COMPOSITE MODAL CHARACTERISTICS OF MULTISECTION, ELASTIC SPACE STRUCTURES.
Abstract
Analysis of the dynamic response of complex structures requries knowledge of the dynamic characteristics of the structure. In many cases a structure is composed of several sections and may be considered to behave linearly. In this report a new method is evolved for analysis of the flexible dynamic characterisitcs of such structures. A matrix eigenvalue equation is derived for determination of the modal characteristics of the composite structure in terms of the characteristics of its sections. Use is made of functional vector modes to describe modal behavior of the sectioons in three-dimensional space. The problem is then formulated in terms of modal and rigid body coordinates of the sections. The eigenvalue equation is derived by application of Lagrange's equations. The connection conditions between sections provide relations between the coordinates. These relations are used to reduce the size of the matrices involved. The method is developed for a tandem series of sections. It may however be extended to multibranch structures. An essential modification of this analysis is also presented. For many applications a large number of section modes are required for good convergence of the composite modal characteristics. Consideration is therefore given to quasistatic behavior of the sections under the loads applied during composite motion. Additional quasistatic coordinates are introduced into the eigenvalue analysis yielding a remarkable improvement in convergence in some cases. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1964
- Accession Number
- AD0626304
Entities
People
- Charles W. Coale
Organizations
- Lockheed Martin Missiles and Space