Title Participants "Voi-based optimization of structural assessment for spatially degrading RC structures" "Eline Vereecken, Wouter Botte, Geert Lombaert, Robby Caspeele" "Structural health monitoring of beam-like and truss structures using frequency response and particle swarm optimization" "R. Zenzen, Samir Khatir, I. Belaidi, Magd Abdel Wahab" "Robustness assessment and optimization of a simplified smart structure model for structural acoustic control" "Herman Van Der Auweraer" "In the past 20 years, fundamental research has been conducted on intelligent materials towards developing smart structures. This has raised industrial interest for the application of smart structures to many problems found in civil life. Among those, noise is gaining an increased attention as it is one of the environmental pressures that most closely affects the EU citizens, as confirmed by public surveys on overall nuisance and health problems. Therefore, intelligent materials have started to be used to reduce noise and vibration in civil structures, machine tools, automobiles, trains, and aerospace systems. The integration of intelligent materials is also seen as key to lightweight design, which is one of the main solutions for reducing vehicle fuel consumption and emissions. In this paper, a simplified model for a structural acoustic control system is applied to a vibro-acoustic analysis model resembling a concrete car structure. This is a simplified car cavity with the cabin dimensions of a typical station wagon car; it has a firewall between the engine compartment and the interior cavity. In this paper, forces are applied to the firewall to control the noise generated by the engine and transmitted through the vibration of the firewall to the passenger compartment. The intensities of the forces are optimized in order to minimize the noise around the driver's head position. Since variability exists in any physical system (manufacturing tolerances, load definition, geometric properties ...), for the present analysis, the variability in input forces direction and intensity, in engine noise level and in firewall thickness has been taken into account and modeled. The robustness of the vibro-acoustic system response to the variability has been first assessed at the deterministic optimal configuration. The system parameters have then been optimized to improve the robustness of the design. The simplified model offers the possibility to demonstrate a methodology that can be applied to more complex systems with multiple sensors and actuators, or more complex model representations thereof, for the integrated control systems and the system-level applications." "Compliance-based topology optimization of structural components subjected to thermo-mechanical loading" "Ticho Ooms, Gieljan Vantyghem, Thomas Thienpont, Ruben Van Coile, Wouter De Corte" "Apart from mechanical actions, structural components in the construction industry may be subjected to a thermal gradient, causing (internally) restrained thermal expansion. These thermal loads can alter the mechanical response of components in a structural topology optimization procedure. Therefore, the influence of thermal loading should be considered in the sensitivity analysis to efficiently update the structural layout of material. In this paper, a density-based topology optimization procedure is developed for compliance minimization of structural components subjected to thermo-mechanical loads considering steady-state heat conduction and weak thermo-mechanical coupling. The adjoint method is employed to obtain the analytical sensitivities, taking into account the influence of the design-dependent temperature field and thermal properties. The proposed topology optimization procedure is demonstrated on the MBB problem, extended with thermal loading, to investigate the influence of the proposed sensitivities on the optimized results. Furthermore, the thermo-mechanical load ratio is quantitatively defined and its effect on the resulting topologies is studied. The results show that the thermo-mechanical load ratio significantly changes the topology of the optimized results. Finally, the topology optimization procedure is presented in an efficient 138-line MATLAB code and provided as supplementary material, serving as a basis for further research." "Density-based topology optimization of structural components considering temperature-dependent thermal and mechanical material properties" "Ticho Ooms, Ruben Van Coile, Wouter De Corte" "Symmetry of solu- tions in discrete and continuous structural topology optimization" "James Richardson, Sigrid Adriaenssens, Rajan Filomeno Coelho, Philippe Bouillard" "In this paper a study is made of symmetry and asymmetry in structural topology optimization with discrete variables. A group theory approach is used to formally de ne the symmetry of the structural problems. This approach allows us to describe the set of symmetric structures and relate it to the entire search space. It is shown that, given a symmetric problem with continuous variables, an optimal symmetric solution (if any) exists. However, it is shown that this does not hold for the discrete case. Finally a number of examples are investigated to demonstrate the ndings of the research." "Symmetry and asymmetry of solutions in discrete variable structural optimization" "James Richardson, Sigrid Adriaenssens, Rajan Filomeno Coelho, Philippe Bouillard" "In this paper symmetry and asymmetry of optimal solutions in symmetric structural optimization problems is investigated, based on the choice of variables. A group theory approach is used to define the symmetry of the structural problems in a general way. This approach allows the set of symmetric structures to be described and related to the entire search space of the problem. A relationship between the design variables and the likelihood of finding symmetric or asymmetric solutions to problems is established. It is shown that an optimal symmetric solution (if any) does not necessarily exist in the case of discrete variable problems, regardless of the size of the discrete, countable set from which variables can be chosen. Finally a number of examples illustrate these principles on simple truss structures with discrete topology and sizing variables." "Design optimization for 3D concrete printing : improving structural and thermal performances" "Gieljan Vantyghem, Marijke Steeman, Wouter De Corte, Veerle Boel" "This paper focuses on optimizing the shape of prefabricated building components that are produced using 3D concrete printing (3DCP) techniques. The proposed method is to improve the structural and thermal properties using heuristic optimization algorithms, as such that they meet the minimum standards determined by building design codes. First, a case study is constructed that is based upon an existing module design found in literature, and a single segment from this design is isolated. The influence of the overall shape and the curvature of the infill line is investigated, and the structural performance is optimized for the hardened material state. In a second attempt, the heat transfer through the segment is also minimized. In parallel to the design’s optimization process, of course, the manufacturing challenges and process limitation need to be considered as well. Therefore, the influence of the infill line on the buildability of a 3DCP element is also demonstrated in a fresh material state (i.e. during printing). For this, the complete printing process of a wall segment is simulated and allows for the prediction of printing failure, elastic buckling and plastic collapse. Based on the outcome of the FEM-based calculations, a design could then be marked fit for printing or allow for further optimization." "Lifetime cost optimization for the structural fire resistance of concrete slabs" "Ruben Van Coile, Robby Caspeele" "Multi-material topology optimization involving simultaneous structural and thermal analyses" "Gieljan Vantyghem, Veerle Boel, Marijke Steeman, Wouter De Corte"