Thilo Bein

A Linear Ultrasonic Motor Using the First Longitudinal and the Fourth Bending Mode

A linear ultrasonic motor was designed using a combination of the first longitudinal and the fourth bending mode. The motor consisted of a straight metal bar bonded with a piezo-ceramic element as a driving element. The resulting displacement was amplified by two teeth and transmitted by the frictional force between the motor and the rail in a linear motion. The basic design is discussed and simulations are compared with the experimental results.

Integrated Solutions for Noise and Vibration Control in Vehicles

A strong issue on the development of new vehicles is the weight reduction, required for the reduction of the fuel consumption and the CO2 emissions. The current vehicles have already a structure optimised to have low weight without reducing the required performances. However, there are some components of the structure that can be further reduced in weight still matching the resistance, crash and fatigue performances, but giving a poor performance in terms of noise and vibrations and increasing both the structure-borne and air-borne sound transmission.In the European FP7 project Green City Car, flexible, integrated passive and active solutions are developed permitting noise and vibration attenuation in vehicles equipped with the next generation of highly fuel-efficient two- or three cylinder internal combustion engines (ICE). Among others, shunted piezoelectric patches and electro-magnetic actuation as well as smart Helmholtz resonators are considered. Additionally, dedicated active noise control systems for the control of broadband rolling noise are developed. Besides, Green City Car addresses and implements novel damping materials and acoustic treatments as well as design approaches for tyres which are an important acoustic source for exterior and interior noise. This holistic approach should lead to a reduction in noise and vibrations levels in the order of 10 dB(A) and more measurable in the city car provided (not on component level). Currently, Green City Car finished its second year and first results are presented and discussed in this paper

Design and Analysis of an Adaptive Vibration Isolation System considering Large Scale Parameter Variations

The reliability assessment of complex adaptive systems requires the identification of dominant input parameters and the quantitative evaluation of the associated effects on the system performance. This can be achieved using experimental and numerical sensitivity analysis methods. In this paper a simulation based approach is presented, assessing the system performance of an active vibration isolation device with respect to parameter variations, such as temperature, load amplitude, material properties and geometry dimensions of the structural elements. The modeling of the active system is described utilizing the Finite Element Method and a Krylov Subspace based model order reduction scheme. The implemented Morris screening technique and variance based sensitivity analysis are discussed. For the example of an active vibration system the sensitivity analysis strategy is outlined and it is shown that a quantitative assessment of the system performance considering large scale parameter variations is provided.

Adaptronik — ein technischer Ansatz zur Lösung bionischer Aufgaben

Adaptronische Systeme bieten dem Maschinenbau vollig neue Gestaltungsmoglichkeiten fur Maschinen und Konstruktionselemente. Wesentlich und grundlegend neu ist hierbei, dass die bisher passive Struktur sich mit Hilfe geeigneter Aktor-, Sensor- und Regelelemente aktiv an die jeweilige Betriebsbedingung anpasst. Eine solche „intelligente“ Struktur arbeitet effizienter, okonomischer und mit erhohter Lebensdauer. Die Natur lebt uns solche adaptiven Systeme vor, z.B. passt ein Vogel seine Flugel standig den Stromungsverhaltnissen an. Die Bionik beschaftigt sich mit der Aufgabe, von der Natur zu lernen und diese Erkenntnisse in neue Konstruktionsprinzipien umzusetzen. Der vorliegende Artikel verdeutlicht das enorme Potential der Adaptronik zur Losung dieser Aufgabe.

Smart Sensor Networks for Structural Health Monitoring

Condition based maintenance (CBM) concepts are widely used in the industry and are also applied to modern vehicles. Since structural components are becoming increasingly complex, e.g. due to lightweight composite materials, it is useful to apply CBM also to those parts. This requires the application of sensors to the components. The permanent instrumentation with systems for structural health monitoring is yet implemented for high performance structures, e.g. in military aircraft. Those rather expensive systems are not directly applicable to a road vehicle. This paper discusses ways to adapt the idea of structural health monitoring to vehicles using smart sensor networks, including signal processing, low-cost hardware platforms and energy supply of wireless sensor nodes.

Advanced materials and technologies for reducing noise, vibration and harshness (NVH) in automobiles

Abstract: The automotive industry is facing the problem more and more of reducing the weight of vehicles but guaranteeing an equivalent level of comfort in terms of noise, vibration and harshness (NVH). To overcome these contradicting requirements traditional design and material choices must be revisited. Besides advanced passive material active systems or smart concepts are being increasingly considered for the NVH optimization of vehicles. Therefore, this chapter addresses different passive and active measures for NVH control with a focus on smart structures. After a general discussion of the NVH problems in automotive engineering, some principal passive and active measures are described. On this basis passive and active measures are presented in different depth from general aspects over specific concepts to some selected applications.

