Session: 02-02-01: Computer-Aided and Simulation Driven Design 1

Paper Number: 164498

Topology Optimization of Orthotropic Materials: Enhancing Sustainability and Performance in Additive Manufacturing 

With the advent of additive manufacturing (AM) and advanced composites, a shift towards orthotropic materials is crucial. Anisotropic materials exhibit direction-dependent properties, which, if accounted just for safety factors definition, may lead to suboptimal structural performance. This work explores topology optimization strategies tailored for orthotropic materials, enabling improved mechanical efficiency and resource utilization in AM. 

Traditional AM workflows often neglect the material orientation effects, particularly in the Z direction, considering the design optimization and the 3D printing as separate. Current methods assume isotropy, omitting the significant impact of fiber orientation, which is especially crucial in composite materials. This research investigates the implications of material anisotropy on structural optimization and proposes methodologies to integrate material properties with topology optimization for enhanced design and manufacturing. 

To model orthotropic materials, engineering constants such as elastic moduli, Poisson’s ratios, and shear moduli are defined based. The selected material, carbon fiber-reinforced polymer (CFRP) PETG, requires a nine-parameter material model. The mathematical formulation incorporates these parameters within the topology optimization algorithm, ensuring that material anisotropy related to the printing direction is reflected in the optimized design. 

A preliminary case study is conducted on a flat lamina with defined boundary conditions and load applications. Topology optimization is performed by varying material orientations considering different 3D printing directions, demonstrating the impact of material directionality on stiffness and weight reduction. Results highlight the necessity of incorporating fiber orientation within topology optimization to maximize performance. 

Building on the insights gained from the lamina study, the methodology is extended to a brake pedal for a Formula SAE vehicle. The pedal, initially made of aluminum, is redesigned for replacement with 3D printed CFRP. The optimized design allows for increased process sustainability while maintaining structural performance under the required load.

 This study paves the way for integrated product and process optimization by simultaneously considering mechanical performance (mass, stiffness) and manufacturing efficiency (material usage, build time, post-processing). Also, by directly 3D printing a CFRP instead of using conventional metal processes, sustainability is significantly increased. The reduction of construction time, material waste, elimination of extensive machining and energy-intensive steps, contribute to a more economical and environmentally friendly production approach. Furthermore, integrating fiber orientation and the related printing direction optimization within the design phase ensures that the material is used efficiently, maximizing both mechanical performance and sustainability.

The findings demonstrate the practical application of topology optimization for orthotropic materials in AM and composite structures. Future work will focus on product and process design integration, including process constraints and multi-objective functions, to enable more efficient and sustainable manufacturing practices. 

Presenting Author: Enrico Dalpadulo University of Modena and Reggio Emilia

Presenting Author Biography: Enrico Dalpadulo is assistant professor at the "Enzo Ferrari" Department of Engineering of the University of Modena and Reggio Emilia. He holds the research doctorate in "Automotive for intelligent mobility" at the Alma Mater Studiorum University of Bologna and the master's degree in "Vehicle Engineering" with honors from the University of Modena and Reggio Emilia. He obtained the qualification to carry out the profession of Industrial Engineer. He has been post-doctoral researcher at the research center InterMech MoRe. Since 2018 he has been carrying out research activities in the disciplinary sector ING-IND/15 (Design and Methods of Industrial Engineering) at the IDEA laboratory (Integrated Design and Engineering Applications) of the "Enzo Ferrari" Department of Engineering. His research field is integrated product-process design based on CAx tools (Computer Aided technologies), in particular for additive manufacturing and for sustainability. He is the author of the doctoral thesis “Development and Application of a Computer-based methodology for Design for Additive Manufacturing of Automotive components” and of 24 Scopus indexed scientific publications focused on methods for the design of additively manufactured components. He participated in an industrial project in collaboration with the "Metal Additive" industrial research center of HPE COXA s.r.l. (Modena). He collaborated with the Fiat Research Center and FCA Italy S.p.A. (Stellantis N.V.) for the development and application of metal Additive Manufacturing technologies. He participated in sundry biomedical research projects for design and development of medical aids and tools. He is currently involved in the national project PNRR - MOST "National Center for Sustainable Mobility ", to develop and integrate mechatronic systems for autonomous vehicles. He has carried out teaching activities in the field of CAD design, industrial technical drawing and additive manufacturing, in the context of university and various training centres.

Authors:

Enrico Dalpadulo University of Modena and Reggio Emilia
Fabio Pini University of Modena and Reggio Emilia
Francesco Leali University of Modena and Reggio Emilia