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1

Comparative Tests of Shear Strength of Adhesive Lap Joints after Thermal Shocks

Kłonica Mariusz, Bielawski Radosław, Żokowski Mariusz

Advances in Science and Technology. Research Journal

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2021

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Vol. 15, no 4

364--375

EN

This work presents the results of comparative tests for the determination of Young’s modulus and the static shear strength of adhesive lap joints, based on grade 316L steel. The tests also concerned the determination of the glass transition temperature of a certain adhesive composition: Epidian 57 epoxy resin with a 10% Z1 hardener content. The paper shows the test results for the surface free energy and selected surface roughness parameters, including photographs of the test specimens after destructive testing. The tests were comparative and performed on adhesive joints, with and without exposure to thermal cycling. The scope of the testing included a relatively short thermal cycling run of 500 cycles with a temperature variation of -40°C to +60°C. An analysis was carried out of the results from testing the static shear resistance of specimens manufactured using various methods of adhesive joint seasoning. The experimental test results were statistically processed in compliance with good research practice.

2

Functional plasma-deposited coatings

Pashechko M., Kindrachuk M., Gumeniuk I., Tisov O., Zahrebelniy V.

Advances in Science and Technology. Research Journal

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2017

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Vol. 11, no 4

301--304

EN

The paper focuses on the problem of low adhesion of plasma sprayed coatings to the substrate. The subsequent laser treatment modes and their influence on the coating-substrate interface were studied. This allows to decrease the level of met-stability of the coating, thus decreasing its hardness down to 11–12 GPa on the surface and to about 9 GPa on depth of 400 μm. The redistribution of alloying elements through solid and liquid diffusion improves mechanical properties and rises the adhesion up to 450 MPa after remelting and up to 90–110 MPa after laser-aided thermal cycling. At the same time, remelting of coating helps to decrease its porosity down to 1%. The obtained complex of properties also allows to improve wear resistance of coatings and to decrease friction factor.

3

Effect of thermal cycling on the tensile behavior of Cf/Al fiber metal laminates

Noor M. F., Pasha R. A., Wakeel A., Nasir M. A, Bilal Y.

Advances in Science and Technology. Research Journal

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2017

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Vol. 11, no 3

80--86

EN

The objective of this research work was to estimate the effect of thermal cycling on the tensile behavior of CARALL composites. Fiber metal laminates (FMLs), based on 2D woven carbon fabric and 2024-T3 Alclad aluminum alloy sheet were manufactured by pressure molding technique followed by hand layup method. Before fabrication, aluminum sheets were anodized with phosphoric acid to produce a micro porous alumina layer on surface. This microporous layer is beneficial to produce a strong bond between the metal and fiber surfaces in FMLs. The effect of thermal cycling (-65 to +70ºC) on the tensile behavior of Cf/Al based FML was studied. Tensile strength was increased after 10 thermal cycles, but it was decreased slightly to some extent after 30 and 50 thermal cycles. Tensile modulus also show similar behavior as that of tensile strength.

4

Comparative analysis of effect of thermal shock on adhesive joint strength

Kłonica M.

Advances in Science and Technology. Research Journal

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2016

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Vol. 10, nr 32

263--268

EN

The aim of this study was a comparative analysis of static shear strength of single-lap adhesive joints of 316L steel adherends, measured prior to and after mechanical treatment with a P320 grit coated abrasive tool. The study was of comparative nature and focused on adhesive joints subjected to thermal cycling. The tests were carried out on joints bonded with Epidian 5 and Epidian 6 epoxy adhesives hardened with Z1 and PAC curing agents. The static shear strength tests results of single-lap adhesive joints were analysed with regard to different surface treatment variants. The scope of tests covered a relatively short fatigue cycle, i.e. 200 cycles in the range of temperatures between -40o C and +60o C. This paper includes the surface free energy and selected surface roughness parameters of substrates and images showing the surface of adherends before and after mechanical treatment with P320 grit coated abrasive tool.

5

Thermal residual stress investigation in AS52/ Al18B4O33 magnesium matrix composite by thermal cycling test

Lee W., Park Y., Park B., Park I., Park Y.

Archives of Materials Science and Engineering

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2008

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Vol. 32, nr 1

17-20

EN

Purpose: MMCs have microscopic scale thermal residual stress that is generated after cooling from high temperature Because of the difference of thermal expansion coefficient between the matrix and reinforcement. Because of their high service temperature, automobile parts experience thermal cycling between room and service temperature. Those thermal cycles can vary the properties of the MMCs by changing residual stress field. In this study, the relations between residual stresses and hardness were investigated. Design/methodology/approach: For the residual stress investigations, thermal cycling test was performed. After thermal cycling testing, the thermal residual stress of the MMC was investigated using high resolution Xray diffraction test. On the other hand, the residual stress was calculated by the finite elements method and it was compared to the experimental results. Findings: The residual stress relaxed in the matrix with thermal cycling. With the relaxation of the residual stress, the hardness of the composite was decreased. Research limitations/implications: In this study, the relaxation of residual stress of MMCs was observed with thermal cycling. Further investigations for the mechanical properties, like tensile behaviour and wear properties, should be needed in next study. Originality/value: In this study, numerically calculated residual stress in magnesium matrix MMCs was compared with experimental results.

