@inproceedings{HacklHirschbergLexetal., author = {Hackl, Andreas and Hirschberg, W. and Lex, C. and Rill, Georg}, title = {Tyre type dependent transient force behaviour by means of a maxwell model}, series = {The Dynamics of Vehicles on Roads and Tracks : Proceedings of the 25th Symposium of the International Association of Vehicle System Dynamics (IAVSD 2017), Rockhampton, Queensland, Australia, 14-18 August 2017}, booktitle = {The Dynamics of Vehicles on Roads and Tracks : Proceedings of the 25th Symposium of the International Association of Vehicle System Dynamics (IAVSD 2017), Rockhampton, Queensland, Australia, 14-18 August 2017}, editor = {Spiryagin, Maksym and Gordon, Timothy and Cole, Colin and McSweeney, Tim}, publisher = {CRC Press}, address = {London}, isbn = {1351057170}, doi = {10.1201/9781315265506}, pages = {157 -- 162}, abstract = {The present papers deals with the usability of an extended Maxwell model to describe the tyre dynamics during transient driving manoeuvres. In the present article, the para-metrisation process of a dynamic tyre model is investigated in a first step, using measurement data of tyre forces from a flat trac tyre test bench, (IABG 2016). Two tyre types of dimensions 255/50 R19 and 175/55 R15 are used. The practical applicability is discussed, considering the measurement procedure and the parameter optimisation process. In a second step, the performance of the dynamic tyre model is validated using measurements of manoeuvres under higher dynamic excitation. As a last step, an outlook is given on further research planned in which the presented model and parametrisation are adapted to a larger frequency range.}, language = {en} } @article{SchuemannMorichKaufholdetal., author = {Sch{\"u}mann, Malte and Morich, J. and Kaufhold, T. and B{\"o}hm, Valter and Zimmermann, Klaus and Odenbach, Stefan}, title = {A mechanical characterisation on multiple timescales of electroconductive magnetorheological elastomers}, series = {Magnetism and Magnetic Materials}, volume = {453}, journal = {Magnetism and Magnetic Materials}, number = {May}, publisher = {Elsevier}, doi = {10.1016/j.jmmm.2018.01.029}, pages = {198 -- 205}, abstract = {Magnetorheological elastomers are a type of smart hybrid material which combines elastic properties of a soft elastomer matrix with magnetic properties of magnetic micro particles. This leads to a material with magnetically controllable mechanical properties of which the magnetorheological effect is the best known. The addition of electroconductive particles to the polymer mix adds electrical properties to the material behaviour. The resulting electrical resistance of the sample can be manipulated by external magnetic fields and mechanical loads. This results in a distinct interplay of mechanical, electrical and magnetic effects with a highly complex time behaviour. In this paper a mechanical characterisation on multiple time scales was conducted to get an insight on the short and long-term electrical and mechanical behaviour of this novel material. The results show a complex resistivity behaviour on several timescales, sensitive to magnetic fields and strain velocity. The observed material exhibits fatigue and relaxation behaviour, whereas the magnetorheological effect appears not to interfere with the piezoresistive properties.}, language = {en} } @article{DiermeierSindersbergerKrenkeletal., author = {Diermeier, Andreas and Sindersberger, Dirk and Krenkel, Lars and Rosell, X. C. and Monkman, Gareth J.}, title = {Controllable Magnetoactive Polymer Conduit}, series = {The Open Mechanical Engineering Journal}, volume = {12}, journal = {The Open Mechanical Engineering Journal}, number = {1}, publisher = {Bentham}, pages = {192 -- 200}, abstract = {Objective: Magneto-active Polymers (MAP) are smart materials whose mechanical characteristics, such as elastic and shear moduli, may be controllable by means of an externally applied magnetic field. Methods: Various additives may be used to influence the characteristics of the polymer matrix whilst a suspension of soft and/or hard magnetic particles determine the magnetic properties of the composite. Both pre-cure and post-cure magnetization is possible. Results: A range of control strategies have been investigated for evaluation of the system using fluids of differing kinematic viscosity. Conclusion: Depending on the degree of magnetic field homogeneity, magneto-deformation and magnetostriction contribute to MAP actuation. This paper presents a novel application in the form of a peristaltic MAP tube system, applicable to flow control and pumping of hemorheological fluids in blood circulatory systems for biomedical research purposes.