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To find the optimal system-level design of hybrid electric vehicles (HEVs), component models are used in simulations to evaluate a large number of different designs within a high dimensional design space. As the electrical machine (EM) represents a key component of the HEV powertrain in terms of energy consumption, models require scalability and sufficient accuracy with manageable computational effort. This paper presents a novel approach for the development of scalable EM models based on Neural Networks (NN). The models are trained with data derived by a Finite Element Analysis (FEA) based scaling procedure and capable to represent the characteristics of a wide range of EM designs without the incorporation of further details. Once a model is trained, it can be directly used in system-level design optimization. The practicality of the model is proven within an exemplary simulation study and its goodness of fit to the training data is validated by a statistical analysis. This approach can help to reduce the computational effort of EM efficiency maps calculation, since only a small number of time-consuming FEA based scaling simulations must be performed prior to the optimization.
Polymer materials that regulate the relative humidity in their environment are relevant for applications in the packaging and building sectors. By integration of salts in polymer structures, such materials are able to absorb and desorb high amounts of water vapor. In this study, films of polylactic acid and polypropylene with dispersed calcium chloride (2 and 4 wt %) were produced and biaxially stretched to induce the formation of cavities. The resulting cavities in these films account up to 10 vol % and are able to contain emerging calcium chloride solution formed by water vapor absorption. These films absorb reversibly up to 15 wt % water vapor at 75% relative humidity at 23 °C. This absorption behavior is described by effective diffusion and effective sorption coefficients. Using a simple model, the effective water vapor diffusion coefficient of these films can be estimated from the permeation coefficient of the polymer and the sorption coefficient of the absorber.
Dieser Beitrag behandelt ein erweitertes analytisches Berechnungsmodell zum mechanischen Verhalten von beliebig rechtwinklig berandeten Mehrschraubenverbindungen (MV). Es werden die Modellvoraussetzungen, -einschränkungen, Theorie und Ergebnisgüte vorgestellt. Dazu werden die Ergebnisse des analytischen Berechnungsmodells den Ergebnissen der numerischen Untersuchungen gegenübergestellt.
Die mechanischen Eigenschaften additiv gefertigter Bauteile lassen sich nicht nur durch bessere Verfahrens- und Anlagentechnik steigern. Vor allem beim Lasersintern lohnt sich ein genauer Blick auf das eingesetzte Polymerpulver. Eine umfangreiche Untersuchung zeigt, warum und wie sich eine spezifische Pulverqualifizierung auswirkt.
The mechanical properties of additively produced components can only be increased by means of improved processing and plant technology. Particularly with laser sintering, a closer look at the polymer powder used is worthwhile. A comprehensive investigation shows why and how such a specific powder qualification has an effect.
Polymer powders for laser sintering must exhibit special intrinsic and extrinsic properties. A new concept for the characterization and evaluation of laser sintering powders permits conclusions to be drawn about aging as well as the suitability of novel powder systems – even before the first build job.
Um konkrete Kundenanforderungen beim Vertrieb neuer Fahrzeuge zuverlässig berücksichtigen zu können, wurde ein Verfahren erarbeitet, mit dem sich Straßen aus Sicht wesentlicher Einsatzparameter wie z.B. die Straßengüte, der Straßentyp sowie die Längs- und Querdynamik aus Sicht der Beanspruchung bewerten und kategorisieren lassen. Das Belastungs- und Beanspruchungsgeschehen lässt sich weitgehend fahrzeugunabhängig nach Höhe, Häufigkeit und Frequenz anhand erfasster Beschleunigungen zutreffend beschreiben. So können Straßen aus Sicht der Beanspruchung bewertet und in Wort und Bild beschriebenen Straßenqualitäts-klassen zugeordnet werden. Umgekehrt erlauben geeignete Kunden-Abfragen mittels eines Anforderungs- und Einsatzkataloges zu Straßenqualität und Einsatzparametern, die kundengerechte Konfiguration von Fahrzeugen.
Eine Möglichkeit zum verstärkten Schutz kühlpflichtiger Molkereiprodukte gegenüber den in der Logistikkette auftretenden mechanischen Belastungen besteht in der räumlichen Trennung von Lebensmitteln und Temperierelementen innerhalb der Versandverpackung. Je nach Art der Isolierverpackung kann das Temperaturhaltevermögen durch die optimierte Anordnung der Temperierelemente deutlich gesteigert werden.
Der Versand kühlpflichtiger Molkereiprodukten muss unter Einhaltung eines definierten Temperaturbereichs erfolgen. Die systematische Analyse auftretender Wärmetransportprozesse an Isolierverpackungen verdeutlicht deren Aufbau und Wirkungsprinzip und signalisiert ergebnisrelevante Einflussgrößen auf das Temperaturhaltevermögen.
