TY - JOUR AB - Abstract:Since fine powders tend strongly to adhesion and agglomeration, their processing withconventional methods is difficult or impossible. Typically, in order to enable the handling of finepowders, chemicals are added to increase the flowability and reduce adhesion. This contributionshows that instead of additives also vibrations can be used to increase the flowability, to reduceadhesion and cohesion, and thus to enable or improve processes such as precision dosing, mixing,and transport of very fine powders. The methods for manipulating powder properties are describedin detail and prototypes for experimental studies are presented. It is shown that the handling of finepowders can be improved by using low-frequency, high-frequency or a combination of low- andhigh-frequency vibration. AU - Dunst, Paul AU - Bornmann, Peter AU - Hemsel, Tobias AU - Sextro, Walter ID - 9991 JF - Actuators 2018, 7(2). KW - powder handling KW - flowability KW - dosing KW - transport KW - mixing KW - dispersion KW - piezoelectricactuators KW - vibrations TI - Vibration-Assisted Handling of Dry Fine Powders ER - TY - CONF AB - A measurement method is presented that combines the advantages of the multisine measurement technique with a prediction method for peak bending behavior. This combination allows the analysis of the dynamic behavior of mechanical structures at distinctly reduced measurement durations and has the advantage of reducing high excitation impacts on the structure under test. AU - Sprock, Christian AU - Sextro, Walter ID - 9889 KW - bending KW - dynamic testing KW - measurement KW - structural engineering KW - vibrations KW - measurement durations KW - mechanical structures KW - multisine measurement technique KW - nonlinear peak bending behavior KW - prediction method KW - time-efficient dynamic analysis KW - Heuristic algorithms KW - Nonlinear systems KW - Oscillators KW - Time measurement KW - Time-frequency analysis KW - Vibrations T2 - Instrumentation and Measurement Technology Conference (I2MTC) Proceedings, 2014 IEEE International TI - Time-efficient dynamic analysis of structures exhibiting nonlinear peak bending ER - TY - CONF AB - Several positioning tasks demand translatory drive instead of rotary motion. To achieve drives that are capable e.g. to drive the sunroof of a car or to lift a car's window, multiple miniaturized motors can be combined. But in this case many other questions arise: the electromechanical behavior of the individual motors differs slightly, the motor characteristics are strongly dependent on the driving parameters and the driven load, many applications need some extra power for special cases like overcoming higher forces periodically. Thus, the bundle of motors has to act well organized and controlled to get an optimized drive that is not oversized and costly. AU - Hemsel, Tobias AU - Mracek, Maik AU - Wallaschek, Jörg AU - Vasiljev, Piotr ID - 9519 IS - Vol.2 KW - drives KW - electromechanical effects KW - linear motors KW - ultrasonic motors KW - car sunroof KW - car window KW - electromechanical behavior KW - high power ultrasonic linear motors KW - multiple miniaturized motors KW - positioning tasks KW - translatory drive KW - Costs KW - Electromagnetic forces KW - Frequency KW - Laboratories KW - Manufacturing KW - Mechatronics KW - Micromotors KW - Ultrasonic imaging KW - Vibrations KW - Voltage SN - 1051-0117 T2 - Ultrasonics Symposium, 2004 IEEE TI - A novel approach for high power ultrasonic linear motors VL - 2 ER - TY - CONF AB - Piezoelectric transformers are well known since the publication of some patent applications at the end of the 1950s. But until today their only business use lies in the field of backlighting systems for LCDs. Due to key features as light-weight, flatness, high step-up at low volume and high efficiency piezoelectric transformers should be usable in a much broader range of applications. This contribution returns to mind their operating principle, shows how to model and to develop such devices as well as give some aspects for development trends that will lead to further applications. AU - Hemsel, Tobias AU - Littmann, Walter AU - Wallaschek, Jörg ID - 8926 IS - vol.1 KW - piezoelectric devices KW - reviews KW - transformers KW - backlighting systems KW - flatness KW - high efficiency piezoelectric transformers KW - high step-up KW - light-weight KW - low volume KW - operating principle KW - piezoelectric transformers KW - Circuits KW - Costs KW - Electromagnetic devices KW - Electromagnetic fields KW - Mechanical energy KW - Piezoelectric materials KW - Power electronics KW - Switching frequency KW - Transformers KW - Vibrations SN - 1051-0117 T2 - Ultrasonics Symposium, 2002. Proceedings. 2002 IEEE TI - Piezoelectric transformers - state of the art and development trends VL - 1 ER - TY - CONF AB - Ultrasonic linear motors have now been investigated for several years. Their key features are high thrust forces related to their volume and good position-accuracy. This contribution consists of two main parts. In the first part we describe the state-of-the-art of linear piezoelectric motors. Characteristics like no-load velocity, maximum thrust force and other technical properties of commercially available devices will be reported as well as those of prototypes. In the second part we report an ongoing research and development project aiming at a linear piezoelectric motor, which is capable of surpassing some of the shortcomings of other piezoelectric motors AU - Hemsel, Tobias AU - Wallaschek, Jörg ID - 8915 KW - linear motors KW - ultrasonic motors KW - linear piezoelectric motor KW - maximum thrust force KW - no-load velocity KW - ultrasonic linear motor KW - Electromagnetic devices KW - Electromagnetic fields KW - Frequency KW - Friction KW - Gears KW - Materials science and technology KW - Piezoelectric materials KW - Research and development KW - Vibrations KW - Wheels SN - 1051-0117 T2 - Ultrasonics Symposium, 2000 IEEE TI - State of the art and development trends of ultrasonic linear motors VL - 1 ER -