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.

An experimental investigation of deep-hole microdrilling capability for a nickel-based superalloy

Abstract: This paper presents the results of an experimental investigation into the feasibility of deep-hole microdrilling a nickel-based superalloy. This material is very challenging to machine and current drilling methods are based on non-conventional machining technologies; the traditional view is that microdrills are too fragile to be used for drilling this high-strength aerospace alloy. The work investigated mechanical microdrilling under various cutting conditions. Mechanical microdrilling may offer the chance of improved hole quality and surface integrity. Initially a review of literature was undertaken with a view to identify the best drill geometry for the production of micro holes in nickel-based alloys. Based on this review the best available commercial micro drills were selected. A special strategy was introduced for selecting the pilot drill in order to ensure gradual loading of the twist drill and reduce the chance of drill breakage. For the cutting tests, 0.5 mm diameter twist drills were used in dri...

Numerical predictions of the anisotropic viscoelastic response of uni-directional fibre composites

Abstract: Finite Element (FE) simulations are conducted to predict the viscoelastic properties of uni-directional (UD) fibre composites. The response of both periodic unit cells and random stochastic volume elements (SVEs) is analysed; the fibres are assumed to behave as linear elastic isotropic solids while the matrix is taken as a linear viscoelastic solid. Monte Carlo analyses are conducted to determine the probability distributions of all viscoelastic properties. Simulations are conducted on SVEs of increasing size in order to determine the suitable size of a representative volume element (RVE). The predictions of the FE simulations are compared to those of existing theories and it is found that the Mori-Tanaka (1973) and Lielens (1999) models are the most effective in predicting the anisotropic viscoelastic response of the RVE.

Gas turbine engine combustor heatshield

Abstract: A gas turbine engine annular combustor has a bulkhead at its upstream end which is protected by an annular array of heatshield segments. The segments are spaced apart from the bulkhead by means of a plurality of flanges. Cooling air apertures provided in the bulkhead direct cooling air into the space between the heatshield and the bulkhead. A portion of the cooling air is directed on to the downstream face of heatshield by means of a plurality of radially extending slots disposed around a fuel nozzle aperture in the centre of each heatshield segment. The slots provide for unrestrained thermal expansion of the heatshield region immediately surrounding the fuel nozzle aperture, thereby to prevent excessive thermal hoop stresses developing in the heatshield during engine operation.