Fluid-Structure Interaction Modeling for an Optimized Design of a Piezoelectric Energy Harvesting MEMS Generator

I. Kuehne[1], A. van der Linden[2], J. Seidel[1], M. Schreiter[1], L. Fromme[2], and A. Frey[1]
[1]Siemens AG, Corporate Research & Technologies, Munich, Germany
[2]Comsol Multiphysics GmbH, G├Âttingen, Germany

This paper reports the design of a piezoelectric energy harvesting micro generator for an energy autonomous tire pressure monitoring wireless sensor node. For our design we use a piezoelectric MEMS generator approach without additional mass. The intrinsic mass of the cantilever is in the microgram region and the resulting acceleration forces are very small.

The generator has a triangular shape to enable a uniform stress distribution in the horizontal surface direction. The cantilever consists of a carrier layer realized in silicon and a piezo layer. The carrier layer serves three purposes: it provides mechanical stability of the structure, it contains the neutral axis and it is used as a storage element for the harvested mechanical energy.

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