Piezo-Metal-Composites as Smart Structures

Abstract

In many applications, vibration and noise are unwanted, but often inevitable. For instance, for passengers in an automobile, a reduction of comfort for the passenger is a result. For products like high precision machine tooling, the appearance of unwanted vibrations can cause negative influences on the quality of produced parts. Adaptronic devices can help to improve the vibration and noise behaviour of structures. Today the production of adaptronic structures consists of two process chains: Firstly, the fabrication of structural parts which occurs in a very efficient process with a low production time. Secondly, there is the functional integration step which normally takes place under laboratory conditions and needs a lot of production time. For creating a smart structure, the assembly of the structural part includes the use of a piezo-composite-module. The authors propose a new process chain for this with the material fabrication and functional integration taking place in one process. This can occur through a laminar piezo-module being inserted between two metal sheets and fixed by using a slow curing adhesive. After assembling the sandwich, the semi-cured adhesive allows forming of the sandwich with a reduced generation of tensile loads due to friction between the metal sheets and the piezo-module. As a last step in the process chain, the adhesive fully cures and giving a high stiffness coupling . Experimental tests have been performed to characterize the functionality and to examine the process limits. Numerical studies have evaluated the stresses and strains in the piezo-module during the forming.