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Additive manufacturing of active struts for piezoelectric shunt damping

: Mayer, Dirk; Stoffregen, Hanns Alexander; Heuss, Oliver; Pöllmann, Jennifer; Abele, Eberhard; Melz, Tobias

25th International Conference on Adaptive Structures and Technologies, ICAST 2014 : The Hague, The Netherlands, 6 - 8 October 2014
Red Hook, NY: Curran, 2015
ISBN: 978-1-63439-808-4
International Conference on Adaptive Structures and Technologies (ICAST) <25, 2014, The Hague>
Conference Paper
Fraunhofer LBF ()
active struts; piezoelectric shunt damping; additive manufacturing

Nowadays a lot of structures, like ships, aircrafts, wind turbines and engines are designed as lightweight structures. They are susceptible to disturbances caused by vibrations and other mostly unwanted excitations. Hence the performance, lifetime and system behavior of the structures are negatively influenced. One strategy to overcome these drawbacks might be an integration of actuators in such a system. As smart devices piezoceramic multilayer actuators (MLA) can be used. They offer the possibility of high level system integration and can generate strong forces. For low-cost system control, semi-passive or-active techniques can be used. The performances of both strategies depend mainly on the ratio of energy which can be transformed from the mechanical structure into electrical circuits. The generalized electromechanical coupling coefficient, a common measure describing this energy transfer, is highly influenced by the host structure's stiffness or the housing. Thus, a flexible and adjustable manufacturing technology is needed to optimize this generalized coupling factor. Emerging additive manufacturing technologies such as selective laser melting (SLM) are capable of a cost-efficient production of individualized parts in rather small production runs and to meet the manufacturing constraints of highly integrated components. In the presented research work SLM is used to manufacture active struts by fully integrating MLA into a metallic, monolithic housing. Besides the fulfillment of associated manufacturing constraints (e.g. low volume, individualization), a major objective of this study is to demonstrate the potential of SLM for application tailored smart components. A six cell truss structure is used as demonstration platform. Based on the numerical simulation of the truss structure and the application of the elastic strain intensity criterion the positioning of the active strut as well as the mode to be damped are determined. A numerical implementation of the active strut, specifically the piezoceramic actuator and corresponding housing, allows the dimensioning of the housing stiffness using the generalized electromechanical coupling factor criterion and are a starting point in the design of a resistive resonant shunt (RL-shunt). Using the results from the numerical simulation active struts with specific stiffness characteristics are manufactured via SLM. An experimental modal analysis of the truss structure is carried out. Measurements with connected RL-shunts using the active struts are performed and compared to the passive system. Results indicate an efficient damping of the desired mode by means of application tailored active struts. In addition, a good accordance between simulation and experimental results is obtained. This allows rapid design and positioning of active struts and corresponding RL-shunts for future work.