}, language = {en} } @inproceedings{FuhrmannNiemetz, author = {Fuhrmann, Thomas and Niemetz, Michael}, title = {Transdisciplinary Bachelor Course Connecting Business and Electrical Engineering}, series = {4th International Conference on Higher Education Advances (HEAd'18), 2018, Universitat Polit{\`e}cnica de Val{\`e}ncia, Val{\`e}ncia}, booktitle = {4th International Conference on Higher Education Advances (HEAd'18), 2018, Universitat Polit{\`e}cnica de Val{\`e}ncia, Val{\`e}ncia}, doi = {10.4995/HEAd18.2018.8056}, abstract = {The OTH Regensburg has a broad variety of study programs in technical, business, social and health sciences. Up to now there is no integral connection in the bachelor curricula between business and technical faculties except for some small subjects. The scope of this project is to develop a new course specialization which connects engineering and business thinking. Electrical engineering students should learn basics of business science and how managers think. Business students should vice versa learn fundamentals of engineering and how engineers solve problems. Students from both faculties work together in projects where they act like start-up companies developing a new product and bringing it into the market. It is seen a transdisciplinary effect: These projects gain innovative results between the disciplines compared to student projects of one isolated discipline. Evaluation results from the first two cohorts indicate high student satisfaction, high learning success as well as directions for further improvement.}, language = {en} } @inproceedings{GrothmannPoelsterlGerling, author = {Grothmann, Benjamin and Poelsterl, Thomas and Gerling, Dieter}, title = {Online compensation of current sensor gain-faults for safety-relevant IPM-drives}, series = {2017 IEEE Transportation Electrification Conference and Expo (ITEC), 22-24 June 2017, Chicago, IL, USA}, booktitle = {2017 IEEE Transportation Electrification Conference and Expo (ITEC), 22-24 June 2017, Chicago, IL, USA}, publisher = {IEEE}, doi = {10.1109/ITEC.2017.7993355}, pages = {701 -- 706}, abstract = {Detection and compensation of current sensor gain-faults regardless of the operating-point is a crucial aspect for safety-relevant servo-drives. This paper presents and investigates a new direct phase-gain re-balancing methodology, especially suited for interior permanent magnet machine (IPM) drives mostly operating at low speed-ranges including standstill. The proposed model-based approach utilizes high-frequency signal-injection (HFI) to facilitate fast and persistent sensor monitoring for any operating state of the drive. No additional sensing hardware is required. Extraction of the HFI-phase-current response enables detection and immediate compensation of sensor gain-faults. Implementation aspects of the proposed concept are discussed thoroughly. Experimental results are presented to prove and investigate robustness, reliability and fault-tolerant performance.}, language = {en} } @inproceedings{HacklHirschbergLexetal., author = {Hackl, Andreas and Hirschberg, Wolfgang and Lex, Cornelia and Rill, Georg}, title = {Parameterization Process of the Maxwell Model to Describe the Transient Force Behavior of a Tire}, series = {WCX 17: SAE World Congress Experience 2017}, booktitle = {WCX 17: SAE World Congress Experience 2017}, publisher = {SAE}, doi = {10.4271/2017-01-1505}, abstract = {The present technical article deals with the modeling of dynamic tire forces, which are relevant during interactions of safety relevant Advanced Driver Assistance Systems (ADAS). Special attention has been paid on simple but effective tire modeling of semi-physical type. In previous investigations, experimental validation showed that the well-known first-order Kelvin-Voigt model, described by a spring and damper element, describes good suitability around fixed operation points, but is limited for a wide working range. When aiming to run vehicle dynamics models within a frequency