Die rasant voranschreitende Digitalisierung treibt die Vermarktung und den Vertrieb von Lebensmitteln via Internet voran. Allerdings weisen die meisten Molkereiprodukte eine enorme Empfindlichkeit gegenüber den in der Logistikkette typisch auftretenden Belastungsarten auf. Die Sicherstellung eines hohen Qualitätsniveaus fordert deren verstärkten Schutz durch eine geeignete Versandverpackung.
In order to be able to reliably take account of specific customer requirements when selling new vehicles, a method has been developed with which roads can be compared from the point of view of essential operational parameters such as, evaluate and categorize the road grade, the type of road and the longitudinal and lateral dynamics in terms of the load. The load and stress conditions can be described largely vehicle-independent according to height, amount and frequency based on detected accelerations. Hence, roads can be assessed in view of stress and combined to street-quality classes described in words and pictures. Conversely, suitable customer queries by means of a requirement catalog for road quality and operational parameters allow a specific configuration of vehicles.
Equations of the form ?[?] = 0, ?: ? ⟶ ?̅ smooth, ?, ?̅ real Banach spaces are investigated with the aim of continuing the basic solution ?[0] = 0 with ? ′ [0] Fredholm operator to a solution curve ?[?(?)] = 0 with the implicit function theorem. If ? ′ [0] is surjective, then the transversality condition of the implicit function theorem can be satisfied in a straightforward way, yielding a regular solution curve, whereas otherwise the equation ?[?] = 0 has to be extended appropriately for reaching a surjective linearization accessible to the implicit function theorem. This extension process, implying in the first step the standard bifurcation theorem of simple bifurcation points, is continued arbitrarily, yielding a sequence of bifurcation results presumably being applicable to bifurcation points with finite degeneracy.
The system of undetermined coefficients of a bifurcation problem
?[?] = 0 in Banach spaces is investigated for proving the existence of families of solution curves by use of the implicit function theorem. The main theorem represents an Artin-Tougeron type result in the sense that approximation of order 2? ensures exact solutions agreeing up to order ? with the approximation
[13], [22]. Alternatively, it may be interpreted as Hensel’s Lemma in Banach spaces. In the spirit of [9] and [18], the required surjectivity condition is interpreted as a direct sum condition of order ? that allows for solving the remainder equation
with respect to graded subspaces derived from an appropriate filtration [24], [25]. In the direction of these subspaces, the determinant can be calculated in a finite dimensional setting, enabling the investigation of secondary global bifurcation phenomena by sign change of Brouwer’s degree [18]. The direct sum
condition seems to be a generalization of the direct sum condition introduced in [9].
The implicit function theorem delivers stability of ? leading coefficients [?̅1 , … , ??̅] with respect to perturbations of order 2? +1 and uniqueness in pointed wedges around the solution curves. Further, denoting by ?̅∞ the subset of arc space ?∞ with [?̅1 , … , ??̅] fixed, ?̅∞ is iteratively approximated by ?̅ 2?+? as ? → ∞. In addition, a lower bound of the Greenberg function ?(?) of a singularity is constructed by use of a step function obtained from ?-degree of different solution curves.
Finally, based on Kouchnirenko’s theorem [17] and an extension in [6], the results are applied to Newton-polygons where it is shown that the Milnor number of a singularity can be calculated by the sum of ?-degrees of corresponding solution curves. Simple ???-singularities are investigated in detail. The main theorem represents a version of strong implicit function theorem in Banach spaces, possibly comparable to theorems in [2]. Moreover, our aim is to extend the direct sum condition of order ? from [9] to certain topics in singularity and approximation theory. Generalizations to modules as well as specializations to polynomials seem to be promising.
A note on an expansion formula with application to nonlinear Differential-Algebraic-Equations
(2019)
In [DL] systems of differential polynomials are investigated with
respect to properties of Artin approximation type. The key tool in [DL] is an extended version of a formula by Hurwitz [Hu] expressing high order derivatives of an expansion by lower ones. The formula is further refined in [VFZ] to deliver sufficient conditions concerning the existence of power series solutions of scalar algebraic differential equations of order?.
In the paper at hand, the main results from [VFZ] are first reproduced and further extended to systems of nonlinear differential algebraic equations. In addition, a simple extension of Tougeron’s implicit function theorem is given in a specific constellation.
The results follow from [S1], [S2] where Artin approximation is treated within a Banach space setting, thereby constructing an expansion formula that expresses accurately the required dependency of low and high order derivatives within the system of undetermined coefficients.