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Development of high-temperature permanent magnet synchronous motor for autonomous robotic navigation: a design and finite element analysis approach

Anand M., Sundaram M., Sivakumar P., Angamuthu A.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2024

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Vol. 72, nr 4

art. no. e150108

EN

Traditional industrial robots come with prime movers, i.e. electric motors (EMs), which range from a few hundred to just a few kilo watts of power ratings. However, for autonomous robotic navigation systems, we require motors which are lightweight with the aspect of high torque and power density. This aspect is very critical when the EMs in robotic navigations are subjected to harsh high temperature survival conditions, where the sustainability of the performance metrics of the electromagnetic system of the EMs degrades with the prevailing high temperature conditions. Hence, this research work addresses and formulates the design methodology to develop a 630 W high temperature PMSM (HTPMSM) in the aspect of high torque and power density, which can be used for the autonomous robotic navigation systems under high temperature survival conditions of 200°C. Two types of rotor configurations i.e. the surface permanent magnet type (SPM) and the interior permanent magnet type (IPM) of HTPMSM are examined for its optimal electromagnetic metrics under the temperature conditions of 200◦C. The 630 W HTPMSM is designed to deliver the rated torque of 2 Nm within the volumetric & diametric constraints of DxL, which comes at 80 × 70 mm at the rated speed of 3 000 rpm with the survival temperature of 200°C and target efficiency greater than 90%. The FEM based results are validated through the hardware prototypes for both SPM and IPM types, and the results confirm the effectiveness of the proposed design methodology of HTPMSM for sustainable autonomous robotic navigation applications.

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Adaptive DLC coatings with different MoS2 content

Osada Piotr, Kot Marcin, Zimowski Sławomir, Wiązania Grzegorz, Lackner Jürgen

Tribologia

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2023

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nr 4

43--51

EN

DLC coatings are widely used in engineering as they are resistant to abrasive wear. However, they exhibit an increased coefficient of friction at temperatures of around 300°C. Soft MoS2 coatings are known to maintain a low coefficient of friction at temperatures up to about 350°C, but suffer from relatively high abrasive wear. Publications from the last decade report a synergistic improvement in the tribological performance of a coating consisting of both these materials. The aim of this study was to investigate the wear resistance of coatings composed of different a-C and MoS2 contents applied by magnetron sputtering on steel. The results obtained in tribological tests conducted using the ball-and-disk method showed at least 20% better adhesion to the substrate of the two-component nanocomposite coating and its increased wear resistance from 15% to as much as 700%, compared to single-component coatings in tests conducted at 20°C and 250°C. The tests showed no deterioration of the two-component coating's coefficient value compared to DLC.

PL

Powłoki DLC znajdują szerokie zastosowanie w technice, ponieważ są odporne na zużycie ścierne. Jednak wykazują podwyższony współczynnik tarcia w temperaturach rzędu 300°C. Miękkie powłoki MoS2 są znane z utrzymywania niskiego współczynnika tarcia w temperaturach do około 350°C, jednak ulegają relatywnie dużemu zużyciu ściernemu. Publikacje z ostatniej dekady podają synergiczne polepszenie parametrów tribologicznych powłoki składającej się z obu tych materiałów. Celem pracy było badanie odporności na zużycie powłok złożonych z różnej zawartości a-C i MoS2 nanoszonych techniką rozpylania magnetronowego na stali. Wyniki uzyskane w testach tribologicznych prowadzonych metodą kula–tarcza wykazały co najmniej 20% lepszą przyczepność do podłoża dwuskładnikowej powłoki nanokompozytowej oraz jej zwiększoną trwałość na zużycie ścierne od 15% do nawet 700%, porównując z jednoskładnikowymi warstwami w badaniach prowadzonych w temperaturze 20°C i 250°C. Badania nie wykazały pogorszenia wartości współczynnika powłoki dwuskładnikowej w porównaniu do DLC.

3

A Novel Approach for Durability Evaluation of Metal Protective Coatings in Dynamic Interplay with the Liquid Alloy

Pałka Paweł, Boczkal Grzegorz, Hotloś Agnieszka, Mrówka-Nowotnik Grażyna

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 4

40--48

EN

The article describes a new test method to quickly evaluate the durability of a protective coating to dynamic contact with liquid metal. The essence of the method is the movement of a drop of liquid metal inside a rotating ring, covered from the inside with the protective coating under test. The parameters determined in the test are analogous to the classic pin-on-disk tribological test. The method was tested for the system: liquid alloy 2017A vs. AlTiN coating on a copper substrate. The test temperature was 750°C, and exposure times ranged from 30 to 90 minutes. Sliding path equivalent for the metal droplet/coating system ranged from 31.6 to 95 m. The study, which included visual evaluation of the surface of the samples, followed by phase and microstructural analysis, showed the high efficiency of the method for assessing the lifetime of protective coatings on contact with liquid metal. The investigated issue was also analyzed from the model side taking into account changes in the diffusion coefficient at the contact of liquid metal with the substrate, occurring with the progressive degradation of the protective coating.

4

Pre- and post-heating mechanical properties of concrete containing recycled fine aggregate as partial replacement of natural sand and nano-silica as partial replacement of cement: experiments and predictions

Shirvani Mohammad Asghari, Khodaparast Afshin, Herozi Morteza Rezaeizadeh, Mousavi Reza, Fallah-Valukolaee Saber

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 4

art. 219, s. 1--27

EN

In this study, the effect of colloidal nano-silica replacing a fraction of cement and recycled concrete fine aggregate replacing natural sand on the post-fire mechanical features and durability of concrete was explored. To achieve this goal, 189 concrete samples were manufactured in total, with key variables being the volume of fine aggregate at 0,50, and 100% replacing natural fine aggregate, the volume of nano-silica at 1.5, 3, 4.5, and 6% replacing the cement weight, and the exposure temperature at 20, 300, and 600oC. Parameters selected for consideration in the concretes consisted of compressive capacity, splitting tensile capacity, elastic modulus, ultrasonic pulse velocity (UPV), and weight loss. Furthermore, using scanning electron microscopy (SEM) imaging, the microstructural condition of different sample groups was investigated. According to the findings, as the content of the recycled fine aggregate (RFA) replacing natural fine aggregate increased, the compressive capacity of the unheated and heated concretes declined, and the rate of this drop became greater as the replacement volume increased. On the other hand, the presence of the nano-silica and an increase in its content replacing the cement content in recycled aggregate concrete improved the compressive strength relative to the reference concrete for all the exposure temperatures, with the greatest improvement for the replacement percentage of 4.5%. In addition, the heat-induced compressive capacity drop was more pronounced at higher replacement levels of nano-silica. With a rise in the exposure temperature of the samples with only the recycled fine aggregate, fewer microcracks formed compared with the samples containing both recycled fine aggregate and nano-silica. The maximum weight loss occurred in the recycled sample containing the highest contents of nano-silica and recycled aggregate. Afterward, it was attempted to estimate the mechanical features of concrete by developing several empirical formulas as a function of temperature and volume fractions of recycled fine aggregate and nano-silica. These formulas were evaluated against the test data of this study and others, which showed an acceptable correlation. Finally, the findings of the tests were evaluated against the predictions of ACI 216, EN 1994-1-2, EN 1992-1-2, and ASCE.