band of excitation up to 8 Hz, these models deliver remarkable deviations from measured tire characteristics. To overcome this limitation, a nonlinear Maxwell spring-damper element was introduced which is qualified to model the dynamic hardening of the elastomer materials of the tire. However, the advantage of a more realistic description of the transient behavior leads to a more complex parametrization process. Therefore, in the proposed article attention is paid to describe the identification process including defined maneuvers to parameterize the tire model, where the accuracy of the parameter strongly depends on the quality of the available input data from measurement. In order to study this important aspect of parameterization, the reference data from simulation of the full physical tire model FTire is applied like a "virtual measurement" of specified testing maneuvers. The procedure of simulation by means of the enhanced first order dynamics model is implemented by the semi-physical tire model TMeasy. Finally, the improvements of the extended model are discussed and an outlook for future work is given.}, language = {en} } @inproceedings{GrimmHaumer, author = {Grimm, Alexander and Haumer, Anton}, title = {EMOTH The EMobility Library of OTH Regensburg}, series = {Proceedings of the 12th International Modelica Conference, Prague, Czech Republic, May 15-17, 2017}, booktitle = {Proceedings of the 12th International Modelica Conference, Prague, Czech Republic, May 15-17, 2017}, publisher = {Link{\"o}ping University Electronic Press}, doi = {10.3384/ecp17132285}, pages = {285 -- 290}, abstract = {The importance of E-Mobility is rapidly increasing, not only for private vehicle traffic but also for public transport. In and around Regensburg, Germany there are a lot of automotive companies. Therefore E-Mobility is an important topic in the curriculum of several courses of study at the East-Bavarian Technical University of Applied Sciences Regensburg (OTH). One Master of Applied Research student at OTH has chosen the topic to develop an open-source simulation tool for electric vehicles - the EMOTH Library - based on Modelica and to refine several aspects of the library during the one and a half year of the master course. After one semester, the basic version of the library is available and will be presented in this paper.}, language = {en} } @inproceedings{DiamantidisLenziSykora, author = {Diamantidis, Dimitris and Lenzi, Daniele and S{\´y}kora, Miroslav}, title = {Optimal decisions based on monitoring - case study of steel roof}, series = {Proceedings of the Joint COST TU1402-TU1406 - IABSE WC1 Workshop, Zagreb 2-3 March 2017}, booktitle = {Proceedings of the Joint COST TU1402-TU1406 - IABSE WC1 Workshop, Zagreb 2-3 March 2017}, doi = {10.5592/CO/BSHM2017.4.7}, pages = {4.7-1 -- 4.7-7}, abstract = {Monitoring of structures and related decisions based on cost optimization are discussed in this contribution. Many research publications and experimental data are currently available on inspection and on monitoring and they represent the outcome of the remarkable work done. Not all the topics of interest are widely debated and implemented in standards. The current state-of-practice in standards is summarized and aspects to be included in future recommendations are proposed. The implementation of risk-based decisions is illustrated in a case study dealing with a stadium roof in Northern Italy. Snow actions are important especially in northern and mountainous regions where heavy snowfalls and related accumulation result to considerable loads. As the roof structure fails to comply with the requirements of Eurocodes, a permanent monitoring system has been installed to allow for real time evaluation of the reliability level of the structure. The system supplies the necessary information supporting immediate decisions on closure of the stadium in case of an extraordinary snow load. Cost-optimal decisions regarding the closure of the stadium are analysed based on a limit state function, on probabilistic models for the influencing parameters including measurement uncertainty, economic losses related to closure and failure consequences. The results demonstrate the potential of the use of the monitoring systems and probabilistic reliability analysis in order to support decisions and highlight the need for their implementation in future standards.