Wyniki wyszukiwania - BazTech

1

Influence of a crosshead rate and a number of stress cycles on measurement results in the in-plane shear test for a cross-ply vinylester-carbon laminate

Bondyra A., Gotowicki P.

Journal of KONES

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2010

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Vol. 17, No. 1

29-40

EN

The paper presents some experimental studies on a regular cross-ply laminate of the [(0/90)F] 4S configuration. Each layer is VE 11-M vinylester resin (the manufacturer: ,,Organika-Sarzvna" Chemical Plants, Sarzyna, Poland) reinforced with plam weave carbon fabric of parameters: Stvle 430, Carbon 6K, substance 300g/m2, warp/weft 400/400 tex, 3.7/3.7 yarn/cm (the manufacturer: C. Cramer GmbH & Co. KG Division ECC). The orthotropic laminate was produced by ROMA private enterprise In Grabowiec, Poland, using the vacuum molding method and the technological parameters developed by ROMA taking into account the VE 11-M material specijication. The PN-EN ISO 14129:1997 standard [1] and closely related standards [2-9] were taken into consideration in experimental studies on the static in-plane shear response by a tensile test of a [(plus or minus 45)F]nS laminate. A program of the experiments was focused on testing a rate of a testing machine crosshead and a number of static stress cycles. An influence of these factors on the in-plane shear modulus was investigated. Based on the conducted investigations, the modified experimental procedure has been proposed for determination of the correct value of the in-plane shear modulus and the in-plane shear strength.

2

Repeatability of experimental procedures to determine mechanical behaviour of ligaments

Öhman C., Baleani M., Viceconti M.

Acta of Bioengineering and Biomechanics

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2009

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Vol. 11, nr 1

19-23

EN

The aim of this study was to investigate intra- and interspecimen repeatability of an experimental procedure, which determines elastic and viscoelastic properties of knee ligaments. The collateral ligaments from sheep were used and the repeatability was evaluated in terms of the coefficient of variation. The results indicated a good intraspecimen repeatability (the coefficient of variation generally less than 5%), whereas the interspecimen repeatability was lower (coefficient of variation of about 50%). In conclusion, since the intraspecimen coefficient of variation was low the test procedure was assumed to be repeatable.

3

The importance of experimental parameters when testing the hardness of rubber

Hodson R., Lackovic S.

Elastomery

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2002

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T. 6, nr 3

17-24

EN

Hardness is one of the most widely measured properties used to characterise rubber as it is a practical way of determining the degree of vulcanization of a sample. Two scales are in general use throughout the world - the IRHD (International Rubber Hardness Degree) scale and the Shore scale. The two test methods use totally different indenture geometries, applied forces, test times and procedures. This paper looks at the instruments in question, studies the differences between the tests and their relationship between scales where possible. It also highlights the merits of each instrument and test type.

PL

Twardość jest najczęściej mierzoną właściwością charakteryzującą gumę i stanowi praktyczny sposób oznaczenia stopnia zwulkanizowania próbki. Ogólnie na świecie używane są dwie skale: IRHD (International Rubber Hardness Degree) i Shore'a. Te dwie metody badania całkowicie różnią się pod względem geometrii czujnika, przyłożonej siły, czasu pomiaru i procedur. W artykule przedstawiono różnice między tymi badaniami i możliwe relacje między skalami (twardości). Wyjaśniono także zasadę działania każdego z aparatów i typ pomiaru.

4

Damage tolerance evaluation of the wing spar with cracked web

Augustin P.

Research Bulletin / Warsaw University of Technology, Institute of Aeronautics and Applied Mechanics

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2001

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nr 11

7-12

EN

Damage tolerance evaluation is required for the aircraft life determination according to FAR Part 25 regulations. This concept is based on the crack propagation and residual strength determination. The damage tolerance evaluation of an aircraft structure, results in the inspection program ensuring that fatigue initiated cracks would involve no failure prior to the detection. The inspection program must be developed for each main structural element in the aircraft. Solutions to this problem usually found in the literature deal mainly with the components subject to tension; such as stiffened panels or lugs. This paper presents the testing program and FEM analysis focused on the wing spar with cracks in the web. It is characteristic of fatigue cracks in the web that they usually change their growth direction due to a complex stress state. The crack shape measured was used for constructing of a FEM model of the spar, the residual strength was calculated and compared with the experimental results.

5

Słabe międzywarstwowe sprzężenie wymienne poprzez quasi-amorficzną przekładkę Ti-Co

Smardz L., Smardz K.

Elektronika : konstrukcje, technologie, zastosowania

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2001

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Vol. 42, nr 3

34-35

PL

Warstwy wielokrotne Co/Ti otrzymano metodą ultra wysoko-próżniowego (5 x 10-10 mbar) rozpylania katodowego DC/RF. Planarny wzrost subwarstw Co i Ti został potwierdzony in-situ metodą rentgenowskiej spektroskopii fotoelektronów. Subwarstwy Co rosły na Ti w miękkiej magnetycznie fazie nanokrystalicznej (średni rozmiar ziarna D << 10 nm) do grubości krytycznej dcrit ~ 3 nm. Dla grubości większych niż dcrit, subwarstwy Co rosły w fazie polikrystalicznej ze średnim rozmiarem ziarna D > 10 nm. Badania pętli histerezy w płaszczyźnie warstw wykazały, że subwarstwy Co są bardzo słabo sprzężone lub rozprzężone dla grubości dTi > 2.7 nm. Szybki zanik sprzężenia wraz ze wzrostem grubości subwarstwy Ti związany jest z silnym jego tłumieniem, wynikającym z quasi-amorficznej struktury przekładki niemagnetycznej Ti-Co, która tworzy się na interfejsach w czasie procesu nanoszenia. Ponadto, nanokrystaliczne subwarstwy Co o grubości 2.2 nm wykazywały słabe 90° sprzężenie wymienne w pobliżu strefy przejściowej od sprzężenia typu ferromagnetycznego do słabego antyferromagnetycznego.

EN

Co/Ti multilayers were prepared using ultra high vacuum (5 x 10 -10 mbar) DC/RF magnetron sputtering. The planar growth of the Co and Ti sublayers was confirmed in-situ by X-ray photoelectron spectroscopy. Cobalt sublayers grow in the soft magnetic nanocrystalline phase (with average grains size D << 10 nm) up to a critical thickness dcrit ~ 3 nm. For a thickness greater than dcrip the Co sublayers undergo a structural transition to the polycrystalline phase with D > 10 nm. In-plane hysteresis loop measurements show that the Co sublayers are very weakly exchange coupled or decoupled for dTi > 2.7 nm. The rapid decrease of the interlayer exchange coupling with increasing of the Ti sublayer thickness could be explained by its strong damping due to formation (during the deposition process) of a nonmagnetic quasi-amorphous Co-Ti alloy layer at the interfaces. The nanocrystalline Co sublayers with dCo = 2.2 nm showed a weak 90° coupling near the transition zone (dTi ~2nm) from ferromagnetic to weak antiferromagnetic coupling.