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1

Conversion of compression test data into flow curve, accounting for barrelling

Khoddam Shahin, Hodgson Peter D.

Computer Methods in Materials Science

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2021

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Vol. 21, No. 3

157--162

EN

Current solutions to convert the axis-symmetric compression test (ACT) data to flow data ignore the barrelling deformation in the sample. This work presents a solution for the test which accounts for the sample’s barrelling by discretising it into a finite number of layers of different radii. The solution assumes a constant and sliding friction at the anvil-sample interface. The sample’s flow behaviour is identified by combining a recent kinematic solution of the test, Prandtl–Reuss–Mises’s equations and a slab-analysis of the layers. It also involves an averaging of the effective plastic stresses developed in the individual layers. The solution is verified for a special case of no-barrelling which matches the currently used solution.

2

Fabrication and Macroscopic Properties of Filler Metal (BCuP-5) on Cu-plate using Laser Cladding Process

Lee Kee-Ahn, Park Joo Hyun, Joo Yeun Ah

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 2

559--563

EN

This study stacked a thin, dense BCuP-5 (Cu-Ag-P based filler metal) on a Cu-plate using the laser cladding (L.C) process to develop a method to manufacture Ag reducing multilayer clad electrical contact material with an Ag-M(O)/Ag/Cu/BCuP-5 structure. Then, the microstructure and macroscopic properties of the manufactured BCuP-5 coating layer were analyzed. The thickness of the manufactured coating layer was approximately 1.7 mm (maximum). Microstructural observation of the coating layer identified Cu, Ag and Cu-Ag-Cu3P ternary eutectic phases like those in the initial BcuP-5 powder. To evaluate the properties of the manufactured coating layer, hardness and adhesion strength tests were performed. The average hardness of the laser cladded coating layer was 183.2 Hv, which is 2.6 times greater than conventional brazed BcuP-5. The average pull-off strength measured using the stud pull test was 341.6 kg/cm2. Cross-sectional observation of the pulled-off material confirmed that the coating layer and substrate maintained a firm adhesion after pull-off. Thus, the actual adhesion strength of Cu/BcuP-5 was inferred to be greater than 341.6 kg/cm2. Based on the above findings, it was confirmed that it is possible to manufacture a sound Ag reducing multilayer clad electrical contact material using the laser cladding process.

3

Roughness Influence on Macro- and Micro-Tribology of Multi-Layered Hard Coatings on Carbon Fibre Polymer Composite

Lackner J. M., Major B., Waldhauser W., Mzyk A., Major Ł., Kot M.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 3

2145--2151

EN

Goal of this work is the investigation of roughness influences on the abrasive wear behaviour of magnetron sputtered multi- -layered, low-friction coatings on carbon-fibre reinforced polymers (CFRP). Higher coating roughness at similar CFRP quality was realized by higher deposition rates, leading to increased heat flux to the substrates during deposition. Thermal expansion of the epoxy matrix on the micro scale results in a wavy, wrinkled surface topography. Both in scratch and reciprocal sliding testing against alumina, the friction coefficients are lower for the smooth coatings, but their wear rate is higher due to low-cycle fatigue caused abrasion.

PL

Celem pracy jest badanie wpływów szorstkości na zużycia abrazyjne osadzonych magnetronowo wielowarstwowych powłoki o niskim współczynniku tarcia na bazie wzmocnionych włóknami węglowych polimerów (CFRP). Większa szorstkość powłoki przy podobnej jakości (CFRP) została uzyskana przez wyższe szybkości osadzania, co prowadziło do zwiększonego strumienia ciepła do podłoża podczas osadzania. Rozszerzalność cieplna matrycy epoksydowej w skali mikro pozwalała na uzyskanie falistej, pofałdowanej topografii powierzchni. Zarówno w teście zarysowania jak i ścierania z przeciwpróbką korundową uzyskano niższe współczynniki tarcia dla gładkich powierzchni zaś ich szybkość zużycia była wyższa ze względu na nisko-cyklowe zmęczenie wywołujace przetarcie.

4

Statement Networks to Condition Monitoring of the Sealless Pump

Rzydzik S., Amarowicz M., Psiuk K., Rogala T.

International Journal of Electronics and Telecommunications

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2014

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Vol. 60, No. 3

265-269

EN

This paper shows an application of multi-layer statement networks to condition monitoring of the sealless magnetic drive pump. In this case, statement networks are computed based on the use of Bayesian probabilities. Moreover, the tool called REx which allows implementing such networks is described. An example of created four-layer network as well as final results of the performed tests shows also.

5

Powłoki optyczne do zastosowania na panele szklane

Domaradzki J., Wojcieszak D., Kaczmarek D., Mazur M., Poniedziałek A.

Elektronika : konstrukcje, technologie, zastosowania

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2014

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Vol. 55, nr 9

42-44

PL

W pracy przedstawione zostały zagadnienia związane z projektowaniem powłok optycznych przeznaczonych do zastosowania na panele szklane. W szczególności, omówiono sposoby projektowania powłok w postaci pojedynczych warstw oraz wielowarstw (na bazie metali oraz tlenków metali), które umożliwiają odbijanie promieniowania świetlnego (na ściśle określonym poziomie) w wybranym zakresie spektralnym (np. w podczerwieni). Oprócz tego, porównano charakterystyki współczynnika odbicia światła dla jedno i wielowarstwowych powłok antyrefleksyjnych (na bazie TiO2 i SiO2). Praca ta zawiera także przykłady optymalizacji konstrukcji wielowarstwych powłok odbijających promieniowanie podczerwone, gdzie przez zwiększenie liczby warstw oraz zastosowanie materiałów o odpowiednich współczynnikach załamania światła można uzyskać ściśle pożądany przebieg charakterystyk Rλ. Innymi, z przedstawionych sposobów modyfikacji konstrukcji powłok odbijających jest zastosowanie metalicznych cienkich warstw lub materiałów gradientowych.

