Accession Number : ADA289304

Title :   Analysis of Modal Behavior at Frequency Cross-Over.

Descriptive Note : Final rept.,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING

Personal Author(s) : Costa, Robert N., Jr

PDF Url : ADA289304

Report Date : 28 NOV 1994

Pagination or Media Count : 250

Abstract : The existence of the mode crossing condition is detected and analyzed in the Active Control of Space Structures Model 4 (ACOSS4). The condition is studied for its contribution to the inability of previous algorithms to successfully optimize the structure and converge to a feasible solution. A new algorithm is developed to detect and correct for mode crossings. The existence of the mode crossing condition is verified in ACOSS4 and found not to have appreciably affected the solution. The structure is then successfully optimized using new analytic methods based on modal expansion. An unrelated error in the optimization algorithm previously used is verified and corrected, thereby equipping the optimization algorithm with a second analytic method for eigenvector differentiation based on Nelson's Method. The second structure is the Control of Flexible Structures (COFS). The COFS structure is successfully reproduced and an initial eigenanalysis completed.

Descriptors :   *UNMANNED SPACECRAFT, COMPUTER PROGRAMS, MATHEMATICAL MODELS, ALGORITHMS, PAYLOAD, OPTIMIZATION, ATTITUDE CONTROL SYSTEMS, FINITE ELEMENT ANALYSIS, STRUCTURAL ANALYSIS, EIGENVECTORS, THESES, PROBLEM SOLVING, FINITE DIFFERENCE THEORY, ARTIFICIAL SATELLITES, NUMERICAL METHODS AND PROCEDURES, CROSSINGS, FLEXIBLE STRUCTURES.

Subject Categories : Unmanned Spacecraft
      Numerical Mathematics
      Computer Programming and Software

Distribution Statement : APPROVED FOR PUBLIC RELEASE