Topology Optimization of Framed Structures using SAP2000

Abstract

Topology optimization (TO) represents a free-form design approach that aims to identify optimized material distribution within the design domain. There are two main broad class of techniques which can be applied: discrete and continuum optimization of the structural system. In this work, TO is applied to structural systems modelled 1D finite elements (i.e. truss and frames) by using SAP2000 which is a well-known commercial software for analysis and design of structural systems that is equipped with an open application programming interface (OAPI). The optimization problem at hand is solved using the High-Performance Topology Optimization Computing Platform (HP-TOCP). The TO problem for the case of structures simulated with 1D finite elements is mainly divided in two stages. First, the generation of the initial design domain, usually called as “ground structures” and second, the formulation of the optimization problem. Most of the articles that can be found in literature and deal with the ground structure generation are applied in 2D structures and have many geometrical limitations. In this work, the Rhino’s plug-in Grasshopper is used, which is a well-known free form design tool with wide range of applications. An additional tool was also developed in C#, to transfer the initial geometry in SAP2000 and formulate the optimization problem. In this work, compliance represents the objective function of the problem while both volume of the final structure and the design code regulations represent the constraints. Without loss of the generality, circular and rectangle cross-sectional geometries are considered in both 2D and 3D test cases.