Aviation and Missile Command