The report documents the development of new computer programs for the automated minimum weight design of aerospace structures. Two programs are discussed in detail, an intermediate capacity linear merit function program, and a large scale nonlinear program. The intermediate capacity program can be used for the optimization of major structural components of up to approximately 170 degrees of freedom with fixed configuration. The large scale program is capable of handling structures with up to 450 degrees of freedom and includes geometric variables. Detailed descriptions of the preparation of input data are included. Examples are given of the application of the program to a wide variety of structures including major airframe components, indicating the weight savings possible through application of the optimization techniques.

The report presents detailed programming information on the use of the developed linear and nonlinear computer programs for the automated design of minimum weight structures. General operational instructions for the programs, which are coded in FORTRAN IV, are given. Detailed requirements for the operating system and machine configurations including peripheral storage devices (such as magnetic tape or disk units) are specified. The report also includes source notation for the programs and instructions for the alterations to the linear program for various machine sizes. Full listings and flow charts of the programs, and detailed input instructions are provided as appendixes.

The report presents detailed programming information on the use of the developed linear and nonlinear computer programs for the automated design of minimum weight structures. General operational instructions for the programs, which are coded in FORTRAN IV, are given. Detailed requirements for the operating system and machine configurations including peripheral storage devices (such as magnetic tape or disk units) are specified. The report also includes source notation for the programs and instructions for the alterations to the linear program for various machine sizes. Full listings and flow charts of the programs, and detailed input instructions are provided as appendixes. (Author).

This book presents the integrated approach of analysis and optimal design of structures. This approach, which is more convenient than the so-called nested approach, has the difficulty of generating a large optimization problem. To overcome this problem a methodology of decomposition by multilevel is developed. This technique, which is also suitable for implementation on parallel processing computers, has the advantage of reducing the size of the optimization problem generated. The geometric programming for both equality and inequality constraints is used in the optimization.

The report considers the state of the art in methods of structural optimization. Mathematical programming based methods, while extremely successful with problems of moderate size tend to become prohibitively costly when applied to large scale structures. A novel approach to the weight optimization of indeterminate structures under multiple loading conditions with strength and displacement constraints has been developed and is presented herein. Using this method significant improvements in computational time have been achieved over direct numerical search methods. In some cases the numbers of iterations required to determine the least weight have been reduced by factors of over 20. The rate of convergence is independent of problem size permitting application to large scale structures. Examples of application of the new approach to a number of problems are included.