Truss Size Optimization by Using Ratio-Extremum Method: Considering Self-weight Loads, Static and Dynamic Constraints

Abstract

For structural self-weight loads being important component in the loads, ignoring self-weight loads cannot be considered as reasonable approximation. In addition, the constraints of stresses, displacements and frequencies must be simultaneously considered to satisfy the requirements of engineering structures. According to the saddle point theory, Ratio-Extremum method is firstly proposed to solve the size optimization problem of the truss simultaneously considering self-weight loads, static and dynamic constraints. It is a great advantage that the step-size factors can be directly determined. Two cases of 72-bar special truss are used to show the effectivity and rationality.