Rolls-Royce Holdings

About: Rolls-Royce Holdings is a company organization based out in Derby, United Kingdom. It is known for research contribution in the topics: Turbine & Gas compressor. The organization has 4027 authors who have published 6305 publications receiving 80517 citations. The organization is also known as: Rolls-Royce Holdings plc.

Microscopic strain localisation in Ti-6Al-4V during uniaxial tensile loading

Abstract: The titanium alloy Ti-6Al-4V is investigated in terms of the effect of macrozones within the microstructure through cross correlation of local strain measurements and microstructure, using digital image correlation (DIC) and electron backscatter diffraction (EBSD) techniques Three different product forms of Ti-6Al-4V including strong-, intermediate- and a no-macrozone condition with a weak texture have been investigated focusing on the impact of the primary macrozone orientation, macrozone dimensions and loading direction Strain localisation was characterised at the microscale using optical microscopy during in-situ uniaxial tensile loading and analysing the recorded images using digital image correlation The no-macrozone material and the strong-macrozone condition loaded parallel to the macrozones exhibited homogeneous strain behaviour in both the elastic and plastic strain regions The strong (soft-orientated) macrozone condition loaded at 45° and 90° both exhibited heterogeneous strain behaviour in grains with their c-axis oriented perpendicular to the loading direction, while the intermediate (hard-oriented) macrozone material exhibited heterogeneous strain behaviour when the majority of grains had their c-axis parallel to the loading direction The strong-macrozone material showed a direct correlation between macrozones with their grains favourably oriented for prismatic slip and high strain regions when loaded at 45° to the elongation direction Correlating a region of high strain localisation with Schmid factor maps for basal and prismatic slip, suggests a likelihood of basal slip when loading at 90°

Boundary layer devices

Abstract: An aerodynamic or hydrodynamic surface is provided with so-called "riblets" for reducing drag by modification of the turbulent boundary layer. The riblets comprise flow-aligned elongate projections of small height. In order to increase their effectiveness in reducing drag, just those parts of the riblets which extend above the height of the virtual surface--established by the riblets themselves due to their displacing the turbulent motion away from the real surface--exhibit an abrupt transition to a cusp-shaped profile which more effectively promotes very small scale flow-aligned vortices which drain energy from the larger drag-inducing low speed flow-aligned vortices or "streaks" in the boundary layer.

Engine core stand arrangement and method of removal and transportation of an engine core

Abstract: Transportation of larger diameter gas turbine engines can be problematic. In such circumstances it is known to separate the fan assembly ( 30 ) from the engine core ( 1 ) and other parts to facilitate transportation. Separation of the fan assembly ( 30 ) and engine core ( 1 ) can require a gantry which adds to inconvenience and costs. By utilising a platform ( 2, 44 ) with suspender members ( 43 ) in the form of boot straps ( 43 ) which extend down from an existing pylon ( 31 ) it is possible to remove an engine core ( 1 ) through a carriage dolly ( 3, 45 ) which moves along a rail ( 21 within the platform ( 2, 44 ) generally laterally until it is possible to lower the engine upon the platform to ground level. The platform ( 2, 44 ) and carriage dolly ( 3, 45 ) can then act as a stand for transportation of the engine core.

A critical evaluation of the microstructural gradient along the build direction in electron beam melted Ti-6Al-4V alloy

Abstract: It is generally recognised that electron beam melted (EBM) Ti-6Al-4V alloys exhibit a microstructural gradient along the build direction, but there have been some inconsistent experimental observations and debate as to the origin and magnitude of this effect. Here we present an unambiguous evaluation of this microstructural gradient and associated mechanical property along the EBM build direction on purpose-built round bar RB samples with build height of 380 mm and rectangular plate RP samples with build height of 120 mm. Columnar prior β grain width was found to increase (from 86 ± 38 to 154 ± 56 µm in RB and from 79 ± 34 to 122 ± 56 µm in RP samples) with the build height and the similar increase was also observed for α lath width (from 0.58 ± 24 to 0.87 ± 33 µm in RB and from 1.50 ± 45 to 1.80 ± 49 µm in RP samples). These observations can be attributed to the thermal gradient in the powder bed that produced a cooling rate gradient along the build height. The measured α lath width variation along the build height followed a log-normal distribution. The graded microstructure resulted in a decrease in micro-hardness which correlated very well with the mean α lath width by following a Hall-Petch relation.