Since September 2016, IT and software provider CENIT has collaborated with nine international industry and research partners in the EU’s “Bionic Aircraft” project, developing new methods and concepts for additive aircraft design and manufacturing. The overarching goal of this research work is to advance resource efficiency. To do this, the primary aim of CENIT’s tasks is to simplify the design process for lightweight bionic structures.
Core aspects of CENIT’s approach include an automated design methodology and a tool for direct generation of specific file formats for 3D printing. The project partners have set themselves the goals of slashing the time needed for end-to-end development of bionic components by about 40% and significantly increasing the weight-saving potential of ALM structures.
An ambitious endeavor that is producing the first results: To create bionically optimized components, CENIT engineering team is developing a CATIA-based CAD catalog of parametrically defined bionic features.
“This provides an automated toolbox to support the cost- and time-intensive manual interpretation and design of topologically optimized components in CAD,” says Jochen Michael, Senior Consultant at CENIT, in explaining the objective. “The parametrization of features also lets the designers adjust geometries more easily. That gives us an additional efficiency and quality boost during the design process.”
By the end of the Bionic Aircraft project in August 2019, a CAD catalog containing about 10 to 15 bionic features is expected.
“The declared goal of the project is to show how such a catalog can be implemented in methodological and practical terms. That places the focus on fundamental research. It has to provide a basis for defining how bionic features can be harnessed to guide topological optimization, and what algorithms are best suited to component recognition and allocation of features,” says Michael. With this research, the project partners are breaking new ground – to date, no CAD program contains bionically optimized features.
For expertise on the nature, suitability and functionality of the bionic features integrated into CAD, the project is relying on experts from the Fraunhofer Institute for Additive Production Technologies, IAPT. Based on analyses of qualitative characteristics, uses, and benefits of topology-based components, they develop the respective bionically optimized features. The aim is to improve the typical behavior of components in everyday use and to make them as lightweight and stable as possible. An example of how even minor adjustments can achieve a significant effect: The risk of component failure can be significantly reduced if components subject to tension loads are designed with fillets which replicate models found in nature. Thus, such a feature will be included in the CAD catalog as a parametric model.
After programming the first bionic features in CAD, it will be time to tackle the next project milestone: Feature recognition. This is a software tool that analyzes a topologically optimized component and allocates it – if possible, automatically – to a functionally equivalent bionic feature contained in the CAD catalog. This capability makes feature recognition an important element in the design of bionic ALM components.
In addition to bionic design, the work package also involves print preparation (pre-processing) aspects. Here, the main focus is on CAD-based generation of the support structures needed for 3D printing and optimum alignment/orientation of components prior to printing.
To develop the support structures, Fraunhofer IAPT was indispensable. The institute conducted systematic studies on criteria such as tensile strength, powder consumption as well as removability of support structures and their influence on component surfaces. It also developed approaches to designing new types of support structure, e.g. graded lattice scaffolds or gyroids.
Based on the parameters needed to determine the orientation of a component for additive layer manufacturing, CENIT’s experts worked with CATIA to also develop functions for optimal, automated alignment of components, including the required support structures. This type of project work is now focused on supplying the production process not only with geometry data but also with geometry attributes (e.g. external contour, surface quality, etc.) as well as defining printing methodologies.
Filed Under: 3D printing • additive manufacturing • stereolithography, Design World articles