This paper presents a new approach to the structural integration of piezoceramics into thin-walled steel components for condition-monitoring applications. The procedure for integrating the sensors into metal components is described, and their functionality is experimentally examined with a 2 mm-thick steel sheet. The signal quality of the produced sensors is investigated in a frequency range from 100 Hz to 50,000 Hz and is compared with the results of piezo patches and strain gauges under the same conditions. The results show that due to a higher signal-to-noise ratio and a better coherence, the structurally integrated piezoceramics and the piezo patches are more qualified sensors for vibration measurement in the examined frequency range than the strain gauges. The measurements also indicate that the patches provide higher amplitudes for the frequency range up to 20 kHz. Beyond that, up to 40 kHz, the integrated sensors supplied higher amplitudes. The better signal quality in different frequency ranges as well as the different manufacturing and application methods can be interpreted as an advantage or disadvantage depending on the boundary conditions of the condition-monitoring system. In summary, structural integrated piezoceramics extend the options of monitoring technology.

With a growing number of electronic devices surrounding our daily life, it becomes increasingly important to create solutions for clear and simple communication and interaction at the human machine interface (HMI). Haptic feedback solutions play an important role as they give a clear direct link and response to the user. This work demonstrates multifunctional haptic feedback devices based on fully printed piezoelectric transducers realized with functional polymers on thin paper substrate. The devices are flexible; lightweight and show very high out-of-plane deflection of 213 µm at a moderate driving voltage of 50 V_rms (root mean square) achieved by an innovative multilayer design with up to five individually controllable active layers. The device creates a very clear haptic sensation to the human skin with a blocking force of 0.6 N at the resonance frequency of 320 Hz, which is located in the most sensitive range of the human fingertip. Additionally the transducer generates audible information above two kilohertz with a remarkable high sound pressure level. Thus the paper-based approach can be used for interactive displays in combination with touch sensation; sound and color prints. The work gives insights into the manufacturing process; the electrical characteristics; and an in-depth analysis of the 3D deflection of the device under variable conditions

This paper presents a new approach to monitoring ultrasonic systems using structurally integrated piezoceramics. These are integrated into the sonotrode at different points and with different orientations. The procedure for integrating the piezoceramics into the sonotrode and their performance is experimentally investigated. We examine whether the measured signal can be used to determine the optimal operating frequency of the ultrasonic system, if integrating several piezoceramics enables discernment of the current vibration shape, and if the piezoceramics can withstand the high strains caused by the vibrations in a frequency range of approximately 20–25 kHz. The signals from the piezoceramic sensors are compared to the real-time displacement at different points of the sonotrode using a 3D laser scanning vibrometer. To evaluate the performance of the sensors, different kinds of excitation of the ultrasonic system are chosen.

Ultrasonic vibration assistance can significantly enhance the performance of manufacturing processes and reduce process limitations. Changing external loads during manufacturing, e.g., process forces or heat flow, require a continuous adjustment of the system’s operating frequency. Conventional approaches based on the readily available electrical signals of the ultrasonic transducer, like a phase-locked-loop approach, are effective but not ideal as the electrical signals are gathered far from the cutting edge. Since the resonance frequencies of the electrical and mechanical resonant circuit do not necessarily match, using signals based on mechanical quantities close to the cutting edge, like acceleration, might offer benefits regarding the current vibration behavior of the system. Therefore, a better control of the ultrasonic system during operation can be provided. In this work a control model for an ultrasonic system using signals based on the acceleration at the cutting edge is designed and evaluated. The data for the modeling of the ultrasonic system is obtained from experiments using an existing system. Two control algorithms, phase-locked-loop and autoresonant control, are modeled and adapted for using mechanical quantities as the input for the control model. The results show the differences between the resonance frequencies of the electrical and the mechanical resonant circuit. The findings support the benefits of using a control algorithm based on mechanical quantities to better control the process. Furthermore, larger displacements at the tool could be achieved using acceleration in the proposed control algorithms.

Ultrasonic vibration superimposed turning represents a highly efficient method for surface microstructuring, which enables a combination with finish machining. However, there are almost no industrial applications of this process due to the special kinematics. Furthermore, the effects of the varying cutting conditions combined with the tool geometry on the resulting surfaces and process stability are not yet fully understood. In experimental investigations, specimens consisting of bronze (CuSn7Pb15-C) are machined by ultrasonic vibration superimposed turning. The influence of the geometry of the MCD-tipped indexable inserts on the surface microstructure is analyzed. Indexable inserts with different rake angles (0°, −10°, and −20°) and artificially generated flank wear lands (widths 50 µm and 100 µm) are used. Moreover, the influences of the cutting speed (120 m/min, 480 m/min) and the feed (0.05 mm, 0.1 mm) are analyzed. While machining, the strain of the sonotrode is detected by an integrated fiber Bragg grating. Subsequent to machining, geometrical surface properties are determined by SEM and 3D surface analysis using focus variation. Furthermore, kinematic simulations are realized, enabling the comparison with the generated surfaces. Generally, there is a high concordance between the simulated and the generated surfaces. However, in particular when the tool flank face gets in contact with the specimen, deviations are visible, especially the formation of burr. Summarized, the research improves the understanding of the mechanisms in ultrasonic vibration superimposed turning and the formation of the surface microstructures.