Experimental and Numerical Study on Efficient Forming Operations of Sheet-Metal-Compounds with Integrated Piezo-Modules

For the manufacturing of piezo-metal-compounds, forming strategies are presented that allow an integration of piezo-module application in the fabrication process. Specimens of sheet-metal-compounds with piezoceramic modules between double-layer-sheets were manufactured and investigated under different forming operations. Simultaneously a numerical study was performed to determine and predict the locations of high load levels. The modules are embedded in a semi-cured adhesive to reduce tensile stresses in the brittle piezo components due to contact pressure and friction between blanks and module in the forming operation. The functionality of the specimens is characterised by the measurement of module capacitance during the forming process as well as actor and sensor tests after forming. The methods provide cumulated values for the functionality. A prediction of the locations of module degradation and the leading influencing parameters are to be achieved by numerical investigations. It is shown that the functionality of integrated modules is fully maintained for bent specimen down to radii of 10 mm, for rectangular cups with a double curvature of 100 mm and 250 mm. Axisymmetric specimens with a punch radius of 50 mm cause damage and lower radii of 25 mm cause significant damage until breakdown depending on the draw depth.

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