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- Bjerkén, Christina, PhD, 1962-, et al.
(författare)
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A numerical method for calculating stress intensity factors for interface cracks in bimaterials
- 2001
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Ingår i: Engineering Fracture Mechanics. - : Elsevier. - 0013-7944 .- 1873-7315. ; 68:2, s. 235-246
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a method For obtaining the complex stress intensity factor (or alternatively the corresponding energy release rate and mode mixity) for an interface crack in a bimaterial using a minimum number of computations. A crack closure integral method for homogeneous materials developed by Rybicki and Kanninen has been modified to include mismatch in material properties. This was achieved directly from the nodal forces at the crack tip and the displacements near the tip as obtained from a finite element analysis using only four-node constant strain elements. Numerical calculations for tensile and mixed mode loading showed good agreement with results from corresponding analytical solutions. The main advantages of this method are that it is straightforward and easy to use and that the number of calculations needed to obtain the stress intensity Factors can be held to a minimum. (C) 2000 Elsevier Science Ltd. All rights reserved.
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| 2. |
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| 3. |
- Jayathilaka, P. A R D, et al.
(författare)
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Effect of nano-porous Al2O3 on thermal, dielectric and transport properties of the (PEO)9LiTFSI polymer electrolyte system
- 2002
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Ingår i: Electrochimica Acta. - 0013-4686. ; 47:20, s. 3257-3268
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Tidskriftsartikel (refereegranskat)abstract
- Thermal, electrical conductivity and dielectric relaxation measurements have been performed on (PEO)9LiTFSI + 10 wt.% Al2O3 nano-porous polymer electrolyte system. It is observed that the conductivity enhances substantially due to the presence of the filler particles with different surface groups. The highest enhancement is found for the filler particles with acidic groups followed by basic, neutral, and weakly acidic. The results reveal that the filler particles do not interact directly with poly(ethelene) oxide (PEO) chains indicating that the main chain dynamics governing the ionic transport has not significantly affected due to the filler. The results are consistent with the idea that the conductivity enhancement is due to the creation of additional sites and favourable conduction pathways for ionic transport through Lewis acid-base type interactions between the filler surface groups and the ionic species. This is reflected as an increase in the mobility rather than an increase in the number of charge carriers. A qualitative model has been proposed to explain the results. © 2002 Elsevier Science Ltd. All rights reserved.
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| 4. |
- Satolli, D, et al.
(författare)
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Macro- and microscopic properties of nonaqueous proton conducting membranes based on PAN.
- 2003
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 1945-7111 .- 0013-4651. ; 150:3, s. A267-A273
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Tidskriftsartikel (refereegranskat)abstract
- In this work we report the electrochemical and physical characterization of proton-conducting gels prepared by means of a swelling procedure proved successful for the synthesis of membranes of interest for lithium battery technology. Basically, this new approach considers the formation of a precursor membrane by the gelification of a selected polymer matrix, e.g., a poly (acrylonitrile), matrix using a suitable solvent. This membrane is then embedded in an acidic solution: by a phase inversion process, the gelling solvent leaves the polymer matrix to be replaced by the acid solution, to finally obtain a self-standing, proton-conducting membrane. Impedance spectroscopy analysis demonstrated the good conductivity of the materials, and infrared, Raman, and fuel-cell studies confirm that this conductivity is due to protonic transport.
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