The novel woven spacer fabrics consist of upper and lower layers which are connected through internal crosslinks. The aim is to weave spacer fabrics with woven crosslinks in a single production step as near net shape sandwich preforms. By this way reproducible and automated manufacturing of sandwich preforms for composites are realized. The paper deals at first with the conception of a new weaving and take-up technology of complete spacer fabrics without subsequent textile assembly processes. Afterwards, the special technology is described, and finally the paper deals with a simulation model for the prediction of dynamic warp thread forces in order to minimize fiber damage during weaving process.

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Polylactic acid (PLA) is a widely used biomaterial in medical applications as a biodegradable and renewable aliphatic polyester type of material. This material is often subjected to different defects and damages from in-service and manufacturing conditions, and the increasing demand for PLA for different applications requires a thorough understanding of its fracture behavior. In this work, a numerical and experimental study of the mixed-mode fracture behaviors of three-dimensional (3D)-printed PLA samples with a zigzag pattern of different filling ratios was performed using a recently developed special loading fixture. The 3D-printed samples were produced with a 200°C nozzle at 60°C bed temperature and 50 mm/s printing speed. Mixed-mode fracture tests from pure tensile to pure shear loading were performed by varying the loading angle, α, from 0 to 90°. Finite-element analyses were conducted by using the Abaqus software program, and geometrical factors were obtained at different loading angles. As a result, the fracture toughness values of pure tensile loading, pure shear loading and mixed modes were determined.

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