Simulation supported manufacturing of profiled composite parts using the braiding technique

Kurzfassung

Composite materials have brought new development and sizing possibilities for structural components in transportation systems. Their high specific material properties are enabling weight reduction while increasing structural performance. On the downside, composite materials are generally related to high material and manufacturing costs and increased characterization efforts. Through the braiding technique, profiled structures can be manufactured in a highly automated and reproducible process. Moreover, braided composites can absorb more energy compared to their unidirectional or woven counterparts. In this paper, we describe the development and validation of a simulation framework as sustainable alternative to material- and cost-intensive experimental testing. Our work aims at considering the influence of manufacturing effects and textile architecture on the material properties and therefore at increasing the reliability of structure sizing. As validation basis, flat specimens of biaxial and triaxial braided composites are first manufactured and tested under quasi-static loading. We then develop a digital twin of the braiding process and its material characterisation. Within this framework, the braid’s textile architecture is predicted with multiple finite-element simulations at the mesoscopic scale. The numerical predictions show the strong influence of braiding angle and braiding core diameter on the textile architecture and consequently on the material properties. More particularly, crucial effects with negative impact on the mechanical properties (presence of gaps or yarn locking) are highlighted. On a pure numerical basis, we finally calculate the process window for braided structures, which links the process parameters to the resulting material properties. The present approach is a crucial step toward the reduction of experimental investigations in early development.