Multifunctional materials stand out because they do not only fulfill a single essential function of a system,but several, such as holding, moving, deforming or even altering a structure. This multifunction is controllable and reversible by external variables. Such materials include, but are not limited to, shape memory alloys, piezoelectric materials, and electroactive polymers. These materials are commonly referred to as "functional materials" or "smart materials".
Some of these materials have been developed for several decades and are used industrially (e.g. piezoelectric accelerometers), while others are still under development, particularly in terms of properties optimisation and large-scale manufacturing and application (e.g. shape memory actuators).
Due to the function integration of multifunctional materials, their application in the redesign of existing and the design of new technical systems can reduce the number of components, space and weight of such systems. However, sufficient knowledge of the material and component behavior is a prerequisite for such design. Therefore, we are engaged in research and teaching with the modeling of multifunctional materials, the components based on them and the total resulting systems. We focus our topics on materials that can be used in actuators:
Shape-memory actuators are based on metals or plastics which material structure can be reversibly changed by temperature or magnetic fields. The change in the material structure in turn results in a change in shape and/or a force effect. Actuators with a comparatively high energy density can be constructed in interaction with external loads. The interplay of material conversion and external variables (temperature, magnetic field, force) might be quite complex. We develop models that sufficiently describe the function of components and that can also be employed for control. These models are validated using prototypes and experiments.