}, language = {en} } @inproceedings{Neidhart, author = {Neidhart, Thomas}, title = {Bodenphysikalische und bodenmechanische Anforderungen an ZFSV (Fl{\"u}ssigboden) als Bettungsmaterialien erdverlegter Hochspannungsleitungen}, series = {Rohrleitungen in digitalen Arbeitswelten : Tagungsband zum 31. Oldenburger Rohrleitungsforum 2017}, booktitle = {Rohrleitungen in digitalen Arbeitswelten : Tagungsband zum 31. Oldenburger Rohrleitungsforum 2017}, editor = {Wegener, Thomas}, publisher = {Vulkan Verlag}, address = {Essen}, isbn = {978-3-8027-2865-5}, pages = {337}, language = {de} } @article{ChatzitakisDawoud, author = {Chatzitakis, Paris and Dawoud, Belal}, title = {An alternative approach towards absorption heat pump working pair screening}, series = {Renewable Energy}, volume = {110}, journal = {Renewable Energy}, publisher = {Pergamon-Elsevier}, organization = {PERGAMON-ELSEVIER SCIENCE LTD}, doi = {10.1016/j.renene.2016.08.014}, pages = {47 -- 58}, abstract = {The successful market penetration of modern absorption heat pumps (AHP) today is critically dependent on their thermodynamic performance as well as other key factors like cost, reliability and inherent safety. Conventional AHPs have a proven record in the first two aspects but crucial shortcomings in the last two. For this reason it has been imperative to search for alternative working pairs that could potentially provide comparable performance while also satisfying the rest of the conditions to the best extent possible. As part of a systematic approach towards this direction, a detailed cycle analysis was performed, utilizing an idealized AHP system containing a real working pair, which enabled the identification of five dimensionless parameters and key thermophysical properties that influence the system's thermodynamic efficiency and the circulation ratio. In order to validate those findings, these parameters were calculated and compared between conventional and alternative AHP refrigerants. It turned out that low molecular weight ratios between absorbent and refrigerant have a beneficial effect on both coefficient of performance and the circulation ratio. Furthermore, both the refrigerant acentric factor and the absorbent vaporization enthalpy shall be minimized to obtain better performance. (C) 2016 Elsevier Ltd. All rights reserved.}, language = {en} } @article{DechantFedulovChashinetal., author = {Dechant, Eduard and Fedulov, Feodor and Chashin, Dmitri V. and Fetisov, Leonid Y. and Fetisov, Yuri K. and Shamonin (Chamonine), Mikhail}, title = {Low-frequency, broadband vibration energy harvester using coupled oscillators and frequency up-conversion by mechanical stoppers}, series = {Smart Materials and Structures}, volume = {26}, journal = {Smart Materials and Structures}, number = {6}, publisher = {IOP Publishing}, doi = {10.1088/1361-665X/aa6e92}, abstract = {The frequencies of ambient vibrations are often low (below 30 Hz). A broadband (3 dB bandwidth is larger than 10 Hz at an acceleration amplitude of 9.81 m s(-2)) vibration based energy harvester is proposed for transducing mechanical energy at such low frequencies into electrical energy. The mechanical setup converts low frequency mechanical vibrations into high frequency resonance oscillations of the transducer. This conversion is done by mechanical impacts on two mechanical stoppers. The originality of the presented design is that both low-frequency and high-frequency oscillators are permanently mechanically coupled. In the equivalent mechanical circuit, this coupling is achieved by connecting the ends of the stiff spring to both seismic masses, whereas one seismic mass (collison member) is also attached to the soft spring used as the constitutive element of a low-frequency oscillator. Further, both mechanical oscillators are not realized as conventional cantilever beams. In particular, the high frequency oscillator with the natural frequency of 340 Hz is a disc-shaped diaphragm with attached piezoelectric elements and a seismic mass. It is shown that it is possible to convert mechanical vibrations with acceleration amplitude of 9.81 m s(-2) in the region between approximately 7 and 25 Hz into electrical power larger than 0.1 mW with the maximum value of 0.8 mW. A simplified mathematical model based on piecewise linear coupled oscillators shows good agreement with experimental results. The ways to enhance the performance of the harvester and improve agreement with experiments are discussed.