Session: 06-01-01 Product And Process Design

Paper Number: 94299

94299 - Methodology for Integrating Biomimetic Beams in Abstracted Topology Optimization Results 

Topology optimization has become of great importance in the development of mechanical components in the last decades, as it is a powerful tool for generation of lightweight design concepts. Based on a design space and relevant boundary conditions, the topology optimization algorithm allocates material inside the design space such that the loads are well supported by the design. Using a minimum mass approach only as much material is allocated as is needed to support the loads without the material reaching a certain threshold, such as 80 % of the yield strength of the material at any point inside the component.

Previous works indicate that, under certain load conditions, biomimetic beams are beneficial in terms of structural integrity compared to cylindrical beams. It is assumed that an added geometric complexity due to substitution of biomimetic beams into topology optimized designs, the mass of the final component can be reduced while sufficiently supporting the acting loads.

To address this hypothesis, a five-step design methodology was developed to generate CAD designs of biomimetic structural components, which is presented in this article.

In step one of the design methodology, all material allocated by the topology optimization is classified as either connecting surfaces, nodes, or beams. Location and orientation of these entities are derived from the topology optimization result and the topology optimization input. A key tool in this step is skeletonization of the design. The output of step one is an auxiliary model consisting of connecting surfaces, cylindrical beams, and ball nodes, which is an abstraction of the original topology optimization result.

In step two, the auxiliary model is first exposed to the original boundary conditions in a finite element analysis (FEA). Then, internal forces (normal force and shear force), torsion (moment around the beam’s main axis) and bending moments in all beams of the auxiliary model are identified with respect to both of their ends.

In step three, the load case in terms of internal forces, torsion, and moments of each beam is given as an input to a database of biomimetic beams. The database gives a biomimetic beam as an output for every input load case. These biomimetic beams are used for the intermediate biomimetic component design.

In step four, adapted nodes have to be generated to connect the biomimetic beams with each other as well as the biomimetic beams and the connecting surfaces of the input topology optimization. Two approaches are presented to generate lightweight nodes for the overall component using topology optimization.

In step five, an intermediate biomimetic model is generated based on steps three and four. This model is then exposed to the original boundary conditions and analyzed with regard to a stress threshold defined for the material of this component. If the stress threshold is not exceeded, the intermediate design becomes the final design as an output of the overall design methodology. If the stress threshold is exceeded at any point of the design, a feedback loop to one of the previous steps of the design methodology is used to adapt the design. The feedback loops are applied until a design is generated in which the stress threshold is not exceeded at any point of the design. This design then becomes the output of the overall design methodology.

The design methodology allows for reproducible biomimetic component designs, a trackable and easily documentable component development process, and, furthermore, the possibility of automation of the design process to ultimately save development costs when designing biomimetic structural components.

Presenting Author: Tim Röver Hamburg University of Technology

Presenting Author Biography: Tim R&#246;ver received both his B.Sc. degree in general engineering science in 2016 and his M.Sc. degree in product development in 2019 from Hamburg University of Technology. In 2017 he was an exchange student at the Unversidade de Aveiro, Portugal for one semester. In his master thesis at Fraunhofer IAPT he worked on design methodologies for additvely manufactured mechanical components. <br/>Currently, he is a research associate at the Institute of Laser and System Technologies of Hamburg University of Technology. <br/>His research interests include design for additive manufacturing, biomimetics, multiphysical simulation and optimization, aerospace engineering and heat exchanger development.

Authors:

Tim Röver Hamburg University of Technology
Robert Johannes Lau Fraunhofer Research Institution for Additive Manufacturing Technologies IAPT
Fritz Lange Fraunhofer Research Institution for Additive Manufacturing Technologies IAPT
Arnd Struve Fraunhofer Research Institution for Additive Manufacturing Technologies IAPT
Cedrik Fuchs Fraunhofer Research Institution for Additive Manufacturing Technologies IAPT
Katharina Bartsch Institute of Laser and System Technologies (iLAS), Hamburg University of Technology (TUHH)
Arthur Seibel Fraunhofer Research Institution for Additive Manufacturing Technologies IAPT
Claus Emmelmann Institute of Laser and System Technologies (iLAS), Hamburg University of Technology (TUHH)