Purpose
Due to the increasing amount of high power density high-speed electrical machines, a detailed understanding of the consequences for the machine’s operational behaviour and efficiency is necessary. Magnetic materials are prone to mechanical stress. Therefore, this paper aims to study the relation between the local mechanical stress distribution and magnetic properties such as magnetic flux density and iron losses.
Design/methodology/approach
In this paper, different approaches for equivalent mechanical stress criteria are analysed with focus on their applicability in electrical machines. Resulting machine characteristics such as magnetic flux density distribution or iron are compared.
Findings
The study shows a strong influence on the magnetic flux density distribution when considering the magneto-elastic effect for all analysed models. The influence on the iron loss is smaller due to a high amount of stress-independent eddy current loss component.
Originality/value
The understanding of the influence of mechanical stress on dimensions of electrical machines is important to obtain an accurate machine design. In this paper, the discussion on different equivalent stress approaches allows a new perspective for considering the magneto-elastic effect.
Propagation-based phase contrast imaging with a laboratory x-ray source is a valuable
tool for studying samples that show only low absorption contrast,
either because of low density, elemental composition, or small feature
size. If a propagation distance between sample and detector is
introduced and the illumination is sufficiently coherent, the phase
shift in the sample will cause additional contrast around interfaces,
known as edge enhancement fringes. The strength of this effect depends
not only on sample parameters and energy but also on the experimental
geometry, which can be optimized accordingly. Recently, x-ray lab
sources using transmission targets have become available, which
provide very small source sizes in the few hundred nanometer range.
This allows the use of a high-magnification geometry with a very short
source–sample distance, while still achieving sufficient spatial
coherence at the sample position. Moreover, the high geometrical
magnification makes it possible to use detectors with a larger pixel
size without reducing the image resolution. Here, we explore the
influence of magnification on the edge enhancement fringes in such a
geometry. We find experimentally and theoretically that the fringes
become maximal at a magnification that is independent of the total
source–detector distance. This optimal magnification only depends on
the source size, the steepness of the sample feature, and the detector
resolution. A stronger influence of the sample feature on the optimal
magnification compared to low-magnification geometries is
observed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.