EN

In this paper the issues related to the design of optical coatings for application to glass panels have beed discussed. In particular, coatings designing methods in the form of single films and multilayers (based on the metals and metal oxide), which reflect light radiation (at a specified level) in the desired spectral range (e.g. in infrared) have been presented. Besides, reflectance characteristics of anti-reflective coatings based on single and multi-layers of TiO2and SiO2 have been compared. This paper also contains examples of optimization of multilayers construction that are reflecting infrared radiation, where by increasing the number of layers and application of materials with the appropriate refractive index the Rλ characteristics can be precisely tuned. Other ways to modify the construction of reflective coatings is the application of metallic thin films or graded materials.

6

Effect of Core Thickness and Intermediate Layers on Mechanical Properties of Polypropylene Honeycomb Multi-Layer Sandwich Structures

Arbaoui J., Schmitt Y., Pierrot J-L., Royer F-X.

Archives of Metallurgy and Materials

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2014

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Vol. 59, iss. 1

11--16

EN

Sandwich structures are widely used in lightweight construction especially in aerospace industries because of their high specific strength and stiffness. This paper investigates the effect of core thickness and intermediate layers on the mechanical properties of a polypropylene honeycomb core/composite facing multilayer sandwich structure under three points bending. We developed a theoretical model which makes it possible to calculate the shear properties in multi-cores. The results obtained by this model are agreed with our experimental results, and the results obtained with bending test showed that the mechanical properties of the composite multilayer structures increase with core thickness and intermediate layers.

PL

Struktury warstwowe są szeroko stosowane w lekkich konstrukcjach, szczególnie w przemyśle lotniczym, z powodu ich wysokiej wytrzymałości i sztywności. Zbadano wpływ grubości rdzenia i warstw pośrednich na właściwości mechaniczne polipropylenowego kompozytu o strukturze piastra miodu (rdzeń) i wielowarstwowej struktury w trakcie trójpunktowego zginania. Opracowano model teoretyczny, który umożliwia obliczenie właściwości ścinania w przypadku wielu rdzeni Uzyskane wyniki modelowania są zgodne z naszymi wynikami eksperymentalnymi. a wyniki uzyskane w teście zginania wykazały. że właściwości mechaniczne kompozytowych struktur warstwowych rosną ze zwiększeniem grubości rdzenia i warstw pośrednich.

7

Shape Optimization of Two-layer Acoustical Hoods Using an Artificial Immune Method

Chiu M-C.

Archives of Acoustics

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2012

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Vol. 37, No. 2

181-188

EN

Research on acoustical hoods used in industry has been widely discussed; however, the assessment of shape optimization on space-constrained close-fitting acoustic hoods by adjusting design parameters has been neglected. Moreover, the acoustical performance for a one-layer acoustic hood used in a high intensity environment seems to be insufficient. Therefore, an assessment of an optimally shaped acoustical hood with two layers will be proposed. In this paper, a numerical case for depressing the noise level of a piece of equipment by optimally designing a shaped two-layer close-fitting acoustic hood under a constrained space will be introduced. Furthermore, to optimally search for a better designed set for the multi-layer acoustical hood, an artificial immune method (AIM) has been adopted as well. Consequently, this paper provides a quick and effective method to reduce equipment noise by optimally designing a shaped multi- layer close-fitting acoustic hood via the AIM searching technique.

8

The selected problems of multi-layer pavements modelling in design and diagnostics

Graczyk M., Rafa J.

Journal of KONES

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2007

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Vol. 14, No. 1

209-218

EN

This paper will present selected problems connected with modelling of multi-layer pavements. Multi-layer pavement models, which utilize solutions such as the one of Boussinesq, Burmister, Kogan, Odemark and others, contain many simplifications, which bas a significant influence on the estimated real value of stress, strain, deflection as well as on the coefficient of pavement layers interaction. In the article based on the experiments carried out, we want to present our own layered-pavement models and solutions to them, which can be used mainly in the diagnostics of bearing capacity. The estimation of bearing capacity is conducted on the basis of full time data obtained with the FWD device. Moreover, the conclusions implicated by the above mentioned analysis are of big importance in design and operation process of road and airfield pavements. They pertain not only to the influence of modulus and thickness of particular layers but also to the way of pavement layers interaction, Poisson's coefficient, thermal characteristics and others.

9

Buckling and initial post-buckling behaviour of thin-walled elliptic shells under bending

Królak M., Kołakowski Z.

Mechanics and Mechanical Engineering

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2004

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Vol. 7, nr 1

97-105

EN

The problem of the buckling and the initial post-buckling equilibrium paths of thin-walled cylindrical and elliptic shells subjected to bending has been carried out. Shell elements can be made of multi-layer orthotropic materials. The problem has been solved within the first order approximation of Koiter's asymptotic- theory, using the transition matrix method.