A Comparison of the Optimization and Analysis of Doubly Curved Shells Using MSC/NASTRAN and ASTROS

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.

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Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1990
Accession Number
ADA230682

Entities

People

  • John R. Dewsnap

Organizations

  • Air Force Institute of Technology

Tags

Communities of Interest

  • Air Platforms
  • Weapons Technologies

DTIC Thesaurus Topics

  • Accuracy
  • Axisymmetric
  • Composite Materials
  • Computer Programs
  • Computers
  • Databases
  • Engineering
  • Finite Element Analysis
  • Geometry
  • Liquid Propellants
  • Materials
  • Optimization
  • Procedures (Computers)
  • Resonant Frequency
  • Rocket Engines
  • Rockets
  • Turbines

Fields of Study

  • Physics

Readers

  • Adaptive Control and Estimation with Uncertainty in Dynamic Systems.
  • Computer Science.
  • Structural Dynamics.