Accession Number : AD0726112

Title :   An Automated Procedure for the Optimization of Practical Aerospace Structures. Volume I. Theoretical Development and User's Information.

Descriptive Note : Final rept. 15 Jan 69-15 Aug 70,

Corporate Author : GRUMMAN AEROSPACE CORP BETHPAGE N Y

Personal Author(s) : Dwyer,Walter J. ; Emerton,Robert K. ; Ojalvo,Irving U.

Report Date : APR 1971

Pagination or Media Count : 207

Abstract : The report documents the development of a new structural optimization algorithm, which is a combination of a modified fully stressed design technique and a redesign procedure based on gradients to deflection constraint surfaces. The algorithm is incorporated into a large finite element program based on the displacement method of structural analysis. Using an IBM 360/75 computer, the program is capable of obtaining near optimum distributions of material for structural idealizations consisting of up to three thousand elements and six thousand degrees of freedom, and subjected to a maximum of twenty loading conditions. Constraints may be placed on the maximum and minimum size of any of the elements, on the stresses in the elements, and on the displacements of the nodal points of the structure. Several examples of structures that were optimized are included to demonstrate the various features of the program, and to compare results with previously obtained solutions. To help make the program useful in the design of major aircraft structures, care has been taken to simplify the input and to present the program output in a form that is meaningful to the aircraft stress engineer. Results of an exploratory investigation into the optimization of dynamically loaded structures are presented, and the conversion of two existing blast-response shell codes into a unified synthesis program is documented. (Author)

Descriptors :   (*AIRFRAMES, OPTIMIZATION), ALGORITHMS, STRUCTURAL PROPERTIES, MECHANICAL PROPERTIES, INPUT OUTPUT DEVICES, LOADS(FORCES), COMPUTER PROGRAMMING

Subject Categories : Aircraft
      Computer Programming and Software
      Computer Hardware
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE