Topology optimization : A comparison between the SIMP and BESO methods using open-source software.

Abstract: Structural optimization is a useful tool for engineers and designers in construction technology as well asvehicle and mechanical engineering. With structure optimization, a computer can, with the help of finiteelement analysis, calculate the smallest possible amount of material needed to meet the requirements onthe part to be produced.The purpose of this report is to use two different implementations for finite element calculations fortopology optimization of a beam. Results from the optimizations will then be 3D printed with differentsettings. The beam will be tested for displacement, stress and strain in a universal testing machine. Theresults from the experiment will be compared with computed simulations of the same beam.For the structural optimization, two methods are used and compared: Solid Isotropic Material withPenalization and Bidirectional Evolutionary Structural Optimization. A total of eight beams, four fromeach method, were printed with a 3D printer with two different positions on the printer bed and withdifferent degrees of infill ratios. These were tested with a machine that could register both pressure anddeformation and were filmed to be able to see the strain. The deformation of the beams was alsosimulated in a software computer program to see what deformation difference there was betweenexperiment and reality.It turned out that the beams that were printed behaved anisotropic even though solid plastic should beincluded among isotropic materials. The deformation of the model looked like the finite elementcalculation, but the actual deformation was significantly larger than what was calculated by the computersoftware.