Optimized Topologies for Steel Frames: Accounting for Buckling and Stress Criteria

Structural topology optimization is a free-form design tool that allows for a systematic search of the design space for optimizing both the structural connectivity and member sizing. This search could be used to eliminate engineering guess-work especially in the preliminary structural design conceptualization, and obtaining high-performance designs. Although many steel structural designs are primarily driven by controlling stress and buckling, the currently developed structural topology optimization algorithms mainly focus on controlling structural stiffness, which is often carried out via controlling displacements in a predefined set of points within the structure. This limitation should be alleviated for better integration of topology optimization with structural engineering. An efficient algorithm for topology optimization of steel frame structures that seeks designs in a safe region of elastic stress, buckling load factors and displacements is presented in this work. Stress-based performance of the structure is optimized by evaluating the von Mises yield criterion in a set of predefined points within the structure and controlling the maximum of these stresses within the optimization algorithm. Moreover, under the assumption of linear buckling, an Eigenvalue problem for determining buckling load factors and the corresponding modes is solved, and the minimum buckling load factor is controlled. Designs suggested by the proposed algorithm are compared with conventional designs and changes in their topologies and performances are discussed.