Papers by Author: Michael Krommer

Abstract: This paper is concerned with the discussion of a general methodology to design continuously distributed strain sensors; the latter are also known as spatial filters. The methodology is based on the application of the principle of virtual work. Hence, solutions for the design problem can be computed from static auxiliary problems; yet, they are valid for actual dynamic problems as well. Moreover, the use of the principle of virtual work enables a simple and straightforward translation of the results to a structural level. Different types of spatial filters, such as modal filters, displacement filters and compatibility filters are presented and their use for structural and health monitoring is discussed. Some illustrative examples for each type of spatial filter are presented, in which piezoelectric sensor networks are used to put the filters into practice; in each example experimental results validate the presented design methodology.

Abstract: The present contribution gives an overview on own research that has been performed from 2008 to 2011 in Area 2, Mechanics and Model Based Control, of the COMET K2 Austrian Center of Competence in Mechatronics (ACCM), which is situated at the Science Park of the Johannes Kepler University of Linz. Area 2 is motivated by the fact that mechanics and control both are rapidly expanding scientific fields, which share demanding mathematical and/or system-theoretic formulations and methods. The goal of Area 2 has been to utilize and extend these relations, with special emphasis on solid mechanics and control methods based on physical models. Some corresponding results will be reviewed subsequently with respect to the mechanical modelling of structures, robots and machines, and with respect to the corresponding model based control as linear/non-linear lumped/distributed parameter systems. Due to limitations in space, the present review restricts itself to work of Area 2 that has been directly performed at the University of Linz. The review contains 118 references to works on mechanics and model based control.

Abstract: This paper is concerned with the design of a proper piezoelectric patch actuator network in order to track the displacement of the sidewalls of a one-story frame structure; both, for the static and the dynamic case. Weights for each network member found in our previous work were based on beam theory; in the present paper a refinement of the weights by modeling the sidewalls of the frame structure as Kirchhoff plates is presented. For the sake of calculating the refined weights approximate solutions of the plate equations are calculated by an extended Galerkin method.

Abstract: Smart structures, which are equipped with piezoelectric actuators and sensors, and which involve automatic control, represent an important branch of Mechatronics. This paper gives a review over own research on smart structures, which has been performed during the last decade based on the principles of analogy and interdisciplinarity. The latter principles form a research strategy, which seems to be perfectly suited in order to answer the innovation request in Mechatronics, namely to decrease the time-lag between consecutive steps in the scientific development, and to keep fundamental and applied research in close co-operation. We start our report with a short excursion into the history of engineering sciences, in order to demonstrate this time-lag, where we use the history of elastic and piezoelastic plates as an example, and we discuss the notions of analogy and interdisciplinarity as means to systematically decrease the timelag. In our own work, we particularly have used an eigenstrain analogy as guideline. In the light of this analogy, various own works in the following fields are reviewed: Accurate electromechanically modeling; dynamic shape control by piezoelectric actuation and sensing; extension of dynamic shape control to closed loop control and active noise cancellation.