Beate Bender

Technical view on requirements for future development of hand-held rehabilitation devices

In recent years, there has been an increasing interest in using different types of hand rehabilitation devices for stroke patients in subjects home. Furthermore, this interest comes along with the desire to motivate the patient and diversify the entertainment during each training session which can be achieved by serious games. The topic of this paper is to point out the main requirements for future development. This is done by discussing and comparing two categories of common devices - glove-like and VR devices - with a brief analysis of their advantages and disadvantages. The results of that will lead to recommendations for future development.

Design of an axially concave pad profile for a large turbine tilting-pad bearing

To improve operational safety and/or achieve a higher load capacity of turbine tilting-pad bearings, an axially concave pad profile is presented. The thermal and mechanical stress of the loaded pads of a test bearing in load between pivot configuration has been analysed. Both film thickness and pressure distribution have been measured at a very high resolution. A fluid film calculation program in combination with a finite-volume-based structural mechanics program is used to simulate the deformation of a single pad under high circumferential speeds. In this context, the axial and tangential heat transfer coefficients of the pad surface, which act as boundary conditions for the calculation of the 3D temperature distribution, are determined using an optimization process. Herein, the match of predicted and measured pad temperatures is the goal. It can be shown that there must be a huge difference in heat transfer in axial and tangential direction in order to match the large measured temperature gradient in circumferential direction. Based on the measured deformed profile the program code is used to derive a concave pad profile, which will result in an axially non-arched sliding surface under the expected thermal load. Therefore, an iterative simulation procedure is used. By decreasing the axial arching of the pad and thus the large film thickness at the axial ends using an improved profile designed for a specific operation point, the minimum film thickness and maximum pad temperature can be influenced beneficially. The comparison of measurement data and calculation results shows very good agreement regarding the pad deformations. The results indicate that by axially concave profiling of the loaded pads of a large tilting-pad bearing for a specific operation point, the static characteristics in the form of temperature, film thickness and load capacity can be improved.

Die frühen Phasen der IPSS-Entwicklung in der Anwendung

Im direkten Zusammenspiel mit Kap. 4 beschaftigt sich der vorliegende Beitrag mit den fruhen Phasen der Entwicklung industrieller Produkt-Service Systeme und erweitert die theoretisch fundierten Erkenntnisse um Erfahrungen aus der industriellen Praxis. Zunachst werden hierfur besonders die Herausforderungen beleuchtet, denen ein klassisch produktorientiertes Unternehmen innerhalb des Transformationsprozesses hin zum IPSS-Anbieter gegenubersteht. Diese Herausforderungen adressierend, zeigt das Buchkapitel Moglichkeiten der methodischen Unterstutzung auf. Dabei steht zum einen die Findung neuer IPSS-Ideen im Zentrum. Besonders die Generierung neuartiger Geschaftsmodelle weist fur Unternehmen einen hohen Neuheitsgrad auf. Um wahrend der Phase der Konzipierung den Losungsraum moglichst umfassend zu erkunden ist es notwendig, die kollaborative Kreativitat im Entwicklerteam zu unterstutzen. Zu diesem Zweck wird ein innovativer Methodenbaustein vorgestellt, der es mithilfe verschiedener Spielmechanismen schafft, den zahlreichen Domanen im IPSS-Kontext gerecht zu werden und somit ein moglichst optimales Losungskonzept zu identifizieren. Die in den Buchkapiteln vorgestellten Methoden wurden letztendlich in einen Softwareprototyp integriert, um die Effizienz (z. B. Wiederverwendbarkeit und Dokumentation) im Praxisalltag sicherzustellen.

