Mass minimisation and print path filtering for TO design & 3D fabrication of multi-material elements

Introduction
For a sustainable built environment, there is an increasing need for optimised (new or renovated) designs, including the customisable fabrication of their components. Here in Eindhoven, research has been carried out that (i) presents a general approach to translate design problems into a Topology Optimisation (TO) strategy; (ii) shows multi-disciplinary TO for multi-material components, including concrete, which behaves differently under compression and tension; and (iii) addresses issues across the process from design to fabrication. Applying the general approach and TO, cases were studied too: a part of a façade panel and a sandwich panel. A TO design for the sandwich panel was tested for fabrication by functional grading and black-and-white printing. These tests revealed that design by TO requires specific print path plans and tweaking of system dynamics for the fabrication by 3D printing. Vice versa, fabrication requires modifications in the design by TO, e.g. geometrical adjustments.

Figure 1, from left to right: TO, print path plan, actual printed component, a future application.

Research goals
In this MSc-thesis research project, two aspects from the above research field are investigated. First, it is studied whether an alternative TO strategy may be useful: This alternative strategy minimises mass (i.e. volume) and uses the stiffness, insulation performance, and possibly maximal stresses as constraints. Second, to fit the TO performance directly to the printed results, it is investigated whether print path dependent density filtering may help. If successful, the alternative strategy and modified filtering will improve the process and products.
 
Method
The project will start with a brief literature research on TO, 3D printing, and their implementations, whereafter the existing Eindhoven MATLAB implementations are explored. Then the alternative strategy is implemented, and its results are compared with the cases as used for the existing strategies. Secondly, print path design is studied, as explained in papers, and as experienced in the Structures Laboratory Eindhoven. Using this background, a print path dependent density filter is implemented, and results with and without this filter are compared related to the performance of the designs. Possibly, a few designs as made by the new filter can be printed in the lab too.