Development and characterization of textile-processable actuators based on shape-memory alloys for adaptive fiber-reinforced plastics

Abstract

Fiber-reinforced plastics (FRPs) with adaptive properties make lightweight structures feasible that not only possess a high mechanical force absorption but are also able to adapt their mechanical characteristics, such as geometry and rigidity, to external influences. Within the framework of the basic research presented here, new adaptive FRPs are developed on a basis of textile reinforcement semi-finished products integrated with actuators made from shape-memory alloys (SMAs). The realization of adaptive FRPs requires not only knowledge of the material-specific actuatory properties of the functional materials. It also necessitates the development of textile-technical solutions fully exploiting the actuatory potential of the SMAs within the composite. Promising approaches are hybrid yarn structures based on friction spinning technology. In order to reduce the great experimental effort, modeling and simulation of the SMA's material behavior and of the adaptive FRPs' complex composite behavior are carried out by means of finite element methods. It is shown that the developed actuators generate sufficiently high tensions of about 700-800 N/mm 2 , to bend the FRP specimen up to 45 .In comparison to conventional isotropic materials such as metals, lightweight constructions from fiber-reinforced plastics (FRPs) have many advantages with regards to the design of material properties. A purposeful alignment and array of the reinforcement thread layers permits the local and global suitable adjustment of strength and rigidity in the FRPs. The applicationoriented material characteristics of FRP composites enable the material and energy-efficient realization of components used in vehicle and aerospace engineering, in the field of regenerative energies, for example, as highly resilient rotor blades in wind power plants.Apart from the possibility to purposefully realize mechanical gradient properties in the reinforcement textile and the composite component by integrating functional threads, the principle of laminated layer construction of FRPs promises great potential in the functionalization of lightweight structures and components. 1-3 By integrating functional elements in the form of sensors and actuators in or between the individual reinforcement layers and the thereby realizable active functional constructions, the high performance already achieved by FRPs can be considerably increased. The integration of actuatorily operating materials allows for the execution of FRPs whose properties can be set selectively, for instance in order to

Bio-inspired semi-flexible joint based on fibre-reinforced composites with shape memory alloys

“…Due to their high specific energy density, they are well-suited for application as artificial muscles within smart structures. Previous work has shown the potential of such structures (Ashir et al, 2017; Kluge et al, 2013), which is mainly based on the good processability of SMA wires on textile machines. The actuator wires can be integrated directly into the reinforcement textiles during the textile forming process (Ashir et al, 2016).…”

Development and testing of controlled adaptive fiber-reinforced elastomer composites

“…The covering is done with a DREF friction spinning machine. Details for this preparation and material specifications can be found in Kluge et al 24,25 The reinforcement textile in this study is a single-layer plain glass fiber weave, in which the covered SMA wires are integrated as weft yarns. In the resulting fabric, the SMA wires are on the upper side of the fabric with a distance of 8.2 mm between the SMA wires.…”

Development and mechanical properties of adaptive fiber-reinforced plastics

“…The use of SMAs as actuators in FRPs, which aims at creating adaptable component parameters, has been a recent international research focus within the composite community [8–16]. Essential goals are the adjustment or control of the component shape, the variation of mechanical properties (such as rigidity) and active vibration dampening.…”

“…The advantage of integrating SMAs into reinforced fabrics in FRPs lies in the fact that they are commercially available in wire form with different diameters. In previous works [5,13–18] carried out by the authors, the modelling and simulation for the actuation behavior of SMAs in AFRPs as well as the development and electro-mechanical characterization of adaptive 3D FRPs were executed. In the case of these AFRPs, SMAs were integrated into reinforced fabrics using the tailored fiber placement method.…”