Characterisation of the relationship between surface texture and surface integrity of superalloy components machined by grinding

The surface texture of a machined component is influenced largely by the processing parameters used during machining and hence, there is a relationship between both the formation of the surface texture and surface integrity of the machined component. In the study to be reported in this paper, GH4169, a hard-to-cut superalloy, widely used in aero-engines, was selected for a detailed investigation into the relationship between the surface texture and the component-performance (surface integrity) of the machined components for which a series of grinding experiments with different grinding-wheels and grinding parameter-values was carried out in order to quantitatively analyze variations of the surface roughness with processing parameters. Further, considering that the features of the ground-surfaces measured are of a random nature, statistic properties of the produced surfaces were revealed and characterised with power spectral density function (PSD) and auto-covariance function(ACV) method respectively

Joint Mail-In Rebate Decisions in Supply Chains Under Demand Uncertainty

This is the author's accepted manuscript. The original publication is available at http://dx.doi.org/10.1111/j.1937-5956.2010.01171.x.We study the joint decisions of offering mail-in rebates (MIRs) in a single-manufacturer–single-retailer supply chain using a game theoretic framework. Either party can offer an MIR to the end consumer if it is in his best interest. The consumer demand is stochastic and depends on the product price and the amount of MIRs. When the retail price is exogenous, we show the existence of a unique Nash equilibrium under both additive and multiplicative demand functions and characterize it completely. We show that any of the following four scenarios can be the equilibrium: both parties offer MIR, only one party offers MIR, none offers MIR. When the retail price is a decision variable for the retailer and the rebate redemption rate increases with the amount of MIR, we once again prove the existence of a unique Nash equilibrium where both the retailer and the manufacturer offer MIRs. Using a numerical study, we show that the average post-purchase price of the product is higher not only than the perceived pre-purchase price but also than the newsvendor optimal price without an MIR. This implies that an MIR makes a product look cheaper while the consumers actually pay more on average

Retro-reflective optics to determine stress resulting from interlaminar corrosion in fuselage lap joints.

A systematic inspection process was developed to locate and measure the sub surface damage of aging aircraft. This process included four steps. First, D sight technology was used to identify and locate pillowing deformations in an aircraft fuselage. Second, ultrasonic inspection was used to detect the degree of corrosion in a small localized deformation area. And then, LVDT contour measurement was conducted to determine the amplitude of pillowing deformation. Finally, finite element techniques in conjunction with mathematical method were used to evaluate the magnitude of the flexure stress superposed on the deformed skin. D sight has been proven as an effective method for large surface inspection. Ultrasonic detection showed the applicability of interlaminar corrosion identification. LVDT contour measurement facilitates quantitative interpretation of the effect of corrosion build-up. The FEA model was developed and was proved to be useful tool for the measurement of stress. This combination process provides a new approach in the evaluation an aging aircraft fuselage.Dept. of Mechanical, Automotive, and Materials Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1996 .G46. Source: Masters Abstracts International, Volume: 34-06, page: 2461. Adviser: W. P. North. Thesis (M.A.Sc.)--University of Windsor (Canada), 1996