Approximate Multiple Configuration Analysis and Allocation for Least Weight Structural Design

Book excerpt: This report describes a rapid reanalysis technique (reducing analysis costs by factors between 2 and 100) and a rapid search procedure (reducing the number of design steps by a factor of 25) for obtaining optimum designs. Reanalysis is an approximate procedure based on extremum energy principles and leading, monotonically, to results as exact as desired. THe desing process is an allocation procedure. Each element of the structure is sized in turn. Optimization is addressed toward least weight design of truss systems with multiple loadings and a discrete set of admissible sizings (materials). The new technique can easily include prestress as a design variable. It can be extended to treat any set of finite elements and is based on use of the force or displacement method or both. Because of the modularity of calculations, it is well suited to computer implementation for multi-element structural systems.