In many scopes of application, efficiency, performance and comfort of technical products depend on the current operating situation. In order to improve the efficiency or the comfort of products, an adaptability to an individual situation could be useful. To conventionally implement an adjustment function in products, components, such as mechanics, motor and gearbox are required. Normally, both, the additional volume, the so-called installation space, and additional mass have a significant negative effect on the overall product performance and create additional costs. Frequently, companies across many industry sectors are under high pressure to improve their products’ performance.
The technology of active hybrid composites is able to open up new potential for different applications in many industries. Active hybrid composites combine the advantages of technical polymers with modern solid-state actuators, the so-called shape memory alloys. Shape memory alloys are smart metals whose shape can be adjusted in a controlled manner by temperature change. Due to the direct integration of the actuator – the shape memory alloy wires – into a plastic part, the actuator system is transferred into the hybrid structure which makes an active shape adaptation of the component possible. Hence, new adjustment functions combined with minimal space, lowest weight, gap-free and kink-free contour are possible.
Within the framework of EXIST research transfer project and promoted by BMWi, since end of 2017 (probably until end of 2020), the spin-off CompActive has been working on the further development of the active hybrid composites’ technology. The aim is reaching market maturity, even for high volume applications. The initial 24-months funding period was extended by eight months. Hence, additional time, material and human resources are available to the CompActive Team to push the development of the technology forward and to prepare the equipment that is needed for a series production of the actuation modules.
Since project launch, important development steps in terms of actuation module construction and series production process have been made.
The CompActive actuation module essentially consists of various components:
- a shape memory alloy grid, consisting of shape memory alloy wires and brass anchors
- two anchor clips, placed at the end of the modules, as well as
- an elastomer layer in the middle.
These components are connected in an automatic sewing process. Particularly, in the manufacturing of shape memory alloy grids, in using anchor clips and in the sewing process, improvements in terms of productivity, reproducibility and quality assurance could be achieved. The new – embossed – SMA-Grid simplifies the handling and offers different ways of electrical connection, for example by soldering, crimping, welding or connecting via plug-ins.
The usage of customized anchor clips, which will be manufactured by injection moulding process in the future, enables additional joining technologies between actuation module and component. Thus, easy-to-build positive connections, such as riveting, bolts or plug-ins without additional expenses can be realized without greater effort. Due to the increased flexibility and a clever connection design between component and actuation module, steel sheets used as substrate are now possible, for example, in addition to fiber-reinforced or pure polymers.
Some parts of the equipment for the production of actuation modules are already available in the laboratories of IVW. Thanks to the increased funding, the procurement of a plant to manufacture the anchors, and an injection moulding unit to manufacture the anchor-clips is possible. Also, a test rig for actuators is already running. First actuators passed 200,000 cycles and keep running.
Dr.-Ing. Moritz Hübler
Institut für Verbundwerkstoffe GmbH
Tel.: +49 631 2017 443