}, language = {en} } @article{PalombaDawoudSapienzaetal., author = {Palomba, Valeria and Dawoud, Belal and Sapienza, Alessio and Vasta, Salvatore and Frazzica, Andrea}, title = {On the impact of different management strategies on the performance of a two-bed activated carbon/ethanol refrigerator: An experimental study}, series = {Energy conversion and management}, volume = {142}, journal = {Energy conversion and management}, publisher = {Elsevier}, doi = {10.1016/j.enconman.2017.03.055}, pages = {322 -- 333}, abstract = {In the present work, an experimental study on a lab-scale adsorption refrigerator, based on activated carbon/ethanol working pair is reported. An extensive testing campaign has been carried out at the CNR ITAE laboratory, with multiple aims. First, the performance has been evaluated in terms of both COP and Specific Cooling Power (SCP), under different boundary conditions, including both air conditioning and refrigeration applications. Attractive SCPs, up to 180 W/kg and 70 W/kg for air conditioning and refrigeration, respectively, were measured. Under the same conditions, COP between 0.17 and 0.08 were obtained. In addition, different management strategies, namely, heat recovery between adsorbers and re-allocation of phase durations, were evaluated to identify their influence on the system. Both strategies confirmed the possibility of increasing COP and SCP up to 40\% and 25\%, respectively. Moreover, a design analysis based on the experimental results has been carried out, to suggest possible improvements of the system. The obtained results demonstrated the possibility of employing a non-toxic refrigerant like ethanol reaching performance comparable with other harmful refrigerants like ammonia and methanol. (C) 2017 Elsevier Ltd. All rights reserved.}, language = {en} } @article{NiemetzHaenninenSchoepe, author = {Niemetz, Michael and H{\"a}nninen, Risto and Schoepe, Wilfried}, title = {On the Transition from Potential Flow to Turbulence Around a Microsphere Oscillating in Superfluid 4He}, series = {Journal of low temperature physics}, volume = {187}, journal = {Journal of low temperature physics}, number = {3-4}, publisher = {Springer Nature}, doi = {10.1007/s10909-017-1745-7}, pages = {195 -- 220}, abstract = {The flow of superfluid around a translationally oscillating sphere, levitating without mechanical support, can either be laminar or turbulent, depending on the velocity amplitude. Below a critical velocity that scales as and is temperature independent below 1 K, the flow is laminar (potential flow). Below 0.5 K, the linear drag force is caused by ballistic phonon scattering that vanishes as until background damping, measured in the empty cell, becomes dominant for K. Increasing the velocity amplitude above leads to a transition from potential flow to turbulence, where the large turbulent drag force varies as . In a small velocity interval \% above , the flow is unstable below 0.5 K, switching intermittently between both patterns. From time series recorded at constant temperature and driving force, the lifetimes of both phases are analyzed statistically. We observe metastable states of potential flow which, after a mean lifetime of 25 min, ultimately break down due to vorticity created by natural background radioactivity. The lifetimes of the turbulent phases have an exponential distribution, and the mean increases exponentially with . We investigate the frequency at which the vortex rings are shed from the sphere. Our results are compared with recent data of other authors on vortex shedding by moving a laser beam through a Bose-Einstein condensate. Finally, we show that our observed transition to turbulence belongs to the class of "supertransient chaos" where lifetimes of the turbulent states increase faster than exponentially.