Metodi di progettazione volumetrici ispirati alla natura per le tecnologie additive

Additive manufacturing (AM) technologies allow producing components layer upon layer in a completely different way with respect to the traditional techniques. This new approach enables unprecedented design freedom; indeed, objects with complex shapes inspired by nature, cellular solids and multiple materials can be produced. However, even though the manufacturing technologies are ready for producing such components, the literature emphasized that the available design tools are not appropriate and do not allow taking full advantage of the AM capabilities. For instance, the geometric modeling of lattice structures requires high computational resources, Boolean operations often fail, and the methods are not robust, while the modeling of multi-material parts require new approaches able to describe the model at each point of the volume, and not only on the boundary. This research project aims to overcome some of the highlighted limitations by developing new volumetric geometric modeling methods suitable for exploiting the capabilities offered by AM from a bio-inspired point of view. To reach the objective, several research topics have been addressed. Methods for the geometric modeling of graded components have been proposed. In this context, four different approaches for the realization of graded lattice structures were presented. Based on volumetric representation, those methods explored the possibilities to create graded density lattice structures by modifying the extrusion parameter in material extrusion technologies, by using implicit TPMS functions, by adopting subdivisions surfaces and by means of distance fields techniques. Graded materials were realized based on the introduction of material ratios in the computer numerical control instructions for material extrusion technologies; an analytical model for the elastic modulus of coextruded materials were proposed and validated experimentally. As a combination of modeling, material, and process topics, silicate-based scaffolds were prepared and tested to compare the mechanical properties. Furthermore, another way was explored concerning the utilization of math models and algorithm describing natural phenomena for geometric modeling purposes. A geometric modeling method based on reaction and diffusion systems was proposed for the realization of tree-like supports for AM. In addition, a method based on curve growing algorithm was proposed. Results showed that the various methods permit to model complex shapes and materials arrangement. The methods for graded lattice structures give a wide range of possibilities, prioritizing the AM process, or the complexity of the shape, or the flexibility of the approach. While methods derived from natural phenomena showed new possibilities and applications. Moreover, the method and application for multimaterial material extrusion technologies proved the feasibility of the approach and open up new investigation routes. Finally, the realization of porous scaffolds showed the critical interplay between design, material, and manufacturing process, which underlines the importance of an integrated approach. Due to the versatility of AM, the outcomes of the research can be adopted in different fields to obtain customized and multifunctional components, as shown by the presented test cases: in the automotive sector, these innovations can be pivotal in the development of lightweight components that enhance energy absorption, leading to reduced fuel consumption and improved performance and safety. Furthermore, these advancements hold promise for high-performance applications such as heat exchangers and biomedical scaffolds, where fluid dynamics plays a key role concurrently to high strength to density ratio; and eventually in consumer area, especially in sport, where tailored goods and equipment could set a new standard, providing individuals with products that are perfectly suited to their needs, enhancing comfort and performance.