Initial prestress design and optimization of cable-stiffened latticed shells

Abstract

The cable-stiffened latticed shell is a hybrid structure composed of a single-layer latticed shell and a cable-strut system. Only after the initial prestress is applied can the rigid and flexible components work together, so this paper proposes a new initial prestress design and optimization method of cable-stiffened latticed shells. Firstly, based on the equilibrium matrix theory and static analysis, independent self-internal force modes of the hybrid structure are obtained accurately. The force finding analysis is carried out by a linear combination of these self-internal force modes, ensuring the initial cable forces in computational models are the same as the design values. Then the design values of the initial forces in a cable-stiffened latticed shell are optimized, taking the combination coefficients of the self-internal force modes as the optimization variables. And the maximum bending moment of the key members and the critical load coefficient when the emergence of slacking cables are considered as optimization objectives. Then, a hybrid multi-objective optimization algorithm is proposed based on the interior point method and NGSA-II algorithm. The optimization example shows that the initial prestress optimization has a significant effect on the stability of the structure. The maximum bending moment can be reduced by 18%, and the ultimate bearing capacity can be increased by 47%, which verifies the correctness and applicability of the proposed design and optimization method.