COLLABORATIVE OPTIMIZATION OF TOPOLOGY AND CROSS-SECTIONAL SHAPE FOR SPACE FRAME STRUCTURES

Frame structures are commonly used in architecture, civil engineering and other fields, and their design often necessitates a balance between weight reduction and the enhancement of mechanical properties. To achieve these design objectives, structural optimization methods are widely used to solve the shape and topology optimization problems of frame structures. The ground structure method serves as a fundamental method for optimization of discrete truss or frame structures, and the node-moving ground structure method has been proposed and effectively expands the design space of traditional methods. However, current research on the node-moving ground structure method mostly is based on circular beam cross-sections, without considering the optimization of cross-sectional shapes or the principal direction design problems arising from irregular cross-sectional shapes. Therefore, this paper proposes a collaborative optimization method for topology and cross-sectional shape of space frame structures, based on Rodriguez rotation and discrete cross-sectional shape optimization. This method addresses the issue of the principal direction updating of beam cross-sections caused by node moving, expanding the design framework of the node-moving ground structure method by introducing rotational angle design variables. The method also takes into account the differences in bending and torsional resistance among beams with different cross-sectional shapes, enabling the automatic selection of various beam cross-sectional shapes to ensure efficient material utilization under complex conditions. Numerical examples demonstrate that through the collaborative optimization of structural topology and cross-sectional shape, frame configurations in three-dimensional space with superior performance can be obtained.