}, language = {en} } @inproceedings{BrunnerRoederKuceraetal., author = {Brunner, Stefan and R{\"o}der, J{\"u}rgen and Kucera, Markus and Waas, Thomas}, title = {Automotive E/E-architecture enhancements by usage of ethernet TSN}, series = {13th Workshop on Intelligent Solutions in Embedded Systems (WISES), 12-13 June 2017, Hamburg, Germany}, booktitle = {13th Workshop on Intelligent Solutions in Embedded Systems (WISES), 12-13 June 2017, Hamburg, Germany}, publisher = {IEEE}, doi = {10.1109/WISES.2017.7986925}, pages = {9 -- 13}, abstract = {A huge upheaval emerges from the transition to autonomous vehicles in the domain of road vehicles, ongoing with a change in the vehicle architecture. Many sensors and Electronic Control Units are added to the current vehicle architecture and further safety requirements like reliability become even more necessary. In this paper we present a potential evolution of the Electrical/Electronic-Architecture, including a Zone Architecture, to enable future functionality. We reveal the impact on the communication network concerning these architectures and present a potential communication technology to facilitate such architectures.}, subject = {Kraftfahrzeug}, language = {en} } @article{BelyaevaKramarenkoShamoninChamonine, author = {Belyaeva, Inna A. and Kramarenko, Elena Yu and Shamonin (Chamonine), Mikhail}, title = {Magnetodielectric effect in magnetoactive elastomers: Transient response and hysteresis}, series = {POLYMER}, volume = {127}, journal = {POLYMER}, publisher = {ELSEVIER}, doi = {10.1016/j.polymer.2017.08.056}, pages = {119 -- 128}, abstract = {Magnetodielectric properties of magnetoactive elastomers comprising micrometer-sized iron particles dispersed in compliant elastomer matrices are experimentally studied in stepwise time-varying dc magnetic fields. It is found that imposition of magnetic field significantly increases both the effective lossless permittivity of these composite materials as well as their effective conductivity. These magnetodielectric effects are more pronounced for larger concentrations of soft-magnetic filler particles and softer elastomer matrices. The largest observed relative change of the effective dielectric constant in the maximum magnetic field of 0.57 T is of the order of 1000\%. The largest observed absolute change of the loss tangent is approximately 0.8. The transient response of the magnetodielectric effect to a step magnetic-field excitation can be rather complex. It changes from a simple monotonic growth with time for small magnetic-field steps (<0.1 T) to a non-monotonic behavior with a significant rapidly appearing overshoot for large magnetic-field steps (>0.3 T). The settling time to the magnetic-field step excitation can reach roughly 1000 s and it depends on the applied magnetic field and sample composition. There is also significant hysteresis of the magnetodielectric effect on the externally applied magnetic field. These findings are attributed to the rearrangement of ferromagnetic filler particles in external magnetic fields. The results will be useful for understanding and predicting the transient behavior of magnetoactive elastomers in applications where the control magnetic field is time dependent. (C) 2017 Elsevier Ltd. All rights reserved.}, language = {en} } @article{SorokinBelyaevaShamoninChamonineetal., author = {Sorokin, Vladislav V. and Belyaeva, Inna A. and Shamonin (Chamonine), Mikhail and Kramarenko, Elena Yu}, title = {Magnetorheological response of highly filled magnetoactive elastomers from perspective of mechanical energy density: Fractal aggregates above the nanometer scale?}, series = {Physical Review E}, volume = {95}, journal = {Physical Review E}, number = {6}, publisher = {Amer Physical Soc}, doi = {10.1103/PhysRevE.95.062501}, abstract = {The dynamic shear modulus of magnetoactive elastomers containing 70 and 80 mass \% of carbonyl iron microparticles is measured as a function of strain amplitude via dynamic torsion oscillations in various magnetic fields. The results are presented in terms of the mechanical energy density and considered in the framework of the conventional Kraus model. The form exponent of the Kraus model is further related to a physical model of Huber et al. [Huber et al., J. Phys.: Condens. Matter 8, 409 (1996)] that uses a realistic representation for the cluster network possessing fractal structure. Two mechanical loading regimes are identified. At small strain amplitudes the exponent beta of the Kraus model changes in an externally applied magnetic field due to rearrangement of ferromagnetic-filler particles, while at large strain amplitudes, the exponent beta seems to be independent of the magnetic field. The critical mechanical energy characterizing the transition between these two regimes grows with the increasing magnetic field. Similarities between agglomeration and deagglomeration of magnetic filler under simultaneously applied magnetic field and mechanical shear and the concept of jamming transition are discussed. It is proposed that the magnetic field should be considered as an additional parameter to the jamming phase diagram of rubbers filled with magnetic particles.