Performance Assessment of an Active Noise Reduction System

In the past decade the field of smart structures and intelligent material systems received a lot of scientific attention. Numerous publications deal with the modeling, design, optimization and performance evaluation of such systems, in which beams, plates or truss structures are often considered as test cases. In the application of this promising new technology to real systems, the designer is often confronted with problem specific issues, e.g. proper formulation of the desired output function, integration of the actuators, sensors made of multifunctional materials and the control scheme to the system model, etc. As an example, the performance assessment of an active facade system is presented in this paper. The facade system consists of distributed piezoelectric sensors and actuators bonded to the surface of the doubleglazed windows. An adaptive feedforward control scheme was implemented to reduce the noise transmission via the active facade. The performance of the active system with four sensor/actuator pairs was first demonstrated in a numerical simulation. A Digital Signal Processing System was used to validate the performance of the system with the help of a demonstrator facade, showing the reduction of the ambient noise experimentally for different types of harmonic and transient excitation.Copyright

Enhanced lightweight design by composites – Results of the EU project ENLIGHT

Over recent decades, cars have become larger and heavier with every new generation. The main drivers of such a weight increase have been the improved safety and comfort requirements. Decades of R&D investments to tackle this tendency have resulted in a substantial increase in the weight-specific performance of components and assemblies in terms of cost, strength and stiffness. However, the need for weight reduction in future electric vehicles, without unduly compromising performance and safety, is even stronger since additional weight translates into either reduced driving range or in larger, heavier and more expensive batteries. Within this context, the European Green Vehicle project ENLIGHT developed highly innovative lightweight material technologies for application in structural vehicle parts of future volume produced electric vehicles. Among others, ENLIGHT developed thermoplastic matrix composite and associated manufacturing technologies to a stage that they were applicable at least in medium volume production. The material development was complemented by investigating the required manufacturing and assembly technologies as well. In this paper, a summary of the major results obtained during the four-year project year is presented. A special focus is given to a semi-active composite control arm with significant reduced weight but enhanced NVH properties.

Adaptronics: Selected papers from the 14th International Adaptronic Congress 2011 (Darmstadt, Germany, 7–8 September 2011)

Adaptronics is the German synonym for smart structures and addresses the development of adaptive structural systems. Recent progress in smart structures was presented and exhibited at the 14th International Adaptronic Congress 2011, which took place for the first time in Darmstadt, a leading center for Adaptronics in Germany. Among others, Darmstadt hosts the Fraunhofer LBF (with its research group on Adaptronics), the Fraunhofer Technology Transfer Center for Adaptronics and the LOEWE-Centre of Adaptronics (AdRIA), a joint initiative of the Fraunhofer LBF, the Technical University of Darmstadt and the University of Applied Sciences Darmstadt. The latter is a unique, large interdisciplinary research project funded by the State of Hessen and is aimed at creating and sustainably implementing an internationally leading research center for adaptronics at the Darmstadt location. More than 170 researchers work together in nine adaptronic-relevant research areas and in three demonstration projects: adaptive car; quiet office; and adaptive absorber networks—all sharing a state-of-the-art research infrastructure. The Adaptronic Congress 2011 was set up as a communication platform bringing together experts from industry and research. The Congress was accompanied by an exhibition presenting new system solutions with smart structure components and current product trends. The lectures given were divided into four topics: applications; tools; components; and development. For the first time, these sessions were complemented by an Adaptronics Academy, a platform where PhD students and young professionals presented their research work. The international importance of the Adaptronic Congress 2011 was reflected in the keynote lectures by Dr Jan Leuridan, Executive Vice-President & CTO of LMS International and Professor Stephen Elliott of the ISVR, University of Southampton. We would like to thank all authors for their high quality contributions. We are also indebted to Professor E Garcia, Editor-in-Chief, and the IOP Publishing team, in particular Natasha Leeper, for providing the opportunity to publish this special section of Smart Materials and Structures.

The quiet office—noise abatement in office buildings by means of smart structures

Noise is a serious form of environmental pollution believed to affect the lives of some 100 million European citizens. The cost of the associated damage is estimated at more than ten billion euro per year. Noise leads to serious health problems, limits the capability to learn and effects the occupant comfort and performance in buildings. In this context, advanced noise abatement concepts are being developed in the demonstration project “Quiet Office” within the LOEWE-Center AdRIA (Adaptronics – Research, Innovation, Application), a large interdisciplinary research project funded by the German federal state of Hessia. As underlying principle for noise reduction concepts, Active Structural Acoustic Control (ASAC) is primarily being considered. Applying ASAC concepts, the noise radiation is controlled either by controlling the structural vibration of the radiating structure or by controlling the structure borne sound path. This paper will present the most recent concepts and results from the “Quiet Office”. ...