Investigation of the structural behaviour of non-conventional beams designed using a Topology Optimisation procedure

In this research we use topology optimisation to design statically determinate rectangular beams with different heights. For the sake of simplification, the constitutive material is assumed to be homogeneous. The aim is to verify the efficiency level that topology optimisation procedure has in removing material from the structural member still preserving the bending strength capacity. Topology optimisation is based on the Bi-directional Evolutionary Structural Optimisation (BESO) and Solid Isotropic Material with Penalisation (SIMP) methods. To use the SIMP method, a 3D parametric model of the beams was implemented in the Rhinoceros3D (Computer-Aided Design) software with the aid of the Grasshopper (Algorithm-Aided Design) plugin. The optimization was performed using the tOpos plugin. For the BESO method, the BESO 2D code developed in RMIT Univervity was used. The output for both codes are compared, highlighting the coherence of the results based on computational time efficiency and physically plausible generated shapes. After Topology Optimization, the structural behaviour was investigated using Karamba3D plugin. To obtain the maximum load for the beams with different heights and their final volume coming from topology optimisation, an additional optimisation method based on genetic algorithms was adopted to maximise an objective function based on deformation. This analysis was performed for local maximum displacement respecting limiting state serviceability criteria considering increasing distributed load and different volume fractions. In all the cases analysed, the width and span are fixed. The results of the optimisation procedure for beams with different heights are compared based on economic-sustainability criteria (volume of material) and load-bearing capacity (maximum bearing moment).