Minimum-weight design of structural frames

Abstract

The paper presents minimum-weight designs of plane structural frames under multiple load systems. Each load system consists of external concentrated and distributed loads, couples and self-weight. It is required that the normal and shear stresses, the maximum transverse deflection and the critical load factor in buckling should not violate respective prescribed limits under any load system. However, in order to simplify the solution procedure and to obtain designs which are practically feasible, the variation of the mass (stiffness) along the frame members is restricted to splines of order zero, one or two. Within these restricted classes of variation, the optimization problem reduces to a nonlinear programming problem whose solution is attempted by several methods. Numerical examples are given to indicate the range of applicability of the various methods.