Die frühen Phasen der IPSS-Entwicklung

Im direkten Zusammenspiel mit Kap. 17 beschaftigt sich der vorliegende Beitrag mit den fruhen Phasen der Entwicklung industrieller Produkt-Service Systeme. Unternehmen die sich entschieden haben, ihr Angebot um innovative IPSS-Geschaftsmodelle zu erweitern, mussen ihr klassisches Entwicklungsverstandnis fundamental uberdenken. Potenzielle IPSS-Anbieter sehen sich vor allem in den bedeutenden fruhen Entwicklungsphasen der Ideen- und Konzeptfindung mit zahlreichen Herausforderungen konfrontiert, die wiederrum den Bedarf fur eine methodische Unterstutzung definieren. Anhand eines industriellen Fallbeispiels werden zunachst die besonderen Charakteristika (Wechselwirkungen zur Entwicklung von Geschaftsmodellen, Langfristigkeit der Entscheidungen, neues Verstandnis von Prinziplosungen) anschaulich abgeleitet und im Anschluss in die damit verbundenen Herausforderungen ubersetzt. Dabei kann vor allem die Integration der beteiligten lebenszyklusubergreifenden Domanen besonderes in den Fokus gestellt werden. Diesen zentralen Aspekt aufgreifend zeigt der Buchbeitrag abschliesend Ansatze fur die methodische Unterstutzung auf.

Model based QFD method with the integrated sensitivity analysis

This manuscript presents a methodology to determine the transfer function in the house of quality tool of the quality function deployment method. The transfer function relates the product characteristics to the customer requirements on the product. Using sensitivity analysis on a model of the product the elements of the transfer function are calculated accurately and with no need on further iterations for the transfer function. The proposed method is applied to a design model of an office paper punch and the results are discussed.

Increase of Operational Safety of Tilting-Pad Journal Bearings by Extraction of Hot Oil at the Trailing Edge

A theoretical study is presented with the main objective on the operational safety parameters (minimum film thickness and maximum pad temperature) and thermomechanical deformations of a o500 mm rocker pad tilting-pad journal bearing (TPJB) for application in large turbo machinery. It can be described by the following specifications: Five pads, 0.23 nominal preload, 60% offset, 56° pad arc angle, 350 mm pad length and 1.28‰ relative bearing clearance. Theoretical investigations are carried out for circumferential speeds up to 78 m/s and static loads up to 3.60 MPa.The simulation tool simultaneously solves both Reynolds and energy equations for the oil film (3D temperature distribution) on the one hand and computes thermomechanical deformations of the pad on the other hand. The simulations are conducted for a single pad and are supported by boundary conditions taken from experiments. The results with regard to static bearing characteristics and pad deformation show good agreement with experiments.The impact of axial pad arching on operational safety parameters and load-carrying capacity are shown and compared to experimental results. It is shown that the axial deviation in film thickness Δh can be even higher than the minimum film thickness hmin. This leads to reduced hydrodynamic pressure build-up towards the axial edges and therefore significantly decreased safety parameters or load-carrying capacity.In order to reduce pad crowning, radial bores through the pad body are modelled to simulate the extraction of hot oil from the trailing edge. In the simulation, the hot oil is used to heat up the back of the pad for a decrease of radial temperature gradients and thus pad arching. It is shown that by extracting 0.4 l/s of hot oil, a decrease in axial pad crowning from Δh = 47μm to Δh = 26μm can be achieved and that this leads to a decrease of 7.8 K in maximum temperature and an increase of 5 μm in minimum film thickness respectively a gain of load-carrying capacity of 0.4–0.6 MPa.Copyright

A Model Based Approach to Support Risk Management in Innovation Projects

New product development is notably affected by uncertainties that are a consequence of insufficient experience and missing knowledge. If uncertainties are not managed adequately, they will finally lead to risks. We therefore advocate an integrated agile development process, allowing for explicit modelling of uncertainties and reaction strategies as well as the evaluation of the resulting risk caused by the changes to the product in development or the development process. As changes can again lead to undesired change propagation, finally resulting in new uncertainties and in consequence new risks, uncertainty response strategies need to be developed, evaluated and conducted collaboratively. In this publication the Integrated System and Risk Managing Model is presented, enabling users to describe and analyze product and process based uncertainties as well as potential response options within one consistent system. This paper elaborates the underlying structure of the model and concentrates on the modelling process, also explaining the application using examples from a case study.