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1
Content available remote Dynamic mechanical behaviour of gfrp composites with SiO2 nano particles reinforced epoxy matrix
Landowski M., Budzik M., Imielińska K.
Advances in Materials Science
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2013
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Vol. 13, nr 4(38)
5--8
EN
Dynamic mechanic (DMA) tests were performed to compare the mechanical behaviour of glass fibre reinforced epoxy laminate composites with SiO2 nanoparticle reinforced matrix. The selection of the most promising nanoparticle concentrations was considered in terms of elastic modulus and glass transition temperature. The reference specimens (0% nanoparticles) did not contain diluent accordingly the results do not allow the exact comparison with unreinforced composite, nevertheless the ranking of the nanocomposites was made. In terms of stiffness requirements 20% nanoparticles composites offer the best behaviour, 25% higher elastic modulus than 5% nanoparticles. For nano composites the glass transition temperature TG is the highest: 80°C, 77°C for 3%, 5% nanoparticles respectively and the lowest 75°C, 72°C , 71°C for 15%, 10% and 20% nanoparticles is respectively .
2
Content available remote Water sorption and blistering of GFRP laminates with varying structures
Landowski M., Budzik M., Imielińska K.
Advances in Materials Science
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2012
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Vol. 12, nr 4(34)
23-29
EN
The microstructures, water absorption as well as blistering was studied for bi- and tri- axial glass fibre vinyl ester and polyester -matrix laminates coated with gel coat layer and uncoated. The effect of manufacturing technique on water sorption characteristics was considered. It was found that water sorption characteristics of GFRP depend on manufacturing methods. The least water intake was found for specimens having perfect microstructure due to manufacturing by infusion process. Water sorption saturation value was reached after ca. 50 days of accelerated test at 70°C and was found to correspond to 250 days conditioning at 20°C. Blistering evolution was illustrated and SEM images shown corresponding to degradation of the gel coat layer and the laminate during the exposure in water.
3
Content available remote Two tests for adhesive bonding long term characterization: principles and applications
Jumel J., Budzik M., Chauffaille S., Shanahan M.
Advances in Materials Science
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2011
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Vol. 11, nr 2(28)
44-55
EN
This article describes recent refinement of the traditional wedge test technique used to characterize durability of the adhesive joints. We propose two types of measuring protocols to monitor precisely and continuously the propagation of an “effective” crack during long term mode I fracture mechanic test. First method is directly derived from the traditional wedge test technique and consist in monitoring the surface strain of adherent with resistive gauges. The second method consist in replacing constant applied displacement by constant force loading and monitoring the beam deflection. Applications of these techniques are presented concerning crack propagation and nucleation monitoring leading to better understanding of the phenomena occurring in the joint subjected to an external load.
4
Content available remote On degradation of glass/polyester laminate immersed in water
Landowski M., Budzik M., Imielińska K.
Advances in Materials Science
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2011
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Vol. 11, nr 1(27)
35-39
EN
Mechanical behaviour was compared for glass/ polyester laminates manufactured in the boatbuilding plant using three methods: hand lay-up, vacuum bagging, infusion. Specimens were tested in dry condition and following accelerated water immersion test (700C- corresponding to the exposure of 30 years at 190C). In three point bending test 40-50% reduction in laminate strength was observed due to water immersion. The highest degradation was in samples manufactured using hand lay-up method, the differences in strength between both vacuum methods were insignificant. Interlaminar shear strength was reduced by 25% for infusion method which is recommended as the most efficient. Matrix plasticization and debondings as well as surface microcracks were responsible for reduction in strength for water conditioned specimens. However, no microstructural difference in type or intensity of internal damage was observed for the three sample types.
5
Content available remote Reliable method of assessing fracture properties of asymmetric bonded joints
Tysarczyk J., Budzik M., Jumel J., Imielińska K., Shanahan M. M.
Advances in Materials Science
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2010
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Vol. 10, nr 1(23)
43-52
EN
Two methods of assessing fracture properties of adhesive joints were studied. Two wedge tests: with continuous deflection and with force measurements were compared. Asymmetric geometry of the bonded joint was considered, i.e. two different plates of aluminium alloys: Al-Cu and Al-Mg, were bonded with epoxy DGEBA adhesive. The analytical model is shown to estimate the values of fracture properties: crack position and critical fracture energy. It was found that both methods allow easy and reliable estimation and comparison of fracture properties, although some differences were observed.
6
Content available remote Facture energy of bonded joints with 2D elastic adhesive layer
Budzik M., Jumel J., Shanahan M. M.
Advances in Materials Science
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2010
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Vol. 10, nr 3(25)
4-16
EN
When bonded joint is subjected to mode I fracture loading, the adhesive joints analytical solutions treats the adhesive layer, usually, as not existing or 1D Hook elastic layer. In the case of 1D elastic layer, represented as Hooks spring element, is acting, only, in direction contrary to the applied load. Basing on the information yielded from sensitive laser profilometry technique, where deflections of bonded part of the joint were measured, within this contribution, 2D Finite Element Method model is introduced. The FEM allows adhesive layer to be simulated as two perpendicular-acting Hook's springs, thus in-plane shear compliance is enabled. Subsequently, appropriate analysis were carried out. Results, in terms of plate deflection, were compared with laser profilometry technique and common analytical solutions. It is concluded that linear 1D model is not sufficient for the asymmetric bonded joint configuration since the adhesive resists actively also in the in-plane shearing direction. Omitting shearing compliance effect can lead to valuable misinterpretation of the fracture energy, up to 20% in cases studied, and thus, cannot be ignored. Finally, power law based, correction factors are given promising fast and reliable data correction.
7
Content available remote Fracture of Aluminium Joints Bonded with Epoxy Adhesive Reinforced by MMT Nanoparticles
Budzik M., Pilawka R., Imielińska K., Jumel J., Shanahan M. M.
Advances in Materials Science
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2009
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Vol. 9, nr 2(20)
4-11
EN
Crack propagation behavior was studied for aluminium/aluminum adhesive joints bonded with two epoxy adhesives: pure and reinforced with clay nanoparticles. The focus was also on the novel use of the constant displacement rate test to study adhesion/adhesives efficiency. The epoxy systems studied were: Epidian E6 produced from bisphenol A and epichlorohydrin, ("Organika -Sarzyna" Poland); pure or strengthened with montmorillonit nanoparticles (MMT). Crack growth rate was estimated for two displacement rates. The nanoparticle reinforced epoxy showed advantage over pure epoxy adhesive (Figs. 4,5). This effect was more pronounced at low deflection rates. The constant displacement rate test was found promising to study microstructural effects in adhesive joints.
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