Design methods for novel, energy-efficient, closed phase change actuators with high action of force

• Applicant: Professor Dr.-Ing. Peter Groche
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing
• Term: since 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 386708634

In the context of automated process chains in Industry 4.0, the adjustability of machines and processes to changes in environmental conditions is of major importance. Disturbances have to be adjusted and changes in temperature or wear compensated. Otherwise, these may cause a superordinate impairment of the process chain. Here, besides sensors, actuators are of central importance. For integration in a wide variety of systems and installation situations, a compact and robust design is necessary. In addition, significant forces are required to achieve effective actuation movements in highly rigid systems.In the first phase of the research project, the principles for the design and implementation of the paraffin-based phase change material actuator in a closed housing design were defined. A housing consisting of two deep drawn cups, which is sealed by a cutting seal and joined by laser welding, was developed. The encapsulated paraffin wax generates the required actuating forces of more than 50 kN by means of heat supply. A previously developed self-locking wedge gear sustains these forces when the energy supply is stopped. Design guidelines were derived for the actuator and numerical models for predicting the actuator behavior based on the characterized material behavior of paraffin wax were created. Furthermore, a production chain was implemented. In general, the unique potential of the phase change actuator for influencing highly rigid systems was identified.The second project phase aims at deepening the understanding and the systematic further development of the identified potentials. For this purpose, the linearization of the characteristic curve field of the phase change actuators is to be implemented. A variety of approaches, e.g. the adaptation of housing design and material or the development of modified paraffin compositions, will be investigated. The second main topic is the development of double-acting phase change actuators. These have an advanced wedge gear, which enables a return stroke by separate heating zones and paraffin chambers. For this purpose, active heating concepts for controlled movements will be developed. The third key objective is to adapt the entire actuator concept to further housing geometries, such as a circular ring geometry. This geometry can be used as an active washer for tensioning screw connections. Concluding, the findings are implemented on three demonstrators, which also highlight the further potential for usage.In its entirety, the present research project represents the necessary second step towards qualifying the expansion actuator for general application.

• DFG Programme: Research Grants