Actuators in fibre-elastomer composite

Researchers at TU Dresden want to develop „a completely new class of materials“ in which actuators and sensors are integrated directly into flexible fibre-elastomer composites. Up to now, actuators and sensors have had to be placed retrospectively, which has led to limitations in many applications.

Fibre composites become self-sufficient

In order to change this, the German Research Foundation (DFG) has approved the second phase of a research training group "Interactive Fibre-Elastomer Composites" at the TU Dresden in collaboration with the Leibniz Institute of Polymer Research. In addition to material and project funding, a total of 22 doctoral students are supported in eleven interdisciplinary sub-projects.

The result should be a simulation-supported development of intelligent material combinations for self-sufficient fibre composites. Actuators and sensors are already integrated into the structures and are no longer placed afterwards, as was previously the case.

Ionic and helical actuator-sensor concepts

In the first research phase, important foundations have already been laid for materials in soft, bionic structures that are capable of large-scale two-dimensional deformation. Building on this, the second research phase will focus on ionic and helical actuator-sensor concepts. Combined with intelligent design and control algorithms, self-sufficient, three-dimensionally deformable material systems will be created. This will make these systems more robust and complex deformation patterns can be customised at the desired location - reversible and contactless.

Coordinator Johannes Mersch explains the technological approaches in the second project phase as follows: „Ionic actuators are electroactive materials. When a voltage is applied, ions move back and forth in the material, resulting in a change in volume. Our aim is to produce these structures as a yarn. In addition, a sensor layer is planned with which the actuators can monitor and regulate themselves.

The planned spiral shape for sensors and actuators has the same aim. However, this helix structure is based on different principles. „The actuator principle is that of a dielectric elastomer actuator, i.e. two conductive electrodes and a dielectric between them. When a high voltage is applied, they deform significantly. However, the helical structure means that unconventional materials can also be used that are not actually stretchable enough.

Fibre-elastomer composites in moving components

Fibre composites are increasingly being used in moving components due to their high specific stiffness and strength and the ability to tailor these properties. The integration of adaptive functions in such materials eliminates the need for the subsequent placement of actuators. This significantly improves the robustness of the system. Textile-based actuators and sensors are particularly promising in this respect, as they can be integrated directly into the fibre composites during the manufacturing process.

Interactive fibre-elastomer composites are predestined for numerous fields of application in mechanical and vehicle engineering, robotics, architecture, orthotics and prosthetics. Examples include systems for precise gripping and transport processes, for example in hand prostheses, or adaptive components such as trim tabs for land and water vehicles.

Source: K-Zeitung - Das Branchenblatt der Kunststoffindustrie vom 01.12.2022