Topology Optimization of Truss-like Structures: from Theory to Practice

The goal of this thesis is the development of theoretical methods targeting the implementation of topology optimization in structural engineering applications. In civil engineering applications, structures are typically assemblies of many standardized components, such as bars, where the largest gains in efficiency can be made during the preliminary design of the overall structure [4]. The work is aimed mainly at truss-like structures in civil engineering applications, however several of the developments are general enough to encompass continuum structures and other areas of engineering research too. The research aims to address the following challenges: • Discrete variable optimization, generally necessary for truss problems in civil engineering, tends to be computationally very expensive, • the gap between industrial applications in civil engineering and optimization research is quite large, meaning that the developed methods are currently not fully embraced in practice, and • industrial applications demand robust and reliable solutions to the realworld problems faced by the civil engineering profession. In order to address these issues, the research is divided into several research papers, included as chapters in the thesis. An overview of the papers making up the chapters is given in figure 1, and the chapters are summarized as follows: Discrete binary variables in structural topology optimization often lead to very large computational cost and sometimes even failure of algorithm convergence. A novel method was developed for improving the performance of topology optimization problems in truss-like structures with discrete design variables, using so-called Kinematic Stability Repair (KSR) [5]. Two typical examples of topology optimization problems with binary variables are bracing systems and steel grid shell structures. These important industrial applications of topology optimization are investigated in the thesis. A novel method is developed for topology optimization of grid shells whose global shape has been determined by form-finding [7]. Furthermore a novel technique for façade bracing optimization [8] is developed. In this application a multiobjective approach was used to give the designers freedom to make changes, as the