Effiziente Ermittlung von Resonanzamplituden für Schwingsysteme mit Anregung durch Piezoaktuatoren

When dealing with the numerical characterisation of vibration systems with excitation by piezo actuators, e.g. for ultrasonic assisted cutting, various expectations of technologists and users are to be met. As result of the characterization often following questions should be answered: - Which eigenmodes are suitable for a specific excitation?- Which vibration amplitudes arise at the drill bit or tool centre point at which excitation frequency? - How high is the electric impedance of the device? This paper shows how to automatically extract those eigenmodes from the multitude of eigenmodes, which can be efficiently excited by the applied piezo actuators. For this purpose a mapping of the eigenmodes of the short-circuited and the open-circuited piezo-mechanical model is done by the mod-al assurance criterion. Based on the piezo-actuator relevant eigenmodes the damping dependent resonance frequencies for mechanical (displacement, velocity, acceleration) and electrical quantities (charge or impedance) are estimated. These resonance frequencies can be used as additional frequency steps in a harmonic analysis. Thereby, the effective determination of interesting resonance amplitudes with a limited number of frequency steps is possible. The method is implemented by using ANSYS Mechanical APDL or ANSYS Mechanical Command Objects.