The overarching goal of CENIT's range of tasks is to significantly simplify the design process for bionic lightweight structures. The core pillars for this include an automated design methodology and a tool for the direct generation of specific file formats for 3D printing. The project participants are aiming to achieve a time saving of around 40% for the overall development of bionic parts and to increase the weight-saving potential of ALM structures.

Automated modular principle for the CAD design of bionic structures
An ambitious undertaking that is now showing initial results: In order to create bionically optimized components, CENIT is developing a CAD catalog with parametrically structured, bionic features based on CATIA. "This supports the previously time-consuming and tedious manual interpretation and redesign of topology-optimized components in CAD with an automated modular principle," explains Jochen Michael, Senior Consultant at CENIT. "The parametrics of the features also make it easier for designers to adapt the geometries. This allows us to achieve further gains in efficiency and quality in the design process," he continues.

By the end of the Bionic Aircraft project in August 2019, CENIT expects to have developed a CAD catalog containing around 10-15 bionic features. "The declared aim of the project was primarily to show how the methodical and practical implementation of such a catalog can be carried out. The focus was therefore on basic research to define how the result of the topology optimization can be covered with bionic features and which algorithms are best suited for the recognition of components and the assignment of features," explains Jochen Michael from CENIT. With this fundamental work, the project participants are entering new, groundbreaking territory - as bionically optimized features have not yet been included in any CAD program.

Experts from the Fraunhofer Research Institution for Additive Production Technologies, IAPT, are contributing their knowledge of the nature, suitability and functionality of the bionic features that CENIT is transferring to CAD. Based on analyses of the quality characteristics, use and benefits of the topology-based components, they are developing the corresponding bionically optimized features. These should improve the typical behavior of the component in practical use and also make it as light and stable as possible. An example - where even small adjustments have a big effect: If curves based on natural models are applied to components subject to tensile stress, the risk of component failure can already be significantly reduced. This feature is also included in the CAD catalog as a parametric pattern.
After programming the first bionic features in CAD, CENIT is tackling another milestone in the project: Feature Recognition - a software tool that analyzes a topology-optimized component and assigns a functionally corresponding bionic feature from the CAD catalog to it as fully automatically as possible. With this functionality, feature recognition is therefore an important element in the design process of bionic ALM components.

Optimized data output and alignment of components for 3D printing
In addition to bionic design, aspects of print preparation (pre-processing) are also part of CENIT's range of tasks. The main focus here is on the CAD-based generation of the support structures of a component required for 3D printing and the optimum alignment of the components for printing.

To program the support structures in CAD, CENIT drew on the results of its research partner Fraunhofer IAPT: the institute carried out systematic investigations into criteria such as tensile strength, powder consumption and removability of the support structures and their influence on the surface and developed approaches for new support structures, such as a graded grid structure or a gyroid.

Using a large number of parameters that determine the alignment of a component for additive manufacturing, the CENIT experts also created functionalities based on CATIA for optimal, automated component alignment, including corresponding support structures. The ongoing goal of CENIT's project work is currently to output not only geometry data, but also attributes of the geometry (e.g. outer contour, surface quality, etc.) to the production process and to define the printing methods at the same time. In coordination with Aconity GmbH, CENIT is currently developing a direct CATIA interface for this purpose.

The ten partners in the consortium will present these and other results to the EU Commission at the halfway point of the Bionic Aircraft project in April 2018.