Long-fiber thermoplastic (LFT) materials compounded via the direct LFT (LFT-D) process are very versatile composites in which polymers and continuous reinforcement fiber can be combined in almost any way. Polycarbonate (PC) as an amorphous thermoplastic matrix system reinforced with glass fibers (GFs) is a promising addition regarding the current development needs, for example battery enclosures for electromobility. Two approaches to the processing and compression molding of PC GF LFT-D materials with various parameter combinations of screw speed and fiber rovings are presented. The resulting fiber lengths averaged around 0.5 mm for all settings. The tensile, bending, Charpy, and impact properties were characterized and discussed in detail. Special attention to the characteristic charge and flow area formed by compression molding of LFT-D materials, as well as sample orientation was given. The tensile modulus was 10 GPa, while the strength surpassed 125 MPa. The flexural modulus can reach up to 11 GPa, and the flexural strength reached up to 216 MPa. PC GF LFT-D is a viable addition to the LFT-D process, exhibiting good mechanical properties and stable processability.
Programmable materials are a novel development, in which specialized production processes are used to introduce a framework of information capabilities into the inner structure of materials. Since the design and fabrication of programmable materials are still challenging, this aims to introduce a design and fabrication concept to pave the way toward industrial application. Herein, complex shape morphing has been implemented in the sense that the shape changes in response to external conditions, following a predefined program. First, the feasibility of a fabrication concept for uniform metamaterials with auxetic behavior is presented. A material with a predetermined nonuniform inner structure that deforms to a symmetrical shape has been developed and fabricated according to this concept. More complex behavior can be implemented by facilitating optimization methods to find inner structures according to a target shape. Lastly, an optimized and producible design for asymmetrical shape morphing is described to demonstrate the applicability of the approach.
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