Günther Pfeifer

Electromechanical Systems in Microtechnology and Mechatronics: Electrical, Mechanical and Acoustic Networks, their Interactions and Applications

▶ Text book for students of graduate and postgraduate level in the fields of microtechnology and precision engineering, technical acoustics, mechatronics, automation engineering Reference book for engineers working in different fields of industries, e.g. measurement and sensor technology, automation engineering, precision engineering, medical engineering, communication engineering Combination with FEM

Sensor Networks for Integration into Textile-Reinforced Composites

The integration of sensor networks into textile-reinforced composites enables monitoring of different physical values like strain, acceleration and temperature in a component. This paper presents a system concept of a modular sensor network supporting different sensor types and the wireless transmission of stored measurements. Sensor and transponder ASICs have been developed for realizing first demonstration examples. The feasibility of integration of discrete components and silicon chips was successfully verified in experiments with a composite made of glass fibers and polypropylene. Two demonstrators with fully functional integrated modules were fabricated in order to show the possibility of integrated strain monitoring and recording of impact events with wireless data transmission.

Messtechnische Eigenschaften von Dehnungssensoren aus Kohlenstoff-Filamentgarn in einem VerbundwerkstoffMeasuring Performance of Carbon Filament Yarn Strain Sensors Embedded in a Composite

Zusammenfassung Mit in Verbundwerkstoffen eingebettetem Kohlenstoff-Filamentgarn können mittlere Dehnungen großer Messflächen erfasst werden. Zur Abschätzung der messtechnischen Praxistauglichkeit wurden in einen Glasfaser-Polypropylen-Verbundwerkstoff integrierte Kohlenstoff-Filamentgarn-Dehnungssensoren hinsichtlich der erreichbaren Messgenauigkeit bei Kurzzeitmessungen (maximal 15 Minuten Messzeit) untersucht. Anhand vergleichender Dehnungsmessungen mit Metallfolien-Dehnungsmessstreifen wurden der Übertragungsfaktor, der Linearitäts-, Hysterese- und Kriechfehler sowie die Wiederholbarkeit bestimmt. Die Einflüsse des Verbundwerkstoffes und der Temperatur wurden ebenso untersucht wie verschiedene Technologien zur elektrischen Kontaktierung von Kohlenstoff-Filamentgarn.

Design and properties of a sensor network embedded in thin fiber-reinforced composites

So far, embedded sensor networks in composites have mostly been used for structure health monitoring. In contrast to that, in the present work a new stand-alone embedded sensor network for load monitoring of a composite component is presented. Design considerations for the manufacturing of a demonstrator as well as measurement results for cyclic loading are discussed. The presented demonstrator comprises two textile manufactured carbon filament yarn strain sensors for measuring the average bending strain of a large area, embedded capacitive keys for manually controlling the load monitoring process, a sensor ASIC for the processing of the measured data as well as a transponder ASIC with an antenna for the wireless transmission of the measured strains to an external reading station.

Combining network models and FE-models for the simulation of electromechanical systems

The combination of Network Methods and Finite Element Methods on user level is a time-efficient method for the simulation of dynamic behavior of electromechanical systems. Combined simulation can be structured into five areas of application: determination of network structures with FE-simulations, determination of network parameters with FEsimulations, inclusion of network elements in FE-models, inclusion of equivalent network structures in FE-models and simulation of models incorporating different model levels. The capabilities of the combined simulation are demonstrated by sample applications. Combined Simulation is suited for a better system insight and fast simulation-based optimization.

