Date of Award
12-1990
Document Type
Thesis
Degree Name
Master of Science in Astronautical Engineering
Department
Department of Aeronautics and Astronautics
First Advisor
Howard Gans, PhD
Abstract
This study identified techniques and software available for the optimization of doubly curved shells and applied them in the context of a large nozzle shape. An optimality criteria scheme that can reduce solution time was evaluated and compared to the Method of Feasible Directions. MSC/NASTRAN and ASTROS were used to perform finite element analysis and optimization, and the results were compared to the theory. The programs give virtually identical results, and if plates and shells are carefully modeled, then stresses, displacements and modes are accurate to within ten percent. A Mindlin-type axisymmetric finite element was implemented in ASTROS that preserved accuracy and reduced the size of the stiffness matrix by a factor of four. Nozzle optimization was performed using static pressure and thermal loads, constrained by the Von Mises stress criteria. Software errors were documented in ASTROS, and four characteristic stress regions identified for the optimized nozzle.
AFIT Designator
AFIT-GA-ENY-90D-4
DTIC Accession Number
ADA230682
Recommended Citation
Dewsnap, John R., "A Comparison of the Optimization and Analysis of Doubly Curved Shells Using MSC/NASTRAN and ASTROS" (1990). Theses and Dissertations. 7908.
https://scholar.afit.edu/etd/7908
Comments
The author's Vita page is omitted.