6

Stabilność rezystorów RuO2 + szkło do zastosowań kriogenicznych

Rycerz D., Mleczko K., Zawiślak Z., Żak D.

Elektronika : konstrukcje, technologie, zastosowania

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2006

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Vol. 47, nr 11

42-44

PL

Wykonane we własnym zakresie rezystory grubowarstwowe RuO2+ szkło badano pod kątem zastosowań w termometrii niskotemperaturowej. Zaprezentowane wyniki badań obejmują stabilność rezystancji próbek poddanych cyklicznym zmianom temperatury (zarówno szybkim jak i powolnym) w przedziale 300..77 K oraz w trakcie długotrwałego wygrzewania (1600 h) w temperaturze 170°C. Zmierzono również wskaźnik szumów próbek poddanych szybkim cyklom termicznym.

EN

Laboratory-made RuO2+ glass thick film resistors have been examinated for their application as cryogenic thermometers. Presented results encompass resistance stability during thermal cycling from 300 K to 77 K - fast (thermal shocks) and slow - and longterm (1600 h) annealing at 170°C. For fast thermal cycling current noise index of the resistors was also measured.

7

Influence of temperature and aging on polarization mode dispersion of tight-buffered optical fibers and cables

Borzycki K.

Journal of Telecommunications and Information Technology

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2005

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nr 3

96-104

EN

This paper presents results of laboratory tests investigating influence of temperature on polarization mode dispersion (PMD) in variety of single mode optical fibers and cables. Research was focused primarily on tight-buffered fibers, where most pronounced effects resulting from buffer shrinkage or expansion were expected. The goal was to verify performance of optical fiber cable exposed to extreme temperatures and to compare behavior of different cables. Very strong temperature dependence of PMD was detected in standard single mode fibers with 0.9 mm tight buffer, commonly used in indoor cables, and in complete cable with such fiber. However, both nonzero dispersion-shifted fibers, spun during drawing and optical unit used in optical ground wire (OPGW), where 12 fibers are stranded showed good stability of PMD during thermal cycling. The same optical unit extracted from OPGW exhibited excellent PMD stability also during accelerated life test.

8

Thermal behaviour of AlSi12CuMgNi piston alloy with and without short fiber reinforcement

Huang Y., Hort N., Kainer K.

Kompozyty

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2003

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R. 3, nr 7

279-284

EN

Mismatch in thermal expansion coefficients could introduce large thermal stress and correspondingly increase the dislocation density in metal matrix composite. The aging behavior could therefore be modified. The CTE mismatch also affects the dimensional stability of metal matrix composites during their service because any fluctuation in environmental temperature could introduce internal thermal stress. The paper presents an overview on our investigations on the thermal behavior of AISi12CuMgNi piston alloy with and without short fiber reinforcement, including aging, thermal expansion and thermal cycling behaviors. Major experimental results obtained up to now are shown and related physical phenomena are discussed.

PL

Niedopasowanie współczynników rozszerzalności termicznej (CTE) może powodować duże naprężenia termiczne i w rezultacie zwiększyć gęstość dyslokacji w kompozycie o osnowie metalowej. Dlatego jego zachowanie może zmieniać się przy starzeniu. Niedopasowanie CTE wpływa także na stabilność wymiarową kompozytów metalowych w trakcie ich użytkowania, ponieważ każda zmiana temperatury otoczenia może wywołać wewnętrzne naprężenia termiczne. Niniejszy artykuł przedstawia przegląd badań nad zachowaniem się niezbrojonego i zbrojonego krótkimi włóknami stopu przeznaczonego na tłoki silnikowe pod wpływem temperatury przy starzeniu, rozszerzaniu cieplnym i pod działaniem cyklicznego obciążenia termicznego. Przedstawiono najważniejsze wyniki dotychczasowych badań i omówiono związane z tym zjawiska fizyczne.

9

The effect of thermal cycling on elastic parameters of concrete for nuclear power plants

Semerak P., Michalko O.

Prace Naukowe Instytutu Budownictwa Politechniki Wrocławskiej. Konferencje

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1999

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Vol. 75, nr 26

161-166

EN

The method of artificial aging of concrete is described in the article. Thermal cycling of the tested specimens carried out this process. The samples were exposed to the temperature -20oC for 45 0C minutes in the conditioning chamber and afterwards to the temperature +650C for the same time. These temperature changes were constantly repeated, the total number of cycles reached 750. The specimens of concrete for nuclear power plants were tested. The resonance and ultrasonic methods during the artificial aging process continuously measured the elastic parameters of concrete, and to control the process, even destructive strength tests were carried out.

PL

W pracy opisano metodę sztucznego starzenia betonu za pomocą cyklu termicznego przetrzymując próbki w temperaturach -200C - przez 45 min i + 650C - również przez 45 min. Wykonano 750 cykli. Do badań właściwości odkształceniowych wykorzystano metodę rezonansową i ultradźwiękową. Otrzymane wyniki mówią o możliwości wyeliminowania badań niszczących z kontroli jakości betonu w obiektach elektrowni jądrowych.