}, language = {en} } @article{DechantFedulovFetisovetal., author = {Dechant, Eduard and Fedulov, Feodor and Fetisov, Leonid Y. and Shamonin (Chamonine), Mikhail}, title = {Bandwidth Widening of Piezoelectric Cantilever Beam Arrays by Mass-Tip Tuning for Low-Frequency Vibration Energy Harvesting}, series = {Applied Science}, volume = {7}, journal = {Applied Science}, number = {12}, publisher = {MDPI}, organization = {MDPI AG}, doi = {10.3390/app7121324}, abstract = {Wireless sensor networks usually rely on internal permanent or rechargeable batteries as a power supply, causing high maintenance efforts. An alternative solution is to supply the entire system by harvesting the ambient energy, for example, by transducing ambient vibrations into electric energy by virtue of the piezoelectric effect. The purpose of this paper is to present a simple engineering approach for the bandwidth optimization of vibration energy harvesting systems comprising multiple piezoelectric cantilevers (PECs). The frequency tuning of a particular cantilever is achieved by changing the tip mass. It is shown that the bandwidth enhancement by mass tuning is limited and requires several PECs with close resonance frequencies. At a fixed frequency detuning between subsequent PECs, the achievable bandwidth shows a saturation behavior as a function of the number of cantilevers used. Since the resonance frequency of each PEC is different, the output voltages at a particular excitation frequency have different amplitudes and phases. A simple power-transfer circuit where several PECs with an individual full wave bridge rectifier are connected in parallel allows one to extract the electrical power close to the theoretical maximum excluding the diode losses. The experiments performed on two- and three-PEC arrays show reasonable agreement with simulations and demonstrate that this power-transfer circuit additionally influences the frequency dependence of the harvested electrical power.}, language = {en} } @article{KalitaSnarskiiShamoninChamonineetal., author = {Kalita, Viktor M. and Snarskii, Andrei A. and Shamonin (Chamonine), Mikhail and Zorinets, Denis}, title = {Effect of single-particle magnetostriction on the shear modulus of compliant magnetoactive elastomers}, series = {Physical review E}, volume = {95}, journal = {Physical review E}, number = {3}, publisher = {American Physical Society}, doi = {10.1103/PhysRevE.95.032503}, abstract = {The influence of an external magnetic field on the static shear strain and the effective shear modulus of a magnetoactive elastomer (MAE) is studied theoretically in the framework of a recently introduced approach to the single-particle magnetostriction mechanism [V. M. Kalita et al., Phys. Rev. E 93, 062503 (2016)]. The planar problem of magnetostriction in an MAE with magnetically soft inclusions in the form of a thin disk (platelet) having the magnetic anisotropy in the plane of this disk is solved analytically. An external magnetic field acts with torques on magnetic filler particles, creates mechanical stresses in the vicinity of inclusions, induces shear strain, and increases the effective shear modulus of these composite materials. It is shown that the largest effect of the magnetic field on the effective shear modulus should be expected in MAEs with soft elastomer matrices, where the shear modulus of the matrix is less than the magnetic anisotropy constant of inclusions. It is derived that the effective shear modulus is nonlinearly dependent on the external magnetic field and approaches the saturation value in magnetic fields exceeding the field of particle anisotropy. It is shown that model calculations of the effective shear modulus correspond to a phenomenological definition of effective elastic moduli and magnetoelastic coupling constants. The obtained theoretical results compare well with known experimental data. Determination of effective elastic coefficients in MAEs and their dependence on magnetic field is discussed. The concentration dependence of the effective shear modulus at higher filler concentrations has been estimated using the method of Pade approximants, which predicts that both the absolute and relative changes of the magnetic-field-dependent effective shear modulus will significantly increase with the growing concentration of filler particles.