Fiber-reinforced rubber composites with integrated shape memory alloy (SMA) actuator wires present a promising approach for the creation of soft and highly elastic structures with adaptive functionalities for usage in aerospace, robotic, or biomedical applications. In this work, the flat-knitting technology is used to develop glass-fiber-reinforced fabrics with tailored properties designed for active bending deformations. During the knitting process, the SMA wires are integrated into the textile and positioned with respect to their actuation task. Then, the fabrics are infiltrated with liquid silicone, thus creating actively deformable composites. For dimensioning such structures, a comprehensive understanding of the interactions of all components is required. Therefore, a simulation model is developed that captures the properties of the rubber matrix, fiber reinforcement, and the SMA actuators and that is capable of simulating the active bending deformations of the specimens. After model calibration with experimental four-point-bending data, the SMA-driven bending deformation is simulated. The model is validated with activation experiments of the actively deformable specimens. The simulation results show good agreement with the experimental tests, thus enabling further investigations into the deformation mechanisms of actively deformable fiber-reinforced rubbers.
The process of integrating smart materials into fiber-reinforced plastics has been used increasingly to create different high-performance products for lightweight applications. This paper presents the development of an adaptive morphing wing based on fiber-reinforced plastics with shape memory alloys integrated into the reinforcing fabrics. Two types of preforms with varying numbers of integrated weft yarns in shape memory alloys were manufactured for a wing structure on a weaving machine using the pleated woven fabric technology. Subsequently, the realized preforms were infiltrated by a thermoset matrix and characterized mechanically to derive a preferred variant. After developing the adaptive morphing wing, its deformation behavior was characterized by varying current flow and time through shape memory alloys. Results revealed that maximum deformation of the investigated adaptive morphing wing was achieved at a current flow and time of 1 A and 60 s, respectively.
23 February 2016 in Smart Materials and Structures
Textile-based lightweight structures offer various possibilities for the design of tailored structures by the selective choice of materials and their processing into textile semi-finished products and fiber-reinforced plastics. Lightweight structures with a high mechanical load capacity are feasible by developing fiber-reinforced plastics with adaptive properties that are able to adapt their characteristics, e.g. geometry or stiffness, to external influences. Thus, the application potential of fiber-reinforced plastics can be further expanded. In this paper, we present novel adaptive fiber-reinforced plastics based on textile semi-finished products with integrated shape memory alloys and their mechanical characterization. The shape memory alloy is textile technically integrated and converted into friction spun hybrid yarn. Next, the produced hybrid yarn is integrated with plain, twill and satin woven reinforcement fabric in the weft direction during the shedding operation in weaving. Adaptive fiber-reinforced plastics are developed by infusing textile semi-finished products. Subsequently, the mechanical characterization of the adaptive fiber-reinforced plastics is carried out. Results show that, by integrating shape memory alloys into adaptive reinforced fabrics, the mechanical performance of fiber-reinforced plastics can be tailored.