1. Analysis of interface at explosive welded plates from low-carbon steel and titaniumBorut Kosec, Ladislav Kosec, Gabrijela Čevnik, Peter Fajfar, Mirko Gojić, Ivan Anžel, 2004, original scientific article Abstract: On the basis of experimentally obtained data, it was established that a very thin layer of a melt is generated at the explosive welding of two metals at the bond interface within which impurities flow at the bond during melting. Rapid cooling after the collision generates an alloy of different structure and very small grains of an average thickness app. 1 to 2 micro m. The generation of such an amorphous layer in the bond area has been noticed with various metal combinations and represents a fundamental mechanism of explosive welding of metals. Using the metallographic analysis, the development of the vortices which were formed by the explosive welding of low-carbon steel and titanium plates is described in the paper.
Keywords: metallurgy, explosion welding, plates, composites, low-carbon steel, titanium, melt, vortex
Published in DKUM: 03.07.2017; Views: 1400; Downloads: 84
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2. Analysis of timber-framed walls coated with CFRP strips strengthened fibre-plaster boardsMiroslav Premrov, Peter Dobrila, Branko Bedenik, 2004, original scientific article Abstract: This paper provides an experimental analysis of timber-framed walls, coated with carbon fibre-reinforced polymers (CFRP) strengthened fibre-plaster boards, usually used as main bearing capacity elements in the construction of prefabricated timber structures. The tensile strength of the fibre-plaster boards is lower than the strength of timber frame, therefore it is convenient to strengthen boards with high-strength materials in order to gain a higher capacity. It has been shown that the inclusion of CFRP diagonal strip reinforcement on the load-carrying capacity can be quite high and that it is maximized when the carbon strips are connected to the timber frame. On the other hand, the ductility itself was not significantly improved. The test samples proved an important distinction in behaviour in timber frame-fibreboard connecting area, dependant on the boundary conditions between inserted CFRP strips and timber frame. It has been shown that proposed simplified Eurocode 5 methods, applicable for wood-based sheathing boards, could be unsuitable for the problems presented.
Keywords: civil engineering, timber structures, panel walls, fibre-plaster boards, steel reinforcement, carbon fibres
Published in DKUM: 01.06.2012; Views: 2542; Downloads: 99
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3. Modelling of fastener flexibility in CFRP strengthened timber-framed walls using modified [gamma]-methodMiroslav Premrov, Peter Dobrila, 2008, original scientific article Abstract: The paper provides semi-analytical modelling for prefabricated timber-framed walls using the modified ▫$/gamma$▫-method. The walls are composed of a timber frame and gypsum plasterboards (GPB) which are flexibly connected to the timber frame. Because the tensile strength of the GPB is approximately 10-times lower than the compressive one, it is convenient to strengthen the boards in their tensile diagonal direction with carbon fibre-reinforced polymer (CFRP) strips, which are glued to the boards. Additionally, in the proposed mathematical model the classical beam theory is used taking into account a fasteners' flexibility in the timber frame - GPB connecting area, as well as crack appearing in the GPB and an influence of the inserted CFRP strips. Therefore the CFRP strip contribution is considered with a modified slip modulus which results in the fictive increased stiffness coefficient of the fasteners.
Keywords: civil engineering, timber structures, frame walls, fibre-plaster boards, steel reinforcement, CFRP strips, carbon fibre-reinforced polymer, mathematical modelling
Published in DKUM: 01.06.2012; Views: 2349; Downloads: 31
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4. Localized dissolution kinetics of low carbon steelAljana Petek, Valter Doleček, 2007, original scientific article Abstract: Localized dissolution of low carbon steel in saturated calcium hydroxide with different amount of sodium chloride has been investigated, using a dc technique. Potentiokinetic polarization curves indicated that pitting potentials ($E_{pit}$) decrease linearly with the log of chloride concentration. The rate of pit nucleation (1/$t_i$), and the rate of pits growth increases with increasing concentration of $Cl^-$ ions. Initiation of pitting attack could be ascribed to the adsorption of $Cl^-$ ions on the oxide surface. Adsorption of $Cl^-$ ions is physisorption and follow the Langmuir isotherm with $Δ_{ads}G^0$ = -21.1 kJ/mol.
Keywords: pitting corrosion, adsorption isotherm, low carbon steel, simulated interstitial solution
Published in DKUM: 31.05.2012; Views: 2767; Downloads: 101
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