A Posterior Adaptation of the Stiffness of Compliant Mechanisms

• Applicant: Professor Dr. Alexander Hasse ; Technische Universität Chemnitz; Institut für Konstruktions- und Antriebstechnik; Professur Maschinenelemente und Produktentwicklung
• Subject Area: Engineering Design, Machine Elements, Product Development
• Term: since 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 418362853

Compliant mechanisms use the deformability of their material to achieve a predefined motion rather than using sliding and rolling components as it is the case with conventional mechanisms. The functional principle requires that strain energy is stored when a compliant mechanism is deflected. With a defined amplitude of movement, the value of the strain energy is determined by the structural stiffness of the mechanism. From the application point of view, the latter is in a field of tension: On the one hand, there are applications in which the stiffness is desired, e.g. with tweezers to generate a restoring force; On the other hand, the stiffness reduces the efficiency of the mechanism during an energy transfer from the mechanism input to the output.Once a compliant mechanism is designed and manufactured, it usually has a defined stiffness. If the mechanism is to be used in different applications with different stiffness requirements, the result is a suboptimal system behavior. There are also applications in which the stiffness is completely undesirable, but this cannot be avoided due to the aforementioned functional principle of compliant mechanisms. It would therefore be advantageous to be able to adjust the stiffness of an existing compliant mechanism a posteriori. The approaches described in the literature in the field of compliant mechanisms partially rely on the targeted introduction of prestresses through force loading of the mechanism. However, the determination of the load is usually based on experience and intuition. With this project we aim to develop an optimization-based method to determine preload forces for the defined adaptation of the stiffness of existing compliant mechanisms.

• DFG Programme: Research Grants