Titanium alloys are widely employed in aerospace applications due to an outstanding combination of properties. The variety loading conditions and microstructures encountered industrial components is urging the development microstructure sensitive modeling capabilities. In particular, reliable predictions require a good knowledge operating deformation mechanisms. present study aims at providing thorough characterization mechanisms near-α Ti-6Al-2Sn-4Zr-2Mo alloy using experiments simulations....

The fundamental frictional behaviour of carbon fibre tows relevant to composite fabric forming is explored. Tow-on-tool and tow-on-tow contact are considered. For tow-on-tool contact, an experiment devised simultaneously observe the true filament length measure friction force over a range normal loads. Filament not constant, as would be given from idealised assumption parallel touching filaments, but increases in characteristic manner with load. Friction follows power law variation load...

This paper provides measurements and analysis at the meso microscopic scales of real contact area between twill carbon fabric a flat glass counterface. The mesoscopic associated with tow contacts is about 55–75% nominal area. However, total length within contacts, fibre level, only 4–8% idealised conditions parallel touching fibres, for pressure around 2 kPa. dependence on shear angle also investigated. estimated 15,000 times higher than pressure. Models or experiments friction in composites...

This paper describes a novel experimental rig and associated method developed to investigate composite fabric/tool contact at the microscopic scale. A key feature of this is that it enables direct observation real scale fibres evolution under simultaneous application shear compression loads. To observe contact, an optical semi-reflective coating used. An algorithm analyse images measure length orientation individual fibres. The applied microcontacts carbon twill fabric. apparent pressure 1.9...

Craze initiation stress was measured in three-point bending isochronal creep tests on a series of entangled bimodal blends polystyrenes narrow dispersity, three broad and four dispersity. Crazing found to increase rapidly with small additions the higher molar mass component, quickly reaching plateau. A simple model based weighted addition crazing contributions individual weight fractions obtained from an established piecewise linear law able predict accurately using power exponent 2.59 (90%...

Hydrophobic surfaces can allow a liquid to slip over the surface and thus reduce friction in lubricated contact working full film regime. Theory supports that amount of be increased if super-hydrophobic are composed textured low energy material used. In this work, polytetrafluoroethylene (PTFE) polymer samples were with femto second laser create by machining hexagonal network small circular holes 10 20 μm lattice sides. The frictional behavior these was compared smooth PTFE samples....

This paper is focused on the characterization of thermomechanical properties semicrystalline poly-ether-ether-ketone (PEKK) and carbon fiber reinforced thermoplastic based laminated composites (C/PEKK) below above glass transition temperature (T_g). Differential Scanning Calorimetry (DSC), Dynamic Mechanical Analysis (DMA) tensile tests are carried out both pure PEKK polymer [(±45)2, +45]s C/PEKK composite samples, showing a significant similarity in behavior. The employment simple...

A new method is presented for the extraction of single-chain form factors and interchain interference functions from a range small-angle neutron scattering (SANS) experiments on bimodal homopolymer blends. The requires minimum three blends, made up hydrogenated deuterated components with matched degree polymerization at two different chain lengths, but carefully varying deuteration levels. validated through an experimental study polystyrene blends [Formula: see text]. By fitting Debye to...

This experimental study is focused on identification of tribological mechanisms acting during forming polymer composites. The range relevant processes includes fibre placement, tape lay-up, moulding, draping, and RTM. Two types experiments, relying both simultaneous application compression shear loadings, are carried out. Firstly, model macromechanical tests undertaken plastic rods millimetric diameter immersed in a viscous liquid, representing composite fibres matrix, respectively. By...

This experimental work focuses on the evaluation of deformation mechanisms due to sliding between carbon fiber tows with a flat tool in dry and lubricated liquid resin conditions. The experiments were carried out manually woven single tows. effect angle tow axes direction was also studied. topography contact transparent glass plate measured 3D optical microscope before after sliding. These measurements revealed decrease roughness all tested conditions, contraction perpendicular orientation,...