Elektromechanische Systeme der Mikrotechnik und Mechatronik

Elektromechanische Systeme aus elektrischen, mechanischen und akustischen Teilsystemen haben im Prazisionsgeratebau, in der Sensorund Aktortechnik, der Elektroakustik sowie in der Medizintechnik eine grose Bedeutung. Die Vermittlung einer anschaulichen, ingenieurmasigen Entwurfsmethode fur diese Systeme auf der Grundlage einer schaltungstechnischen Darstellung ist das Hauptanliegen des Lehrbuchs. Es ermoglicht einen raschen Einstieg in die mechanischen, akustischen, hydraulischen und thermischen Problemstellungen durch die Anwendung des schaltungstechnischen Grundwissens. Die 2. Auflage wurde neu bearbeitet und didaktisch verbessert. Die Netzwerkbeschreibungsmethodik wurde auf finite Netzwerkelemente und die Kombination mit der Finite-Elemente-Beschreibung (FEM) erweitert: aus der Kombination der Vorteile beider Beschreibungsmethoden ergeben sich neuartige Losungsansatze vor allem im hoheren Frequenzbereich. Das Buch bietet zahlreiche aktuelle Beispiele zum Entwurf von Sensoren und Aktoren sowie von direkt gekoppelten Sensor-Aktor-Systemen. Der Anhang enthalt anspruchsvollere Grundlagen zur Signalbeschreibung sowie eine Zusammenstellung wichtiger Materialdaten.

Electromagnetic Network Models of Planar Coils on a Thin or Thick Magnetic Layer

A method is presented to determine the magnetic reluctance of a thin or a thick magnetic layer of permeability ¿ underneath a planar coil based on inductance measurements. The procedure is substantiated on the basis of the linear electromagnetic network model. The influence of the involved magnetic reluctances on the inductance is analyzed by a transformation into the electrical domain applying linear network theory. From inductance measurements the individual contributing inductances can be calculated and from the back transformation into the magnetic domain the reluctances and further parameters, such as the magnetic field strength for a given electrical current or the permeability. Analytical results are compared with FEM simulations and with measurements obtained from a magnetostrictive bending sensor.

Integrated Sensor Network with Event-Driven Activation for Recording Impact Events in Textile-Reinforced Composites

This paper presents the system concept and first experimental results of the realization of a sensor network for monitoring suddenly occurring temporary events such as impacts. The system consists of modules with sensor and transponder ASIC that can be integrated into a composite component made of glass fibers and polypropylene. The power consumption in standby is very low because the power supply for the ASICs is only activated when a relevant event is detected by a startup sensor. A fast start of the data acquisition process at the beginning of the event is therefore extremely important. The achievable startup time is demonstrated with a test setup.

Efficient Dynamic Modeling and Simulation of Smart Structures With (Equivalent) Circuits

The modeling and simulation of smart structures and systems involves coupled field calculations which cause currently high computational costs. Especially time and frequency analyses of sensor or actuator constructions described by equation systems with 10,000 to several 100,000 degrees of freedom demand efficient design methods. A successful approach to solve this problem is to increase the abstraction in a model hierarchy by switching to macro models. In this paper the merits of multi-physics network models applied as macro models are discussed. The main advantage is the significant reduction of the degree of freedom and the transition from PDEs to ODEs. Steady state problems can be efficiently solved with algebraic equations in the complex domain. Another important aspect appreciated by design engineers is the structural graphical system representation offered by networks. Particularly, feedback mechanisms, e.g. from an acoustic subsystem into the mechanical subsystem, can be overviewed. Moreover, linear time-invariant (LTI) multi-physics networks allow the transformation of network elements from one physical domain into another domain. As a consequence transducers can be eliminated and thus the network be simplified. Besides this, passive LTI systems are reversible. This property is the basis of precise measurement techniques.© 2013 ASME

Magnetostrictive Unimorph Transducer Network Model

A new rotational magnetomechanical transducer network model for a magnetostrictive unimorph is presented. Often these laminated structures define an operating point about which the mechanical, magnetic and electrical quantities show only small variations and the behavior can be decribed by a linear model. It is shown how the magnetomechanical transduction coefficient in actuation direction, which is obtained via classical laminated plate theory, holds also for the sensing relation. The magnetomechanical model is combined with electromagnetic coil models. The electromagnetic and the magnetomechanical transducer are connected by a magnetic voltage divider which takes demagnetization or the planar coil field distribution into account. The presented models can be used for a fast analysis of existing systems and also for the optimization of new designs. The resulting circuit description can be simplified, e.g. to a single impedance, by transforming network elements into other domains.