}, language = {en} } @inproceedings{KoderZacherlRabletal., author = {Koder, Alexander and Zacherl, Florian and Rabl, Hans-Peter and Mayer, Wolfgang and Gruber, Georg and Dotzer, Thomas}, title = {Jatropha Oil as an Alternative Fuel for Modern Diesel Engines - Injection Characteristics and EGR-Compatibility}, series = {WCX 17: SAE World Congress 2017}, booktitle = {WCX 17: SAE World Congress 2017}, publisher = {SAE International}, doi = {10.4271/2017-01-5000}, abstract = {An effective way to reduce greenhouse gas emissions (GHGs) is to use rurally produced straight jatropha oil as a substitute for diesel fuel. However, the different physical and chemical properties of straight vegetable oils (SVOs) require a customized setup of the combustion engine, particularly of the injection timing and quantity. Therefore, this study demonstrates the differences in the injection and combustion processes of jatropha oil compared to diesel fuel, particularly in terms of its compatibility with exhaust gas recirculation (EGR). A 2.2 l common-rail diesel engine with a two-stage turbocharging concept was used for testing. To examine the differences in injection rate shaping of diesel fuel and jatropha oil, the injector was tested with an injection rate analyzer using both the fuels. To investigate the combustion process, the engine was mounted at an engine test bench and equipped with a cylinder pressure indication system. All limited emissions, as well as fuel consumption, were measured. Various injection strategies, boost and rail pressure levels were tested at different EGR rates in terms of their impact on the combustion process. EGR in particular offers a great potential in the case of jatropha oil combustion due to its oxygen content. In addition, the investigation of injection rate shaping in combination with cylinder pressure analysis allowed a detailed thermodynamic evaluation of the combustion process. Ignition delay (ID) was also analyzed using a new method to calculate the start of combustion (SOC)}, language = {en} } @article{TrostSternerBruckner, author = {Trost, Tobias and Sterner, Michael and Bruckner, Thomas}, title = {Impact of electric vehicles and synthetic gaseous fuels on final energy consumption and carbon dioxide emissions in Germany based on long-term vehicle fleet modelling}, series = {Energy}, volume = {141}, journal = {Energy}, publisher = {Elsevier}, issn = {0360-5442}, doi = {10.1016/j.energy.2017.10.006}, pages = {1215 -- 1225}, abstract = {Based on a prospective scenario analysis, possible vehicle fleet developments for the individual motor car traffic (vehicle categories N1 and M1) are investigated for Germany in order to determine the long-term vehicle fleet structure, final energy demand, and related carbon dioxide emissions until the year 2050. In this framework, a vehicle fleet model was developed which combines a bottom-up consumer demand model with a dynamic stock-flow approach. Special emphasis is thereby given to different electric power-trains and synthetic gaseous fuels based on the power-to-gas technology. In detail, two different main scenarios are developed and, in addition, the impact of different carbon dioxide taxation levels of fossil fuels on the vehicle fleet structure are analysed. The scenario results reveal a broad range of possible future vehicle fleet structures. In the short to medium timeframe, the internal combustion engine dominates the fleet as a result of efficiency improvements and an increased use of natural gas as automotive fuel. The development of electric power-trains is initially marked by hybrid vehicles, whereas battery electric vehicles dominate the fleet structure in the long-term. Under favourable conditions, also synthetic gaseous fuels are competitive which can reduce carbon dioxide emissions even further.}, language = {en} }